A research team led by Zhijie Chen and Bing-Jie Ni presents a comprehensive review that positions high-entropy amorphous catalysts (HEACs) as a promising, versatile platform for next-generation water electrolysis. The paper synthesizes structural principles, synthetic routes, mechanistic understanding, performance benchmarks, and practical prospects for HER, OER and overall water splitting.
Why HEACs matter
- Activity and durability synergy: Combining multielement (high-entropy) composition with amorphous structural disorder creates abundant, unsaturated active sites and flexible coordination environments that boost intrinsic activity while tolerating harsh operational conditions.
- Broad operability: HEACs show strong performance across pH regimes and in challenging media such as seawater and industrial wastewater thanks to adaptive surface reconstruction.
- Design space: The multicomponent “cocktail” enables tunable electronic structure and adsorption energetics not achievable in unary/binary catalysts.
Key structural and mechanistic insights
- Abundant defects & flexible coordination: Short-range order, high defect densities, and varied local coordinations expose more active centers and facilitate alternative reaction pathways.
- Multimetallic synergy: Charge redistribution and orbital hybridization among constituent metals tune d-band positions and intermediate binding, optimizing HER/OER steps.
- In-situ reconstruction: Under electrochemical bias many HEACs transform to amorphous–crystalline core–shell or oxy(hydr)oxide surface phases that act as the true active layers while retaining an amorphous core for stability.
Innovative synthetic strategies & architectures
- Diverse, scalable methods: Electrodeposition, hydro/solvothermal synthesis, melt-spinning +dealloying, ball milling and solution chemical reduction are reviewed with their roles in controlling amorphization, composition homogeneity and morphology.
- Nanocomposites & heterostructures: Integrating HEACs with conductive supports (carbon, MXene) or constructing crystalline–amorphous interfaces enhances conductivity, mass transfer and operational robustness.
Applications, benchmarks and outlook
- Performance highlights: Representative HEACs achieve low overpotentials and favorable Tafel slopes for both HER and OER, with several examples demonstrating ampere-level stability in alkaline and saline media.
- Future directions: The authors call for DFT–machine-learning integration for predictive design, deeper operando studies of non-oxide anionic HEACs (for seawater electrolysis), engineering in-situ amorphization interfaces, and coupling water splitting with value-added redox chemistries.
Challenges and opportunities
Scalability, precise control of amorphous site chemistry, conductivity limitations, and reproducible prediction of adsorption energetics on disordered surfaces remain open challenges — yet the review argues these are addressable through high-throughput computation, operando characterization and smart compositional design.
This review delivers a clear roadmap: by embracing controlled disorder and multielement design, HEACs can unlock efficient, durable and scalable electrolyzers. Look out for more experimental and ML-guided advances from this growing community.