High-temperature flame spray pyrolysis induced stabilization of Pt single-atom catalysts

Obtaining stable single-atom catalysts (SACs) for high-temperature applications remains challenging due to the thermodynamically favourable metal sintering under harsh reaction conditions. Taking advantage of the high-temperature process conditions (> 1000 °C), we hereby report the preparation of thermally stable metal oxide-supported single-atom Pt catalysts by flame spray pyrolysis. Among the four common supports (Al2O3, SiO2, TiO2 and ZrO2) evaluated, single-atom Pt species were identified on Al2O3, TiO2 and ZrO2, among which ZrO2 was the best to stabilize atomically dispersed Pt. Compared to single-atom Pt catalysts prepared through the conventional impregnation method, samples synthesized by flame spray pyrolysis displayed excellent catalytic performance in CO oxidation, methane combustion and methane partial oxidation reactions. Characterization results revealed that flame spray pyrolysis favoured the formation of tetragonal-monoclinic phase of ZrO2 with improved redox property, thus leading to enhanced catalytic activity in high-temperature applications.