Impact of {100} polar surfaces of α-Bi 2 O 3 on photocatalytic dye degradation and hydrogen production

This study investigated the impact of alpha-Bi2O3 {100} polar surfaces on photocatalytic performance. alpha-Bi2O3 crystals with three different proportions of exposed {100} facets were fabricated through precipitation or hydrothermal processes, followed by appropriate ball-milling treatments. Photocatalytic activities of alpha-Bi2O3 with various proportions of {100} facets were evaluated through methyl orange (MO) dye degradation and hydrogen production experiments to understand the photo-induced redox reactions related to the polar surfaces. To complement the experimental findings, DFT calculations were performed to analyze the polar effect on the electronic band structure for a better comprehension of charge carrier transfer behaviors. The DFT results indicate that a spontaneous internal electric field (IEF) generated along the [100] axis leads to localized surface states that govern the diffusion pathways of electrons and holes. Briefly, the polar surface is favorable for electron-driven reduction, while the nonpolar surfaces are more conducive to hole-dominated oxidation. The PABM48 sample The PA-BM48 sample, preserving significant {100} polar surfaces and revealing more nonpolar surfaces through ball milling, exhibited enhanced photocatalytic performance in both the degradation of MO dye and the H2 production. Under Pt cocatalysis, PA-BM48 achieved a hydrogen production rate of 566 mu mol/g & sdot;h under visible light illumination.