Chemical and Morphological Evolution of Copper Nanoparticles

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C: Physical Processes in Nanomaterials and Nanostructures

Chemical and Morphological Evolution of Copper Nanoparticles Obtained by Pulsed Laser Ablation in Liquid Daria A. Goncharova, Tamara S. Kharlamova, Ivan N. Lapin, and Valery Anatolyevich Svetlichnyi J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.9b03958 • Publication Date (Web): 12 Aug 2019 Downloaded from pubs.acs.org on August 17, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

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The Journal of Physical Chemistry

Chemical and Morphological Evolution of Copper Nanoparticles Obtained by Pulsed Laser Ablation in Liquid Daria A. Goncharova1*, Tamara S. Kharlamova1, Ivan N. Lapin1, Valery A. Svetlichnyi1* 1Tomsk

State University, 36, Lenin Ave., Tomsk, Russia 634050

ABSTRACT. The pulsed laser ablation in liquid (PLAL) is a promising method to prepare copper/copper oxide nanoparticles (NPs), with the liquid used being an important factor to control their properties. The roles of the species dissolved in the liquid in the course of NPs formation during the PLAL as well as the effects of organic solvents in the stabilization of the colloids obtained remain debating. The peculiarities of the formation and alteration of the particles in ethyl alcohol as well as the effect of low amounts of oxidizing and acid-base species on the composition, structure, morphology, and stability of the NPs in the water colloids are examined. The observed high resistance of Cu NPs towards deep oxidation in ethyl alcohol suspension is shown to be connected with a competitive adsorption mechanism rather than the formation of carbon shell. The PLA of copper in distilled water yields cubic Cu2O NPs, while low amounts of NaOH and H2O2 species change the transformation route of copper NPs in the colloids formed. In case of H2O2, the primary formation of the sheet-like and flower-like Cu(OH)2 particles occurs in the course of PLA followed by their pseudomorphous

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transformation into CuO particles during the suspension aging. The presence of NaOH yields the leaf-like CuO mesostructures via the tetrahydroxocuprate anion mechanism. Based on the results obtained, the schemes for the formation of the particles are proposed.

1. INTRODUCTION Copper and its oxides are among the most widely studied transition metal compounds due to their distinctive optical, electrical, thermal, and magnetic properties.1–5 Nanosized CuOx is widely used in heterogeneous catalysis for redox and photodegradation reactions.5,7–11 Besides, copper and its compounds are effective biocidal and antibacterial agents.12–14 Copper and copper oxide NPs can be obtained in various ways, including hydrothermal,5,10 sonochemical combined thermal synthesis,8 chemical precipitation,4,9,10 sol-gel method,5,10,15 solid-state thermal conversion of precursors,11 pulsed laser ablation (PLA),16 etc. The pulsed laser ablation in liquid (PLAL) is associated with the injection of a large amount of powerful laser energy into a target to form the plasma that is cooled down in the solvent to form a colloidal solution. The NPs obtained by the PLAL have several unique properties that give them an advantage over NPs synthesized by traditional chemical methods. Thus, the catalytic and antibacterial activities of NPs are known to depend strongly on the composition of their surfaces.17,18 PLAL makes it possible to obtain NPs with “bare and clean” surfaces in contrast to those prepared by chemical synthesis routes, where densely adsorbed reaction residues have a “barrier” effect on functional properties.19,20 The disadvantage of this method is the low product yield. However, recent advances in understanding the mechanisms of the PLA have allowed increasing productivity at the level of grams per hour.21


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On the other hand, the mechanisms of the particle nucleation and growth under specific experimental conditions of the PLAL, including complex chemical reactions between a solid and a liquid, are still debating.20,22–24 The formation of the primary particles, including plasma formation, cooling, and interaction with the liquid, occurs in a split second and is difficult to study. Generally, it is possible to analyze only the resulting colloidal solution. However, the primary colloidal system obtained under nonequilibrium conditions is usually unstable and relaxes over time. Such a relaxation (or aging) involves phase transitions, particle growth, agglomeration, and coagulation. The stability and changing of the primary colloidal system particularly depend on the liquid used for the PLAL. Therefore, the selection of the liquid for the PLA is an important factor to control the chemical composition and morphology of the obtained particles as well as the total stability of the colloidal system. There is a large number of works devoted to the PLAL of copper, with distilled/deionized water being the most studied liquid.16,25–33 Either Cu or/and CuOx NPs can be formed in water depending on the condition used.16,22–33 For example, Cu2O and Cu phases were determined after PLA of copper in distilled water using the Nd:YAG laser (1064 nm, 20 Hz, 7 ns).25–27 However, in Refs.28–33 the authors found CuO instead of Cu2O. Different results observed for PLA of copper in water indicate a significant role of both the aging processes and the presence of oxygen and other species in water in the particle formation.16,32 The presence of different ligands or surfactants was shown to affect the oxidation and subsequent stability of the Cu NPs obtained in water.27,31,32 There are reports on the PLA of copper in water solutions of hydrogen peroxide (1–5%) showing that the presence of H2O2 in the PLAL process favors the production of Cu/CuO with a nanorod-like structure.34,35 However, the effect of low concentrations (14 days). The long-time suspension aging (>30 days) results in a further change of the shape of CuO NPs to a lenticular-like one (Figure 3c). According to the HRTEM data, the lenticular-like particles also possess a nanodomain structure, with the presence of only CuO nanocrystallites being confirmed (Figure 3g).

Figure 3. Typical HRTEM images of NPs obtained by PLA of Cu in water aged in the mother liquor for 48 hours (a, b, d, e, f) and 30 days (c, g): (a), (b) general view of Cu particles in


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suspension aged for 48 h; (c) general view of Cu particles in suspension aged for 30 days; (d) particle microstructure in the central part (labeled as I in panel (a)); (e) particle microstructure close to nanoribbons (labeled asII in panel (a)); (f) particle microstructure on nanoribbons (labeled asIII in panel (a)); (g) particle microstructure Figure 2b shows the absorption spectra of the dispersions in the UV-visible region. The spectrum of the fresh dispersion obtained by PLA of Cu in water is characterized by a humplike absorption at 335 and 454 nm and a weak broad peak at 635 nm (Figure 2b, curve 1). The absorption at 250–500 nm is complicated by scattering due to a pronounced Tyndall effect observed for the fresh suspension. Being in agreement with the XRD and TEM data, the absorption bands at 335 and 454 nm are attributed to nanocrystalline Cu2O, whereas the peak at 635 nm is assigned to the band gap transition of CuO that can exist at the surface of particles due to the incipient self-oxidation of Cu2O.43–45 The absorption spectrum of the suspension aged for two weeks does not contain the abovementioned bands (Figure 2b, curve 2), but shows a broad peak centered at 373 nm with a tail that stretches beyond 850 nm that is characteristic for CuO.43,46 Thereby, the absorption spectra additionally confirm the complete transition of Cu2O to CuO in the course of suspension aging. The absorption spectrum of the powder obtained from the fresh suspension is similar to the one of fresh suspension and is characterized by the hump-like absorption at 343 and 450 nm and a weak broad peak at 650 nm (Figure 2b, curve 3). The absorption spectroscopy data indicate that Cu2O is not strongly oxidized in air at room temperature in contrast to the stored suspension in water. This can be due to the fact that CuO formation in the gas phase is kinetically prohibited and requires heating to relatively high temperatures.43,47,48 The spectrum


