Polyoxometalate Cluster Sensitized with Copper-Viologen Framework

Oct 12, 2018 - An efficient photocatalyst based on the broadband solar response molecular system was designed and constructed for pollutant degradatio...
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Letter Cite This: ACS Appl. Mater. Interfaces 2018, 10, 35671−35675

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Polyoxometalate Cluster Sensitized with Copper-Viologen Framework for Efficient Degradation of Organic Dye in Ultraviolet, Visible, and Near-Infrared Light Xiaojuan Sun,†,‡ Jie Zhang,† and Zhiyong Fu*,†,‡ †

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The Key Lab of Fuel Cell Technology of Guangdong Province, Guangdong, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, 510640, China ‡ State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou, 350002, P. R. China S Supporting Information *

ABSTRACT: An efficient photocatalyst based on the broadband solar response molecular system was designed and constructed for pollutant degradation in near-neutral conditions via utilizing guest polyoxometalate cluster sensitized with electron deficient host network. Photoelectrochemical analysis reveals electron−hole pairs are generated efficiently upon both visible and NIR light excitation. Its photocatalytic activity in the visible and NIR light regions is enhanced because of the contribution from the broad absorption of copper-viologen framework and the strong host−guest interactions. This stable heterogeneous catalyst is easily recollected and regenerated without the loss of activity for the next cycle.

KEYWORDS: metal organic framework, copper-viologen framework, polyoxometalate cluster, crystalline material, photocatalysis, broadband solar response

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well-defined HOMO and LUMO.18 Considering the photosensitive characters of viologen components,19 a new type of photocatalysts may readily be constructed by the suitable assembly of metal-viologen frameworks and POM clusters. The light responsive property of metal-viologen frameworks would make them beneficial in exploring novel photonic materials for light harvesting.20−23 Herein, we present the first example of an organic−inorganic hybrid system [Cu2(CPBPY)4(H2O)2][PW12O40][OH]·6H2O 1 (CPBPY = N-(3-carboxyphenyl)-4,4′-bipyridinium) with NIR light catalytic activity by using metal-viologen framework as a media to extend the absorption spectrum from ultraviolet to the NIR region. In its well-defined assembly architecture, keggin type PW12O403− anion locates tightly at the cage of copper-viologen networks, avoiding the problems of POM leaching and recovery. The complex displays full-spectrum solar energy absorptions, especially in the NIR region (λ > 800 nm) which also make the photocatalyst degrade the dye wastewater effectively. Compound 1 was obtained by a hydrothermal reaction of Cu(NO3)2·3H2O, CPBPY, Na2HPW12O40·2H2O, and water (see Supporting Information). Powder X-ray diffraction

hotocatalytic degradation offers an essential way for the control of organic pollutants because of its high efficiency, simplicity, and easy handling.1,2 Among various photocatalysts, polyoxometalates (POMs) have proven to be one of the most promising candidates. Their ability to form peroxo complexes or to support catalytically active metal ions in high oxidation states enables them as valuable catalysts in organic pollutant degradation.3−5 Nevertheless, the inherent drawbacks of pure POMs solid catalysts, such as high solubility in aqueous solution or low stability under catalytic conditions, make them face the problems of poor recyclability and recovery in the practical applications.6 In view of that, immobilizing POMs on a solid support (such as TiO2, ZrO2, SiO2, and organic polymers) emerges as an effective way to solve them.7 Although the method avoids the problem of recollection, it still suffers other difficulties including ill-defined structure, nonuniform sites, POM leaching and low loading.8 Recently, crystalline organic−inorganic complex hybrid systems offer a new opportunity for combining the redox nature of POM moiety and the characters of metal organic framework.9−13 It emerges as a useful strategy to stabilize and optimize traditional POM fragments. More than 50% of the solar energy falls in the Near-infrared light (NIR) range.14,15 One of the challenging tasks in polyoxometalatic catalysts is to expand their solar-light absorption region.16,17 Most of the POMs complexes only have photocatalytic activity under ultraviolet light irradiation, due to the large energy gap between their © 2018 American Chemical Society

Received: June 29, 2018 Accepted: October 12, 2018 Published: October 12, 2018 35671

DOI: 10.1021/acsami.8b10777 ACS Appl. Mater. Interfaces 2018, 10, 35671−35675

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ACS Applied Materials & Interfaces

Figure 1. Structure of compound 1: (a) the asymmetric unit and (b) the packing arrangement with encapsulated PW12O403− anions.

