The Bifunctional Electrocatalysis of Carbon Monoxide Oxidation Reaction

Carbon monoxide electrochemical oxidation reaction (COR) follows the surface-confined Langmuir–Hinshelwood (L–H) mechanism leading to the formation of carbon dioxide from active “reactant-pair” of CO ads –OH ad . The bifunctional electrocatalysis of COR focuses on how to enhance the generation of one of the “reactant-pair,” that is, OH ad . This can be realized by (1) direct electrocatalyst surface modifications with increasing defect sites, depositing adatoms, or adding alloying elements that are more oxyphilic than the original element; (2) strongly adsorbed molecular species located at the inner Helmholtz plane, such as strongly adsorbed CO; and (3) species located at the outer Helmholtz plane, such as OH − or hydrated metal cations. Casting them in a general framework of bifunctional electrocatalysis will stimulate new inquiries and open up new routes for developing new electrochemistry in the field of electrocatalysis.