Jiayuan Zhang

Lattice strain engineering, rooted in symmetry-breaking lattice distortion, is an effective strategy for modulating the electronic structure and catalytic performance of electrocatalysts. Herein, non-noble metal CuCoNiCrMo_x high-entropy carbides with tunable Mo content (HEC_Mo-x) were rapidly synthesized within seconds via a high-temperature shock method. By leveraging composition-dependent lattice distortion engineering to deliberately break local translational symmetry, these catalysts were developed to optimize the alkaline hydrogen evolution reaction (HER). Density functional theory calculations reveal that lattice distortion optimizes the d-band center and regulates the electronic configuration. Concurrently, kinetic isotope effect tests and variable-potential electrochemical impedance spectroscopy measurements verify that this modulation balances the reaction kinetics of water dissociation and hydrogen adsorption, thereby accelerating the alkaline HER process. Consequently, the optimized HEC_Mo-15% electrocatalyst exhibits outstanding activity, requiring an overpotential of only 34 mV at 10 mA cm⁻². Furthermore, it exposes abundant active sites and maintains long-term operational stability with negligible attenuation over 23 h. This work provides a feasible design strategy and a practical paradigm for developing non-noble metal high-entropy carbides as highly efficient electrocatalysts for energy conversion applications.

The development of highly efficient and durable electrocatalysts for water electrolysis is fundamentally constrained by sluggish reaction kinetics, limited active-site regulation, and structural degradation under harsh operating conditions. High-entropy materials (HEMs), featuring maximized compositional diversity and configurational entropy, have emerged as versatile platforms for catalytic optimization. However, the rational incorporation of rare-earth (RE) elements into high-entropy systems and their intrinsic roles in regulating catalytic behavior remain largely unexplored. Owing to their unique electronic configurations, large atomic size mismatch, variable oxidation states, and strong affinity toward oxygen species, RE elements provides additional opportunities to manipulate electronic structures, lattice distortion, defect chemistry, and surface reconstruction behaviors within high-entropy frameworks. Rather than cataloguing individual catalyst systems, this review critically organizes RE-regulated HEMs along a structure-activity chain linking the high-entropy host and RE incorporation to local coordination/electronic effects, catalytic pathways, operando reconstruction, and long-term stability. The fundamental design principles and various modulation strategies, along with their catalytic applications toward the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and overall/seawater electrolysis are discussed, along with emphasis on the structure-activity relationships revealed by advanced characterization techniques and theoretical calculations. Finally, the remaining challenges and perspectives associated with RE incorporation regarding the activity-stability trade-off, long-term structural evolution, resource efficiency, and practical scalability are analyzed, aiming to offer guidelines for the rational design of RE-engineered high-entropy electrocatalysts with optimized activity, stability, and practical applicability for sustainable energy conversion technologies.