(PXRD) data prove phase purity of the as-synthesized bulky sample (Figure S1). Single-crystal data indicates that the photoactive complex is built by the [Cu2(CPBPY)4(H2O)2]4+ cationic host framework, [PW12O40]3− guest anion, hydroxide anion, and solvent water molecules. The Cu2+ center is five coordinated with one water molecule, two unidentate carboxylate groups and two nitrogen atoms from CPBPY ligands in a square pyramidal geometry. An extended 2D network with a square cavity (15 × 15 Å) that shelters the [PW12O40]3− cluster (Figure 1) is built by the assembly of the copper ions and the bridging CPBPY ligands, presenting a compact host−guest structure. The interplanar distance between the pyridinium rings of the host paralleled layer framework is 10 Å. The guest POM clusters form strong interactions with the host frame (Figure S2). Each PW12O403− anion is surrounded by six close chains. The guest polyphosphotungstate clusters are embedded into a onedimensional channels formed by the layer-by-layer stacking mode. Compound 1 shows a stable system in water treatment at ambient condition verified by TG and PXRD data. An initial weight loss of ca. 4.1% is observed between 30 and 158 °C in the TG curve of 1 (Figure S3), which can be attributed to the removal of solvent and coordinated water molecules (3.79% calculated). The framework of the composite material remains its stability until 200 °C supported by the good agreement of the peaks in the PXRD diagrams, even after the leaving of the water molecules (Figure S4). Weight loss at 260 °C proves the decomposition of the main framework. The UV−vis spectrum of inorganic keggin polyphosphotungstate Na2HPW12O40·2H2O only shows absorption bands from 200 to 350 nm, located in the UV region (Figure S5). By comparison, the band absorptions expand to visible and nearinfrared region (from 200 to 1200 nm) when the PW12O403− cluster is included to the copper-viologen cage (Figure 2). For the rest of near-infrared bands of 1, the peak at 1450 nm is assigned to the combination band of the symmetric and asymmetric stretching vibration modes of water molecules,24 the peak at 1675 nm is the phenyl CH stretching overtone band,25 and the peak at 1950 nm belongs to the lattice and OH stretching modes of water molecules.26,27 Absorption intensities of the peaks at 1450 and 1950 nm are markedly affected by heating. The assembly presents the successful construction of an organic−inorganic composite system with wide-band absorption. Photocatalytic activity of the catalyst (particle size is reduced to 0.1−0.6 μm by ball milling, Figure 3) is evaluated by photodegradation of methylene blue (MB) solution under

Figure 2. UV/vis/NIR absorption spectrum of 1.

Figure 3. SEM images of 1 after ball milling. Scale bars at 1 μm to show the particle sizes.

various light irradiation. Following PXRD characterization shows that 1 retains its structure and crystallinity after size reduction (Figure S6). A 300W xenon lamp, with a 400 nm filter/200 nm ∼780 nm reflector plate, and with a 800 nm filter/full spectrum reflector plate are used as full spectrum, visible, and NIR light sources, respectively. The MB solution is observed to be completely degraded in 30 min under full spectrum light irradiation (Figure 4). Interestingly, around 98.2% of MB was degraded in 60 min and around 97.7% of MB was degraded in 100 min under visible and NIR light irradiation, respectively. For the blank reaction without 35672

DOI: 10.1021/acsami.8b10777 ACS Appl. Mater. Interfaces 2018, 10, 35671−35675

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ACS Applied Materials & Interfaces

Figure 4. Degeneration rates of MB with full spectrum, visible, and NIR light irradiation. Initial concentrations: MB (10 mg/L, pH= 6.3), cat. 1 (0.05 g). Inset: UV−vis absorption spectra of MB solution recorded during NIR light photodegradation.

