Fabricate dual interface build-in electric fields by introducing Au nanospecies into Z-scheme heterojunction to propel photocatalytic CO2 reduction

Fabricating Z-Scheme heterojunction is a conventional method to improve the photocatalytic activity, but how to further drive its photogenerated charge separation through structural design is still a challenging issue. Here, a Z-scheme Co3O4/Au/PCN heterojunction is assembled by a new structural design strategy that is fabricating the dual interface build-in electric fields by introducing Au nanospecies between Co3O4 and PCN. Driven by the dual interface build-in electric fields, the photogeneated holes of PCN and photogeneated electrons of Co3O4 can transfer to Au continuously and recombine rapidly, which significantly improves the overall carrier separation efficiency of Z-scheme Co3O4/Au/PCN heterojunction. As a consequence, the Z-scheme Co3O4/Au/PCN heterojunction exhibits the outstanding activity, stability and reusability in photocatalytic CO2 reduction. The average rate of CO generation over the optimal Co3O4/Au/PCN-5 sample in water is about 1.81 and 1.62 times that of PCN and Co3O4/PCN. Meanwhile, the average rate of CO generation over the optimal Co3O4/Au/PCN-5 sample is up to about 1.80 and 3.46 times as high as that over Co3O4/PCN and PCN, and the average rate of CH4 generation is about 3.80 and 8.92 times larger than that over Co3O4/PCN and PCN, respectively. This work provides a new solution for efficiently propellig charge separation of Z-scheme heterojunction, with the aim of contributing to the photocatalytic application in the energy and environmental problems going forward.