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does not contain strong absorption due to scattering in the range of 250–500 nm indicating the agglomeration of the particles. The zeta potential of the particles in the fresh suspension obtained by the copper PLA in water is +34.45 mV at a pH of 6.4 (Figure 2c, black line). Titration of the initial suspension with the KOH solution decreases the zeta potential of the particles. The isoelectric point (IEP) is observed at a pH of 9.4 and can be assigned to the CuO/Cu(OH)2 surface characterized by the establishing of Cu(II)–OH/Cu(II)–OH2+ and Cu(II)–O-/Cu(II)–OH equilibria during the titration.49 This is consistent with the data of absorption spectroscopy of the fresh suspension that indicates the presence of CuO in the sample that can exist at the surface of Cu2O particles and govern their electrokinetic properties. The pH dependence of zeta potential for chemically obtained CuO and Cu(OH)2 additionally confirms such an assignment (Figure S1 in the Supporting Information). The zeta potential of the particles in the suspension aged for 14 days was +27.68 mV at a pH of 6.0 (Figure 2c, green line). When the suspension was titrated with the KOH solution, the IEP was also observed at a pH of ~ 9 due to the presence of Cu(II) oxide species on the particle surface characterized by the Cu(II)-OH/Cu(II)-OH2+ equilibrium at pH below 7–10.49 This is consistent with the data of UV-vis spectroscopy that indicate the transition of Cu2O to CuO in the course of suspension aging (Figure 2b). 3.2 The composition, structure, morphology and stability of the particles obtained in the diluted sodium hydroxide solution. Figure 4 summarizes the results of the study of the sample prepared by the copper PLA in the NaOH water solution. The suspension obtained is characterized by brown color (Figure 4b) and low stability. The precipitate appears within two days.


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Figure 4. Data for NPs obtained by PLA of copper in NaOH solution: (a) X-ray diffraction pattern of the powder obtained from the fresh suspension; (b) UV-vis absorption spectra of fresh (curve 1) and aged (curve 2) suspensions, and powder obtained from the fresh suspension (curve 3); (c) typical TEM image and SAED patterns of NPs in the fresh suspension; and (d) zeta potential at different pH values for fresh suspension. The XRD data indicate the presence of the monoclinic CuO phase with an admixture of a cubic phase of metallic copper (~3%) in the powder obtained from the fresh dispersion (Figure 4a). The TEM data show the primary formation of the leaf-like particles with an admixture of some spherical particles, with the SAED image indicating the presence of CuO and metallic Cu


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phases that is consistent with the XRD data for the powder (Figure 4c). The leaf-like particles are characteristic for CuO,10 and spherical particles are typical for Cu.27,30 The amount of leaflike and spherical particles formed depends on the concentration of the NaOH solution used and the suspension storing time (Figure S2 in the Supporting Information).26 The TEM image under high magnification shows that the leaf-like particles represent structured agglomerates comprised of numerous small particles (see fragment in Figure 5a). A similar aggregation was observed for CuO at room temperature and was caused by the formation of primary CuO NPs in a mother liquor via the preferential 1D [001] orientation of a limited number of NPs at an early stage.10 The agglomerates formed are unstable under the electron beam during the HRTEM study (Figure 5b), which can be caused by a lack of bonding between the particles in the agglomerates aged for 2 days. The formation of secondary CuO particle from such agglomerates is observed on the periphery during HRTEM examination (Figure 5c).

Figure 5. Typical HRTEM images particles obtained by PLA of Cu in the sodium hydroxide solution aged in the mother liquor during 48 hours. Figure 4b (curve 1) shows the absorption spectrum of the fresh suspension obtained using NaOH solution. The spectrum is characterized by the hump-like absorption at 290, 352, 460,


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and 630 nm, with the absorption in the range of 250–500 nm being complicated by scattering due to the Tyndall effect. The bands observed are attributed to transitions of CuO NPs that exhibit quantum confinement effects arising due to the fact that the electronic energy levels are discrete in nature in small semiconductor particles.50 This is consistent with the TEM data indicating the formation of structured agglomerates of CuO NPs. A red-shift and a broadening of the absorption bands accompanied by the decrease of scattering below 500 nm are observed in the spectrum of the aged suspension (Figure 4b, curve 2). The band shift and broadening can be caused by an increase in the sizes of NPs due to the formation of secondary particle via orientation attachment of small particles in leaf-like aggregates.10 The absorption spectrum of the powder obtained from fresh suspension (Figure 4b, curve 3) is characterized by a wide absorption from 300 to 900 nm associated with the crystalline CuO. Figure 4d presents the results of the electrokinetic studies of the samples obtained by copper PLA in the NaOH water solution. The particles in the initial suspension prepared in the 0.04% solution of NaOH are characterized by a zeta potential of –41.44 mV at a pH of 12. The suspension titration with the solution of nitric acid results in an increase in zeta potential (Figure 4d). The recharging of the surface occurs at a pH of 7.4. The observed value of the IEP corresponds to a crystalline CuO characterized by Cu(II)–OH/Cu(II)–OH2+ and Cu(II)–O– /Cu(II)–OH equilibria on the surface during titration.49 This is consistent with the data of other methods and electrokinetic data for chemically synthesized model materials (Figure S1 in the Supporting Information). The particles strongly agglomerate (the size of the agglomerates exceeds 1000 nm) and are completely precipitated during the suspension storage for 30 days. The aged suspension


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remains unstable to sedimentation even after ultrasonic treatment due to the formation of hard agglomerates. The formation of the precipitate occurs within 30 seconds during the analysis, and this does not allow measuring the zeta potential correctly by the method used. 3.3 The composition, structure, morphology and stability of particles obtained in the diluted hydrogen peroxide solution. Figure 6 shows the results for the sample prepared by PLA of copper in the H2O2 water solution. The fresh dispersion obtained by the PLA of copper in hydrogen peroxide has a light brown color (Figure 6b) and is stability to sedimentation at least for one month. The monoclinic CuO phase is determined by the XRD of the powders obtained from fresh suspensions (Figure 6a), with no phase composition of the powder being changed due to suspension aging (the XRD pattern is similar and is not shown). The sheet-like and flower-like NPs are observed in the TEM images of the sample (Figure 6c). The SAED pattern of the particles corresponds to the monoclinic CuO in agreement with the XRD results. The morphology of the particles obtained in NaOH and H2O2 solutions seems to be very similar at a first glance. However, in the case of H2O2, the particles are much wider (D : L = 1 : 4, D is width, L is length) than those obtained in case of NaOH (D : L = 1 : 10), which can be clearly seen when considering the particles taken with the same magnification using the same microscope (Figure S3 in Supporting Information). Besides, in contrast to the particles obtained in the NaOH solution, the sheet-like and flower-like particles obtained in the H2O2 water solution are stable under the electron beam during the HRTEM study. The particles possess a polycrystalline (defective) structure with a nanodomain size of about 2–8 nm and without a fixed orientation dependence between the different nanodomains according to the HRTEM image (Figure 7). There are several interplanar distances (2.7, 2.5, 2.3, and 1.9 Å) corresponding to the (110), (002)/(11-1), (111), and (11-2) CuO planes.