Figure 5. Photocurrent responses (0.4 V bias) of 1 in 0.5 M Na2SO4 electrolyte under visible light (blue) and NIR light (red), as well as the FTO glass under NIR light as a blank sample (black).

catalyst, the degeneration rate is fairly low (Figure S11). These results show that the composite system possesses UV, visible and very impressive NIR light photocatalytic activity for the photocatalytic degradation of MB. According to our knowledge, the system is one of the high photocatalytic activity materials for MB photodegration (50 mg, 30 min, 98.6%, 300 W Xe lamp) because of its full spectrum absorption ability (comparison of MB photodegration efficiency of analogous copper-ligand/POM hybrid systems: Cu2Cl(trz)8[PW12O40], 100 mg, 60 min, 56.7%, 300 W Xe lamp;28 [Cu8L8[Mo12O46(AsPh)4]2·H2O, 70 mg, 180 min, 70%, 500 W Xe lamp;29 [CuLo]4[PW12O40], 40 mg, 60 min, 78.4%, 125 W Hg lamp30). The used visible or NIR light sources are verified by the spectra shown in Figure S7. It can be observed that the used NIR light source falls in the range higher than 800 nm, which approve the NIR-responsive photocatalytic activity of 1 without any disturbing from UV or visible light. This stable heterogeneous catalyst is easily recollected and regenerated without the loss of activity for the next cycle (Table S3 and Figure S14). PXRD and IR data support that the framework remains its stability without the leaching of PW12O403− guests during the catalytic process (Figures S1 and S8). The mechanism of degradation with PW12O403− component as photocatalyst has been well documented.31 The HOMO− LUMO energy levels of compound 1 are obtained from the CV and diffuse reflectivity spectral data (Figure S15). Its energy level diagram indicates the values are favorable for the generation of superoxide radicals (Figure S16). Photoexcited oxygen−tungsten charge transfer generates electron−hole separation. Electrons accumulates on the photocatalyst via hole oxidation of organic compounds. The delivery of electrons to the photoelectron trap reagent O2 results in OH· radicals with the interaction of water, which are used for the following oxidation reaction. As the behavior of photogenerated charge carriers is important for the photodegradation process, PEC (photoelectrochemical) behavior was performed to investigate the photoelectric interactions in 1 (Figure 5).32 The photocurrent response is recorded under visible or NIR light irradiation with ON-OFF switches of 60 s. For control experiments, the blank sample is obtained from FTO glass only. The electrodes indicate the photocurrent responses as high as 0.3 μA·cm−2 and 0.1 μA·cm−2 under visible and NIR light irradiation, respectively. The different

