Facile construction of ultrastable alumina anchored palladium catalysts via a designed one pot strategy for enhanced methane oxidation†
Improving catalytic activity and stability is imperative for efficient methane oxidation and emission control. Herein, we proposed a designed one pot strategy adopting deoxycholic acid as a template and polyvinylpyrrolidone as a bridging agent to facilely anchor palladium on alumina by building an Al–O–Pd bond. There is no need to introduce foreign elements or perform post-synthetic chemical modifications to the simple-component Pd–Al2O3 catalyst. Due to the bonding, highly dispersed palladium particles could be kept from aggregating even during successive heating and cooling ramps of 250–850 °C, as evidenced by the small variation in particle size (1–2 nm). Encouragingly, the constructed catalysts exhibited an excellent catalytic activity with a T99 of 355 °C, along with the significantly enhanced durability in comparison to conventional Pd/Al2O3 catalysts under demanding conditions (different reaction temperatures with or without water vapor). The enhancement was primarily associated with the stabilized PdO phase, which derived from the anchored small palladium particles and the consequently promoted oxygen mobility.