First-principles calculations and experimental investigation on SnO@ZnO heterojunction photocatalyst with enhanced photocatalytic performance.

In this study, branch-like SnO@ZnO heterojunction photocatalyst was successfully fabricated via a simple two-step hydrothermal process. The optical and electronic properties were characterized in detail and the results indicated that SnO@ZnO nanocomposites (TZNCs) exhibited superior photocatalytic performance under visible light irradiation as compared to pure SnO and ZnO. The excellent photocatalytic performance of TZNCs can be ascribed to the heterojunction structure between ZnO and SnO which depresses the recombination of photogenerated electron-hole pairs. In addition, the branch-like morphology can provide large specific surface. Moreover, the density functional theory (DFT) computation on the Fermi level results confirmed that heterojunction structure between ZnO and SnO is more favor of the transfer of photogenerated eletrons from ZnO to SnO, effectively improving separation of photogenerated electron-hole pairs. Noteworthy, this work would pave the route for the two semiconductor materials with a big work function difference which would lead to the high contact potential difference, surely contributing to improving the performance of photocatalysts.