Sub-5 nm SnO2 chemically coupled hollow carbon spheres for efficient electrocatalytic CO2 reduction

The electrochemical CO2 reduction reaction (CO2RR) represents a sustainable approach to convert the continuously accumulating CO2 emission into fuels or value-added chemicals. Tin and its compounds are recognized as formate selective CO2RR catalysts, while their catalytic activities and stabilities significantly depend on the micro/nanostructures and the corresponding electronic structures of the catalysts. Herein, we developed a sub-5 nm SnO2 nanoparticle-decorated hollow carbon spherical structure (SnO2/C) as an efficient CO2RR electrocatalyst. Compared to the plain SnOx nanoparticle-aggregated hollow spheres and hollow carbon spheres, SnO2/C achieved a much enhanced CO2RR catalytic performance, including better faradaic efficiencies (FE) and enhanced electrochemical stability. The much improved CO2RR activity and stability of SnO2/C were attributed to the Sn–O–C linkages between SnO2 and the carbon sphere, which led to the increased CO2 chemisorption, fast electron transfer, and the increased number of catalytically active sites.