Controlled Growth of Monodisperse Ferrite Octahedral Nanocrystals

Subscriber access provided by STEPHEN F AUSTIN STATE UNIV

Article

Controlled growth of monodisperse ferrite octahedral nanocrystals for biomass-derived catalytic applications Ping Tan, Guanna Li, Ruiqi Fang, Liyu Chen, Rafael Luque, and Yingwei Li ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.6b02853 • Publication Date (Web): 14 Mar 2017 Downloaded from http://pubs.acs.org on March 14, 2017

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 free 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 accessible to all readers and 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.

ACS Catalysis is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 10

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

ACS Catalysis

Controlled growth of monodisperse ferrite octahedral nanocrystals for biomass-derived catalytic applications Ping Tan,† Guanna Li,‡ Ruiqi Fang,† Liyu Chen,† Rafael Luque*§ and Yingwei Li*† † State Key Laboratory of Pulp and Paper Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China ‡ Catalysis Engineering, Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629 HZ Delft, The Netherlands § Departamento de Química Orgánica, Universidad de Córdoba, Edif. Marie Curie, Ctra Nnal IV-A, Km 396, E14014, Córdoba, Spain ABSTRACT: Metal/metal oxide nanoparticles with controllable size and shape are of importance to tailor the catalytic performances of metal nanoparticles. However, a facile synthesis of supported monodisperse metal/oxide polyhedra in the absence of capping agents remains a significant challenge, especially at high metal loadings. In this work, a surfactantfree MOF (metal-organic framework) thermolysis strategy is developed for the synthesis of monodisperse ferrite octahedral nanocrystals with uniform composition for the first time. The achievement of our synthesis relies on the use of CO as directing agent that may control the growth rate of specific facets at the solid−gas interface and subsequently the shape of the resultant metal oxide nanostructures. As-prepared octahedral ferrite materials exhibited an interesting shape-dependent catalytic performance in 5-hydroxymethylfurfural (HMF) oxidation, achieving significantly improved activity and selectivity as compared to those synthesized under pure inert atmosphere. Density functional theory (DFT) calculations suggest a relatively weak interaction between 2,5-diformylfuran (DFF) and catalyst that is highly beneficial for product desorption, avoiding over-oxidation reactions taking place on the catalyst surface to some extent and partially contributing to the high DFF selectivity.

KEYWORDS: Biomass, ferrite, heterogeneous catalysis, metal-organic frameworks, nanocrystals.

INTRODUCTION Metal/metal oxide nanoparticles are of great interest for a variety of research fields owing to their unique properties and broad applications, particularly in catalysis.1 Industrial heterogeneous catalysts based on metal/oxide nanoparticles have been widely investigated due to their high surface to volume ratio at reduced particle size.2 However, most of these catalysts still employ nanoparticles with broad size distributions and poorly defined shapes. As well established by computational simulations and experimental studies, both reactivity and selectivity of metal nanoparticles in a structure-sensitive reaction can be enhanced by controlling the size and arrangement of atoms on the surface.3 Therefore, an accurate control of size and shape is highly desirable to tailor the catalytic properties of metal nanomaterials. A great deal of research efforts have been devoted over the past decade to the development of synthetic methods that allow a careful control of both nanoparticle size and shape, with a range of reported uniform metal nanocrystals featuring different shapes.4 Among the de-

veloped techniques, colloidal synthetic approaches have been demonstrated to be most effective, reliable and versatile routes to control shapes (and sizes) of metal nanocrystals.5 Despite notable achievements in recent years, the generally employed wet chemical approaches normally require a large amount of surfactant/capping agents.4-6 The presence of such organic compounds on the nanoparticles would be detrimental to catalytic applications as the catalytic process takes place on the particle surface. A promising approach dealing with the dispersion/deposition of the nanocrystals on porous materials has been employed to design stabilized surface-clean polyhedral nanoparticles.7 In this regard, a number of efficient methodologies have been developed to incorporate metal polyhedra on various supports including carbons, silicas and metal-organic frameworks (MOFs).8 Surfactant/capping agents are not employed during materials preparation in such protocols, or are eventually removed after metal deposition, e.g., by thermal treatment. In spite of the achieved success to date, it is still difficult to avoid loss of the well-defined size and shape of the nanocrystals

