We report an efficient electrochemical conversion of CO2 to CO on surface-activated bismuth nanoparticles (NPs) in acetonitrile (MeCN) with the assistance of 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([bmim][OTf]) at ambient conditions. The surface activation (hydrazine treatment), is featured by the effective removal of the native inhibiting layer (surface capping ligands and oxides) generated from the synthesis and purification process. The activated 36 nm Bi NPs exhibit a Faradaic efficiency for CO evolution (FECO) of 96.1%, higher than the untreated Bi NPs (FECO 76.2%), and a mass activity of 15.6 mA mg-1, three-fold higher than the electrodeposited Bi, at -2.0 V (vs. Ag/AgCl). Further investigation demonstrates that in contrast to that of surface-activated Bi catalysts, the particle size has a significant effect on FECO when the surface of Bi is air-oxidized. This work elucidates the importance of the surface-activation for an efficient CO2 electrochemical conversion on metal NPs and paves the way for understanding the CO2 electrochemical reduction mechanism in non-aqueous media.

Rational design of Bi nanoparticles for efficient electrochemical CO2 reduction

254th National Meeting (2017)

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