Molecular Mechanism of Adsorption-Coupled Electron Transfer

Herein, we describe our recent studies on the molecular mechanism of adsorption-coupled electron transfer (ACET). ACET is ubiquitous and crucial in many important electrode reactions to generate irreversibly adsorbed products in electrodeposition and electrointercalation and reversibly adsorbed intermediates in electrocatalysis and photoelectrocatalysis. ACET reactions, however, are highly complex owing to the coexistence of concerted and non-concerted mechanisms. We established the theoretical framework of voltammetry to discriminate between the two mechanisms, which was demonstrated experimentally for the first time by using not cyclic voltammetry but transient voltammetry based on scanning electrochemical microscopy (SECM). The novel ACET mode of SECM will enable us to quantitatively understand the coupling between electron transfer and specific adsorption.