ACS Paragon Plus Environment

ACS Catalysis

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

upon deposition. Consequently, a facile synthesis of supported monodisperse metal/oxide polyhedra in the absence of capping agents remains a significant challenge, especially at high metal loadings. Herein, we disclose a simple and novel surfactantfree strategy for the preparation of monodisperse metal nanoparticles with controlled phases and sizes by using carbon monoxide as a directing agent during MOFs thermal annealing to limit nanoparticle growth at the solid−gas interface. MOFs are a new class of porous materials that have been demonstrated as promising materials for a variety of applications, such as gas adsorption, separation, and catalysis.9 More recently, MOFs have also been proved to be excellent precursors for the synthesis of various carbon-based nanomaterials including metal/metal oxide decorated porous carbons via thermal decomposition.10 However, it is extremely difficult to tailor the size and shape of the carbon-embedded metal/metal oxide nanoparticles from thermal aggregation of metal ions in MOFs. To the best of our knowledge, so far there is no report on the synthesis of metal/metal oxide nanoparticles with controlled shape from MOFs thermolysis at the solid−gas interface.

EXPERIMENTAL SECTION Synthesis of MIL-88b. Typically, FeCl3•6H2O and terephthalic acid (H2BDC) were dissolved in N,N’dimethylformamide (DMF) (30 mL) with a molar ratio of 1:1:65. The mixture was added into an autoclave, and then crystallized at 100 °C for 12 h at a heating rate of 1 °C min-1 from room temperature. After filtration, the resulting solid was washed with DMF at room temperature for several times, and then dried at 50 °C in a vacuum oven for 5 h to obtain the final MIL-88b solid. Synthesis of FeOx/C materials. The typical preparation procedure was as follow: MIL-88b (1.0 g) was loaded in a quartz boat and heated at 500 °C for 3 h with a heating rate of 1 °C min-1 from room temperature under different atmosphere with a flow rate of 100 ml min-1 in an open tubular furnace. The prepared material was denoted as FeOx/C. VCO:VAr indicated the volume ratio of CO to Ar in the calcination atmosphere. Characterization. Powder X-ray diffraction (PXRD) patterns of the materials were obtained on a Rigaku diffractometer (D/MAX-IIIA, 3 kW) using Cu Kα radiation (40 kV, 30 mA, λ = 0.1543 nm). BET surface areas and pore-size distribution were determined with N2 adsorption/desorption isotherms at 77 K on a Micromeritics ASAP 2020M instrument. Before measurements, the samples were degassed at 150 ºC for 10 h. Raman spectra were obtained at room temperature on a LabRAM Aramis Raman system with a laser of 532 nm. The iron contents in the samples were measured quantitatively by atomic absorption spectroscopy (AAS) on a HITACHI Z-2300 instrument. Elemental analysis was performed on an Ele-

Page 2 of 10

mentar Vario EL III equipment with sample weights of 2– 3 mg. H2-TPD data were obtained on a Micromeritics AutoChem II 2920 instrument with a quartz reactor of 5 mm internal diameter. Before measurements, the sample was treated under flowing Ar at 500 °C for 2 h. The size and morphology of the materials were investigated by using a high-resolution transmission electron microscopy (HR-TEM, C/M300, Philips). The elemental mappings were obtained on a scanning transmission electron microscope (STEM) unit with a high-angle annulardark-field (HAADF) detector (HITACHI S-5500). EDX analysis was recorded on a Bruker XFlash 5030T operating at 200 kV. The samples for TEM test were prepared by suspending the samples in ethanol and then subjected to ultrasound for 30 min. After that, a very small amount of suspensions were taken out using microsyringe and then dropped on a copper online. FFT patterns corresponding to the HRTEM images were obtained with the software of Digital Micrograph. X-ray photoelectric spectroscopy (XPS) measurements were performed on a ultra-high vacuum (UHV) multipurpose surface analysis system (SpecsTM model Germany) operating at pressures 600 °C (Figure S15) with slightly higher surface areas to those obtained at 500 °C (Figure S16, Table S1).

