具有可见光响应的高效液膜旋转光催化燃料电池的设计制备及性能研究

Photocatalytic fuel cell (PFC), which exploits sunlight as energy source, could realize efficient pollutants degradation by utilizing the semiconductor excitation and obtain electric energy by deriving the electrons originated from the catalytic process, solving the environmental problems and energy crisis. Herein, we propose to design and fabricate a high-efficient aqueous-film rotating PFC based on BiVO4/TiO2 NT photoanode and Cu2O/TiO2 NT photocathode. This PFC would use BiVO4 and Cu2O as the main photocatalysts, extending the photoresponsive region of electrodes to visible light region and thus improving the light utilization. The heterojunction between BiVO4/TiO2 and Cu2O/TiO2 can improve the quantum yield of catalyst and the consequential pollutant degradation efficiency. The three-dimensional array structure of TiO2 nanotubes could contribute to the directional transmission of electrons and the increase of catalytic sites. During the photocatalytic process, the disc type electrodes will keep rotating and therefore the thin aqueous film on the upper part would be continuously refreshed. Compared with bulk reaction, the photon propagation distance in aqueous film will be greatly shortened, and the possibility of light absorption by solution would be correspondingly reduced. The continuous update of pollutants on electrode could also be beneficial to catalytic reaction. This project will lay a foundation for the preparation of high efficient and low cost PFC, which is of great significance to the current environmental pollution and energy shortage.

光催化燃料电池以太阳光为能源，利用半导体激发降解污染物，同时将催化过程产生的电子导出获得电能。该技术在解决环境污染问题的同时，可有效应对能源危机。本项目拟制备基于BiVO4/TiO2 NT光阳极和Cu2O/TiO2 NT光阴极的高效液膜旋转光催化燃料电池。该电池采用BiVO4和Cu2O作为光阳极和光阴极的主要催化材料，将电极的光响应区域拓展到可见光区，提高光能利用率；利用TiO2与BiVO4和Cu2O间的异质结提高催化剂的量子产率，TiO2 NT的三维阵列结构也有利于电子的定向传递和催化点位的增加。通过催化过程中圆盘式光电极的不断旋转，可在其上半部形成不断更新的液膜。与体相反应相比，光子穿过液膜到达电极表面的路程大大缩短，被溶液吸收的可能性降低，电极表面的不断更新也有利于催化反应的进行。本项目为新型高效、价格低廉的光催化燃料电池设备的制备奠定基础，这对于应对环境污染和能源紧缺问题意义重大。

光催化燃料电池利用太阳光激发半导体降解污染物，还可将催化过程产生的电子导出获得电能，解决环境污染问题的同时有效应对能源危机。本项目制备了基于BiVO4/TiO2 NT光阳极和Cu2O/TiO2 NT光阴极的高效光催化燃料电池：采用BiVO4和Cu2O作为光阳极和光阴极的主要材料，将电极的光响应区域拓展到可见光区，提高光能利用率，利用BiVO4/TiO2和Cu2O/TiO2间的异质结提高催化剂的量子产率。TiO2 NT的三维阵列结构也有利于电子的定向传递和催化点位的增加。BiVO4/TiO2 NT-Cu2O/TiO2 NT PFC降解对氯苯酚的动力学常数是BiVO4/TiO2 NT-Pt PFC和Pt-Cu2O/TiO2 NT-PFC的1.21和2.26倍，降解诺氟沙星的动力学常数是上述单电极PFC的1.72和1.40倍，降解盐酸四环素（TCH）的动力学常数是单电极PFC的1.04和2.57倍；其最大输出功率（Pmax）分别为BiVO4/TiO2 NT-PFC的1.23、1.49和1.68倍，为Cu2O/TiO2 NT-PFC的3.56、5.57和6.66倍。此外，设计开发了g-C3N4/WO3-Cu2O双极室光催化燃料电池，利用窄带半导体g-C3N4和WO3的激发提高电极的光捕获效率，g-C3N4和WO3间Z-scheme在抑制光生载流子复合的前提下，最大程度地保留g-C3N4和WO3的强还原和氧化能力。将此光阳极与Cu2O光阴极匹配，利用两电极间的电势差实现高效电子导出获得电能（Pmax为g-C3N4/WO3-Pt PFC的2.2倍），同时在阳极室和阴极室进行快速的氧化（去除TCH）和还原（降解Cr(VI)）反应。本项目为新型高效、价格低廉的光催化燃料电池设备的制备奠定基础，这对于应对环境污染和能源紧缺问题意义重大。