Selective Photocatalytic CO ₂ Reduction via Enhanced CO ₂ Adsorption and Activation Over Co‐Salen Functionalized Zr‐MOF Catalyst

Abstract

ABSTRACT Achieving highly selective production from photocatalytic CO 2 reduction in aqueous systems remains a major challenge due to the competitive hydrogen evolution reaction (HER). Herein, we propose a node‐docking strategy to graft Co‐Salen molecular complexes onto Zr‐MOF (NKM‐906) to achieve the selective photoreduction of CO 2 to CO. Experimental results demonstrate that the NKM‐906 with unique SCU topology and microporous structure can effectively concentrate CO 2 molecules near the Co‐Salen active sites. Moreover, the confined Co‐Salen exhibits superior adsorption and activation toward CO 2 over H 2 O, which is a key factor in suppressing the HER. Density functional theory (DFT) calculations further indicate that, compared to other mononuclear (Ni, Cu, Zn, Mn) and binuclear (Co 2 ) metal‐Salen complexes, the mononuclear Co‐Salen complex exhibits superior performance in the adsorption and activation of CO 2 . As a result, the Co‐NKM‐906 demonstrates a notable CO generation rate of 2.63 mmol g −1 h −1 with a CO selectivity of 83% in a water‐containing system, indicating its outstanding catalytic efficacy in the selective photoreduction of CO 2 .