Effect of morphology and structure of CuTCPP nanomaterials on the electrocatalytic CO2 reduction to methane and ethylene

The effect of Cu–N 4 , Cu–O 4 and/or –COOH sites on the electrocatalytic CO 2 reduction (ECR) activity and selectivity is rarely evaluated together and directly confirmed through the morphology and structure dependence of ECR performance. Here, the ECR performance of CuTCPP nanoparticles , nanorods , nanosheets and nanoflowers are systematically investigated. The experimental results show that their total ECR activity is nanoflowers > nanosheets > nanoparticles > nanorods. CuTCPP nanosheets with more Cu−N 4 sites exposed showed the best ethylene selectivity of 40.6 % at –1.2 V vs. RHE. CuTCPP nanoflowers with more Cu−O 4 sites were more stable than the nanosheets, showing 61.0 % methane selectivity at –1.3 V vs. RHE. A series of characterizations reveal that Cu−O 4 is mainly responsible for methane production, while Cu–N 4 is the main active site for ethylene production and its synergy with Cu–O 4 or –COOH groups can improve the ethylene selectivity.