Hollow mesoporous CeO2 microspheres for efficient loading of Au single-atoms to catalyze the water-gas shift reaction

The atomically dispersed catalysts have aroused great attention in the recent decade. However, the preparation of atomically dispersed Au catalysts presents more challenge than other atomically dispersed catalysts such as Pt, Pd, etc. From the aspect of support, this work contributes a novel hollow mesoporous CeO2 microspheres (CeO2-hm) for efficient dispersion of single Au atoms (Au1). Contributed by the high specific surface area and mesoporous structure, CeO2-hm possesses much higher capacity for undertaking Au1, than commercial CeO2 particles (CeO2-c). Typically, with Au loading of 0.2 at%, CeO2-hm supported Au (Au1/CeO2-hm) presents atomic dispersion while CeO2-c supported Au (Au/CeO2-c) contains large amount of Au nanoparticles. Confirmed by catalyzing the water-gas shift (WGS) reaction, the obtained Au1/CeO2 catalysts exhibit notably higher performance than the Au-based catalysts supported by CeO2-c and CeO2 synthesized through co-precipitation and sol-gel strategies. For example, 0.2 at% Au1/CeO2-hm exhibits 9.1 times reactivity of equal Au loaded Au/CeO2-c catalyst. Besides, the CeO2-hm supported single-atom Au catalyst presents good tolerance under long-time WGS running.