High-entropy alloys in water electrolysis: Recent advances, fundamentals, and challenges

Abstract

As a clean energy carrier, hydrogen energy has become part of the global clean energy strategy and one of the necessary routes to achieve global carbon neutrality. Driven by renewable electricity, water electrolysis promises to be an ideal long-term hydrogen production method that can realize net zero carbon emissions. Compared with conventional alloys, high-entropy alloys (HEAs) have much more catalytic active sites due to their unique structural features including occupation disorder and lattice ordering. They have various promising applications in the field of hydrolysis catalysts. Herein, in this review, the mechanisms of electrolysis of water, catalytic principles of HEAs in hydrolysis processes and latest research progress of HEAs as water electrolysis catalysts are summarized. We also provide perspectives on the difficulties and potential linked to novel HEA design approaches in this attractive sector, with a focus on the connection between both the surface morphology and the catalysis activity. The compositions and possible applications of HEAs in water electrolysis and other emerging fields are outlined.

Hollow Carbon Cages Derived from Polyoxometalate‐Encapsuled Metal‐Organic Frameworks for Energy‐Saving Hydrogen Production

“…Hence, global researchers have dedicated their passion to develop next‐generation energy devices for clean and renewable energy conversion and storage, such as overall water splitting (OWS) devices, [1–3] metal‐based batteries [4–6] and fuel cells [7–9] . Among these technologies, electrocatalytic OWS, consisting of cathodic hydrogen evolution reaction (HER) and anodic OER, is considered as one of the ideal routes to transform renewable energy to hydrogen (H 2 ), due to the high energy density and zero carbon emission of H 2 when using as energy source [10–13] . Ni and Co based electrocatalysts have shown appealing performances towards OWS [14–16] .…”

“…[7][8][9] Among these technologies, electrocatalytic OWS, consisting of cathodic hydrogen evolution reaction (HER) and anodic OER, is considered as one of the ideal routes to transform renewable energy to hydrogen (H 2 ), due to the high energy density and zero carbon emission of H 2 when using as energy source. [10][11][12][13] Ni and Co based electrocatalysts have shown appealing performances towards OWS. [14][15][16] However, the OER process involves multiple electrons along with sluggish kinetics, which hinders the energy efficiency of OWS device.…”

Synthesis of Fe Atom-Doped Monodisperse Co2P Nanorods with a Dual-Ligand Strategy for Excellent Electrocatalytic Hydrogen Evolution Performance

“…The resulting Co 2 P nanorods exhibited uniform size and morphology, which are favorable for enhancing the selectivity and efficiency of catalytic reactions. Compared to other morphologies, nanorods have a higher aspect ratio, which increases the contact area with other substances and enhances the catalytic reaction processes. − When the Co:Fe molar ratio was 1:0.2, Fe-doped Co 2 P nanorods showed the best electrocatalytic activity for the HER. This is because the geometric structure of Fe atoms is similar to that of Co, but with slightly lower electronegativity.…”

Amorphous Fe–Co oxide as an active and durable bifunctional catalyst for the urea-assisted H2 evolution reaction in seawater

“…It is widely accepted that the oxygen evolution reaction (OER) has sluggish kinetics and unreceptive thermodynamics, and the OER largely impedes the overall efficiency of water electrolysis. 12,13 To overcome this obstacle, the oxidation of small molecules (i.e., urea, hydrazine, and glucose) at the anode offers better alternatives for the OER. 14,15 In particular, urea, one of the contaminants in water from agriculture, industrial processes, and animal excrements, can be easily electrooxidized to generate N 2 /CO 2 and the theoretical potential of the urea oxidation reaction (UOR) is much lower than that of the OER, 16 which can theoretically achieve 70% energy saving.…”

“…It is widely accepted that the oxygen evolution reaction (OER) has sluggish kinetics and unreceptive thermodynamics, and the OER largely impedes the overall efficiency of water electrolysis. 12,13 To overcome this obstacle, the oxidation of small molecules ( i.e. , urea, hydrazine, and glucose) at the anode offers better alternatives for the OER.…”