多酸分子催化剂与半导体捕光材料耦合促进的光催化水氧化的研究

光催化全分解水的瓶颈是水的氧化半反应，构建稳定高效的水氧化催化体系是实现全分解水的有效途径。为了解决均相体系中捕光材料不稳定以及多相体系中半导体表面催化反应效率低的缺点，本项目结合本课题组多酸水氧化催化剂和半导体捕光材料两个方向上的研究基础，拟采用稳定的BiVO4、g-C3N4和介孔黑TiO2为捕光材料，高效的多酸化合物为催化剂，通过两者间的物理吸附、化学成键以及引入石墨烯作为载流子传导介质来构建新型光催化水氧化体系。首先测试光催化产氧反应动力学速率，然后采用表面光电压谱、扫描开尔文探针显微镜和时间分辨的瞬态吸收谱等技术来研究上述三种水氧化耦合体系。结合动力学以及谱学表征的结果，澄清光生载流子从激发态的半导体向多酸分子催化剂迁移的规律，从而获得最佳的水氧化反应耦合方式。通过本项目的实施，以期建立新型、高效、稳定的光催化水氧化体系，为发展全分解水体系提供新思路和新途径。

Water oxidation reaction is usually regarded as the bottleneck of overall solar water splitting. To achieve overall solar water splitting, stable and efficient water oxidation system is necessary. Photosensitizers in the homogeneous water oxidation system are not stable while semiconductors in heterogeneous one suffer the weakness of slow kinetic for the surface catalytic reaction. In order to resolve these problems, we want to design a new efficient photocatalytic water oxidation system coupled with stable BiVO4，g-C3N4 and ordered mesoporous black TiO2 as the light-harvesting reagents and polyoxometalates as the molecular catalysts，which is based on our previous photocatalytic water oxidation research using polyoxometalates and semiconductor. The light-harvesting reagents and catalysts are designed to couple together by physical adsorption, chemical binding and using graphene as the carrier conducting medium. Kinetics of O2 formation using the above photocatalytic systems are studied firstly, and then the photocatalytic systems are characterized by surface photovoltage spectrum apparatus, Kelvin probe force microscopy and time-resolved transient absorption measurement. Based on the results, the transfer rule of photo-induced carriers from semiconductors to polyoxometalates and the best couple method between light-harvesting reagents and polyoxometalate catalysts are expected to be gained. The new, robust and efficient water oxidation system will provide new concept and route for the future realizable solar water splitting.