Cooperative copper centres in a metal–organic framework for selective conversion of CO2 to ethanol

Abstract

Selective conversion of CO2 to ethanol is of great interest but presents a significant challenge in forming a C–C bond while keeping a C–O bond intact throughout the process. Here, we report cooperative CuI sites on a Zr12 cluster of a metal–organic framework (MOF) for selective hydrogenation of CO2 to ethanol. With the assistance of an alkali cation, the spatially proximate Zr12-supported CuI centres activate hydrogen via bimetallic oxidative addition and promote C–C coupling to produce ethanol. The Cs+-modified MOF catalyst, in 10 hours, produces ethanol with >99% selectivity and a turnover number (based on all Cu atoms) of 4,080 in supercritical CO2, with 30 MPa of CO2 and 5 MPa of H2 at 85 °C, or a turnover number of 490 at 2 MPa of CO2/H2 (1/3) and 100 °C. Our work highlights the potential of using MOFs as a tunable platform to design earth-abundant metal catalysts for CO2 conversion. The synthesis of ethanol via CO2 hydrogenation is a challenging process, often hampered by low selectivity. This work reports a Zr12 cluster-based metal–organic framework as support for cooperative Cu(i) sites that catalyse CO2 hydrogenation to ethanol with remarkable selectivity upon promotion with caesium. Credit: Cloud background, CC0 1.0 Universal Public Domain Dedication.