Bioinspired cobalt molecular electrocatalyst for water oxidation coupled with carbon dioxide reduction

Abstract

AbstractTo mimic photosynthesis in green plants, it is a crucial challenge to drive water oxidation and CO2 reduction in one single system. In this study, we present a bioinspired trinuclear pyridinedicarboxylate cobalt complex (Et3NH)2[CoIII2CoII(OH2)(pda)5]·H2O (1) that is capable of homogeneously electrocatalytic water oxidation and CO2 reduction simultaneously. The designed mix‐valent cobalt complex is in a V‐configuration composed of two terminal CoIII ions and one central CoII ion coordinated with one water ligand, which is resemble to aqua ligation of the natural catalytic complex in oxygen‐evolving complex (OEC). The electrochemical results show that this trinuclear cobalt complex could electrocatalyze water oxidation under neutral condition at the potentials of 1.15 V and 2.00 V versus NHE, with the Faraday efficiency as high as about 96% and 82%, and the TOF of 2.22 and 10.20 s−1, respectively. Meanwhile, it also displays electrocatalytic activity for the reduction of CO2 to CO with the TOF of 0.93 s−1. The cobalt complex has good catalytic performance for the conversion of H2O and CO2 into O2 and CO, respectively, which may be mainly due to the key role of the flexible water ligand on the central CoII ion in the catalytic process. This work represents the first multinuclear cobalt complex for mimicking bio‐system to drive water oxidation coupled with carbon dioxide reduction simultaneously.