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Figure 6. Data for NPs obtained by PLA of copper in H2O2 water solution: (a) X-ray diffraction pattern of the powder obtained from the fresh suspension; (b) UV-vis absorption spectra of fresh (curve 1) and aged (curve 2) suspensions, and powder obtained from the fresh suspension (curve 3); (c) typical TEM image and SAED pattern of NPs in the fresh suspension; and (e) zeta potential at different pH values for the fresh (black line) and aged (green line) suspension. The absorption spectrum of the fresh dispersion obtained by PLA of copper in hydrogen peroxide contains bands at 275 and 341 nm and a weak band at 620 nm (Figure 6b, curve 1) attributed to Cu(OH)2.51 This assumes the primary formation of Cu(OH)2 in the suspension due to the PLA of copper in the H2O2 solution. The spectrum of the suspension changes over time (Figure 6b, curve 2). The spectrum of the suspension stored for 30 days is characterized by the


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hump-like absorption at 297 and 355 with a tail from 400 to 850 nm corresponding to transitions of CuO. This indicates that Cu(OH)2 particles transform into CuO particles during the aging in the suspension. The spectrum of the powder also differs from the one of the fresh suspension (Figure 6b, curve 3) and contains wide adsorption in the range from 250 to 850 nm attributed to the crystalline CuO, which is consistent with the XRD and TEM data.

Figure 7. Typical HRTEM image and FFT pattern of NPs obtained by PLA of copper in H2O2 water solution aged in the mother liquor during 48 hours. The initial suspension prepared in the presence of hydrogen peroxide is characterized by a pH of 6 and zeta potential of +40.98 mV (Figure 6d, black line). A decrease in the zeta potential occurs when the initial suspension is titrated with the KOH solution. The IEP is determined at a pH of 10.3 that corresponds to copper (II) hydroxide.49 The suspension aged for 30 days is characterized by a pH of 6.22 and a zeta potential of +15.39 mV (Figure 6d, green line). When the suspension is titrated with the KOH solution, the IEP is observed at a pH of 7.62 that corresponds to copper(II) oxide.49 Thereby, the electrokinetic data additionally confirm the


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primary formation of Cu(OH)2 as a result of the PLA of copper in the H2O2 solution followed by its transformation into CuO. 3.4 The composition, structure, morphology and stability of the particles obtained in ethyl alcohol. Figure 8 shows the results for the sample prepared by copper PLA in ethyl alcohol. The fresh suspension is black maroon with a green tinge (Figure 8b). The obtained suspension is rather stability to sedimentation (for a month). The XRD data (Figure 8a) show that the powder obtained from the fresh suspension consists of ~70% metallic copper (PDF Card # 04-010-6011) and ~30% Cu2O (PDF Card # 01-080-7711). According to the TEM data, the NPs formed in colloids have a spherical shape (Figure 8c). The size of the particles formed varied from 10 to 170 nm. The SAED pattern of the sample (in the insert) reveals the presence of the crystalline Cu2O and Cu phases that is consistent with the XRD data. Figure 9 shows typical lattice-resolved HRTEM images of the particles. The dark particle (region I) is represented by the metallic copper phase as evidenced by the Fast Fourier Transform (FFT) image corresponding to the [220] zone axis of the Cu crystal. Partial oxidation of Cu to Cu2O resulting in the corrugated structure is observed along the edge of the metal particle (region II) that is confirmed by the FFT. Similar results are observed for the oxidation of metallic copper particles with oxygen.52,53 Along with such partially oxidized Cu particles, the small particles of Cu2O are observed in the HRTEM images. No carbon shells are confirmed for the particles obtained by the PLA of copper in ethyl alcohol in accordance with Kazakevich et al.36 Some NPs coated with an amorphous phase are observed during the sample examination by HR TEM (Figure S4 in the Supporting Information). However, this amorphous phase is unstable and is removed under the electron beam during the examination. This can be


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attributed to the ethanol adsorption layer on the particle surface (for details see Supporting Information).

Figure 8. Data for NPs obtained by PLA of copper in ethyl alcohol: (a) X-ray diffraction pattern of the powder obtained from the fresh suspension; (b) UV-vis absorption spectra of fresh (curve 1) and aged (curve 2) suspensions, and powder obtained from the fresh suspension (curve 3); (c) typical TEM image and SAED pattern of NPs in the fresh suspension; and (d) zeta potential at different pH values for the fresh (black line) and aged (green line) suspensions.


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Figure 9. HRTEM image and FFT pattern of NPs obtained by PLA of copper in ethyl alcohol aged in the mother liquor during 48 hours. The absorption spectrum of the freshly prepared dispersion obtained by PLA of copper in ethyl alcohol has an intense peak at 600 nm and a broad extinction in the region of 4.5–5.49 The obtained pH dependence of zeta potential is similar to the one obtained for the chemically synthesized Cu(I) oxide, with some shift towards lower values being due to the effect of the ethyl alcohol on pH measurements (Figure S1 in the Supporting Information). However, the water suspension prepared using powder obtained by drying of the ethyl alcohol suspension yields the IEP at a pH of 4.0 (Figure S7 in the Supporting Information). This additionally confirms that the presence of copper(I) oxide on the particle surface governs their electrokinetic properties. 4. DISCUSSION 4.1. General mechanism for PLA in liquid. The results presented clearly show the influence of the presence of oxidative or base agents in the liquid as well as liquid nature used as a media for PLA of Cu on the phase composition, structure, and morphology of the particles formed in the suspension obtained. The liquid used can affect the properties of the particles at different stages of their formation, including direct interaction during the PLA process and in the course of subsequent processes. It is widely accepted that the interaction of pulsed (ns) laser radiation with a metal material occurs as follows.19,22,23,60 The target material absorbs powerful focused laser radiation, whereas a quasi-stationary equilibrium is achieved between the atoms of the metal lattice and free electrons. Local overheating of the target, absorption of light, and excitation of material occur. In addition, melting and evaporation (heterogeneous boiling, explosive boiling as a result of the Coulomb explosion) of the target material in the form of excited clusters, atoms, and ions are observed. A hemispherical cavitation bubble containing vapors of metal and solvent is formed in the presence of a liquid after the emission of a shock wave. According to,23 the bubble is essentially composed of solvent molecules (up to 80%). The transfer of the species dissolved in


