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

摘要

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 degrees 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 mmolH(2) g(Ru)(-1) min(-1) at 450 degrees 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.