磷酸钴修饰Cu_(3)V_(2)O_(8)/ZnO光阳极的动力学特性及光电化学水分解研究

Investigation of the Kinetic Properties and Photoelectrochemical Water Splitting of Cu_(3)V_(2)O_(8)/ZnO Photoanode Modified by Cobalt Phosphate

钒酸铜是一种新兴的应用前景广阔的光阳极材料.本工作首先制备了不同厚度的Cu_(3)V_(2)O_(8)光电极,通过强度调制光电流谱、电化学阻抗谱等手段深入探究了影响Cu_(3)V_(2)O_(8)光电性能的关键因素在于光生载流子扩散距离短造成的载流子体相复合严重以及缓慢的氧化动力学造成的表面复合严重.为解决该问题,本工作提出了将一维ZnO纳米棒阵列作为支撑骨架以及负载CoPi助催化剂的策略.一维ZnO纳米棒阵列可作为电子快速传输通道促进光生载流子的体相分离,CoPi助催化剂可提高光生载流子表面分离效率提升氧化动力学.

Copper vanadate(Cu_(3)V_(2)O_8) has emerged as a promising material for photoelectrochemical applications due to its unique electronic and optical properties.In this study,the preparation of Cu_(3)V_(2)O_(8) photoelectrodes with different thicknesses was reported and the factors that affect their photoelectrochemical performance were investigated.It is found that the primary limitation of Cu_(3)V_(2)O_(8) as a photoanode material is the short diffusion distance of the photo-generated charge carriers,which leads to severe bulk recombination and limits the photocurrent density and efficiency.To overcome this limitation,a novel strategy of using one-dimensional ZnO nanorod arrays as a support framework and loading CoPi cocatalyst to enhance the photoelectrochemical performance of Cu_(3)V_(2)O_(8) was proposed.The ZnO nanorod arrays serve as a rapid electron transfer channel to promote the bulk separation of photo-generated charge carriers,while the Co Pi cocatalyst improves the surface separation efficiency of photo-generated charge carriers and enhances the oxidation kinetics.The incorporation of ZnO nanorod arrays and CoPi cocatalyst significantly enhances the photocurrent density and efficiency of Cu_(3)V_(2)O_(8) photoelectrodes,resulting in a more than 2-fold increase in the photocurrent density and a 50% increase in the photoconversion efficiency.To further understand the underlying mechanisms behind the improved photoelectrochemical performance,a comprehensive analysis of the intensity-modulated photocurrent spectroscopy and electrochemical impedance spectroscopy data was performed.The results show that the incorporation of ZnO nanorod arrays and CoPi cocatalyst leads to a significant reduction in the charge transfer resistance and a decrease in the recombination rate of photo-generated charge carriers,which are responsible for the improved photocurrent density and efficiency.Overall,the study demonstrates the potential of using ZnO nanorod arrays and CoPi cocatalyst as a novel strategy to enhance the photoelectrochemical performance of Cu_(3)V_(2)O_(8) photoelectrodes.The proposed approach provides a new direction for the development of high-performance photoanode materials for solar energy conversion and other photoelectrochemical applications.