Activating coordinative conjugated polymer via interfacial electron transfer for efficient CO2 electroreduction

Abstract

With tunable local electronic environment, high mass density of MN4 sites, and ease of preparation, metal–organic conjugated coordinative polymer (CCP) with inherent electronic conductivity provides a promising alternative to the well-known M−N−C electrocatalysts. Herein, the coordination reaction between Cu2+ and 1,2,4,5-tetraaminobenzene (TAB) was conducted on the surface of metallic Cu nanowires, forming a thin layer of CuN4-based CCP (Cu-TAB) on the Cu nanowire. More importantly, interfacial transfer of electrons from Cu core to the CuN4-based CCP nanoshell was observed within the resulting CuTAB@Cu, which was found to enrich the local electronic density of the CuN4 sites. As such, the CuTAB@Cu demonstrates much improved affinity to the *COOH intermediate formed from the rate determining step; the energy barrier for C–C coupling, which is critical to convert CO2 into C2 products, is also decreased. Accordingly, it delivers a current density of −9.1 mA cm−2 at a potential as high as −0.558 V (vs. RHE) in H-type cell and a Faraday efficiency of 46.4% for ethanol. This work emphasizes the profound role of interfacial interaction in tuning the local electronic structure and activating the CuN4-based CCPs for efficient electroreduction of CO2.