Nanostructured Bifunctional Redox Electrocatalysts

Abstract

Electrocatalysts are playing a prominent role in the design of renewable energy devices. Benefiting from a long and prosperous history of synthesizing individual hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) electrocatalysts, the development of bifunctional ORR/OER or HER/OER electrocatalysts has recently emerged as a new research hotspot. In this review, a brief account of recent developments of bifunctional electrocatalysts for ORR/OER and HER/OER are introduced, aiming to provide insights into theoretical understanding of these reactions through analysis and comparison of various bifunctional electrocatalysts. The related reaction mechanisms and the associated activity descriptors for aforementioned reactions in the recent literatures are also presented. Different series of bifunctional electrocatalysts with much improved performances are discussed in detail and their design principles are outlined. Finally, the existing challenges and the future effort directions for enhancing the performance of bifunctional electrocatalysts are proposed.

Biomass Derived Graphene‐Like Carbons for Electrocatalytic Oxygen Reduction Reaction

“…Intense attention has been drawn to develop highly efficient electrode materials to oxygen reduction reaction (ORR). This reaction is a very key cathodic process in fuel cells and metal−air batteries . As known, platinum‐based catalysts are the most commonly used electrocatalysts for ORR,, but the high cost, poor stability and intolerance to fuel crossover have hampered the large‐scale application of them in renewable energy technologies .…”

Enhancing Oxygen Evolution Reaction at High Current Densities on Amorphous‐Like Ni–Fe–S Ultrathin Nanosheets via Oxygen Incorporation and Electrochemical Tuning

“…Great expectations have been held for electrolytic water splitting technologies with potential renewable and sustainable energy source to meet the rising energy demands 1. As a half reaction process in water electrolysis, the oxygen evolution reaction (OER) severely suffers from the sluggish kinetics and thus restricts the overall efficiency of energy conversion 2.…”

Electrosynthesis of Bifunctional WS3−x/Reduced Graphene Oxide Hybrid for Hydrogen Evolution Reaction and Oxygen Reduction Reaction Electrocatalysis

“…Due to the intimate relationship between HER and ORR, in which the products of the former reaction form the feedstock of the latter reaction, it is desirable to design bifunctional catalysts that exhibit excellent electrocatalytic performances towards both reactions. To this end, many groups have attempted the fabrication of hybrids comprising of different materials that individually display exceptional activities towards either reaction . The composites that demonstrated outstanding activities are often fabricated through energy‐demanding or environmentally damaging methods, which defeats the initial objective for the development of renewable technologies.…”