High‐Entropy Materials for Water Electrolysis

Abstract

Green hydrogen production by renewables‐powered water electrolysis holds the key to energy sustainability and a carbon‐neutral future. The sluggish kinetics of water‐splitting reactions, namely, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), however, remains a bottleneck to the water electrolysis technology. High‐entropy materials, due to their compositional flexibility, structural stability, and synergy between various elemental components, have recently aroused considerable interest in catalyzing the water‐splitting reactions. Herein, a timely review of the recent achievements is provided in high‐entropy materials for water electrolysis. An overview of different kinds of high‐entropy materials for catalyzing the HER and OER half‐reactions is introduced, followed by a discussion of theoretical and experimental efforts in understanding the fundamental origins of the enhanced catalytic performance observed on high‐entropy catalysts. Various materials design strategies, including control of size and shape, construction of a porous structure, engineering of defect, and formation of hybrid/composite structure, to develop high‐entropy catalysts with improved catalytic performance are highlighted. Finally, the remaining challenges are pointed out and the corresponding perspectives to address these challenges are put forward to promote the development of the research field of high‐entropy water‐splitting catalysts.

Amorphous Co-Mo-B Film: A High-Active Electrocatalyst for Hydrogen Generation in Alkaline Seawater

“…The growing global energy crisis and environmental problems caused by the massive consumption of traditional non-renewable resources drive humans to explore eco-friendly and renewable energy, and hydrogen (H 2 ) is a desirable alternative to fossil fuels on account of its high calorific value and pollution-free features [ 1 , 2 , 3 , 4 ]. Water electrolysis technology provides a facile and sustainable route for the massive generation of high-purity H 2 [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 ].…”

B-site substitution in NaCo1−2xFexNixF3 perovskites for efficient oxygen evolution

“…Thus, electrocatalysts with high activity are desired to enhance the overall efficiency of these energy-conversion devices. [1][2][3][4][5][6] Although noble metal oxides (e.g. IrO 2 and RuO 2 ) are considered as high-activity catalysts, their typical high cost and severe scarcity have restricted their large-scale application.…”

Nanoneedles of Mixed Transition Metal Phosphides as Bifunctional Catalysts for Electrocatalytic Water Splitting in Alkaline Media

“…In this work, we changed their chemical environment by preparing a series of mixed compounds (Ni/Co and Ni/Fe) to understand their reciprocal interaction and synergic effects. The interaction of different metals in close contact is an approach used to overcome the OER slow kinetics for water electrolysis and metal–air batteries [ 18 , 19 , 20 , 21 , 22 ]; this approach is also the founding principle of the chemical activity of high-entropy materials [ 23 ]. The combination of Ni and Co has been deeply investigated for HER, where the synergy among the catalytic properties of Ni, which lowers the HER over-potential, and Co, which increases the hydrogen adsorption, is realized and allows to obtain a larger value of exchange current density [ 24 ].…”