Vertical SrNbO₂N Nanorod Arrays for Solar‐Driven Photoelectrochemical Water Splitting

Abstract

Although SrNbO 2 N with a bandgap of ≈1.9 eV has been considered as a promising photocatalyst for solar water splitting, its photocatalytic activity is generally very poor under ordinary conditions, primarily due to bad photocarrier generation, separation, and transportation. Herein, vertical SrNbO 2 N nanorod arrays are first achieved using a facile hydrothermal method with a nitridation process for solar‐driven photoelectrochemical (PEC) water splitting. The obtained SrNbO 2 N nanorod arrays exhibit vertical aligned nanorod morphology and high crystallinity, which are beneficial for photocarrier generation and charge carrier transportation. After being uniformly covered with CoO x nanoparticles, the SrNbO 2 N nanorod arrays present a photocurrent of 1.3 mA cm −2 at 1.23 V RHE , which is ≈2.6 times higher than that of a SrNbO 2 N nanoparticle thin film electrode, under irradiation by AM1.5G simulated sunlight. This PEC water splitting activity is one of the best values among all reported SrNbO 2 N electrodes. Thus, this work offers a new strategy to develop bimetal oxynitride nanorod arrays for PEC applications.