Cocatalyst modification of niobium-substituted silver tantalate photocatalyst for enhanced solar water-splitting activity

Abstract

As a photocatalyst for solar water splitting, niobium-substituted silver tantalate (AgTa0.7Nb0.3O3) modified with platinum (Pt) and cobalt phosphate (Co–Pi) was synthesized by a combination of hydrothermal synthesis and photodeposition. Under simulated solar light, AgTa0.7Nb0.3O3 could split water into hydrogen and oxygen in a stoichiometric ratio, and enhancement of the reaction rate owing to the cocatalyst deposition was observed. In particular, co-loading of Pt and Co–Pi considerably enhanced the photocatalytic activity, whereas the enhancement was moderate when either was loaded alone. A possible mechanism for the enhancement is explained based on the band position of AgTa0.7Nb0.3O3 against redox potentials for hydrogen and oxygen evolution.