Selective electroreduction of CO2 to CH4 by Zr-based metal–organic framework integrated binuclear copper cluster

Abstract

Electrocatalytic carbon dioxide reduction (ECO₂RR) technology is of great significance for achieving carbon peaking, carbon neutralization, and alleviating energy and environmental crises. Achieving high selectivity of methane (CH₄) in ECO₂RR is still a huge challenge, because the possible products have similar reduction potential and slow carbon dioxide (CO₂) activation kinetics. Cu and its oxides are one of the most effective electrocatalysts at present. In this study, NU-1000-Cu was obtained by post-synthetic modification (PSM) of Zr-based metal–organic framework (MOF), NU-1000, which not only improved the stability of NU-1000, but also improved its electrocatalytic performance. CO₂ can be reduced to CH₄ in an acidic electrolyte with a Faraday efficiency (FE) of 82.4 % and a local current density of 21.4 mA cm⁻². In addition, the catalytic mechanism was further studied by density functional theory (DFT) calculation to reveal the key role of copper active sites in promoting the reduction of CO₂ to CH₄.