Study of CO2 reduction at Pt-Ru electrocatalyst in polymer electrolyte cell by differential electrochemical mass spectrometry and liquid chromatography

Abstract

We describe the CO2 reduction characteristics at the theoretical potential of the CO2 reduction by the Pt-Ru electrocatalyst assessed by differential electrochemical mass spectrometry (DEMS) and high-performance liquid chromatography (HPLC) in a polymer electrolyte single cell. When using the Pt-Ru black catalyst, a small amount of the reduced CO2 was possibly adsorbed on the electrode surface compared to the Pt-Ru/C catalyst. Based on the DEMS analysis of the CO2 electroreduction at the Pt-Ru black catalyst, the methane was not or slightly detected and the generation of carboxylic acids was suggested in the potential range where H2 evolution does not occur. On the other hand, the HPLC analysis demonstrated for the first time that the formic acid, acetic acid, and lactic acid were obtained by the CO2 reduction at the Pt-Ru black electrocatalyst. Based on these results, one interesting production mechanism in which three or four kinds of compounds (formic acid, acetic acid, lactic acid, with/without methane) are produced depending on how to desorb the intermediate adsorbents from the electrocatalyst surface could be considered.