Abstract
Constructing Z-scheme type photocatalyst is an efficient way to improve the charge separation efficiency and enhance the photocatalytic activity. In this report, the Cd:TiO2 nanoparticles are prepared via the sol-gel route and employed as a starting material. When it was reduced by NaBH4 at 300°C, the surface oxygen vacancies were produced and Cd2+ was reduced into metal Cd0 nanoparticle (denoted as R-Cd:TiO2). Subsequently, the formed R-Cd:TiO2 was treated with thioureain the hydrothermal reaction. Through the decomposition of thiourea, the oxygen vacancies were refilled by S2− from thiourea to form S:TiO2/TiO2 (d-TiO2) and Cd was partially converted into CdS to form CdS/Cd/d-TiO2 composite. The formed CdS/Cd/d-TiO2 composite exhibits improved photocatalytic activity. Under visible light irradiation (λ>400 nm), the H2 production rate of CdS/Cd/d-TiO2 reaches 119 μmol h−1 with 50 mg of photocatalyst without any cocatalyst, which is about 200 and 60 times higher than that of S:TiO2/TiO2 (0.57 μmol h−1), CdS (2.03 μmol h−1) and heterojunction CdS/d-TiO2 (2.17 μmol h-1) materials, respectively. The results illustrate that metal Cd greatly promotes the charge separation efficiency due to the formation of Z-scheme type composite. In addition, the photocatalytic activity in the visible light region was dramatically enhanced due to the contribution of both CdS and d-TiO2. The method could be easily extended to other wide bandgap semiconductors for constructing visible light responsive Z-scheme type photocatalysts.
摘要
构建Z型光催化体系是提高光生电荷分离效率和光催化活性的一种有效途径. 本文通过溶胶凝胶方法制备了Cd掺杂的TiO2纳米颗粒, 并通过一步NaBH4固相热还原的方式在材料表面可控地引入氧空位(VO), 同时掺入的Cd2+可被还原为金属Cd0纳米粒子(即R-Cd:Ti〇2). 进一步将获得的R-Cd:TiO2材料与硫脲热水反应, 材料表面VO的可被S2−替代同时部分金属Cd0硫化, 从而获得CdS/Cd/d-TiO2 Z型光催化复合材料. 研究结果表明该Z型光催化复合材料具有优异的模拟太阳光及可见光区光催化活性和稳定性. 通过实验分析证明掏建这种全固态金属-无机半导体Z型光催化复合材料, 金属介质层显著促进了光生电荷的分离与迁移; 此外, 由于CdS和d-TiO2在可见光区的光吸收作用, 该CdS/Cd/d-TiO2 Z型光催化复合材料在可见光区的光催化活性获得了显著增强.
Article PDF
Similar content being viewed by others
References
Osterloh FE. Inorganic nanostructures for photoelectrochemical and photocatalytic water splitting. Chem Soc Rev, 2013, 42: 2294–2320
Ran J, Zhang J, Yu J, et al. Earth-abundant cocatalysts for semiconductor- based photocatalytic water splitting. Chem Soc Rev, 2014, 43: 7787–7812
Navarro Yerga RM, Alvarez Galván MC, del Valle F, et al. Water splitting on semiconductor catalysts under visible-light irradiation. ChemSusChem, 2009, 2: 471–485
Maeda K, Domen K. Photocatalytic water splitting: recent progress and future challenges. J Phys Chem Lett, 2010, 1: 2655–2661
Ma XC, Dai Y, Yu L, et al. Energy transfer in plasmonic photocatalytic composites. Light Sci Appl, 2016, 5: e16017
Shi R, Cao Y, Bao Y, et al. Self-assembled Au/CdSe nanocrystal clusters for plasmon-mediated photocatalytic hydrogen evolution. Adv Mater, 2017, 29: 1700803
Rao PM, Cai L, Liu C, et al. Simultaneously efficient light absorption and charge separation in WO3/BiVO4 core/shell nanowire photoanode for photoelectrochemical water oxidation. Nano Lett, 2014, 14: 1099–1105
Wang H, Zhang L, Chen Z, et al. Semiconductor heterojunction photocatalysts: design, construction, and photocatalytic performances. Chem Soc Rev, 2014, 43: 5234–5244
Moniz SJA, Shevlin SA, Martin DJ, et al. Visible-light driven heterojunction photocatalysts for water splitting—a critical review. Energ Environ Sci, 2015, 8: 731–759
Zhang J, Zhang M, Sun RQ, et al. A facile band alignment of polymeric carbon nitride semiconductors to construct isotype heterojunctions. Angew Chem, 2012, 124: 10292–10296
