高效太阳光驱动的CuM2O4-TiO2异质结型纳米光催化剂的构筑及其制氢性能

The increasingly serious energy crisis and the environmental contamination have stimulated intense research on solar energy utilization. Hydrogen energy has been recognized as a potentially significant alternative form of storable and clean energy for the future. Therefore, the development of a novel solar photocatalytic hydrogen production system has important scientific significance. Based on the thermodynamic principle, a novel solar photocatalytic hydrogen production system with different p-n type heterojunction complex catalysts was obtained by using an appropriate band gap energy p-type semiconductor coupled with n-type TiO2 semiconductor containing strong photocatalytic oxidation-reduction capability. Then, a series of high efficient photocatalytic hydrogen production materials with different p-n type heterojunctions are fabricated by doping, metal deposition and oxide coated modified as-prepared complex catalysts. These materials have an enhanced absorbance in the visible-light region and high light quantum efficiency. First, the mechanism of nano-heterojunction built-in electric field to inhibit light-induced charge recombination is explored. The objective of the study is to explore the basic dynamics principle to improve the efficiency of photocatalytic hydrogen production; Second, the intrinsic relationship between photocatalyst structure, composition and the activity of hydrogen production, and the band structure matching relation of the as-prepared heterojunction semiconductor materials are discussed. The objective of the study is to provide a theoretical basis for thermodynamics to solve the possibility of photocatalytic hydrogen production. Last, the internal and external factors on photocatalytic hydrogen production performance are also explored. The objective of the study is to provide many effective experimental data and reference theory to improve the efficiency of photocatalytic hydrogen production for spinel complex photocatalysts.

开发新型高效太阳光催化体系，实现氢能的廉价开发和便捷利用，解决人类日益严峻的燃烧污染和能源紧缺问题，具有重要的科学价值和深远的现实意义。本项目基于热力学原理，优选带隙能适合的p型半导体与较强光催化氧化还原能力，且与光催化产氢有相匹配的能带结构的n-型半导体TiO2复合，构筑光响应范围宽，光量子效率高的p-n型纳米异质结复合太阳光催化产氢新体系。并对复合体进行掺杂、金属沉积和氧化物包覆等修饰，获得多种带隙的半导体相耦合，不同异质结协同作用的高效光催化产氢材料。研究纳米异质结内建电场抑制光致电荷复合机理，为动力学上提高光催化产氢效率探索基本规律；研究异质结半导体材料的能带结构匹配性，探索光催化剂的结构、组成与产氢活性的内在关系，为热力学上解决光催化产氢的可能性提供理论依据。研究各种内在、外部因素对光催化产氢性能的影响，为全面提高晶尖石类复合光催化剂产氢效率提供有效的实验数据和理论参考。

环境污染和能源危机成为人类必须面临的两个严峻挑战。半导体氧化物由于在环境污染深度处理及太阳能转换领域具有潜在的应用价值，其相关研究倍受关注。由于现有光催化剂光响应范围窄，载流子复合率高，开发一类高效复合氧化物半导体材料成为光催化领域的研究热点。本项目探讨了AO与AB2O4半导体间异质结形成基本原理，为AO/AB2O4系列光催化剂高效分解水产氢提供理论依据。项目采用共沉淀法制备了ZnO/ZnAl2O4复合光催化剂；通过分散剂和模板剂，一步水热法制备了粒径和形貌可控的“球中球”结构ZnO/ZnAl2O4；并修饰获得了ZnO/CuO/ZnAl2O4三元复合氧化物空心球。项目用水热法制得了蓬松、多孔结构的CuO/CuAl2O4复合光催化剂；用贵金属沉积和金属硫化物负载对其进行了修饰，Pt和CuS的修饰能表现出良好协同效应，提高了光生电荷的分离和光催化产氢活性；用水热模板法合成Zn-CuO/CuAl2O4空心球，Zn掺杂有助于提高样品的光吸收能力，拓展可见光响应范围。项目通过液相法制备了二元（Zn/Cr、Zn/Ga）、三元（Zn/Cu/Al、Zn/Ni/Al）类水滑石，金属离子比和焙烧温度对复合氧化物的结构、形貌和异质结形成有较大影响。项目通过阳极氧化法制备了TiO2纳米管，研究了氧化电压、氧化时间及纳米管焙烧温度等对纳米管光电转换性能影响。采用阴极电沉积-电化学氧化技术，将金属氧化物沉积于纳米管内、外，测试了各样品的光电催化产氢性能，表明纳米管的高比表面积和强电子转移能力很好提高复合光催化剂的产氢效率。通过水热法制备了复合金属硫化物，（改性）石墨烯负载修饰能有效提高其光电催化产氢性能。对所获得复合氧化物样品从结构、组成、形貌、表面性质和光电性能进行了表征分析。通过电化学工作站和产氢实验装置评价了样品的光电转换性能及产氢效率。并探讨了制备、反应条件和异质结形成对光催化性能的影响。本项目揭示了尖晶石异质结间过渡带隙形成过程及光生电荷分离内在规律；发展了分级组装高比表面复合空心球(多孔)结构光催化剂合成方法；完善了复合光催化剂的多种制备、修饰的基本方法；通过类水滑石前驱体法获得一类组成可控、高度分散、结构特殊，吸附性强且活性极高的光催化材料。