Continuously Improved Photocatalytic Performance of Zn₂SnO₄/SnO₂/Cu₂O Composites by Structural Modulation and Band...

Improving the photocatalytic performance of multi-component photocatalysts through structural modulation and band alignment engineering has attracted great interest in the context of solar energy utilization and conversion. In our work, Zn₂SnO₄/SnO₂ hierarchical architectures comprising nanorod building block assemblies were first achieved via a facile solvothermal synthesis route with lysine and ethylenediamine (EDA) as directing agents, and then chemically etched in NaOH solution to enlarge the surface area and augment active sites. The etched Zn₂SnO₄/SnO₂ hierarchical architectures were further decorated by Cu₂O nanoparticles though an in situ chemical deposition method based on band alignment engineering. In comparison with unetched Zn₂SnO₄/SnO₂, the specific surface area of Zn₂SnO₄/SnO₂/Cu₂O hierarchical architectures became larger, and the responsive region and absorbance intensity became wider and higher in the whole visible-light range. Zn₂SnO₄/SnO₂/Cu₂O hybrid photocatalysts presented enormously improved visible-light photocatalytic behaviour for Rhodamine B (RhB) decomposition. The enhancement of photocatalytic behaviour was dominantly attributed to the synergy effect of the larger specific surface area, higher light absorption capacity, and more effective photo-induced charge carrier separation and migration. A proposed mechanism for the enormously promoted photocatalytic behaviour is brought forth on the basis of the energy-band structure combined with experimental results.