Research advances in earth-abundant-element-based electrocatalysts for oxygen evolution reaction and oxygen reduction reaction

Abstract

The oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are crucial half-reactions of green electrochemical energy storage and conversion technologies, such as electrochemical water-splitting devices and regenerative fuel cells. Researchers always committed to synthesizing earth-abundant-element-based nanomaterials as high-efficiency electrocatalysts for realizing their industrial applications. In this review, we briefly elaborate on the underlying mechanisms of OER and ORR during the electrochemical process. Then, we systematically sum up the recent research progress in representative metal-free carbon (C)-based electrocatalysts; metal-nitrogen-C electrocatalysts; and nonprecious-metal OER/ORR electrocatalysts, including transition-metal oxides, phosphides, nitrides/oxynitrides, chalcogenides, and carbides. Among these, some representative bifunctional electrocatalysts for the OER/ORR are mentioned. In particular, we discuss the effects of physicochemical properties-morphology, phases, crystallinity, composition, defects, heteroatom doping, and strain engineering-on the comprehensive performance of the abovementioned electrocatalysts, with the aim of establishing the nanostructure-function relationships of the electrocatalysts. In addition, the development directions of OER and ORR electrocatalysts are determined and highlighted. The generic approach in this review expands the frontiers of and provides inspiration for developing high-efficiency OER/ORR electrocatalysts.

Designing a Schottky coupled p–n junction to enhance the kinetic behavior of the oxygen evolution reaction

“…On the other hand, the scarcity and high cost of these noble metal catalysts further hinder their wide application. 7–9 Therefore, developing highly active and durable non-precious metal OER catalysts is challenging.…”

Hierarchically porous aggregates of Co–N–C nanoparticles for oxygen electrocatalysis

“…Therefore, many efficient bifunctional transition metal-based materials have been developed. 7–15 Currently, metal–organic frameworks (MOFs), 16 two-dimensional (2D) materials 17,18 and transition metal-based catalysts 19 show efficient electrocatalytic ORR/OER activity. Among these materials, M–N–C materials have attracted increasing attention.…”