MOF-Stabilized Pd Nanosheets With Exposed Active Crystal Planes for Efficient Hydrogen Evolution.

Achieving the exposure of high-energy active crystal planes is a very challenging issue due to the thermodynamic limitations. Herein, Pd nanosheets with exposed high-energy (1-10) crystal planes were constructed on IRMOF via layer-by-layer (LBL) electrodeposition. The metal-organic framework (MOF) matrix prevents Pd nanosheets aggregation through spatial isolation, while Pd─N bonds with ─NH2 groups in IRMOF stabilize the high-energy Pd (1-10) crystal planes, enabling their continued activity under acidic hydrogen evolution reaction (HER) conditions. Benefiting from the intrinsically favorable hydrogen adsorption thermodynamics of the Pd (1-10) crystal plane and the high density of low-coordination Pd sites, the optimized Pd/IRMOF-3 achieves an ultralow overpotential of 15 and 370 mV at 10 and 1000 mA cm-2, respectively, outperforming commercial Pt/C. Moreover, it exhibits outstanding durability, sustaining HER for 320 h at 10 mA cm-2, accompanied by preserved crystallinity and surface chemistry after long-term HER. This work demonstrates that MOF-stabilized Pd nanosheets with exposed active crystal planes offer a design for achieving simultaneously high activity and long-term stability of electrocatalysts, providing insights for the rational construction of next-generation electrocatalysts.