In-situ growth Cu2O on C-BiOI to fabrication p-p heterojunction with enhanced visible-light reduction of CO2

Green and precious metal-free photocatalysts have been focused on the viewpoint of practical application. In this study, novel homotypic (p-p) heterojunctions based on the coupling of Cu2O and C-BiOI were synthesized under mild conditions using a two-step method. The microscopic morphology, optical, photoelectrochemical, and photocatalytic properties of the synthesized samples were investigated. The catalytic properties of the samples were also investigated by photocatalytic CO2 reduction. The results showed that Cu2O30%@C3-BiOI exhibited the best photocatalytic performance when the molar ratio of C to Bi was 1:15 and the loading of Cu2O was 30%, and the yields of methanol and ethanol from CO2 within 8 h were 722.88 mu mol/gcat and 264.46 mu mol/gcat, respectively. In addition, the introduction of C improved the light absorption of BiOI, and the introduction of Cu2O effectively improved the migration and separation efficiency of photogenerated carriers. The results of DRS, photocurrent, PL, and EIS proved the photocatalytic reaction mechanism.