Redox-Active Crystalline Coordination Catalyst for Hybrid Electrocatalytic Full Reaction.

Hybrid CO 2 electroreduction in which carbon dioxide reduction reaction (CO 2 RR) is coupled with a thermodynamically more favorable anodic oxidation reaction is recognized as a very important strategy to improve the total value of redox products and energy conversion efficiency. In this work, a coordination catalyst model system for hybrid electrocatalytic full reaction, including Ni 8 -TET with active oxidation sites, Ni-TPP with active reduction sites and PCN-601 with redox-active sites, was established for the first time. Compared with the other two compounds, PCN-601 can complete both anodic methanol oxidation reaction and cathodic CO 2 RR with FE HCOOH and FE CO over 90%. Furthermore, due to the photosensitivity of metalloporphyrins, the performances of PCN-601 can be further improved with light irradiation (FE HCOOH over 90% at 1.8 - 2.5 V and FE CO nearly 100% at 2 - 2.4 V), which is the first crystalline coordination catalyst that can complete oxidation and reduction reactions, simultaneously. DFT calculation shows that the electrons transferring from Ni 8 clusters to Ni ions in the porphyrin under electric fields results in the raised oxidability of Ni 8 clusters and raised reducibility of metalloporphyrin, which is responsible for the improved electrocatalytic performance of PCN-601. Significantly, it is the first report to use one crystalline coordination catalyst to achieve the hybrid electrocatalytic full reaction. Moreover, this work serving as a well-defined model system puts forward a new design idea for establishing efficient catalysts for hybrid CO 2 electroreduction reaction.