Twisted Ru Homostructures Enable High‐Efficiency Alkaline Hydrogen Oxidation Reaction

Designing potential catalysts for the alkaline hydrogen oxidation reaction (HOR) to replace Pt is crucial for the development of anion exchange membrane fuel cells (AEMFCs). Ru-based catalysts especially heterostructures are considered to be the most promising alternatives to Pt. However, the activity of Ru-based heterostructures still falls short of displacing commercial Pt-based catalysts, primarily due to their limited number of high-activity sites and high energy barriers for intermediate migration near the interface. Herein, we designed an efficient HOR catalyst on the basis of twisted Ru homostructures. The stress effect and coordination deficiencies generated at the grain boundaries of twisted Ru homostructures could simultaneously optimize the thermodynamics and increase the migration kinetics of intermediates (H* and OH*), effectively overcoming the inherent drawbacks associated with heterostructure catalysts. Owing to the unique electronic structure of the twisted homostructures, our catalyst demonstrated exceptional alkaline HOR catalytic performance (j_k = 77.2 mA cm^-2 @ 50 mV). When evaluated in the fuel cell configuration, the catalyst achieves a record peak power density of 1.81 W cm^-2, surpassing commercial PtRu/C (1.36 W cm^-2) and Pt/C (1.23 W cm^-2), representing the highest performance among reported pure metallic catalysts.