Abstract
. (GaN)1-x(ZnO)x (GZNO) is capable of visible-light driven overall water-splitting, but its band-gap (>2.7 eV) makes for poor visible-light absorption. Unfortunately, methods to narrow its band-gap by incorporating higher ZnO concentrations are accompanied by extensive Urbach tailing near the absorption-edge, which is indicative of structural disorder or chemical inhomogeneities. Here, the synthesis of GZNO derived from layered double hydroxide (LDH) precursors is described which minimizes Zn-loss and chemical inhomogeneities for enhanced visible-light absorption. The average and local atomic structures of LDH-derived GZNO are investigated using scattering methods and correlated with their oxygen-evolution rates. The findings suggest that the intrinsic positional disorder of GZNO arise from short-range ordering due to its heterovalent nature, which can be thought of in terms of a bond-valence scheme. Furthermore, crystallite size is revealed to correlate more than positional disorder to the performance of GZNO as a photocatalyst for particle-based solar-fuel conversion. These findings signify the importance examining of the local structure of multinary photocatalysts to improve schemes for effective photoconversion.
