Electrochemical reduction of CO2 on SnO2/nitrogen-doped multiwalled carbon nanotubes composites in KHCO3 aqueous solution

•SnO2 nanoparticles were decorated on the surface of N-MWCNTs.•SnO2/N-MWCNTs are more active for electrochemical reduction of CO2 than N-MWCNTs.•The faradaic efficiency for producing formate on SnO2/N-MWCNTs is up to 46%.

Nitrogen-doped multiwalled carbon nanotubes (N-MWCNTs) have been prepared from n-propylamine precursor with Co0.1Mg0.9MoO4 catalyst. Then, SnO2 nanoparticles are decorated on the surface of N-MWCNTs through wet-chemical method. The cyclic voltammetry curves of the SnO2/N-MWCNTs composites in CO2 saturated 0.1 mol L−1 KHCO3 aqueous solution show that SnO2 will not be reduced to Sn2+ or Sn if the cathode potential is higher than −1.3 V vs. Ag/AgCl. The electrochemical reduction of CO2 produces formate in the aqueous solution during the potentiostatic electrolysis and its faradaic efficiency is up to 46%, whereas that on the N-MWCNTs is lower than 10%.

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