Rare‐Earth‐Induced Charge Polarization in Medium‐Entropy Alloy Driving Fast Hydrogen Generation

Abstract Ammonia borane (NH 3 BH 3 , AB) is an ideal hydrogen storage material due to its high hydrogen content (19.6 wt%) and ambient stability. However, the large‐scale application of hydrogen production via catalyzed AB methanolysis is limited by the sluggish methanol dehydrogenation kinetics. Particularly, the adsorption and activation steps in this process are not clearly distinguished and investigated comprehensively, which hinders the development of highly efficient catalysts. Herein, a rare‐earth‐induced charge polarization strategy is employed to design catalysts with pronounced interatomic charge differences. A rare‐earth element with strong electron‐donating ability is introduced to the CuCoNi medium‐entropy alloy (MEA) system to modulate the charge distribution. As a result, positively charged La atoms preferentially adsorb O atoms via electrostatic interactions, while negatively charged Cu/Co/Ni atoms can donate electrons to promote H radical dissociation. This adsorb‐activate cooperation significantly enhances the catalytic efficiency of AB methanolysis. The optimized CuCoNiLa 0.3 /C MEA nanoparticles catalyst achieves a turnover frequency (TOF) of 147.9 mol H2 mol cat −1 min −1 at 30 °C, which presents a substantial improvement compared to the CuCoNi/C (98.1 mol H2 mol cat −1 min −1 ). This work provides a reliable strategy for designing high‐performance catalysts for AB methanolysis.