Dynamic Surface Chemistry of Catalysts in Oxygen Evolution Reaction

Abstract

Electrocatalytic oxygen evolution reaction (OER) is a crucial anode reaction where electrocatalysts are the key elements and their dynamic surface chemistry runs throughout the entire process. Herein, we examine the latest advances and challenges in understanding of the dynamic surface chemistry of OER electrocatalysts. There are electrochemical origin and driving force for the dynamic surface nature, where several processes can take place either concurrently or sequentially, including reconstruction (i.e., phase formation/transformation, morphological change, and compositional change), vacancy generation and filling/refilling, and the intermediate adsorption-desorption process on catalytic surface. These dynamic surface processes of OER catalysts are impacted by not only the reaction and service conditions, including the (local) pH and its gradient distribution, applied potential, types and concentration of exotic ions and external fields on top of the nature of catalysts/precatalysts, but also their interactions. Due to the local, time-dependent and instant nature, there are considerable challenges in tracing, modelling and understanding of the complete dynamic surface chemistry of catalysts in OER, by means of ex situ, in situ and operando experimental investigations. Therefore, computational studies and dynamic simulations help provide key insights in future pursuits, where there is critical need for a multiscale computational modelling approach encompassing all these aspects.

Recent Advances in Design of Electrocatalysts for High‐Current‐Density Water Splitting

“…Apart from the aforementioned similarity effects that current density acts on catalyst performance, differences between OER and HER under HCD conditions are also noteworthy. First, OER catalyst suffers an oxidation potential at which most metals and compounds are oxidized and reconstructed, [ 78 ] leading to the change in activity and stability of catalysts. Such a change becomes critical to designing OER catalyst at HCDs.…”

Energy‐Saving Hydrogen Production by Seawater Electrolysis Coupling Sulfion Degradation

“…The OWS efficiency is fundamentally restricted by a high potential barrier of anodic OER (1.23 V vs RHE) with slow multiple proton-coupled electron-transfer kinetics. [16][17][18][19][20] Such a thermodynamic difficulty predetermines high cell voltages (>1.7-2.4 V) and electricity expense of the commercial alkaline water electrolysis. Replacing the OER by faster electro-oxidation reactions with lower potential offers a ground-breaking solution to this problem.…”

Organic/Inorganic Hybrid Fibers: Controllable Architectures for Electrochemical Energy Applications

“…At present, IrO 2 and RuO 2 are identified as the best OER catalysts because of their superior stabilities in acidic environments, but their scarcity and high cost impede the scale-up of these materials for commercial applications. [190,191] To date, many efforts have been devoted to exploit nonprecious metal-based catalysts, such as metal alloys, oxides, hydroxides, phosphates, and carbides. [192][193][194] Due to the simplicity of functionalization, fibrous materials are considered to be an ideal substrate for growing the above functional materials.…”