High-entropy layered hydroxide nanocatalysts via in-situ etching-growth of ZIF-67 for robust hydrogen generation from concentrated NaBH 4 solution

Abstract Sodium borohydride (NaBH4) solution is a promising liquid “fuel” for continuous hydrogen supply through catalytic hydrolysis, offering a safer alternative to compressed hydrogen to fuel cells. However, the harsh thermal and chemical environments of concentrated NaBH4 hydrolysis cause rapid catalyst deactivation. Herein, we synthesized a high-entropy layered hydroxide (HELH, FeCoNiCuZn@ZIF-67 (ZIF-67 = zeolitic imidazolate framework-67)) nanocatalyst via an in-situ etching-growth strategy with ZIF-67. The mechanical structure of residual ZIF-67 inside ensures the robustness of active centers and particles. The efficiency of hydrogen generation is guaranteed by the synergy of different metals in high-entropy structures, which involves borohydride adsorption and H2 release. Benefiting from this cooperative architecture, the HELH catalyst achieves a high hydrogen generation rate of 8 L·min−1·g−1 in a 25 wt.% NaBH4 solution. Density functional theory and electrochemical analyses reveal that abundant oxygen vacancies and multi-metal synergy optimize water activation and lower the reaction barrier. This work provides an effective strategy for designing robust high-entropy catalysts for extreme conditions.