Figure 3. HMF conversion and DFF selectivity of FeOx/C(VCO/VAr=0) and FeOx/C(VCO/VAr=1) in HMF oxidation with error bars on the basis of 5 different batches of decomposed MIL-88b (a); ATR-IR spectra of catalysts after adsorption of HMF: black, without catalyst; blue, FeOx/C(VCO/VAr=0); red, FeOx/C(VCO/VAr=1) (b); and plausible reaction mechanism of HMF oxidation over the FeOx/C(VCO/VAr=1) (c).

FeOX/C materials were tested as catalysts in the selective oxidation of biomass-derived 5hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF). This reaction is commercially important because DFF is an important precursor in the synthesis of pharmaceuticals, fungicides, and functional polymers. HMF is a typical heteroaromatic alcohol and its oxidation to DFF could easily lead to various byproducts including 5-formyl-2furancarboxylic acid (HMFCA), 5-formyl-2furancarboxylic acid (FFCA) and 2,5-furandicarboxylic (FDCA) as shown in Figure 3. Therefore, many efforts have been made designing highly selective catalysts in order to obtain the high-value chemical DFF, and high DFF yields have been obtained using noble metal (e.g., Ru,

ACS Paragon Plus Environment

ACS Catalysis

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

Pt, Pd) or toxic vanadium homogeneous catalysts.17 In the light of these premises, the development of highly efficient and reusable non-noble heterogeneous catalysts for the selective transformation of HMF to DFF remains a significant challenge to date. The reaction was carried out at 1 MPa O2 and 150 °C using toluene as solvent. Both HMF conversion and DFF selectivity remarkably increased with an increase in CO concentration in the calcination atmosphere (Figure S17, Table S2). For FeOx/C(VCO/VAr=0) prepared under pure Ar, the conversion of HMF was only 18% with 33% selectivity to DFF within 12 h (Figure 3a). In contrast, using the FeOx/C(VCO/VAr=1) with uniformly dispersed octahedral ferrite as active phase, a comparably high selectivity of DFF (ca. 99%) at >99% conversion of HMF was achieved (Figure 3a). At the same conversion, the selectivity was remarkably enhanced by a factor of ca. 3 under otherwise identical conditions (Figure S17). For comparison, we also prepared an activated carbon supported Fe3O4 catalyst by using a solvothermal method. As shown in Table S2, the as-synthesized carbon supported ferrite catalyst exhibited much lower activity and selectivity than FeOx/C(VCO/VAr=1) under identical reaction conditions. Moreover, to eliminate the possible influence of toluene oxidation on the reaction, we performed toluene oxidation reactions under identical conditions over FeOx/C(VCO/VAr=0) and FeOx/C(VCO/VAr=1). No conversion of toluene was observed over the catalysts, suggesting toluene could not be oxidized under the investigated conditions (Table S3). The results suggest that the oxidation of HMF to DFF would be preferred over octahedral Fe3O4 particles, i.e., (111) planes. This observation was further confirmed from results of HMF oxidation over FeOx/C materials prepared under VCO/VAr=1:1 at different temperatures of 600 and 700 °C or various heating rates of 0.5, 2.0 and 3.0 °C/min, which exhibited significantly reduced selectivities to DFF to those observed for FeOx/C prepared at 1.0 °C/min and 500 °C due to the presence of a part of irregular ferrite particles (Figures S18 and S19, Table S2). To address the effect of metal surface area on the reaction, we performed H2-TPD on the catalysts. As shown in Figure S20, the chemisorbed H2 decreased in the order: FeOx/C(VCO/VAr=1) (2.0 °C/min) > FeOx/C(VCO/VAr=1) (1.0 °C/min) > FeOx/C(VCO/VAr=0) (1.0 °C/min). Combining with the catalytic performances, these results demonstrate that FeOx facets should play a critical role in determining the catalytic property of the FeOx/C materials in HMF oxidation. In order to additionally support the unique shape dependent selectivity of octahedral Fe3O4 particles for HMF oxidation, in situ ATR-IR experiments of HMF and DFF adsorption on the catalysts were performed. As shown in Figure 3b and Figure S21, the characteristic peaks assigned to HMF, e.g., 1526 cm-1 for C=C stretching

