Enhanced Performance of Particulate Oxynitride Photoanodes by Electron‐Collecting‐Oxide Array Insertion for Photoelectrochemical Water Oxidation

Abstract The collection of photogenerated electrons is a bottleneck to the photoelectrochemical performance of particulate photoanodes. In this work, the electron‐conducting array insertion strategy is applied for the assembly of LaTiO 2 N and SrNbO 2 N particulate photoanodes, and the candidates of conductive arrays are expanded from rigid vertically grown ZnO nanorod arrays to multi‐directionally grown ZnO nanoparticle arrays. ZnO nanorod arrays and ZnO nanoparticle arrays were inserted via electrodepositing ZnO from Zn(NO 3 ) 2 aqueous solution and n ‐butanolic solution, respectively. By inserting a ZnO nanoparticle array, the performance of the assembled LaTiO 2 N micron particulate photoanodes is improved by 2 orders of magnitude compared to the uninserted one, and the photocurrent at 1.23 V RHE reaches 4.53 mA cm −2 , slightly higher than 4.03 mA cm −2 (of the one assembled with a ZnO nanorod array). On the other hand, the performance of SrNbO 2 N hundred‐nanometer particulate photoanodes assembled with ZnO nanoarrays are 6–11 times of the uninserted one, and the photocurrent at 1.23 V RHE of the one assembled with a ZnO nanoparticle array reaches 1.88 mA cm −2 , significantly higher than 0.97 mA cm −2 (of the one assembled with a ZnO nanorod array).