Z-scheme Bi/AgBiS2/P25 for enhanced CO2 photoreduction to CH4 and CO with photo-themal synergy

A ternary Bi/AgBiS2/P25 has been successfully designed by a one-step solvothermal treatment for enhanced photocatalytic CO2 reduction. Bi/AgBiS2 decoration enhances carriers separation and transfer efficiency of P25 by constructing AgBiS2/P25 heterojunction and loading Bi as electron receiver. Besides, Bi/AgBiS2 decoration contributes to enhanced light-harvesting capability and high surface area of composite, both of which favor CO2 reduction. More importantly, increased -OH and enhanced CO adsorption efficiency on Bi/AgBiS2/P25 surface could enhance CH4 production by providing more available protons and stabilizing more key intermediates for CH4 formation. The CH4 production was improved from 0.23 mu mol/g/h of P25 to 4.31 mu mol/g/h of Bi/AgBiS2/P25, and CO production from 3.52 mu mol/g/h to 6.37 mu mol/g/h, respectively, which have surpassed most TiO2 based works for CO2 photoreduction. Additionally, photo-thermal synergy can further enhance photocatalytic performance.