Development of cocatalysts for photocatalytic overall water splitting on (Ga1-xZnx)(N1-xOx) solid solution

The development of cocatalysts promoting overall water splitting on (Ga1-x Zn-x )(N1-x O-x ) solid solution photocatalyst is presented. The (Ga1-x Zn-x )(N1-x O-x ) is a stable visible-light-driven photocatalyst for stoichiometric water splitting upon loading with a suitable nanoparticulate cocatalyst. Loading with a combination of Cr and Rh oxides, Rh2-y Cr-y O-3, is demonstrated to raise the quantum efficiency of (Ga1-x Zn-x )(N1-x O-x ) for overall water splitting to 2.5% at 420-440 nm. This represents a 10-fold increase in efficiency over the highest efficiency previously obtained using nanoparticulate RuO2 as a cocatalyst. In addition to the composition, the dispersion and size of cocatalyst nanoparticles are identified as important factors affecting the degree of enhancement for stoichiometric water splitting.