First-principles calculations and experimental investigation on SnO₂@ZnO heterojunction photocatalyst with enhanced photocatalytic performance

In this study, branch-like SnO₂@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 SnO₂@ZnO nanocomposites (TZNCs) exhibited superior photocatalytic performance under visible light irradiation as compared to pure SnO₂ and ZnO. The excellent photocatalytic performance of TZNCs can be ascribed to the heterojunction structure between ZnO and SnO₂ 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 SnO₂ is more favor of the transfer of photogenerated eletrons from ZnO to SnO₂, 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.