Page 6 of 10

vibration in furan rings, 1667 cm-1 for C=O stretching and 3382 cm-1 for –OH stretching were clearly present in all samples.18 It can be seen that after the addition of FeOx/C(VCO/VAr=0) the peaks were slightly weakened (Table S4) as compared to those in the absence of any catalyst possibly due to the weak adsorption (e.g., Van der Waals’ forces) of HMF on the catalyst surface. Interestingly, different from the adsorption on FeOx/C(VCO/VAr=0), the peak intensity of –OH stretching was significantly reduced on the FeOx/C(VCO/VAr=1) catalyst. These results indicated that the adsorption of –OH bond of HMF on FeOx/C(VCO/VAr=1) was much stronger than that on FeOx/C(VCO/VAr=0), leading to higher activity and selectivity. This difference could be mostly attributed to the more exposed Fe3O4 (111) facets on FeOx/C(VCO/VAr=1), considering the similar composition of the MOF-derived materials prepared under different atmosphere. This explanation could be further supported by the ATR-IR results on the FeOx/C prepared with a VCO/VAr ratio of 0.2, 0.5, 2, or ∞, respectively (Figure S21). FeOx/C(Vco/VAr=2) and FeOx/C(Vco/VAr=∞) exhibited similar peak intensity of –OH stretching in ATR-IR, thus having similar catalytic performance. In contrast, the peak intensity of –OH stretching on the FeOx/C(Vco/VAr=0.2) or FeOx/C(Vco/VAr=0.5) showed a relatively small reduction as compared to that on the FeOx/C(VCO/VAr=0) (Table S4), and thus they showed inferior activity and selectivity than the sample with VCO/VAr = 1. On the basis of the ATR-IR results, we proposed a plausible reaction mechanism for HMF oxidation over FeOx/C(VCO/VAr=1) (Figure 3c). First, HMF will adsorb on (111) facets via –OH bond due to its stronger adsorption as compared to C=O on FeOx/C(VCO/VAr=1). The adsorbed HMF then undergoes oxidative dehydrogenation to produce DFF. On the other hand, the weak adsorption of C=O bond (see Figure S22 and Table S4) could prevent the further oxidation of DFF and also the reaction of C=O bond of HMF to yield undesired byproducts including HMFA, FFCA and FDCA (Figure 3c). The unique adsorption properties of FeOx/C(VCO/VAr=1) are believed to be beneficial for the excellent chemical selectivity achieved over the catalyst. To further support the ATR-IR results that the interaction of DFF with Fe3O4 (111) is relatively weaker as compared to that of HMF, periodic density functional theory (DFT) calculations were performed. For this purpose the most stable termination of Fe3O4 (111) surface was employed and the adsorption energies of HMF and DFF on it were evaluated. According to the previous reaction mechanism study by Liu et al.,17d HMF is dissociatively adsorbed to produce an alcoholate (C5H3O2CH2O*) and hydrogen species (H*) on the catalyst surface. Both HMF and DFF molecules prefer adsorption configurations with the furan rings parallel to the surfaces (Figure 4), which allows a maximum interaction adsorbate/surface. In the case of HMF, both terminal

ACS Paragon Plus Environment

Page 7 of 10

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

ACS Catalysis

oxygen atoms of C=O carbonyl and CH2O moiety of the dissociated HMF interact with two surface Fe sites, while the H* species binds to the adjacent oxygen site to form a OH group on the catalyst surface (Figure 4a, 4b). Similarly, DFF adsorbs on the surface by simultaneous coordination of the two oxygen atoms of its formyl groups with two surface Fe sites (Figure 4c, 4d). DFT calculation indicates that the adsorption energy (∆Eads) of HMF dissociative adsorption is -333 kJ/mol. The interaction between DFF and the surface is weaker (-302 kJ/mol). This weaker DFF/catalyst interaction is beneficial for the product desorption, which could prevent over-oxidation reactions on the catalyst surface to some extent and partially contribute to the high DFF selectivity. Further machanism investigations are required to understand the excellent selectivity to DFF under the catalysis of Fe3O4 (111) nanoparticles more clearly.

Figure 5. (a) Reuses of the FeOx/C(Vco/VAr=1) catalyst for HMF oxidation. Reaction conditions: 0.5 mmol HMF, catalyst (metal 20 mol%), 2 mL toluene, 1 MPa O2, 150 ºC, 6 h; (b) th TEM image of FeOx/C(Vco/VAr=1) after 6 cycles; and (c) PXRD of FeOx/C(Vco/VAr=1) after 6th cycles.

