Hollow AgPt@Pt core-shell cocatalyst with electron-rich Ptδ− shell for boosting selectivity of photocatalytic H2O2 production for faceted BiVO4

Abstract

Platinum (Pt) is an excellent oxygen reduction cocatalyst with great potential for the photocatalytic production of H₂O₂. However, its catalytic efficiency is limited by the strong adsorption of O₂, which facilitates O–O bond cleavage and reduces selectivity for the 2-electron oxygen reduction reaction (ORR). Fortunately, the strength of the Pt–O bond can be weakened by adjusting the structure of the cocatalyst to modify the electronic structure of Pt. In this paper, Pt and Ag cocatalysts are successively modified on the (010) facet of BiVO₄ through a two-step photodeposition method. Due to the occurrence of a displacement reaction during the process, a synergistic catalyst with a hollow AgPt alloy core and an electron-rich Pt^δ− shell (AgPt@Pt) structure is ultimately synthesized. Photocatalytic experiments demonstrated that the H₂O₂ production from BiVO₄ modified with hollow AgPt@Pt reached an impressive 1021.5 ​μmol ​L⁻¹. This corresponds to an AQE of 5.1%, which is 28.6 times higher than that of the Pt/BiVO₄ photocatalyst with only 35.7 ​μmol ​L⁻¹. Furthermore, research results show that AgPt can transfer electrons to the Pt shell to generate electron-rich Pt^δ− active sites, thus increasing the antibonding orbital occupancy of Pt–O_ads in AgPt@Pt catalysts. This electron redistribution weakens the adsorption strength of O₂ on Pt, promoting the 2-electron ORR and facilitating the efficient generation of H₂O₂. This synthesis strategy offers a versatile approach for preparing other Pt-based nano-alloy cocatalysts with improved activity for the selective reduction of O₂ to H₂O₂.