Metal-specific modulation of Co3O4 in propane oxidation: Contrasting effects of Pt, Pd, and Ru on active sites and reactivities

Co 3 O 4 is a promising catalyst for propane combustion but is limited by poor water resistance and insufficient high-temperature stability. Noble metal loading is widely employed to enhance its performance, however, the metal-specific effects remain poorly understood. In this work, Co 3 O 4 -supported Pt, Pd, and Ru catalysts were systematically investigated for propane oxidation. It was found that all noble metals decreased the surface Co 2+ content and oxygen vacancies, leading to modified redox behavior and propane activation ability. Among them, Ru incorporation enhanced the catalytic activity (T 90 = 266 °C) of Co 3 O 4 (T 90 = 286 °C) and significantly improved its water resistance and thermal stability. These improvements are mainly attributed to the abundant partially oxidized RuO x species, which provide additional active sites and facilitate propane adsorption and activation. In contrast, Pt and Pd modification inhibited propane oxidation due to the intrinsically low activity of highly oxidized Pt species and PdO, as well as the coverage of Co 3 O 4 active sites caused by highly dispersed Pt and particulate PdO. The findings offer mechanistic insights for the rational design of efficient catalysts for propane combustion and VOCs abatement.