CONCLUSION

Figure 4. Optimized geometries and adsorption energies of HMF (a, b) and DFF (c, d) on the (111) surface of Fe3O4, in top and side view.

One crucial issue for shape-controlled particles relates to the stability and reusability of the materials because the surface atom may change dynamically upon its participation in a catalytic reaction, making it extremely challenging to retain the initial activity and selectivity.3f As shown in Figure 5, there was no appreciable reduction in activity and selectivity even after six runs for HMF oxidation over FeOx/C(VCO/VAr=1), in accordance with XRD and TEM observations (Figure 5). The excellent stability and recyclability of FeOx/C(VCO/VAr=1) could be related to the confinement and dispersion effect offered by the carbonaceous matrix from the MOF utilised as template.

In summary, we have demonstrated a novel surfactantfree strategy to synthesize monodisperse ferrite octahedral nanocrystals of uniform composition through a facile one-step thermolysis of MOF. The use of CO was found to play an important role in controlling the growth rate of specific facets and subsequently the morphology of resultant metal oxide nanostructures at the solid−gas interface. The as-prepared octahedral ferrite materials exhibited interesting shape-dependent catalytic performance in HMF oxidation, achieving significantly improved activity and DFF selectivity as compared to those prepared under pure inert atmosphere. Furthermore, the catalysts were highly stable and readily reusable. The present synthetic strategy are believed to be extendible to the preparation of a variety of other shape-controlled MOF-derived materials by simply modulating the thermolysis atmosphere, and opens up a new avenue for developing highly active and selective catalysts for advanced catalytic applications.

AUTHOR INFORMATION Corresponding Authors * [email protected]; [email protected]

Notes The authors declare no competing financial interest

ASSOCIATED CONTENT

ACS Paragon Plus Environment

ACS Catalysis

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

Supporting Information The Supporting Information is available free of charge on the ACS Publications website at DOI: Additional TEM images, XRD patterns, BJH pore size distributions, IR spectra, TG curves, XPS spectra, reaction results, etc. (PDF)

ACKNOWLEDGMENT This work was supported by the National NSF of China (21322606, 21436005, and 21576095), the State Key Laboratory of Pulp and Paper Engineering (2017ZD04), FRFCU (2015ZP002 and 2015PT004), and Guangdong NSF (2013B090500027 and 2016A050502004). Dr. G. Li acknowledges financial support from The Netherlands Organization for Scientific Research (NWO) for her personal VENI grant (no. 016.Veni.172.034) and NWO-SurfSARA for providing access to supercomputer resources.

