In-situ Analysis of CO₂ Electroreduction on Pt and Pt Oxide Cathodes

Abstract

The issue of excessive amounts of CO 2 in the atmosphere has promoted the study of methods of removing it from the atmosphere. In the field of electrochemistry, electroreduction of CO 2 has become an area of significant scientific interest. Our previous work has shown Pt oxide exhibits a higher CO 2 electroreduction activity than Pt. In this study, the surface adsorption species on Pt and Pt oxide during electroreduction were investigated with SEIRAS to clarify the mechanisms of the superior electroreduction activity of Pt oxide. The main adsorption species during CO 2 electroreduction were methanol and HCOO − on the Pt oxide, and methanol and linear-CO on the Pt. We confirmed that the CO 2 electroreduction reaction proceeds via HCOO − on Pt oxide, and through CO on Pt. The CO 2 electroreduction activity is significantly affected by the adsorption species because CO strongly adsorbs on the active site and inhibits subsequent reactions. The residual oxygen in the reduced Pt oxide electrode may cause the difference in adsorption species, controlling the reaction pathway. We conclude that the superior CO 2 electroreduction activity of Pt oxide is due to the difference in the reaction pathway, possibly caused by residual oxygen and oxygen vacancies in the Pt oxide electrode.

Engineering Pt-Pt coordination environment to enhance the four-electron oxygen reduction reaction

“…5). The oxidation state of Pt is often used as an indicator of catalytic activity during ORR 1,53,54 as the formation of oxides during the reaction passivates the surface. 1 Performing LCF analysis of the in situ XAFS spectra shows that the Pt clusters in Pt1Pd2.4 initially contain 100% Pt(0) and are steadily oxidised to 12.4% Pt(IV) between 1.3 V (anodic) and 1.1 V (cathodic) vs. RHE (Fig.…”