Proton‐Coupled Electron Transfer in Electrocatalytic Water Splitting

Abstract

Proton‐coupled electron transfer (PCET) plays a crucial role in a diverse array of natural and artificial energy conversion processes. Herein, we will introduce the fundamentals of electrochemical PCET with a focus on its role in water splitting. Besides, perspectives of future development of PCET are presented with regard to the investigation of reaction mechanisms and the design of advanced electrocatalysts.

Breaking the Scaling Relationship of Oxygen Evolution Reaction and Chlorine Oxidation Reaction via MnO2 Polymorphic Engineering for Selective Seawater Electrolysis

“…This indicates faster kinetics of COR over γ-MnO 2 and δ-MnO 2 electrocatalysts, which again validates that γ-MnO 2 and δ-MnO 2 are more suitable for COR, while αand β-MnO 2 electrocatalysts are more favorable for OER. 42 The reason for the faster kinetics of γ-MnO 2 and δ-MnO 2 is because they have more COR active sites, which is also observed via the double layer capacitance plot in Figure 4e,f. The growth of double layer capacitance (C dl ), which corresponds to electrochemical active sites, is almost negligible for α-MnO 2 and β-MnO 2 when compared to only the OER electrolyte and the OER + COR electrolyte.…”

“…The Tafel slope at a higher overpotential range is preferable for COR desorption reaction and is lower as compared to the Tafel slope on the higher overpotential side in only the OER electrolyte. This indicates faster kinetics of COR over γ-MnO 2 and δ-MnO 2 electrocatalysts, which again validates that γ-MnO 2 and δ-MnO 2 are more suitable for COR, while α- and β-MnO 2 electrocatalysts are more favorable for OER . The reason for the faster kinetics of γ-MnO 2 and δ-MnO 2 is because they have more COR active sites, which is also observed via the double layer capacitance plot in Figure e,f.…”

The isomer-sensitive electrochemical HER of ruthenium(ii)–hydrido complexes involving redox-active azoheteroaromatics

“…The Tafel slope for [ 1a ]ClO 4 clearly showed the Volmer step to be the rate-determining step. 13,35…”

“…Previous reports have shown that the Tafel slopes strongly depend on the surface coverage. 35 Furthermore, the Tafel slope becomes pH-dependent when the coverage of intermediates changes with the pH (Fig. S8, see the ESI†).…”

“…S8, see the ESI†). 35 This complicates the identification of a rate-limiting step by a single Tafel slope at a particular pH. 36 We therefore carried out the Tafel analysis at different pH values under controlled potential chronoamperometry.…”