A Stable Metal-azolate Framework with Cyclic Tetracopper(I) Clusters for Highly Selective Electroreduction of CO2 to C2 Products

Abstract

It is of great significance for constructing electrocatalysts with accurate structures and compositions to pinpoint the active sites, thereby improving the C2 products (C2H4, C2H5OH and CH3COOH) selectivity during electrocatalytic CO2 reduction raction. Here, we report a tetracopper(I) cluster-based metal-organic framework that exhibits long-term stability and remarkable performance for electroreduction CO2 towards C2 products in an H-type cell with a maximum Faradaic efficiency (FE) of 72%, and delivers a current density of 350 mA cm−2 with a FE(C2) up to 46% in a flow cell device, outperforming most of the Cu-based electrocatalysts such as Cu derivatives and Cu nanostructured materials. Importantly, no obvious degradation was observed at 350 mA cm–2 over 20 hours of continuous operation, strengthening the practicability. In-situ infrared spectroscopy analysis showed the cooperative effect of adjacent Cu(I) ions in tetracopper(I) cluster may promote the C−C coupling to generate C2 products.