Molecular-level electrocatalytic CO 2 reduction reaction mediated by single platinum atoms.

The activation and transformation of H 2 O and CO 2 mediated by electrons and single Pt atoms is demonstrated at the molecular level. The reaction mechanism is revealed by the synergy of mass spectrometry, photoelectron spectroscopy, and quantum chemical calculations. Specifically, a Pt atom captures an electron and activates H 2 O to form a H-Pt-OH - complex. This complex reacts with CO 2 via two different pathways to form formate, where CO 2 is hydrogenated, or to form bicarbonate, where CO 2 is carbonated. The overall formula of this reaction is identical to a typical electrochemical CO 2 reduction reaction on a Pt electrode. Since the reactants are electrons and isolated, single atoms and molecules, we term this reaction a molecular-level electrochemical CO 2 reduction reaction. Mechanistic analysis reveals that the negative charge distribution on the Pt-H and the -OH moieties in H-Pt-OH - is critical for the hydrogenation and carbonation of CO 2 . The realization of the molecular-level CO 2 reduction reaction provides insights into the design of novel catalysts for the electrochemical conversion of CO 2 .