optical densities for visible light and NIR light of used xenon lamp light source account for the difference in current density.33 These results confirm that electron−hole pairs in 1 can be excited by both visible and NIR light irradiation. The process is the first and most essential step of a photocatalytic reaction. Therefore, it is evidence that 1 has visible and NIR light photocatalytic activity. As known, only UV light responsive character of POMs restricts their application in photocatalysis for the catalysts can usually utilize only less than 5% of the solar light.34 Embedding POMs into MOFs is one of the most promising strategies to enlarge the range of solar absorption. Control experiments are carried out to investigate the factors (MOF metal Cu(II), ligand and POM) that affect the photocatalytic performance of 1 (see Figures S9 and S10). At the same reaction condition, [HCPBPY]3[PW12O40]2 (without Cu(II) ion), Cu2Cl(trz)8[PW12O40] (different Nheterocyclic ligand),28 and H2 K 2[Cu(CPBPY)(H 2O) 3 ][P2W18O62]·8H2O (different POM) give conversion of 24.1% in 45 min, 56.7% in 60 min, and 96.9% in 40 min, respectively (Figures S12 and S13). These results indicate the POM [PW12O40]3− embedded in the cavity of copper-viologen framework enlarges light absorption range and increases photocatalytic efficiency of the catalyst. Viologen is an electron deficient molecule and it is well-known as light sensitizing components having been widely utilized in solar energy conversion.35,36 Multi-interactions between the guest cluster and the host frame not only help for stabilizing the included active catalytic component but also enhance the electron−hole separation of it, showing an interesting synergistic catalytic structural mode (Figure S2). The absorption of 1 in UV−vis− NIR range is strengthened and widened via overlapping bands of O−W, ligand field d−d transitions of copper complex37,38 and the transitions of the host framework, which helps for the enhancement of solar energy utilization and photocatalytic activity. In addition, compound 1 also shows highly efficient catalytic ability in their photodegration reactions for other organic dyes methyl orange and rhodamine B (Figures S17− S20). In conclusion, an UV, visible, and NIR photocatalyst is constructed based on a full spectrum activated PW12O40/ copper-viologen organic−inorganic hybrid system, showing high efficient photocatalytic degradation of MB. Because of the absorption broaden from UV to NIR regions and interactions with electron deficient components, efficient electron−hole 35673

