HER Competition

Nature Chemistry: The overlooked carbonate ion in CO₂RR actually restructures the interfacial water

CO₂ electroreduction commonly uses bicarbonate electrolytes. Past discussions of the reaction mechanism have typically focused on CO₂, metal cations, and the catalyst surface, with bicarbonate/carbonate ions often treated as buffer components or sources of carbon loss. This Nature Chemistry paper by Christopher S. Kley's team at the Helmholtz Centre for Materials and Energy in Berlin, Germany, reintroduces the discussion of carbonate ions within the context of interfacial reactions. Using in-situ ATR-SEIRAS, differential electrochemical mass spectrometry (DEMS), isotope labeling, and DFT calculations, the paper demonstrates that in Au-catalyzed CO₂RR, carbonate ions and their radicals can modulate the interfacial water structure, further influencing the competitive relationship between CO₂RR and HER.