In situ Selenization Induced Electron-Rich Pd with Weakened O2 Adsorption for Boosted Photocatalytic H2O2 Production.

Pd cocatalysts show great potential for the photocatalytic production of H2O2. However, the catalytic efficiency of Pd cocatalyst is limited due to the strong adsorption of O2, which promotes O-O bond cleavage and thus reduces selectivity for the two-electron O2 reduction reaction. Considering that adjusting the electron density of Pd can predominately optimize Pd-Oads bond strength, in this work, electron-rich Pd sites are constructed by introducing Bi2Se3 middle layer between Pd cocatalysts and (010) facet of BiVO4 using an in-situ selenization strategy. The photocatalytic results indicate that the designed BiVO4/Bi2Se3-Pd(0.3%) photocatalyst achieves a high H2O2 yield of 2166 μmol L-¹ in 2 h, which is 36 times and 3.75 times higher than BiVO4/Bi2Se3 and BiVO4/Pd photocatalyst, respectively. Additionally, the corresponding AQE value of BiVO4/Bi2Se3-Pd is 6.71%. The subsequent Density functional theory (DFT) calculations and XPS spectra confirm that the introduction of Bi2Se3 via in-situ selenization increases the electron density of Pd. This enhances the formation of electron-rich Pd sites, reduces O2 adsorption, and ultimately improves the photocatalytic H2O2 yield. This strategy provides insights into designing efficient photocatalysts for H2O2 production through electronic structure modulation.