The electrocatalytic reduction of CO2 at carbon-supported
Au-Pd core–shell nanoparticles is investigated systematically as a
function of the Pd shell thickness. Liquid- and gas-phase products were
determined by off-line 1H NMR spectroscopy and on-line
electrochemical mass spectrometry. Our results uncover the relationship
between the nature of the products generated and the Pd shell thickness.
CO and H2 are the only products generated at 1 nm thick shells, whereas shells of 5 and 10 nm produced HCOO−, CH4 and C2H6. The concentration of HCOO−
detected in the electrolyte was dependent on the applied potential and
reached a maximum Faradaic efficiency of 27 % at −0.5 V versus the
reversible hydrogen electrode for 10 nm thick shells. We conclude that
collisions between absorbed hydrogen at relaxed Pd lattices and strongly
bound “CO-like” intermediates promote the complete hydrogenation to C1
and C2 alkanes without the generation of other products, such as
alcohols and aldehydes.
- Carbon Dioxide
- Structure-Activity Relationships