Photocatalytic Overall Water Splitting on Gallium Nitride Powder

Gallium nitride (GaN) powder was studied as a photocatalyst for overall water splitting. The photocatalytic activity of GaN for the reaction was found to be strongly dependent on the crystallinity of the material and the cocatalyst employed. Modification of well-crystallized GaN with Rh2−yCryO3 nanoparticles as a cocatalyst for H2 evolution resulted in the stable stoichiometric decomposition of H2O into H2 and O2 under ultraviolet irradiation (λ > 300 nm) by the band gap transition. RuO2 modification did not bring about appreciable H2 and O2 evolution. Low-crystallinity GaN exhibits negligible activity for overall water splitting, regardless of the kind of cocatalyst applied.