BiVO_(4)/CuBi_(2)O_(4)薄膜光电极的制备及光电性能

Preparation and Photoelectrochemical Performance of BiVO_(4)/CuBi_(2)O_(4) Thin Film Photoanodes

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CuBi_(2)O_(4)沉积在BiVO_(4)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-BiVO_(4)/p-CuBi_(2)O_(4),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,BiVO_(4)/CuBi_(2)O_(4)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/cm^(2),负载磷酸钴(Co-Pi)的BiVO_(4)/CuBi_(2)O_(4)/Co-Pi光电极,光电流密度达到4.45 mA/cm^(2),分别为BiVO_(4)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,BiVO_(4)/CuBi_(2)O_(4)和BiVO_(4)/CuBi_(2)O_(4)/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.

The poor separation and significant recombination of electron-hole pairs and slow transfer mobility of charge carriers limit the performance of BiVO_(4) for photoelectrochemical(PEC)water splitting.Herein,we present the ternary metal oxide deposition of p-type CuBi_(2)O_(4) as a route to obtain a novel photocatalyst layer on BiVO_(4) to form n-BiVO_(4)/p-CuBi_(2)O_(4) a novel composite photoanode for PEC water splitting.It is found that BiVO_(4)/CuBi_(2)O_(4) and BiVO_(4)/CuBi_(2)O_(4)/Co-Pi thin films addition show better PEC performance compared with bare BiVO_(4) under visible illu⁃mination.At 1.23 V(vs.RHE)potential,BiVO_(4)/CuBi_(2)O_(4) thin film show excellent PEC water oxidation performance,and the photocurrent density reaches 2.8 mA/cm^(2).The photocurrent density of BiVO_(4)/CuBi_(2)O_(4)/Co-Pi thin film loaded with cobalt-phosphate(Co-Pi)reaches 4.45 mA/cm^(2).The curront densities are 3.1 times and 4.9 times of bare BiVO_(4),respectively.BiVO_(4) and CuBi_(2)O_(4) construct a p-n heterojunction to boost its poor electron-hole separation and trans⁃port properties using the built-in electrical potential.The X-ray diffraction(XRD),UV-Vis measurements,electrochemical impedance spectroscopy(EIS)and schematic diagram of band structure absorption spectra reveal the en⁃hanced PEC performance and light stability of the prepared electrode materials,when it is applied to PEC water split⁃ting.Based on the study,we have gained an in-depth understanding of the BiVO_(4)/CuBi_(2)O_(4) and BiVO_(4)/CuBi_(2)O_(4)/Co-Pi composite as high potential in efficient PEC water splitting devices.