Vertical SrNbO_2N Nanorod Arrays for Solar-Driven Photoelectrochemical Water Splitting

摘要

Although SrNbO_2N 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_2N nanorod arrays are first achieved using a facile hydrothermal method with a nitridation process for solar-driven photoelectrochemical (PEC) water splitting. The obtained SrNbO_2N 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_2N nanorod arrays present a photocurrent of 1.3 mA cm~(-2) at 1.23 VRHE, which is ≈2.6 times higher than that of a SrNbO_2N 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_2N electrodes. Thus, this work offers a new strategy to develop bimetal oxynitride nanorod arrays for PEC applications.