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the liquid into the primary plasma due to the phase explosion of water during the initial process of the ablation was also shown.61 The bubble oscillates and collapses after a few hundred microseconds. The bubble oscillations comprise an expansion stage and a subsequent compression stage that can be repeated several times like a damping oscillator. These are accompanied by changing of temperature and pressure in the bubble from 1000 K and 107 Pa to s.c. between the expansion and the compression stages.22 This assumes that hydrothermal conditions can be implemented in the bubbles during the compression stage. The initial interaction between the metallic forms (particles/clusters) and the solvent molecules/ions is believed to begin in the cavitation bubble, and after its destruction the particles diffuse in the liquid, and the colloid is formed. However, the subsequent aging of the initially formed particles in the mother liquor is also very important for the genesis of their final structure and composition.62,63 This includes various physical and chemical processes leading to crystallization, growth, and agglomeration of particles, changes in phase and chemical composition. At this stage of the particle formation, the interaction with the liquid during both the ablation after the collapse of the cavitation bubbles and storage of the obtained suspension can also be crucial. The composition and structure of the particles formed are governed by the chemical properties of copper compounds. Metal copper is found to be readily oxidized by oxygen at room temperature to form a thin Cu2O oxide layer.64,65 The deep oxidation of copper to Cu2O requires a temperature increase above 100 °C. CuO is formed via Cu2O oxidation but not through the direct oxidation of metallic Cu. The transformation from Cu to Cu2O is more facile than that from Cu to CuO based on the similarity of their cubic crystal structures.65,66 The formation of monoclinic CuO on Cu is required for atom rearrangement and lattice/unit cell


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reconstruction. The oxidation of Cu2O is known to be governed by the faster outward copper diffusion relative to the inward oxygen diffusion. The formation of CuO in dry air proceeds at temperatures above 200 °C. However, in the presence of water vapor, the formation of the CuO overlayer on Cu2O can proceed at room temperature.64 Platzman et al. proposed an oxidation mechanism involving the formation of a Cu(OH)2 metastable overlayer due to the interaction of Cu+ ions with hydroxyl groups present at the surface followed by their transformation to a more stable CuO layer.67 Such transformation is very fast at room temperature in aqueous surroundings in the presence of hydroxide ions OH–.67,68 In this case, CuO formation occurs via the formation of tetrahydroxocuprate anions as a precursor according to the following reaction: Cu(OH)2(s) + 2 (OH–)(aq) → Cu(OH)42–(aq) ↔ CuO(s) +2OH–(aq) + H2O

(1)

However, copper (II) hydroxide can stay several months in pure water at room temperature.54 The formation of NPs of copper (II) oxide from hydroxide in solid state occurs during the destruction process of interplanar H-bonds, dehydration, and transformation of the orthorhombic phase of Cu(OH)2 into monoclinic CuO with an elongated shape (spindle-shaped, rod-like, ellipsoidal).10,68 The transition from Cu(OH)2 to CuO can take place at room temperature in a slightly alkaline solution69 or during thermal exposure.70 Based on the above information and the experimental data obtained, the mechanisms of the formation of copper-containing NPs in the liquid used were suggested. 4.2. Mechanisms of NPs formation in copper colloids obtained by PLAL. The results obtained for PLA of copper in distilled water (Figure 10a) indicate the primary formation of cubic Cu2O particles, which proceeds via the interaction of Cu clusters and NPs with water and oxygen dissolved under hydrothermal conditions in the cavitation bubble. The formation of


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such particles in the course of PLA of copper in water was also observed elsewhere.16,25,32 However, the obtained results also indicate a significant role of the aging of these particles in the formed water suspension. In the course of aging, the aggregation of primary Cu2O NPs to form supercrystals and the oxidation of Cu2O to CuO occurs and results in the formation of anisotropic particles with nanoribbons at the ends. Similar processes were described for Cu2O cubes in water at room temperature by Y. Na et al.42 The aging for more than 30 days results in a restructuring of the CuO particles to yield lenticular-like particles.


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Figure 10. Scheme of the NP formation by PLA of Cu in different liquids: (a) distilled water; (b) sodium hydroxide water solution; (c) hydrogen peroxide water solution; and (d) ethyl alcohol.


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In the case of PLA of copper in the diluted NaOH solution, the results obtained differ greatly from those obtained in distilled water. Figure 10b shows the scheme of NPs formation and changes. It is most likely that Cu clusters and NPs interact with water and NaOH in the cavitation bubble to form 1D CuO NPs. This should include rapid oxidation of Cu to Cu2O followed by the formation of tetrahydroxocuprate anions that are transformed into CuO.67,68 It is also possible that the formation of Cu2O NPs occurs in the cavitation bubbles followed by their further rapid oxidation after the destruction of the bubbles. This is confirmed by the presence of large metal particles in the fresh suspension due to their slow transformation after complete oxidation of the Cu2O layer formed on the surface of large particles in cavitation bubbles (insert in Figure 4c). The aggregation of primary 1D CuO NPs to form leaf-like and flower-like mesostructures proceeds in the mother liquor after their formation. The aging in the suspension or drying of the sample results in the formation of secondary CuO particle based on the leaf-like and flower-like structured aggregates. In the case of the PLA of copper in the diluted H2O2 solution, the primary formation of the suspension of Cu(OH)2 is observed, which is confirmed by the absorption spectra and the zeta potential dependence on pH. The CuO formation is observed after subsequent aging or drying of the obtained Cu(OH)2 suspension. The primary formation of Cu(OH)2 can be caused by the presence of different reactive oxygen species during the PLA process due to hydrogen peroxide decomposition observed under the action of laser radiation.71 Therefore, rapid consecutive oxidation of Cu to Cu2O in the cavitation bubbles and then Cu2O to Cu(OH)2 in the cavitation bubbles or in the suspension after collapsing of the cavitation bubble is assumed to proceed during the ablation (Figure 10c). The formed Cu(OH)2 NPs seems to aggregate to form nanowires followed by their self-assembly to form petal-like particles.72,73 The sample aging or


