Site-selective photocoupled electrocatalytic CO2 reduction over efficient Al-oxo chain based-porphyrin framework

Abstract

Photo-coupled electrocatalytic CO2 reduction is an emerging method to promote energy efficiency of electrocatalytic CO2 reduction. However, precisely designing a precatalysts with site-selectivity for efficient photo-coupled electrocatalytic CO2 reduction is still a challenge. Here, a photo-coupled electrocatalyst bearing aluminum (Al)-oxo chain as metal node and transition metal sites as metal center, is dedicated to reducing CO2 for the first time. A satisfactory CO2-to-CO conversion is achieved for Al-PMOF(Co), showing a Faradaic efficiency as high as ∼90% and a long-term stability over 35 h under visible light. The improved performance stem from Al-oxo chain imparting high stability, atomic Co site expediting charge transfer rate (Kct) and visible light accelerating charge transfer across interface. Theoretical calculations and in situ reflection infrared spectroscopy show that the 3dz2 orbital of atomic Co site exists a large resonance with the 2p orbital of *COOH intermediate, thus inducing CO2 reduction though a favorable pathway.