New insight into heterointerfacial effect for heterogenized metallomacrocycle catalysts in executing electrocatalytic CO2 reduction

The heterogenized metallomacrocycles with atomically dispersed active sites are identified as the promising candidates for electrocatalytic CO 2 reduction reaction (CO 2 RR), where their unique heterointerface with interaction between sp 2 carbon and macrocyclic molecules is important but remains vague. Herein, based on well-structured nickel phthalocyanine and porphyrin with the same functional groups (MeNiPc and MeNiPp), the influences of heterointerfacial effect on catalytic performances are systematically disclosed. Through the molecular structure-induced self-adaptive adsorption with optimized heterointerfacial distance, MeNiPc/graphene reveals a high CO Faradaic efficiency of ~99% in a wide potential window, greatly outperforming the MeNiPp/graphene counterpart (≤29.6%). Detailed measurements and theoretical calculations decipher that the higher CO 2 RR activity of MeNiPc/graphene is attributed to the unique electronic structures of the Ni-N 4 configurations suitable for well-suited heterointerfacial charge transfer and rapid CO desorption. Additionally, the extended research confirms the universality of heterointerface engineering on boosting the catalytic performances.