Hydroxyl-enriched hydrous tin dioxide-coated BiVO4 with boosted photocatalytic H2O2 production

Abstract

The rapid decomposition of H₂O₂ on the surface of inorganic photocatalyst (BiVO₄) and insufficient proton supply from water leads to a low photosynthetic yield of H₂O₂. Herein, hydrous tin dioxide (HSnO) with massive hydroxyl groups is coated on the BiVO₄ surface to greatly improve the photocatalytic H₂O₂ activity via simultaneous realization of providing sufficient protons and inhibiting H₂O₂ decomposition. After coating HSnO, Au nanoparticles as the O₂-reduction active sites are selectively deposited on the (010) facet of BiVO₄ to synthesize Au/BiVO₄@HSnO photocatalyst. The resulting Au/BiVO₄@HSnO photocatalyst exhibits excellent H₂O₂-production performance, in which the photogenerated H₂O₂ concentration (210.7 μmol L⁻¹) is about 4.8 times higher than that of Au/BiVO₄ after 2 h light irradiation in pure water. The outstanding photocatalytic performance can be attributed to simultaneous enhancement of H₂O₂ generation and the suppression of H₂O₂ decomposition by HSnO coating. Specifically, the HSnO coating with massive hydroxyl groups provides enough protons to promote the catalytic transformation of O₂ into H₂O₂ on Au nanoparticles. More importantly, this coating not only allows water molecules to effectively permeate onto BiVO₄ surface for rapid oxidation reaction, but also greatly inhibits the reverse reaction of H₂O₂ decomposition via decreasing its affinity with BiVO₄ surface. This research offers new insights for boosting photocatalytic H₂O₂ production through surface coating strategy.