Stable Hydrogen Evolution from an AgRhO2 Photocathode under Visible Light

Abstract

In the search for improved materials for photoelectrochemical water splitting, it has become important to identify new classes of semiconductor materials that may serve as improved photocathodes. To this end, p-type AgRhO2 has been synthesized and tested as a photocathode for water splitting. The AgRhO2 photocathode is found to exhibit excellent photocatalytic capability for reducing protons to H2 across a wide range of pH values with nearly 100% faradaic efficiency and good photostability. Polycrystalline AgRhO2 electrodes exhibit strong preferred c-axis orientation, resulting in anisotropic conductivity, evident from resistivity measurements. AgRhO2 photocathodes are found to provide improved performance and photostability when compared to prior work using a p-CuRhO2 electrode. Enhanced performance is in part attributed to the unusual degree of c-axis orientation found in this material. In addition, there is a significantly lower kinetic barrier for H2 production at the AgRhO2 interface.