Chen S, Qi Y, Hisatomi T, et al. Efficient visible-light-driven Zscheme overall water splitting using a MgTa2O6-xNy/TaON heterostructure photocatalyst for H2 evolution. Angew Chem, 2015, 127: 8618–8621
Maeda K. Z-scheme water splitting using two different semiconductor photocatalysts. ACS Catal, 2013, 3: 1486–1503
Zhou P, Yu J, Jaroniec M. All-solid-state Z-scheme photocatalytic systems. Adv Mater, 2014, 26: 4920–4935
Li H, Tu W, Zhou Y, et al. Z-scheme photocatalytic systems for promoting photocatalytic performance: recent progress and future challenges. Adv Sci, 2016, 3: 1500389
Wang X, Liu G, Wang L, et al. ZnO-CdS@Cd heterostructure for effective photocatalytic hydrogen generation. Adv Energ Mater, 2012, 2: 42–46
Tada H, Mitsui T, Kiyonaga T, et al. All-solid-state Z-scheme in CdS–Au–TiO2 three-component nanojunction system. Nat Mater, 2006, 5: 782–786
Jin J, Yu J, Guo D, et al. A hierarchical Z-scheme CdS-WO3 photocatalyst with enhanced CO2 reduction activity. Small, 2015, 11: 5262–5271
Yu ZB, Xie YP, Liu G, et al. Self-assembled CdS/Au/ZnO heterostructure induced by surface polar charges for efficient photocatalytic hydrogen evolution. J Mater Chem A, 2013, 1: 2773–2776
Ye L, Liu J, Gong C, et al. Two different roles of metallic Ag on Ag/AgX/BiOX (X = Cl, Br) visible light photocatalysts: surface plasmon resonance and Z-scheme bridge. ACS Catal, 2012, 2: 1677–1683
Zheng D, Pang C, Wang X. The function-led design of Z-scheme photocatalytic systems based on hollow carbon nitride semiconductors. Chem Commun, 2015, 51: 17467–17470
Wang JC, Zhang L, Fang WX, et al. Enhanced photoreduction CO2 activity over Direct Z-Scheme α-Fe2O3/Cu2O heterostructures under visible light irradiation. ACS Appl Mater Interfaces, 2015, 7: 8631–8639
Wang Q, Hisatomi T, Ma SSK, et al. Core/shell structured La- and Rh-codoped SrTiO3 as a hydrogen evolution photocatalyst in Zscheme overall water splitting under visible light irradiation. Chem Mater, 2014, 26: 4144–4150
Iwashina K, Iwase A, Ng YH, et al. Z-schematic water splitting into H2 and O2 using metal sulfide as a hydrogen-evolving photocatalyst and reduced graphene oxide as a solid-state electron mediator. J Am Chem Soc, 2015, 137: 604–607
Ma K, Yehezkeli O, Domaille DW, et al. Enhanced hydrogen production from DNA-assembled Z-scheme TiO2-CdS photocatalyst systems. Angew Chem Int Ed, 2015, 54: 11490–11494
Si H, Kang Z, Liao Q, et al. Design and tailoring of patterned ZnO nanostructures for energy conversion applications. Sci China Mater, 2017, 60: 793–810
Liu Z, Zhao ZG, Miyauchi M. Efficient visible light active CaFe2O4/WO3 based composite photocatalysts: effect of interfacial modification. J Phys Chem C, 2009, 113: 17132–17137
Chen X, Huang X, Yi Z. Enhanced ethylene photodegradation performance of g-C3N4-Ag3PO4 composites with direct Z-scheme configuration. Chem Eur J, 2014, 20: 17590–17596
Iwase A, Ng YH, Ishiguro Y, et al. Reduced graphene oxide as a solid-state electron mediator in Z-scheme photocatalytic water splitting under visible light. J Am Chem Soc, 2011, 133: 11054–11057
Li W, Feng C, Dai S, et al. Fabrication of sulfur-doped g-C3N4/Au/CdS Z-scheme photocatalyst to improve the photocatalytic performance under visible light. Appl Catal B-Environ, 2015, 168–169: 465–471
Xie K, Wu Q, Wang Y, et al. Electrochemical construction of Zscheme type CdS–Ag–TiO2 nanotube arrays with enhanced photocatalytic activity. Electrochem Commun, 2011, 13: 1469–1472