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drying leads to the pseudomorphic transformation of copper hydroxide into petal-like CuO particles.10,72, 74 In the case of PLA of copper in ethyl alcohol, the rather stable suspension containing NPs of Cu with a sub-monolayer of copper(I) oxide and an individual Cu2O NPs are obtained. The suspension remains practically unchanged for a long time (Figures S6 and S9 in the Supporting Information), with very slow oxidation of Cu NPs being detected to form the thicker layer of Cu2O on the particle surface. The formation of the suspension containing both NPs of metallic Cu with a sub-monolayer of copper(I) oxide and individual Cu2O NPs can be caused by the presence of some water and oxygen dissolved in ethyl alcohol used for the PLA. The particle formation begins in the cavitation bubbles composed of the molecules of the media used, where the rigorous hydrothermal conditions can be realized during the compression stage that provides oxidation of a part of the primarily Cu particles to Cu2O by the admixtures of water and oxygen (Figure 10d). After the destruction of the bubbles, the particles diffuse in ethyl alcohol, where slow additional oxidation of Cu to Cu2O by the dissolved oxygen proceeds in the course of aging. This is consistent with the data obtained for the suspension prepared in ethyl alcohol with higher water amount (20 wt/%) indicating the formation of a higher amount of Cu2O NPs (Figure S8 in the Supporting Information). The high resistance of the formed Cu particles towards deep oxidation during the suspension aging is not caused by the carbon shell formation. The observed retardation of the deep oxidation of Cu NPs in sustention of ethyl alcohol suspension can be explained by a competitive adsorption mechanism.53 This includes the sorption of ethyl alcohol molecules on the particle surface preventing the rapid dissociative adsorption of oxygen. After the formation of Cu2O monolayer on the copper particles, the ethyl alcohol adsorption prevents the Cu2O oxidation to CuO in the suspension that requires the


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interaction of Cu+ ions with the surface hydroxyl groups.67 The opportunity of ethyl alcohol adsorption to form the ethoxy groups on the surface of copper particles75-78 is confirmed by the IR spectroscopy (Figure S5 in the Supporting Information). The studies of the evolution of the Cu NPs in the ethanol suspensions diluted 20 times with water indicating a rather fast oxidation of copper particle in the presence of water additionally confirms the mechanism proposed (Figure S9 in the Supporting Information). The high water dilution of ethanol suspension seems to result in partial or primary removal of ethanol from the particle surface that results in rather fast oxidation of copper particle in aqueous media.

5. CONCLUSIONS The comprehensive study of the evolution of morphology, structure, and composition of the NPs in copper colloids obtained by the nanoseconds PLA in water and ethyl alcohol is reported in this work, and the effect of the presence of small amounts of NaOH and H2O2 species in water is considered. The reasons for the stabilization of colloids in ethyl alcohol are also discussed. Copper-containing NPs of various sizes, shapes, and compositions were obtained depending on the liquid used as a medium for ablation. The characteristics of the NPs in the suspension were shown to be governed by the interaction of copper with the media during the ablation in the cavitation bubbles and in the liquid after the collapsing of the cavitation bubbles, and the subsequent aging of the suspension formed. The rather stable suspension of Cu NPs with a submonolayer of copper(I) oxide and an individual Cu2O NPs were obtained in the ethyl alcohol during PLA, with the alcohol adsorption on the surface of the particles preventing the rapid subsequent oxidation of Cu to Cu2O and CuO in the suspension. In the course of the PLA of


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copper in water, the initial formation of cubic Cu2O NPs occurs followed by the aggregation to form supercrystals and are subsequently oxidized to CuO to form anisotropic particles with nanoribbons at the ends and finally lenticular-like particles in the course of aging. The presence of NaOH and H2O2 changes the route of copper NPs transformation in water colloids. The formation of 1D CuO NPs followed by their fast aggregation to form the leaf-like and flower-like particles proceeds in the course of the PLA of copper in the NaOH solution and subsequent aging of the suspension. In the case of PLA of copper in the diluted H2O2 solution, the primary formation of the sheet-like and flower-like Cu(OH)2 particles occurs followed by their pseudomorphous solid state transformation into CuO particles via dehydration during the suspension aging. The findings presented in this paper contribute to the general knowledge of the targeted synthesis of copper-based NPs for different applications.

ASSOCIATED CONTENT Supporting Information. The dependence of zeta potential on pH for Cu2O, CuO, and Cu(OH)2 reference materials; Typical TEM image of NPs in the fresh suspension obtained by PLA of Cu in NaOH solution of 0.01 mass. %; UV-vis spectra of copper colloids obtained by PLA in ethyl alcohol; the dependence of zeta potential on pH for water suspension prepared using powder obtained by PLA of Cu in ethyl alcohol followed by drying; Typical HRTEM image and FFT pattern of NPs in the suspension obtained by PLA of Cu in the ethyl alcohol– water (20 wt.%) mixture followed by aging for 48 hours; AT-FTIR spectra of powder obtained by PLA of Cu in ethyl alcohol (PDF). AUTHOR INFORMATION


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Corresponding Author * E-mail: [email protected]. * E-mail: [email protected]. ORCID Daria A. Goncharova: 0000-0002-3247-4441 Tamara S. Kharlamova: 0000-0002-6463-3582 Ivan N. Lapin: 0000-0001-5736-3791 Valery A. Svetlichnyi: 0000-0002-3935-0871 ACKNOWLEDGMENT This work was supported by the Ministry of Education and Science of the Russian Federation (3.9604.2017/8.9). The authors thank Dr. M. A. Salaev for language review.

REFERENCES (1)

Baloach, Q.-A.; Tahira, A.; Mallah, A. B.; Abro, M. I.; Uddin, S.; Willander, M.;

Ibupoto, Z. H. A Robust, Enzyme-Free Glucose Sensor Based on Lysine-Assisted CuO Nanostructures. Sensors 2016, 16 (11), 1878, 1–10. (2)

Hwang, H.-J.; Kim, D.-J.; Jang, Y.-R.; Hwang, Y.-T.; Jung, I.-H.; Kim, H.-S. Multi-

Pulsed Flash Light Sintering of Copper Nanoparticle Pastes on Silicon Wafer for HighlyConductive Copper Electrodes in Crystalline Silicon Solar Cells. Appl. Surf. Sci 2018, 462, 378–386.


32

Page 33 of 44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(3)

Shabalina, A. V; Svetlichnyi, V. A.; Ryzhinskaya, K. A.; Lapin, I. N. Copper

Nanoparticles for Ascorbic Acid Sensing in Water on Carbon Screen-Printed Electrodes. Anal. Sci. 2017, 33 (12), 1415–1419. (4)

Gupta, D.; Meher, S. R.; Illyaskutty, N.; Alex, Z. C. Facile Synthesis of Cu2O and CuO

Nanoparticles and Study of Their Structural, Optical and Electronic Properties. J. Alloys Compd. 2018, 743, 737–745. (5)

Zoolfakar, A. S.; Rani, R. A.; Morfa, A. J.; O’Mullane, A. P.; Kalantar-zadeh, K.