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(6) Sartorel, A.; Carraro, M.; Bagno, A.; Scorrano, G.; Bonchio, M. Asymmetric Tetraprotonation of γ-[(SiO4)W10O32]8‑ Triggers a Catalytic Epoxidation Reaction: Perspectives in the Assignment of the Active Catalyst. Angew. Chem., Int. Ed. 2007, 46, 3255−3258. (7) Green, M.; Harries, J.; Wakefield, G.; Taylor, R. The Synthesis of Silica Nanospheres Doped with Polyoxometalates. J. Am. Chem. Soc. 2005, 127, 12812−12813. (8) Zhu, K. K.; Hu, J. Z.; She, X. Y.; Liu, J.; Nie, Z. M.; Wang, Y.; Peden, C. H. F.; Kwak, J. H. Characterization of Dispersed Heteropoly Acid on Mesoporous Zeolite Using Solid-State 31P NMR Spin-Lattice Relaxation. J. Am. Chem. Soc. 2009, 131, 9715− 9721. (9) Ye, Y. X.; Guo, W. G.; Wang, L. H.; Li, Z. Y.; Song, Z. J.; Chen, J.; Zhang, Z. J.; Xiang, S. C.; Chen, B. L. Straightforward Loading of Imidazole Molecules into Metal-Organic Framework for High Proton Conduction. J. Am. Chem. Soc. 2017, 139, 15604−15607. (10) Yu, R. M.; Kuang, X. F.; Wu, X. Y.; Lu, C. Z.; Donahue, J. P. Stabilization and Immobilization of Polyoxometalates in Porous Coordination Polymers Through Host-Guest Interactions. Coord. Chem. Rev. 2009, 253, 2872−2890. (11) Qin, J. S.; Du, D. Y.; Guan, W.; Bo, X. J.; Li, Y. F.; Guo, L. P.; Su, Z. M.; Wang, Y. Y.; Lan, Y. Q.; Zhou, H. C. Ultrastable Polymolybdate-Based Metal-Organic Frameworks as Highly Active Electrocatalysts for Hydrogen Generation From Water. J. Am. Chem. Soc. 2015, 137, 7169−7177. (12) Moussawi, M. A.; Leclerc-Laronze, N.; Floquet, S.; Abramov, P. A.; Sokolov, M. N.; Cordier, S.; Ponchel, A.; Monflier, E.; Bricout, H.; Landy, D.; Haouas, M.; Marrot, J.; Cadot, E. Polyoxometalate, Cationic Cluster, and γ-Cyclodextrin: From Primary Interactions to Supramolecular Hybrid Materials. J. Am. Chem. Soc. 2017, 139, 12793−12803. (13) Parrot, A.; Bernard, A.; Jacquart, A.; Serapian, S. A.; Bo, C.; Derat, E.; Oms, O.; Dolbecq, A.; Proust, A.; Metivier, R.; Mialane, P.; Izzet, G. Photochromism and Dual-Color Fluorescence in a Polyoxometalate-Benzospiropyran Molecular Switch. Angew. Chem., Int. Ed. 2017, 56, 4872−4876. (14) Llewellyn, B. A.; Davies, E. S.; Pfeiffer, C. R.; Cooper, M.; Lewis, W.; Champness, N. R. Thionated Perylene Diimides with Intense Absorbance in the Near-IR. Chem. Commun. 2016, 52, 2099− 2102. (15) Han, C.; Quan, Q.; Chen, H. M.; Sun, Y. G.; Xu, Y. J. Progressive Design of Plasmonic Metal-Semiconductor Ensemble toward Regulated Charge Flow and Improved Vis-NIR-Driven Solarto-Chemical Conversion. Small 2017, 13, 1602947. (16) Lv, H. J.; Guo, W. W.; Wu, K. F.; Chen, Z. Y.; Bacsa, J.; Musaev, D. G.; Geletii, Y. V.; Lauinger, S. M.; Lian, T. Q.; Hill, C. L. A Noble-Metal-Free, Tetra-Nickel Polyoxotungstate Catalyst for Efficient Photocatalytic Hydrogen Evolution. J. Am. Chem. Soc. 2014, 136, 14015−14018. (17) Wu, W. M.; Wu, X. Y.; Zhang, L.; Xiong, J. H.; Wu, L.; Lu, C. Z. A Nickel Phosphotungstate Catalyst for Efficient Visible-LightDriven H2 Evolution From Water Splitting in a Noble-Metal-Free System. Int. J. Hydrogen Energy 2016, 41, 139−144. (18) Hiskia, A.; Mylonas, A.; Papaconstantinou, E. Comparison of the Photoredox Properties of Polyoxometallates and Semiconducting Particles. Chem. Soc. Rev. 2001, 30, 62−69. (19) Toma, O.; Allain, M.; Meinardi, F.; Forni, A.; Botta, C.; Mercier, N. Bismuth-Based Coordination Polymers with Efficient Aggregation-Induced Phosphorescence and Reversible Mechanochromic Luminescence. Angew. Chem., Int. Ed. 2016, 55, 7998−8002. (20) Gong, T.; Yang, X.; Fang, J. J.; Sui, Q.; Xi, F. G.; Gao, E. Q. Distinct Chromic and Magnetic Properties of Metal-Organic Frameworks with a Redox Ligand. ACS Appl. Mater. Interfaces 2017, 9, 5503−5512. (21) Zhang, H.; Wu, X. T. Calix-Like Metal-Organic Complex for High-Sensitivity X-Ray-Induced Photochromism. Adv. Sci. 2016, 3, 1500224−1500228. (22) Wang, L. H.; Ye, Y. X.; Li, Z. Y.; Lin, Q. J.; Ouyang, J.; Liu, L. Z.; Zhang, Z. J.; Xiang, S. C. Highly Selective Adsorption of C2/C1

pairs generation are demonstrated by PEC analysis, which helps for the enhancement of photocatalytic activity in visible and NIR range. These outstanding characters display the advantages of doping polyphosphotungstate clusters into electron deficient metal−organic frameworks, which open a promising way to search for more full-spectrum POM catalysts, especially those possess NIR-activated catalytic behavior.

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ASSOCIATED CONTENT

* Supporting Information S

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsami.8b10777. Details about synthesis and general characterizations, crystal data, additional graphics, PXRD and TG data, and UV and IR spectra (PDF) Crystallographic data for compound 1 (CIF)

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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Fax: +86-20-8711-2965. ORCID

Zhiyong Fu: 0000-0003-1292-8052 Notes

The authors declare no competing financial interest. CCDC 1565359 contains the supplementary crystallographic data for compound 1 in this paper. This data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12, Union Road, Cambridge CB2 1EZ, UK; fax: + 44 1223 336033.

