MXene-Based Electrocatalysts for Alkaline Water Electrolysis: a Review

Abstract

The growth in energy consumption and the limited nature of fossil resources are driving the search for alternative energy sources. Hydrogen is an environmentally friendly fuel, especially when produced by water electrolysis. However, its efficiency depends on the overpotential at the electrodes, which is related to the choice of catalyst. Noble metals, such as platinum, are effective but expensive. An alternative is catalysts based on transition metals, especially in alkaline media, where they are more resistant to corrosion. Oxides, nitrides, sulfides, and phosphides exhibit the highest catalytic activity; however, their efficiency is limited due to particle aggregation and poor adhesion to the substrate. MXene materials – layered transition metal carbides and nitrides – possess high electrical conductivity, stability, and potential for modification. They form robust freestanding electrodes, effectively bind with additives, and provide a large contact area with the electrolyte. This review analyzes hydrogen evolution reaction catalysts in alkaline media based on MXene and its modifications. Key relationships between the composition, structure, and activity of the catalysts are identified, and pathways to improve the quality of research in this field are proposed.