Nanostructured Copper Oxide Semiconductors: A Perspective on Materials, Synthesis Methods and Applications. J. Mater. Chem. C 2014, 2 (27), 5247–5270. (6)

Svintsitskiy, D. A.; Chupakhin, A. P.; Slavinskaya, E.M.; Stonkus, O.A.; Stadnichenko,

A.I.; Koscheev, S. V.; Boronin, A.I. Study of Cupric Oxide Nanopowders as Efficient Catalysts for Low-Temperature CO Oxidation. J. Mol. Catal. A: Chem. 2013, 368–369, 95–106. (7)

Liu, X.; Cheng, Y.; Li, X.; Dong, J. High-Efficiency and Conveniently Recyclable

Photo-Catalysts for Dye Degradation Based on Urchin-like CuO Microparticle/Polymer Hybrid Composites. Appl. Surf. Sci. 2018, 439, 784–791. (8)

Mosleh, S.; Rahimi, M. R.; Ghaedi, M.; Dashtian, K.; Hajati, S. Sonochemical-Assisted

Synthesis of CuO/Cu2O/Cu Nanoparticles as Efficient Photocatalyst for Simultaneous Degradation of Pollutant Dyes in Rotating Packed Bed Reactor: LED Illumination and Central Composite Design Optimization. Ultrason. Sonochem. 2018, 40, 601–610. (9)

Bhosale, M. A.; Karekar, S. C.; Bhanage, B. M. Room Temperature Synthesis of

Copper Oxide Nanoparticles: Morphological Evaluation and Their Catalytic Applications for


33


Page 34 of 44

Degradation of Dyes and C–N Bond Formation Reaction. Chem.Select 2016, 1 (19), 6297– 6307. (10) Zhang, Q.; Zhang, K.; Xu, D.; Yang, G.; Huang, H.; Nie, F.; Liu, C.; Yang, S. CuO Nanostructures: Synthesis, Characterization, Growth Mechanisms, Fundamental Properties, and Applications. Prog. Mater Sci. 2014, 60, 208–337. (11) Xu, L.; Sithambaram, S.; Zhang, Y.; Chen, C.-H.; Jin, L.; Joesten, R.; Suib, S. L. Novel Urchin-like CuO Synthesized by a Facile Reflux Method with Efficient Olefin Epoxidation Catalytic Performance. Chem. Mater. 2009, 21 (7), 1253–1259. (12) Milenkovic, J.; Hrenovic, J.; Matijasevic, D.; Niksic, M.; Rajic, N. Bactericidal Activity of Cu-, Zn-, and Ag-Containing Zeolites toward Escherichia Coli Isolates. Environ. Sci. Pollut. Res. 2017, 24 (25), 20273–20281. (13) Mathews, S.; Kumar, R.; Solioz, M. Copper Reduction and Contact Killing of Bacteria by Iron Surfaces. Appl. Environ. Microbiol. 2015, 81 (18), 6399–6403. (14) Svetlichnyi, V. A.; Goncharova, D. A.; Shabalina, A. V.; Lapin, I. N.; Nemoykina, A. L. Cu2O Water Dispersions and Nano-Cu2O/Fabric Composite: Preparation by Pulsed Laser Ablation, Characterization and Antibacterial Properties. Nano Hybrids Composite. 2017, 13, 75–81. (15) Zayyoun, N.; Bahmad, L.; Laânab, L.; Jaber, B. The Effect of PH on the Synthesis of Stable Cu2O/CuO Nanoparticles by Sol–gel Method in a Glycolic Medium. Appl. Phys. A 2016, 122 (5), 488.


34

Page 35 of 44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(16) Marzun, G.; Bönnemann, H.; Lehmann, C.; Spliethoff, B.; Weidenthaler, C.; Barcikowski, S. Role of Dissolved and Molecular Oxygen on Cu and PtCu Alloy Particle Structure during Laser Ablation Synthesis in Liquids. ChemPhysChem 2017, 18 (9), 1175– 1184. (17) Védrine, J. C. Fundamentals of Heterogeneous Catalysis. In Metal Oxides in Heterogeneous Catalysis; Elsevier: Amsterdam, 2018; pp 1–41. (18) Wang, L.; Hu, C.; Shao, L. The Antimicrobial Activity of Nanoparticles: Present Situation and Prospects for the Future. Int. J. Nanomed. 2017, 12, 1227–1249. (19) Zhang, J.; Chaker, M.; Ma, D. Pulsed Laser Ablation Based Synthesis of Colloidal Metal Nanoparticles for Catalytic Applications. J. Colloid Interface Sci. 2017, 489, 138–149. (20) Zhang, D.; Gökce, B.; Barcikowski, S. Laser Synthesis and Processing of Colloids: Fundamentals and Applications. Chem. Rev. 2017, 117 (5), 3990–4103. (21) Streubel, R.; Barcikowski, S.; Gökce, B. Continuous Multigram Nanoparticle Synthesis by High-Power, High-Repetition-Rate Ultrafast Laser Ablation in Liquids. Opt. Lett. 2016, 41 (7), 1486. (22) Zhang, D.; Liu, J.; Liang, C. Perspective on How Laser-Ablated Particles Grow in Liquids. Sci. China Phys., Mech., Astron. 2017, 60 (7), 074201. (23) Lam, J.; Lombard, J.; Dujardin, C.; Ledoux, G.; Merabia, S.; Amans, D. Dynamical Study of Bubble Expansion Following Laser Ablation in Liquids. Appl. Phys. Lett. 2016, 108 (7), 074104.


35


Page 36 of 44

(24) Mansoureh, G.; Parisa, V. Synthesis of Metal Nanoparticles Using Laser Ablation Technique. Emerging Applications of Nanoparticles and Architecture Nanostructures; Elsevier: Amsterdam, 2018; Chapter 19, pp 575–596. (25) Swarnkar, R. K.; Singh, S. C.; Gopal, R. Effect of Aging on Copper Nanoparticles Synthesized by Pulsed Laser Ablation in Water: Structural and Optical Characterizations. Bull. Mater. Sci. 2011, 34 (7), 1363–1369. (26) Jung, H. J.; Yu, Y.; Choi, M. Y. Facile Preparation of Cu2O and CuO Nanoparticles by Pulsed Laser Ablation in NaOH Solutions of Different Concentration. Bull. Korean Chem. Soc. 2015, 36 (1), 3–4. (27) Liu, P.; Wang, H.; Li, X.; Rui, M.; Zeng, H. Localized Surface Plasmon Resonance of Cu Nanoparticles by Laser Ablation in Liquid Media. RSC Adv. 2015, 5 (97), 79738–79745. (28) He, H.; Dong, J.; Li, K.; Zhou, M.; Xia, W.; Shen, X.; Han, J.; Zeng, X.; Cai, W. Quantum Dot-Assembled Mesoporous CuO Nanospheres Based on Laser Ablation in Water. RSC Adv. 2015, 5 (25), 19479–19483. (29) Khashan, K. S.; Sulaiman, G. M.; Abdulameer, F. A. Synthesis and Antibacterial Activity of CuO Nanoparticles Suspension Induced by Laser Ablation in Liquid. Arab. J. Sci. Eng. 2016, 41 (1), 301–310. (30) Tilaki, R. M.; Iraji zad, A.; Mahdavi, S. M. Size, Composition and Optical Properties of Copper Nanoparticles Prepared by Laser Ablation in Liquids. Appl. Phys. A 2007, 88 (2), 415– 419.


