A metal-supported single-atom catalytic site enables carbon dioxide hydrogenation

Abstract

Nitrogen-doped graphene-supported single atoms convert CO ₂ to CO, but fail to provide further hydrogenation to methane – a finding attributable to the weak adsorption of CO intermediates. To regulate the adsorption energy, here we investigate the metal-supported single atoms to enable CO ₂ hydrogenation. We find a copper-supported iron-single-atom catalyst producing a high-rate methane. Density functional theory calculations and in-situ Raman spectroscopy show that the iron atoms attract surrounding intermediates and carry out hydrogenation to generate methane. The catalyst is realized by assembling iron phthalocyanine on the copper surface, followed by in-situ formation of single iron atoms during electrocatalysis, identified using operando X-ray absorption spectroscopy. The copper-supported iron-single-atom catalyst exhibits a CO ₂-to-methane Faradaic efficiency of 64% and a partial current density of 128 mA cm ⁻², while the nitrogen-doped graphene-supported one produces only CO. The activity is 32 times higher than a pristine copper under the same conditions of electrolyte and bias.

Abstract

Converting CO2 and H2O into value-added chemical feedstocks and fuels offers a carbon neutral approach to tackling global energy and climate concerns. Here the authors report a metal supported single-atom catalytic site enabling the electrocatalytic reduction of CO2 to methane.