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ACKNOWLEDGMENTS The authors thank the program for the NSFC (21573076, 21703070), NSF (Guangdong, 2015A030312007), FRFCU (2017BQ064), Science and Technology Program of Guangzhou (201804010131, 201804010176), and the SRP Program for financial support.

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DEDICATION This work is dedicated to Professor Xin-Tao Wu on the occasion of his 80th birthday REFERENCES

(1) Wang, C. C.; Li, J. R.; Lv, X. L.; Zhang, Y. Q.; Guo, G. S. Photocatalytic Organic Pollutants Degradation in Metal-Organic Frameworks. Energy Environ. Sci. 2014, 7, 2831−2867. (2) Das, M. C.; Xu, H.; Wang, Z. Y.; Srinivas, G.; Zhou, W.; Yue, Y. F.; Nesterov, V. N.; Qian, G. D.; Chen, B. L. A Zn4O-Containing Doubly Interpenetrated Porous Metal-Organic Framework for Photocatalytic Decomposition of Methyl Orange. Chem. Commun. 2011, 47, 11715−11717. (3) Dui, X. J.; Yang, W. B.; Wu, X. Y.; Kuang, X.; Liao, J. Z.; Yu, R. M.; Lu, C. Z. Two Novel POM-Based Inorganic-Organic Hybrid Compounds: Synthesis, Structures, Magnetic Properties, Photodegradation and Selective Absorption of Organic Dyes. Dalton. Trans. 2015, 44, 9496−9505. (4) Wang, S. S.; Yang, G. Y. Recent Advances in PolyoxometalateCatalyzed Reactions. Chem. Rev. 2015, 115, 4893−4962. (5) Huang, L.; Wang, S. S.; Zhao, J. W.; Cheng, L.; Yang, G. Y. Synergistic Combination of Multi-Zr(IV) Cations and Lacunary Keggin Germanotungstates Leading to a Gigantic Zr24-ClusterSubstituted Polyoxometalate. J. Am. Chem. Soc. 2014, 136, 7637− 7642. 35674

