Photocatalytic oxidation of tetracycline, reduction of hexavalent chromium and hydrogen evolution by Cu2O/g-C3N4 S-scheme photocatalyst: Performance and mechanism insight

An efficient Step-scheme heterojunction of Cu2O/g-C3N4 catalyst was synthesized and used in the degradation of pollutants and energy generation. Among the as-synthesized catalysts, 1-Cu2O/g-C3N4 showed the highest catalytic activity, the photocatalytic reduction efficiency of Cr6+ and the photocatalytic oxidation efficiency of tetracycline (TC) were 77.7% and 95.1%, respectively. The highest H-2 production rate for the 1-Cu2O/g-C3N4 sample was 480.6 mu mol g(-1).h(-1), which is 12 times that of a pristine Cu2O sample. The Cu2O/g-C3N4 catalyst showed satisfactory stability and perfect photocatalytic performance, which was attributed to the efficient interfacial charge separation and the formation of Step-scheme heterojunction photocatalyst retaining strong photocatalytic oxidation and reduction capabilities. Importantly, the charge density difference of Cu2O/g-C3N4 composite sample was simulated, which suggested that a built-in electric field was formed, it was helpful for fabricating the Step-scheme heterojunction structure between g-C3N4 and Cu2O.