基于聚光“光-热耦合”的光电催化分解水制氢体系构建与机制研究

光电催化分解水制氢是一种利用太阳能制取清洁燃料极具前景的技术，但目前低成本光电极、尤其是氧化物光阳极的研究进入了“瓶颈期”。以往光解水反应大多是在一个太阳光强、常温下进行，面临空间大、成本较高、光电转换效率和催化效率较低的限制。聚光会显著改变光电催化体系中光场、温度场等多物理场的分布，有望在光电极上形成高活性的“反应热点”。因此，本项目提出通过聚光产生的光-热效应协同提高光电催化分解水性能，首先单独研究光强（光效应）或温度（热效应）对不同光电极性能的影响机制，进而采用光热材料修饰光电极，探索聚光下光解水的“光-热耦合”作用机制。通过实验研究与理论建模相结合的方法认清聚光下多物理场分布特性，阐明光电极中光效应和热效应的匹配原则。通过光电极形貌、成分、微结构的设计耦合电解液工程，在聚光条件下利用光效应和热效应同时强化光吸收、载流子传输、界面反应、溶液传质，最终实现高效光电催化分解水体系的构建。

Photoelectrocatalytic water splitting is a promising technology for converting solar energy into clean chemical fuels. However, the development of low-cost photoelectrodes, especially oxide photoanodes, has currently encountered a "bottleneck". In the past, photoelectrocatalytic water splitting was generally carried out at room temperature under one-sun irradiation. Its application is restricted by the large space, relatively high cost, as well as low photoelectric and catalytic efficiencies. The concentrated light can change the multi-physics field (such as optical and thermal fields) in the photoelectrocatalytic system, which can lead to the generation of “hot spots” with high activities. Therefore, it is proposed that the photic and thermal coupling effects generated by concentrated light can be utilized to improve the performance of photoelectrocatalytic water splitting. In this project, the effects of light intensity (photic effect) and temperature (thermal effect) on the different photoelectrodes are first studied, respectively. Then the photoelectrodes modified by the photothermal materials are used to explore the coupling mechanism of photic and thermal effects during photoelectrocatalytic water splitting for hydrogen production under concentrated light irradiation. Through the combination of experimental and computational tools, the distribution characteristics of the multi-physics field under concentrated light can be recognized. In addition, the matching principle of the photic and thermal effects in the photoelectrode can be clarified. By designing the morphology, composition, and microstructure of the photoelectrode, together with the electrolyte engineering, the coupled photic and thermal effects can be used to simultaneously promote light absorption, carrier transport, interface reaction, and solution mass transfer, and eventually to construct highly efficient photoelectrocatalytic system for water splitting.