REFERENCES (1) (a) Baiker, A. In Handbook of Heterogeneous Catalysis, 2nd ed.; Ertl, G.; Knozinger, H.; Weitkamp, J. Wiley-VCH: Weinheim, 1997; Vol. 8, 1309-1338; (b) Farmer, J. A.; Campbell, C. T. Science 2010, 329, 933-936; (c) Lee, H.; Habas, S. E.; Somorjai, G. A.; Yang, P. D. J. Am. Chem. Soc. 2008, 130, 5406-5407; (d) Burda, C.; Chen, X.; Narayanan, R.; El-Sayed, M. A. Chem. Rev. 2005, 105, 1025-1102; (e) Corma, A.; Garcia, H.; Llabres i Xamena, F. X. Chem. Rev. 2010, 110, 4606-4655. (2) Mostafa, S.; Behafarid, F.; Croy, J. R.; Ono, L. K.; Li, L.; Yang, J. C.; Frankel, A. I.; Cuenya, B. R. J. Am. Chem. Soc. 2010, 132, 15714-15719. (3) (a) Sander, M.; Imbihl, R.; Schuster, R.; Barth, J. V.; Ertl, G. Surf. Sci. 1992, 272, 159-169; (b) Zhou, K.; Li, Y. Angew. Chem. Int. Ed. 2012, 51, 602-613; (c) Wang, Z. L. J. Phys. Chem. B. 2000, 104, 1153-1175; (d) Narayanan, R.; El-Sayed, M. A. J. Am. Chem. Soc. 2004, 126, 7194-7195; (e) An, K.; Somorjai, G. A. ChemCatChem 2012, 4, 1512-1524; (f) Ruditskiy, A.; Choi, S.-Il; Peng, H.; Xia, Y. MRS Bull. 2014, 39, 727-737; (g) Somorjai, G. A.; Park, J. Y. Angew. Chem. Int. Ed. 2008, 47, 92129228; (h) Xie, X.; Li, Y.; Liu, Z.; Haruta, M.; Shen, W. Nature 2009, 458, 746-749; (i) Niu, W.; Gao, Y.; Zhang, W.; Yan, N.; Lu, X. Angew. Chem. Int. Ed. 2015, 54, 8271-8392. (4) (a) Xia, Y.; Xiong, Y.; Lim, B.; Skrabalak, S. E. Angew. Chem. Int. Ed. 2009, 48, 60-103; (b) Lim, B.; Xia, Y. Angew. Chem. Int. Ed. 2011, 50, 76-85; (c) Fan, Z.; Zhang, H. Chem. Soc. Rev. 2016, 45, 63-82; (d) Weiner, R. G.; Kunz, M. R.; Skrabalak, S. E. Acc. Chem. Res. 2015, 48, 2688-2695. (5) (a) An, K.; Alayoglu, S.; Ewers, T.; Somorjai, G. A. J. Colloid Interface Sci. 2012, 373, 1-13; (b) Ren, J. T.; Tilley, R. D. J. Am. Chem. Soc. 2007, 129, 3287-3291; (c) Lim, B.; Jiang, M. J.; Camargo, P. H. C.; Cho, E. C.; Tao, J.; Lu, X. M.; Zhu, Y. M.; Xia, Y. N. Science 2009, 324, 1302-1305; (d) Habas, S. E.; Lee, H.; Radmilovic, V.; Somorjai, G. A.; Yang, P. Nat. Mater. 2007, 6, 692-697; (e) Bratlie, K. M.; Lee, H.; Komvopoulos, K.; Yang, P. D.; Somorjai, G. A. Nano Lett. 2007, 7, 3097-3101; (f) Peng, H. C.; Xie, S.; Park, J.; Xia, X.; Xia, Y. J. Am. Chem. Soc. 2013, 135, 3780-3783; (g) Yu, T.; Kim, D. Y.; Zhang, H.; Xia, Y. Angew. Chem. Int. Ed. 2011, 50, 2773-2777; (h) Crespo-Quesada, M.; Yarulin, A.; Jin, M.; Xia, Y.; Kiwi-Minsker, L. J. Am. Chem. Soc. 2011, 133, 12787-12794; (i) Xia, X.; Choi, S. I.; Herron, J. A.; Lu, N.; Scaranto, J.; Peng, H. C.; Wang, J.; Mavrikakis, M.;

