p–p Orbital Hybridization Stabilizing Lattice Oxygen in Two‐Dimensional Amorphous RuO x for Efficient Acidic Oxygen Evolution

Developing efficient Ru-based catalysts is crucial in reducing reliance on costly Ir for the acidic oxygen evolution reaction (OER). However, these Ru-based catalysts face a fundamental stability challenge due to the highly reactive nature of lattice oxygen. In this work, we propose an effective strategy to stabilize lattice oxygen in 2D amorphous RuO_x through p-p orbital hybridization by incorporating dopants such as Al, Ga, and In. Notably, Ga doping exhibits remarkable acidic OER performance, leading to a 137 mV reduction in overpotential at 10 mA cm^-2 and a 125-fold improvement in stability compared to undoped RuO_x. This also surpasses the performances of most reported Ru-based catalysts. In contrast, doping with other elements from the same period, such as Mn, Co, or Cu, shows negligible improvements in catalytic performance. In situ electrochemical spectroscopic analysis, couples with theoretical calculations, reveals that the p-p orbital hybridization in the Ga-O coordination within Ga-RuO_x effectively reduces the reactivity of lattice oxygen, suppresses the overoxidation of Ru, and switches the reaction pathway from the lattice oxygen mechanism to the adsorbate evolution mechanism. This novel p-p orbital hybridization strategy holds great potential for the development of efficient and robust electrocatalysts for OER and beyond.