Crystal-phase-dependent metal-support interaction in Ru/TiO2 catalysts for low-temperature oxidation

Understanding crystal-phase effects in oxide-supported metal catalysts is critical for designing efficient oxidation catalysts. Here, Ru catalysts supported on anatase and rutile titanium oxide (TiO 2 ) were evaluated for the low-temperature catalytic oxidation of representative air pollutants, including propane (C 3 H 8 ), propylene (C 3 H 6 ), carbon monoxide (CO), and ammonia (NH 3 ). Rutile TiO 2 significantly enhances oxidation activity over anatase TiO 2 across all probe molecules. Systematic characterizations reveal that lattice matching between RuO 2 and rutile TiO 2 strengthens the metal-support interaction, promoting high dispersion of Ru species and stabilizing active sites. The highly dispersed Ru species on rutile TiO 2 exhibit superior low-temperature redox properties, directly correlating with enhanced catalytic oxidation performance. In contrast, weaker interaction on anatase TiO 2 results in lower dispersion and reduced activity. These results establish crystal-phase-dependent metal-support interactions as a key factor governing low-temperature oxidation in Ru/TiO 2 catalysts and provide guidance for designing oxide-supported noble metal catalysts for air pollutant abatement.