Towards high-performance electrocatalysts: Activity optimization strategy of 2D MXenes-based nanomaterials for water-splitting

Water splitting has been considered as a sustainable and environmentally-friendly technique to realize green hydrogen production. However, the production of H2 fuel is restricted by the sluggish kinetics and high overpotentials of the hydrogen evolution and oxygen evolution reactions. It is crucial to seek for high-efficiency electrocatalysts to boost the performance of water splitting. Among a great class of nanomaterials, MXenes-based nanomaterials can be utilized as excellent substrates to design novel materials due to their large specific surface area (SSA), fast electronic transmission, and excellent mechanical stability. However, the breakthroughs are at the experimental synthesis stage and lack all understanding of basic principles on catalytic mechanism, and then severely impede the development of high-efficiency electrocatalyst. Hence, some challenges still need to be clarified and resolved for fur-ther applications in electrocatalytic water splitting. In this review, the recent process on the synthesis routes, physical properties and performance improvement strategies for electrocatalytic water splitting of MXenes are summarized. We comprehensively summarize the electrocatalytic water splitting mech-anism of MXenes both experimentally and theoretically. The in-depth discussion on structure-activity relationships and the basic understanding on electrocatalytic mechanisms of MXenes are also reviewed. At last, an insight into the future challenges, opportunities and further research directions of MXenes and related materials in the water-splitting application is prospected. This review offers a significant under-standing for the design and optimization of high-efficiency MXenes-based electrocatalysts in water-splitting applications. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Water splitting is an important technique for green hydrogen production, but its efficiency is limited by the slow kinetics and high overpotentials of the hydrogen and oxygen evolution reactions. MXenes-based nanomaterials show promise as efficient electrocatalysts due to their unique properties, but their catalytic mechanism is not well understood. This review summarizes recent progress in the synthesis, physical properties, and performance improvement strategies of MXenes for electrocatalytic water splitting, and provides insights into the challenges and future research directions of MXenes in this application.