36

Page 37 of 44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(31) Muniz-Miranda, M.; Gellini, C.; Giorgetti, E. Surface-Enhanced Raman Scattering from Copper Nanoparticles Obtained by Laser Ablation. J. Phys. Chem. C 2011, 115 (12), 5021– 5027. (32) Herbani, Y.; Irmaniar; Nasution, R. S.; Mujtahid, F.; Masse, S. Pulse Laser Ablation of Au, Ag, and Cu Metal Targets in Liquid for Nanoparticle Production. J. Phys.: Conf. Series 2018, 985, 012005. (33) Rafique, M.; Rafique, M. S.; Butt, S. H.; Afzal, A.; Kalsoom, U. Laser Nature Dependence on Enhancement of Optical and Thermal Properties of Copper Oxide Nanofluids. Appl. Surf. Sci. 2019, 483, 187–193. (34) Gondal, M. A.; Qahtan, T. F.; Dastageer, M. A.; Saleh, T. A.; Maganda, Y. W.; Anjum, D. H. Effects of Oxidizing Medium on the Composition, Morphology and Optical Properties of Copper Oxide Nanoparticles Produced by Pulsed Laser Ablation. Appl. Surf. Sci. 2013, 286, 149–155. (35) Gondal, M. A.; Qahtan, T. F.; Dastageer, M. A.; Saleh, T. A.; Maganda, Y. W. Synthesis and Characterization of Copper Oxides Nanoparticles via Pulsed Laser Ablation in Liquid. In 2013 High Capacity Optical Networks and Emerging/Enabling Technologies, Magosa, Cyprus, Dec 11–13; IEEE: Piscataway, NJ, 2013, 146–150. (36) Kazakevich, P. V; Voronov, V. V; Simakin, A. V; Shafeev, G. A. Production of Copper and Brass Nanoparticles upon Laser Ablation in Liquids. Quantum Electron. 2004, 34 (10), 951–956.


37


Page 38 of 44

(37) Galvão, A. C.; Robazza, W. S.; Sarturi, G. N.; Goulart, F. C.; Conte, D. Sucrose Solubility in Binary Liquid Mixtures Formed by Water–Methanol, Water–Ethanol, and Methanol–Ethanol at 303 and 313 K. J. Chem. Eng. Data 2016, 61 (9), 2997–3002. (38) Pires, R. M.; Costa, H. F.; Ferreira, A. G. M.; Fonseca, I. M. A. Viscosity and Density of Water + Ethyl Acetate + Ethanol Mixtures at 298.15 and 318.15 K and Atmospheric Pressure. J. Chem. Eng. Data 2007, 52 (4), 1240–1245. (39) Herráez, J. V.; Belda, R. Refractive Indices, Densities and Excess Molar Volumes of Monoalcohols + Water. J. Solution Chem. 2006, 35 (9), 1315–1328. (40) Urréjola, S.; Sánchez, A.; Hervello, M. F. Refractive Indices of Lithium, Magnesium, and Copper(II) Sulfates in Ethanol−Water Solutions. J. Chem. Eng. Data 2010, 55 (1), 482– 487. (41) Kumar, S.; Parlett, C. M. A.; Isaacs, M. A.; Jowett, D. V.; Douthwaite, R. E.; Cockett, M. C. R.; Lee, A. F. Facile Synthesis of Hierarchical Cu2O Nanocubes as Visible Light Photocatalysts. Appl. Catal. B: Environ. 2016, 189, 226–232. (42) Na, Y.; Lee, S. W.; Roy, N.; Pradhan, D.; Sohn, Y. Room Temperature Light-Induced Recrystallization of Cu2O Cubes to CuO Nanostructures in Water. CrystEngComm 2014, 16 (36), 8546–8554. (43) Pedersen, D. B.; Wang, S.; Liang, S. H. Charge-Transfer-Driven Diffusion Processes in Cu@Cu2Oxide Core−Shell Nanoparticles: Oxidation of 3.0 ± 0.3 Nm Diameter Copper Nanoparticles. J. Phys. Chem. C 2008, 112 (24), 8819–8826.


38

Page 39 of 44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(44) Yin, M.; Wu, C.-K.; Lou, Y.; Burda, C.; Koberstein, J. T.; Zhu, Y.; O’Brien, S. Copper Oxide Nanocrystals. J. Am. Chem. Soc. 2005, 127 (26), 9506–9511. (45) Borgohain, K.; Murase, N.; Mahamuni, S. Synthesis and Properties of Cu2O Quantum Particles. J. Appl. Phys. 2002, 92 (3), 1292–1297. (46) Kawasaki, M. Laser-Induced Fragmentative Decomposition of Fine CuO Powder in Acetone as Highly Productive Pathway to Cu and Cu2O Nanoparticles. J. Phys. Chem. C 2011, 115 (12), 5165–5173. (47) Xu, J.; Li, X.; Wu, X.; Wang, W.; Fan, R.; Liu, X.; Xu, H. Hierarchical CuO Colloidosomes and Their Structure Enhanced Photothermal Catalytic Activity. J. Phys. Chem. C 2016, 120 (23), 12666–12672. (48) Shinde, S. L.; Nanda, K. K. Facile Synthesis of Large Area Porous Cu2O as Super Hydrophobic Yellow-Red Phosphors. RSC Adv. 2012, 2 (9), 3647. (49) Kosmulski, М. Surface Charging and Points of Zero Charge (Surfactant science); Boca Raton: СRC Press, 2009; pp 1065. (50) Wang, X.; Gao, Q.; Wu, C.; Hu, J.; Ruan, M. Preparation, Channel Surface Hydroxyl Characterization and Photoluminescence Properties of Nanoporous Nickel Phosphate VSB-1. Microporous Mesoporous Mater. 2005, 85 (3), 355–364. (51) Li, Y.; Li, Y.; Huang, L.; Bin, Q.; Lin, Z.; Yang, H.; Cai, Z.; Chen, G. Molecularly Imprinted Fluorescent and Colorimetric Sensor Based on TiO2@Cu(OH)2 Nanoparticle Autocatalysis for Protein Recognition. J. Mater. Chem. B 2013, 1 (9), 1256.