Li H, Yu H, Quan X, et al. Uncovering the key role of the Fermi level of the electron mediator in a Z-Scheme photocatalyst by detecting the charge transfer process of WO3-metal-gC3N4 (metal = Cu, Ag, Au). ACS Appl Mater Interfaces, 2016, 8: 2111–2119
Li P, Zhou Y, Li H, et al. All-solid-state Z-scheme system arrays of Fe2V4O13/RGO/CdS for visible light-driving photocatalytic CO2 reduction into renewable hydrocarbon fuel. Chem Commun, 2015, 51: 800–803
Jia Q, Iwase A, Kudo A. BiVO4–Ru/SrTiO3:Rh composite Zscheme photocatalyst for solar water splitting. Chem Sci, 2014, 5: 1513–1519
Ismail AA, Al-Sayari SA, Bahnemann DW. Photodeposition of precious metals onto mesoporous TiO2 nanocrystals with enhanced their photocatalytic activity for methanol oxidation. Catal Today, 2013, 209: 2–7
Fan J, Boettcher SW, Stucky GD. Nanoparticle assembly of ordered multicomponent mesostructured metal oxides via a versatile solgel process. Chem Mater, 2006, 18: 6391–6396
Tan H, Zhao Z, Niu M, et al. A facile and versatile method for preparation of colored TiO2 with enhanced solar-driven photocatalytic activity. Nanoscale, 2014, 6: 10216–10223
Chen X, Burda C. The electronic origin of the visible-light absorption properties of C-, N- and S-doped TiO2 nanomaterials. J Am Chem Soc, 2008, 130: 5018–5019
Acknowledgements
Sun Z thanks the financial support from the National Natural Science Foundation of China (21671011), Beijing High Talent Program, Beijing Natural Science Foundation (KZ201710005002). The authors thank China Postdoctoral Science Foundation, Beijing Postdoctoral Research Foundation, and Dongguan Program for International S&T Cooperation. Zhao Z thanks the support from China Scholarship Council. This research was also supported by the National Science Foundation (DMR-1506661, Feng P).
Author information
Authors and Affiliations
Corresponding authors
Additional information
Zhao Zhao received his PhD degree from Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun, China. He is currently a lecturer in the Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education, Jilin Normal University. His main research area includes photocatalyst based on inorganic semiconductors.
Zaicheng Sun is a professor of Beijing Key Lab for Green Catalysis and Separation, Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing. China. His research interests are mainly on the photocatalytic nano materials for water splitting, H2 production, and self-cleaning optical coating, fluorescent carbon dots for theragnostics.
Pingyun Feng is a professor of the Department of Chemistry, University of California, Riverside, CA, USA. She received her PhD degree from the Department of Chemistry, University of California, Santa Barbara. Her research interest centers on the development of synthetic methodologies to prepare novel materials for energy conversion and storage. These materials integrate uniform porosity, high surface area, semi conductivity, optical property, photocatalytic, acid- or base-catalytic properties and have a variety of applications.
Electronic supplementary material
Rights and permissions
About this article
Cite this article
Zhao, Z., Xing, Y., Li, H. et al. Constructing CdS/Cd/doped TiO2 Z-scheme type visible light photocatalyst for H2 production. Sci. China Mater. 61, 851–860 (2018). https://doi.org/10.1007/s40843-017-9170-6
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s40843-017-9170-6