Photoactivation of Cu Centers in Metal–Organic Frameworks for Selective CO2 Conversion to Ethanol

CO2 hydrogenation to ethanol is of practical importance but poses a significant challenge due to the need of forming one C–C bond while keeping one C–O bond intact. CuI centers could selectively catalyze CO2-to-ethanol conversion, but the CuI catalytic sites were unstable under reaction conditions. Here we report the use of low-intensity light to generate CuI species in the cavities of a metal–organic framework (MOF) for catalytic CO2 hydrogenation to ethanol. X-ray photoelectron and transient absorption spectroscopies indicate the generation of CuI species via single-electron transfer from photoexcited [Ru(bpy)3]2+-based ligands on the MOF to CuII centers in the cavities and from Cu0 centers to the photoexcited [Ru(bpy)3]2+-based ligands. Upon light activation, this Cu–Ru–MOF hybrid selectively hydrogenates CO2 to EtOH with an activity of 9650 μmol gCu–1 h–1 under 2 MPa of H2/CO2 = 3:1 at 150 °C. Low-intensity light thus generates and stabilizes CuI species for sustained EtOH production.