Page 8 of 10

Kim, M. J.; Xia, Y. J. Am. Chem. Soc. 2013, 135, 15706-15709; (j) Lai, J.; Niu, W.; Luque, R.; Xu, G. Nano Today 2015, 10, 240267. (6) (a) Mourdikoudis, S.; Liz-Marzán, L. M. Chem. Mater. 2013, 25, 1465-1476; (b) Huang, X.; Tang, S.; Mu, X.; Dai, Y.; Chen, G.; Zhou, Z.; Ruan, F.; Yang, Z.; Zheng, N. Nat. Nanotechnol. 2011, 6, 28-32; (c) Kang, Y.; Ye, X.; Murray, C. B. Angew. Chem. Int. Ed. 2010, 49, 6156-6159. (7) (a) Lee, I.; Morales, R.; Albiter, M. A.; Zaera, F. Proc. Nat. Acad. Sci. 2008, 105, 15241-15246; (b) Lee, I.; Delbecq, F.; Morales, R.; Albiter, M. A.; Zaera, F. Nat. Mater. 2009, 8, 132-138; (c) Chen, Q.; Xu, Z.; Peng, S.; Chen, Y.; Lv, D.; Wang, Z.; Sun, J.; Guo, G. J. Power Sour. 2015, 282, 471-478. (8) (a) Huang, X.; Zhao, Z.; Cao, L.; Chen, Y.; Zhu, E.; Lin, Z.; Li, M.; Yan, A.; Zettl, A.; Wang, Y.; Duan, X.; Mueller, T.; Huang, Y. Science 2015, 348, 1230-1234; (b) Huang, X.; Zhao, Z.; Chen, Y.; Zhu, E.; Li, M.; Duan, X.; Huang, Y. Energy Environ. Sci. 2014, 7, 2957-2962; (c) Primo, A.; Esteve-Adell, I.; Blandez, J. F.; Dhakshinamoorthy, A.; Álvaro, M.; Candu, N.; Coman, S. M.; Parvulescu, V. I.; García, H. Nat. Commun. 2015, 6, 8561; (d) Aijaz, A.; Akita, T.; Tsumori, N.; Xu, Q. J. Am. Chem. Soc. 2013, 135, 16356-16359; (e) Higgins, D. C.; Hassan, F. M.; Seo, M. H.; Choi, J. Y.; Hoque, M. A.; Lee, D. U.; Chen, Z. J. Mater. Chem. A 2015, 3, 6340-6350; (f) Zhang, C.; Oliaee, S. N.; Hwang, S. Y.; Kong, X.; Peng, Z. Nano Lett. 2016, 16, 164-169. (9) (a) Furukawa, H.; Cordova, K. E.; O’Keeffe, M.; Yaghi, O. M. Science 2013, 341, 1230444; (b) Zhao, D.; Timmons, D. J.; Yuan, D.; Zhou, H. Acc. Chem. Res. 2011, 44, 123-133; (c) Wu, C.; Lin, W. Angew. Chem. Int. Ed. 2007, 46, 1075-1078; (d) Sato, H.; Matsuda, R.; Sugimoto, K.; Takata, M.; Kitagawa, S. Nat. Mater. 2010, 9, 661-666. (10) (a) Liu, B.; Shioyama, H.; Akita, T.; Xu, Q. J. Am. Chem. Soc. 2008, 130, 5390-5391; (b) Tang, J.; Salunkhe, R. R.; Liu, J.; Torad, N. L.; Imura, M.; Furukawa, S.; Yamauchi, Y. J. Am. Chem. Soc. 2015, 137, 1572-1580; (c) Jiang, H.; Liu, B.; Lan, Y.; Kuratani, K.; Akita, T.; Shioyama, H.; Zong, F.; Xu, Q. J. Am. Chem. Soc. 2011, 133, 11854-11857; (d) Xia, B.; Yan, Y.; Li, N.; Wu, H.; Lou, X.; Wang, X. Nat. Energy 2016, 1, 15006-15009; (e) Lin, Q.; Bu, X.; Kong, A.; Mao, C.; Zhao, X.; Bu, F.; Feng, P. J. Am. Chem. Soc. 2015, 137, 2235-2238; (f) Wu, H.; Xia, B.; Yu, L.; Yu, X.; Lou, X. Nat. Commun. 2015, 6, 6512; (g) Ma, T.; Dai, S.; Jaroniec, M.; Qiao, S. J. Am. Chem. Soc. 2014, 136, 13925-13931; (h) Gadipelli, S.; Guo, Z. ChemSusChem 2015, 8, 2123-2132; (i) Pachfule, P.; Shinde, D.; Majumder, M.; Xu, Q. Nat. Chem. 2016, 8, 718-724; (j) Zhong, W.; Liu, H.; Bai, C.; Liao, S.; Li, Y. ACS Catal. 2015, 5, 1850-1856; (k) Bai, C.; Yao, X.; Li, Y. ACS Catal. 2015, 5, 884-891; (l) Wezendonk, T.; Warringa, Q.; Santos, V.; Chojecki, A.; Ruitenbeek, M.; Meima, G.; Makkee, M.; Kapteijn, F.; Gascon, J. Farad. Discuss 2017, doi: 10.1039/C6FD00198J; (m) Wezendonk, T.; Santos, V.; Nasalevich, M.; Warringa, Q.; Dugulan, A.; Chojecki, A.; Koeken, A.; Ruitenbeek, M.; Meima, G.; Islam, H.; Sankar, G.; Makkee, M.; Kapteijn F.; Gascon, J. ACS Catal. 2016, 6, 32363247; (n) An, B.; Cheng, K.; Wang, C.; Wang, Y.; Lin, W. ACS Catal. 2016, 6, 3610-3618; (o) Santos, V.; Wezendonk, T.; Delgado Jaén, J.; Dugulan, A.; Nasalevich, M.; Islam, H.; Chojecki, A.; Sartipi, S.; Sun, X.; Hakeem, A.; Koeken, A.; Ruitenbeek, M.; Davidian, T.; Meima, G.; Sankar, G.; Kapteijn, G.; Makkee, M.; Gascon, J. Nat. Commun. 2015, 6, 6451.

