Surface plasmon enhancement of 1D Ag nanowires modified electro-treated BiVO4 photoanode with abundant oxygen vacancies for solar water oxidation

Abstract

The high carrier complexation rate is still one of the main obstacles for bismuth vanadate (BiVO4) to be used in photoelectrochemical (PEC) water oxidation. In this work, we used a simple method for dropping one dimension (1D) silver nanowires (Ag NWs) on the surface of electro-treated BiVO4 (Ag NWs/E-BiVO4). The photocurrent of Ag NWs/E-BiVO4 under AM 1.5 G illumination reaches to 3.12 mA/cm2 which is about 6.2 times than the pure BiVO4 photoelectrode. Meanwhile, the photogenerated charges injection efficiency of Ag NWs/E-BiVO4 photoelectrodes increasing from 12.7 % to 77.5 % than the pure BiVO4 photoelectrode. This is because the surface plasmon resonance (SPR) effect of 1D Ag nanowires enhanced the visible light absorption and provide more Ag active sites. Furthermore, the density functional theory (DFT) calculations show that the Ag NWs/E-BiVO4 have the best adsorption capacity for OH– and the electro-treated BiVO4 with rich oxygen vacancies greatly improves the electron transport efficiency which is benefit for improving the PEC catalytic performance. Thus, this work provides a simple method to enhance the PEC water splitting performance of BiVO4.