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

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 (gamma-Bi2O3) exhibited significantly enhanced charge separation ability compared with that of the alpha phase (alpha-Bi2O3) and beta phase (beta-Bi2O3). Charge-carrier dynamics revealed that the decay lifetime was increased in gamma-Bi2O3, indicating the enhanced charge carrier separation and migration ability in the gamma phase of Bi2O3. As expected, the gamma-Bi2O3 photocatalyst exhibited a remarkably improved photocatalytic CO2 reduction activity of 48.10 mu mol h(-1) g(-1), which was nearly 3.19 and 1.62 times higher than that of alpha-Bi2O3 and beta-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.