Ceria-supported ruthenium clusters transforming from isolated single atoms for hydrogen production via decomposition of ammonia

Ru clusters catalysts have been prepared by reducing atomically dispersed Ru species on CeO2 under ammonia atmosphere. The obtained Ru clusters are uniformly dispersed and stably anchored on CeO2 support. The Ru/CeO2 catalyst shows extremely high catalytic activity and excellent stability for decomposition of ammonia, which gives at least one-order improvement on the hydrogen formation yield than any other catalysts ever reported. [Display omitted] •The stable Ru clusters are prepared by reducing isolated Ru single atoms on CeO2.•Ru clusters anchored on CeO2 act as excellent catalysts for NH3 decomposition.•This high activity is due to the synergic effect between Ru clusters and ceria support. Supported cluster catalyst exhibits significant superiority in catalytic performance, but the structure uniformity and reactivity stability of the clusters under harsh conditions remains challenges. Here, we report the synthesis of stable ruthenium (Ru) clusters (ca. 1.5 nm) by reducing Ru single atoms under ammonia atmosphere at 550 °C, where the Ru clusters are uniformly dispersed on the surface of ceria. The supported Ru cluster catalysts show outstanding activity for decomposition of ammonia with an extremely high hydrogen yield of 9,924 mmolH2 gRu−1 min−1 at 450 °C. Such a value exhibits at least one-order enhancement on the hydrogen formation yield compared to the previously reported results. Through comprehensive in-situ characterizations and temperature programmed desorption by NH3 techniques, we clearly explored the structure-function relation of the Ru/CeO2 catalyst that ceria support itself effectively adsorbed ammonia, meanwhile the Ru clusters stabilized by ceria decomposed ammonia to produce hydrogen.