Dependence of the intrinsic phase structure of Bi2O3 catalysts on photocatalytic CO2 reduction

Abstract

Rapid recombination of charge carriers and the low efficiency of surface catalysis limit the photocatalytic CO₂ reduction performance. Herein, models of Bi₂O₃ with different phase structures were investigated to achieve in-depth understanding of the role that phase structure plays in the photocatalytic CO₂ process. The gamma phase of Bi₂O₃ (γ-Bi₂O₃) exhibited significantly enhanced charge separation ability compared with that of the alpha phase (α-Bi₂O₃) and beta phase (β-Bi₂O₃). Charge-carrier dynamics revealed that the decay lifetime was increased in γ-Bi₂O₃, indicating the enhanced charge carrier separation and migration ability in the γ phase of Bi₂O₃. As expected, the γ-Bi₂O₃ photocatalyst exhibited a remarkably improved photocatalytic CO₂ reduction activity of 48.10 μmol h⁻¹ g⁻¹, which was nearly 3.19 and 1.62 times higher than that of α-Bi₂O₃ and β-Bi₂O₃, respectively. This work indicates how phase structure affects charge separation and photocatalytic activity, and could open new opportunities for achieving highly efficient photocatalysts and reaction systems.