39


Page 40 of 44

(52) LaGrow, A. P.; Ward, M. R.; Lloyd, D. C.; Gai, P. L.; Boyes, E. D. Visualizing the Cu/Cu2O Interface Transition in Nanoparticles with Environmental Scanning Transmission Electron Microscopy. J. Am. Chem. Soc. 2017, 139 (1), 179–185. (53) Cure, J.; Glaria, A.; Collière, V.; Fazzini, P.-F.; Mlayah, A.; Chaudret, B.; Fau, P. Remarkable Decrease in the Oxidation Rate of Cu Nanocrystals Controlled by Alkylamine Ligands. J. Phys. Chem. C 2017, 121 (9), 5253–5260. (54) Rice, K. P.; Walker, E. J.; Stoykovich, M. P.; Saunders, A. E. Solvent-Dependent Surface Plasmon Response and Oxidation of Copper Nanocrystals. J. Phys. Chem. C 2011, 115 (5), 1793–1799. (55) Ghodselahi, T.; Vesaghi, M. A. Localized Surface Plasmon Resonance of Cu@Cu2O Core–shell Nanoparticles: Absorption, Scattering and Luminescence. Physica B: Condens. Matter 2011, 406 (13), 2678–2683. (56) Mott, D.; Galkowski, J.; Wang, L.; Luo, J.; Zhong, C.-J. Synthesis of Size-Controlled and Shaped Copper Nanoparticles. Langmuir 2007, 23 (10), 5740–5745. (57) Barrière, C.; Piettre, K.; Latour, V.; Margeat, O.; Turrin, C.-O.; Chaudret, B.; Fau, P. Ligand Effects on the Air Stability of Coppernanoparticles Obtained from Organometallic Synthesis. J. Mater. Chem. 2012, 22 (5), 2279–2285. (58) Peña-Rodríguez, O.; Pal, U. Effects of Surface Oxidation on the Linear Optical Properties of Cu Nanoparticles. J. Opt. Soc. Am. B 2011, 28 (11), 2735.


40

Page 41 of 44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(59) Pfeiffer, C.; Rehbock, C.; Huhn, D.; Carrillo-Carrion, C.; de Aberasturi, D. J.; Merk, V.; Barcikowski, S.; Parak, W. J. Interaction of Colloidal Nanoparticles with Their Local Environment: The (Ionic) Nanoenvironment around Nanoparticles Is Different from Bulk and Determines the Physico-Chemical Properties of the Nanoparticles. J. R. Soc. Interface 2014, 11 (96), 20130931–20130931. (60) Yan, Z.; Chrisey, D. B. Pulsed Laser Ablation in Liquid for Micro-/Nanostructure Generation. J. Photochem. Photobiol. C: Photochem. Rev. 2012, 13 (3), 204–223. (61) Matsumoto, A.; Tamura, A.; Honda, T.; Hirota, T.; Kobayashi, K.; Katakura, S.; Nishi, N.; Amano, K.; Fukami, K.; Sakka, T. Transfer of the Species Dissolved in a Liquid into Laser Ablation Plasma: An Approach Using Emission Spectroscopy. J. Phys. Chem. C 2015, 119 (47), 26506–26511. (62) Boistelle, R.; Astier, J. P. Crystallization Mechanisms in Solution. J. Cryst. Growth 1988, 90 (1–3), 14–30. (63) Linnikov, O. D. Mechanism of Precipitate Formation during Spontaneous Crystallization from Supersaturated Aqueous Solutions. Russ. Chem. Rev. 2014, 83 (4), 343– 364. (64) Ostrovskii, V. E. The Chemisorption of Oxygen on Group IB Metals and Their Surface Oxidation. Russ. Chem. Rev. 1974, 43 (11), 921. (65) Gattinoni, C.; Michaelides, A. Atomistic Details of Oxide Surfaces and Surface Oxidation: The Example of Copper and Its Oxides. Surf. Sci. Rep. 2015, 70 (3), 424–447.


41


Page 42 of 44

(66) Chen, K.; Song, S.; Xue, D. Vapor-Phase Crystallization Route to Oxidized Cu Foils in Air as Anode Materials for Lithium-Ion Batteries. CrystEngComm 2013, 15 (1), 144–151. (67) Platzman, I.; Brener, R.; Haick, H.; Tannenbaum, R. Oxidation of Polycrystalline Copper Thin Films at Ambient Conditions. J. Phys. Chem. C 2008, 112 (4), 1101–1108. (68) Cudennec, Y.; Lecerf, A. The Transformation of Cu(OH)2 into CuO, Revisited. Solid State Sci. 2003, 5 (11–12), 1471–1474. (69) Singh, D. P.; Ojha, A. K.; Srivastava, O. N. Synthesis of Different Cu(OH)2 and CuO (Nanowires, Rectangles, Seed-, Belt-, and Sheetlike) Nanostructures by Simple Wet Chemical Route. J. Phys. Chem. C 2009, 113 (9), 3409–3418. (70) Xiao, H.-M.; Fu, S.-Y.; Zhu, L.-P.; Li, Y.-Q.; Yang, G. Controlled Synthesis and Characterization of CuO Nanostructures through a Facile Hydrothermal Route in the Presence of Sodium Citrate. Eur. J. Inorg. Chem. 2007, 2007 (14), 1966–1971. (71) Schumb, W.C.; Satterfield, C.N.; Wentworth, R.S. Hydrogen Peroxide; ACS Monograph Series 128; Reinhold Pub. Corp.: New York, 1955; pp 579. (72) Du, G. .; Van Tendeloo, G. Cu(OH)2 Nanowires, CuO Nanowires and CuO Nanobelts. Chem. Phys. Lett. 2004, 393 (1–3), 64–69. (73) da Silva, A. G. M.; Rodrigues, T. S.; Parussulo, A. L. A.; Candido, E. G.; Geonmonond, R. S.; Brito, H. F.; Toma, H. E.; Camargo, P. H. C. Controlled Synthesis of Nanomaterials at the Undergraduate Laboratory: Cu(OH)2 and CuO Nanowires. J. Chem. Educ. 2017, 94 (6), 743–750.


42

Page 43 of 44 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(74) Lu, C.; Qi, L.; Yang, J.; Zhang, D.; Wu, N.; Ma, J. Simple Template-Free Solution Route for the Controlled Synthesis of Cu(OH)2 and CuO Nanostructures. J. Phys. Chem. B 2004, 108 (46), 17825–17831. (75)

Garbarino, G.; Riani, P.; Villa García, M.; Finocchio, E.; Sanchez Escribano, V.; Busca,

G. A Study of Ethanol Dehydrogenation to Acetaldehyde over Copper/Zinc Aluminate Catalysts. Catal. Today 2019, In Press. (76)

Bowker, M.; Madix, R. J. XPS, UPS and Thermal Desorption Studies of Alcohol

Adsorption on Cu(110): II. Higher Alcohols. Surf. Sci. 1982, 116 (3), 549–572. (77)

Wang, Z.-T.; Xu, Y.; El-Soda, M.; Lucci, F. R.; Madix, R. J.; Friend, C. M.; Sykes, E.

C. H. Surface Structure Dependence of the Dry Dehydrogenation of Alcohols on Cu(111) and Cu(110). J. Phys. Chem. C 2017, 121 (23), 12800–12806. (78)

Kasmia, A. E.; Vieker, H.; Wu, L.; Beyer, A.; Chafik, T.; Tian, Z. Enhanced Property of

Thin Cuprous Oxide Film Prepared through Green Synthetic Route, Chin. Phys. Soc. 2019, 32 (3), 365–372.


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Chemical and Morphological Evolution of Copper Nanoparticles

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