A dual Z-scheme heterojunction Cu-CuTCPP/ Cu2O/CoAl-LDH for photocatalytic CO2 reduction to C1 and C2 products

In this research, a ternary Cu-CuTCPP/Cu2O/CoAl-LDH composite with a dual Z-scheme heterostructure was fabricated based on a Cu2O photocatalyst and applied in photocatalytic CO2 reduction. The physicochemical properties of the prepared catalysts and the possible reaction mechanism in CO2 reduction were analyzed and studied by various characterization methods. The activity of CO2 reduction significantly increased, especially forming C-2 products. The optimal yield of C2H4 and C2H6 reached 1.56 and 1.92 mu mol g(-1) h(-1) respectively, which was 14.45 and 17.45 times that from using the Cu2O monomer. In addition, the selectivity of C-2 products reached 37.4%. The satisfactory C-2 yield was mainly due to the fact that Cu-2(1+delta)(COO) (3) nodes in Cu-CuTCPP contained adjacent Cu sites, which effectively promoted the C-C coupling reaction. Moreover, the dual Z-scheme heterojunction stimulated the separation of photogenerated electron-hole pairs and diminished the recombination rate. This work contributes to the development of novel photocatalysts with a dual Z-scheme heterojunction and facilitates the generation of valuable C2 products.