BiVO4/CuBi2O4薄膜光电极的制备及光电性能

通过金属有机物分解法(MOD)协同光电化学沉积法, 将p型氧化物半导体CuBi₂O₄沉积在BiVO₄纳米薄膜上, 形成包覆性异质结结构, 制备了一种新型p-n异质结光阳极n-BiVO₄/p-CuBi₂O₄， 用于太阳能光电化学(Photoelectrochemical, PEC)水分解. 研究结果表明, 在1.23 V(vs. RHE)电势下, BiVO₄/CuBi₂O₄ 异质结光阳极表现出优良的PEC水氧化性能, 光电流密度达到2.8 mA/cm², 负载磷酸钴(Co-Pi)的BiVO₄/CuBi₂O₄/Co-Pi光电极, 光电流密度达到4.45 mA/cm², 分别为BiVO₄电极光电流密度的3.1倍和4.9倍. X射线衍射(XRD)、 紫外-可见吸收光谱(UV-Vis)、 电化学阻抗谱(EIS)和能级结构图等结果也证实, BiVO₄/CuBi₂O₄和BiVO₄/CuBi₂O₄/Co-Pi复合电极材料在内建电场和能带弯曲作用下, 光吸收特性增强, 载流子界面转移电阻减小, 具有良好的光电化学性能与稳定性.

Preparation and Photoelectrochemical Performance of BiVO4/CuBi2O4 Thin Film Photoanodes

The poor separation and significant recombination of electron-hole pairs and slow transfer mobility of charge carriers limit the performance of BiVO₄ for photoelectrochemical（PEC） water splitting. Herein， we present the ternary metal oxide deposition of p-type CuBi₂O₄ as a route to obtain a novel photocatalyst layer on BiVO₄ to form n-BiVO₄/p-CuBi₂O₄ a novel composite photoanode for PEC water splitting. It is found that BiVO₄/CuBi₂O₄ and BiVO₄/CuBi₂O₄/Co-Pi thin films addition show better PEC performance compared with bare BiVO₄ under visible illumination. At 1.23 V（vs. RHE） potential， BiVO₄/CuBi₂O₄ thin film show excellent PEC water oxidation performance， and the photocurrent density reaches 2.8 mA/cm². The photocurrent density of BiVO₄/CuBi₂O₄/Co-Pi thin film loaded with cobalt-phosphate（Co-Pi） reaches 4.45 mA/cm². The curront densities are 3.1 times and 4.9 times of bare BiVO₄， respectively. BiVO₄ and CuBi₂O₄ construct a p-n heterojunction to boost its poor electron-hole separation and transport properties using the built-in electrical potential. The X-ray diffraction（XRD）， UV-Vis measurements， electro-chemical impedance spectroscopy（EIS） and schematic diagram of band structure absorption spectra reveal the enhanced PEC performance and light stability of the prepared electrode materials， when it is applied to PEC water splitting. Based on the study， we have gained an in-depth understanding of the BiVO₄/CuBi₂O₄ and BiVO₄/CuBi₂O₄/Co-Pi composite as high potential in efficient PEC water splitting devices.