ACS Paragon Plus Environment

Page 9 of 10

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

ACS Catalysis

(11) (a) Kresse, G.; Hafner, J. Phys. Rev. B 1993, 48, 13115-13118; (b) Perdew, J. P.; Burke, K.; Ernzerhof, M. Phys. Rev. Lett. 1996, 77, 3865-3868; (c) Blöchl, P. E. Phys. Rev. B 1994, 50, 17953-17979; (d) Grimme, S.; Antony, J.; Ehrlich, S.; Krieg, H. J. Chem. Phys. 2010, 132, 154104-154113; (e) Yu, X.; Huo, C.-F.; Li, Y.-W.; Wang, J.; Jiao, H. Surf. Sci. 2012, 606, 872-879; (f) Okudera, H.; Kihara, K.; Matsumoto, T. Acta Crystallographica Section B 1996, 52, 450-457; (g) Aragón, R. Phys. Rev. B 1992, 46, 5328-5333; (h) Kiejna, A.; Ossowski, T.; Pabisiak, T. Phys. Rev. B 2012, 85, 125414; (i) Shimizu, T.K.; Jung, J.; Kato, H.S.; Kim, Y.; Kawai, M. Phys. Rev. B 2010, 81, 235429; (j) Fonin, M.; Pentcheva, R.; Dedkov, Y.S.; Sperlich, M.; Vyalikh, D.V.; Scheffler, M.; Rüdiger, U.; Güntherodt, G. Physical Review B 2005, 72, 104436; (k) Pentcheva, R.; Moritz, W.; Rundgren, J.; Frank, S.; Schrupp, D.; Scheffler, M. Surface Science 2008, 602, 1299-1305. (12) Surble, S.; Serre, C.; Mellot-Draznieks, C.; Millange, F.; Ferey, G. Chem. Commun. 2006, 3, 284-286. (13) (a) Faria, D.; Silva, S.; Oliveira, M. J. Raman Spectro. 1997, 28, 873-878; (b) Kaczmarczyk, J.; Zasada, F.; Janas, J.; Indyka, P.; Piskorz, W.; Kotarba, A.; Sojka, Z. ACS Catal. 2016, 6, 1235-1246. (14) Yamashita, T.; Hayes, P. Appl. Sur. Sci. 2008, 254, 24412449. (15) (a) He, W.; Jiang, C.; Wang, J.; Lu, L. Angew. Chem. Int. Ed. 2014, 53, 9503-9507; (b) Fang, R.; Luque, R.; Li, Y. Green Chem. 2016, 18, 3152-3157. (16) (a) Herrero, E.; Franaszczuk, K.; Wieckowski, A. J. Phys. Chem. 1994, 98, 5074-5083; (b) Schauermann, S.; Hoffmann, J.; Johanek, V.; Hartmann, J.; Libuda, J.; Freund, H. J. Angew. Chem. Int. Ed. 2002, 41, 2532-2535; (c) Ge, W.; Sato, R.; Wu, H.; Teranishi, T. ChemPhysChem 2015, 16, 3200-3205. (17) (a) Ma, J.; Du, Z.; Xu, J.; Chu, Q.; Pang, Y. ChemSusChem 2011, 4, 51-54; (b) Partenheimer, W.; Grushin, V. V. Adv. Synth. Catal. 2001, 343, 102-111; (c) Yadav, G.; Sharma, R. Appl. Catal. B 2014, 147, 293-301; (d) Nie, J.; Xie, J.; Liu, H. J. Catal. 2013, 301, 83-91. (18) Zakzeski, J.; Grisel, R. J. H.; Smit, A. T.; Weckhuysen, B. M. ChemSusChem 2012, 5, 430-437.

ACS Paragon Plus Environment

ACS Catalysis

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

Insert Table of Contents artwork here

ACS Paragon Plus Environment

Page 10 of 10