Metal–organic framework derived carbon supported Cu–In nanoparticles for highly selective CO2 electroreduction to CO

Abstract

Cu-based materials are promising electrocatalysts for the CO₂ reduction reaction (CO₂RR). However, they still suffer from intense hydrogen evolution, as well as low selectivity and efficiency for the CO₂RR. In this work, Cu–In bimetallic catalysts for the CO₂RR were prepared by the pyrolysis of Cu–In metal–organic framework (MOF) materials. Cu₉₀In₁₀/C with a Cu/In molar ratio of 9/1 exhibited a high CO selectivity of up to 85% at −0.75 V versus the reversible hydrogen electrode, compared with 3.1% on Cu/C and 10.8% on In/C. On the Cu₉₀In₁₀/C catalyst, In was found to be locally distributed on the surface of Cu nanoparticles, forming Cu₄In, changing the geometric and electronic structures of the Cu surface. These modifications were supposed to have modulated the adsorption properties of the catalyst for *H, CO₂ and the intermediates during the CO₂RR, therefore the electrochemical conversion of CO₂ to CO was enhanced and hydrogen evolution was mitigated. The enlarged electrochemically active surface area and the accelerated charge transfer and reaction kinetics of this Cu–In bimetallic catalyst also contributed much to its excellent CO₂RR performance. This work not only highlights the superior CO₂ electroreduction performance of bimetals over monometals, but also provides a new method to develop bimetallic catalysts.