DOI: 10.1021/acsami.8b10777 ACS Appl. Mater. Interfaces 2018, 10, 35671−35675

Letter

ACS Applied Materials & Interfaces Mixtures and Solvent Dependent Thermochromic Properties in Metal−Organic Frameworks Containing Infinite Copper-Halogen Chains. Cryst. Growth Des. 2017, 17, 2081−2089. (23) Zhang, Z. J.; Xiang, S. C.; Guo, G. C.; Xu, G.; Wang, M. S.; Zou, J. P.; Guo, S. P.; Huang, J. S. Wavelength-Dependent Photochromic Inorganic−Organic Hybrid Based on a 3D Iodoplumbate Open-Framework Material. Angew. Chem., Int. Ed. 2008, 47, 4149−4152. (24) McCabe, W. C.; Subramanian, S.; Fisher, H. F. A Near-Infrared Spectroscopic Investigation of the Effect of Temperature on the Structure of Water. J. Phys. Chem. 1970, 74, 4360−4369. (25) Takeuchi, T.; Tsuge, S.; Sugimura, Y. Near-Infrared Spectrophotometric Analysis of Styrene-Acrylonitrile Copolymer. J. Polym. Sci., Part A-1: Polym. Chem. 1968, 6, 3415−3417. (26) Hunt, G. R.; Salisbury, J. W. Visible and Near-Infrared Spectra of Minerals and Rocks: I Silicate Minerals. Mod. Geol. 1970, 1, 283− 300. (27) Hunt, G. R.; Salisbury, J. W.; Lenhoff, C. Visible and NearInfrared Specta of Minerals and Rocks: III. Oxides and Hydroxides. Mod. Geol. 1971, 2, 195−205. (28) Lu, X. X.; Luo, Y. H.; Liu, Y. S.; Ma, W. W.; Xu, Y.; Zhang, H. Assembly of Three Stable POM-Based Pillar-Layer CuI Coordination Polymers with Visible Light Driven Photocatalytic Properties. CrystEngComm 2016, 18, 3650−3654. (29) Liu, B.; Yu, Z. T.; Yang, J.; Hua, W.; Liu, Y. Y.; Ma, J. F. First Three-Dimensional Inorganic-Organic Hybrid Material Constructed From an “Inverted Keggin” Polyoxometalate and a Copper(I)Organic Complex. Inorg. Chem. 2011, 50, 8967−8972. (30) Xu, L.-J.; Zhou, W.-Z.; Zhang, L.-Y.; Li, B.; Zang, H.-Y.; Wang, Y.-H.; Li, Y.-G. Organic-Inorganic Hybrid Assemblies Based on Ti Substituted Polyoxometalates for Photocatalytic Dye Degradation. CrystEngComm 2015, 17, 3708−3714. (31) Cao, M. N.; Lin, J. X.; Lü, J.; You, Y. L. J.; Liu, T. F.; Cao, R. Development of a Polyoxometallate-Based Photocatalyst Assembled with Cucurbit[6]uril via Hydrogen Bonds for Azo Dyes Degradation. J. Hazard. Mater. 2011, 186, 948−951. (32) Sun, C.; Xu, G.; Jiang, X. M.; Wang, G. E.; Guo, P. Y.; Wang, M. S.; Guo, G. C. Design Strategy for Improving Optical and Electrical Properties and Stability of Lead-Halide Semiconductors. J. Am. Chem. Soc. 2018, 140, 2805−2811. (33) Jiang, W. Y.; Bai, S.; Wang, L. M.; Wang, X. J.; Yang, L.; Li, Y. R.; Liu, D.; Wang, X. N.; Li, Z. Q.; Jiang, J.; Xiong, Y. J. Integration of Multiple Plasmonic and Co-Catalyst Nanostructures on TiO2 Nanosheets for Visible-Near-Infrared Photocatalytic Hydrogen Evolution. Small 2016, 12, 1640−1648. (34) Wang, G.; Huang, B. B.; Ma, X. C.; Wang, Z. Y.; Qin, X. Y.; Zhang, X. Y.; Dai, Y.; Whangbo, M. H. Cu2(OH)PO4, a NearInfrared-Activated Photocatalyst. Angew. Chem., Int. Ed. 2013, 52, 4810−4813. (35) Fu, Z.; Liao, S. J.; Dai, J. C.; et al. Copper Based Metal-Organic Molecular Ring with Inserted Keggin-Type Polyoxometalate: a Stable Photofunctional Host-Guest Molecular System. Chem. Commun. 2012, 48, 6154−6156. (36) Toma, O.; Mercier, N.; Allain, M.; Kassiba, A. A.; Bellat, J. P.; Weber, G.; Bezverkhyy, I. Photo- and Thermochromic and Adsorption Properties of Porous Coordination Polymers Based on Bipyridinium Carboxylate Ligands. Inorg. Chem. 2015, 54, 8923− 8930. (37) Huai, W. J.; Shen, J. N.; Lin, H.; Chen, L.; Wu, L. M. ElectronDeficient Telluride Cs3Cu20Te13 with Sodalite-Type Network: Syntheses, Structures, and Physical Properties. Inorg. Chem. 2014, 53, 5575−5580. (38) Lin, H.; Chen, H.; Zheng, Y. J.; Chen, Y. K.; Yu, J. S.; Wu, L. M. Ba5Cu8In2S12: a Quaternary Semiconductor with a Unique 3D Copper-Rich Framework and Ultralow Thermal Conductivity. Chem. Commun. 2017, 53, 2590−2593.

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DOI: 10.1021/acsami.8b10777 ACS Appl. Mater. Interfaces 2018, 10, 35671−35675