Transition metal carbide-based nanostructures for electrochemical hydrogen and oxygen evolution reactions

Abstract

Extensive consumption of limited fossil fuel resources generates serious environmental problems, such as release of large amounts of the greenhouse gas CO₂. It is, therefore, urgently necessary to look for alternative energy resources to meet increasing energy demands. Hydrogen is a clean, environmentally friendly, and sustainable energy source. Electrochemical water splitting is one of the cleanest and greenest technologies available for hydrogen production. Unfortunately, large-scale water electrolysis is hindered by the high costs of catalysts, since noble metal-based materials have been demonstrated to be the best catalysts (e.g., Pt for the cathode and Ru/Ir-oxide for the anode catalyst). Recently, transition metal carbides (TMCs) have drawn significant attention for use in electrochemical water splitting, especially for hydrogen evolution reactions, owing to their high intrinsic catalytic activities, extraordinary electrical conductivities, and abundant source materials. TMCs exhibit Pt-like electronic structures and are considered suitable alternatives for Pt. This review systematically summarizes recent advances in the uses of representative TMCs for the electrochemical hydrogen and oxygen evolution reactions and highlights advantages in the electrocatalytic effects provided by nanostructuring. Finally, existing challenges and future perspectives for use of these electrocatalysts are discussed.