Catalytically active Ru subnano species on N-doped carbon for anhydrous hydrazine decomposition

The catalytic decomposition of anhydrous hydrazine, a monopropellant, shows widespread utilization in aerospace propulsion systems. The Ru-based catalysts show promising application for this process, while the active configuration of Ru species remains underexplored. Here, we design a series of Ru supported on N-doped carbon (Ru/NC) catalysts to systematically investigate the influence of Ru size and its induced electronic structure on the performance of hydrazine decomposition. It is found that the Ru/NC catalyst with particle size in a subnano scale of ∼1.1 nm (Ru/NC-1.1) exhibits the highest intrinsic activity with complete conversion of hydrazine at 80 °C, better than other Ru-based catalysts with larger size. Various characterizations indicate that the Ru/NC-1.1 catalyst features lower Ru-Ru coordination while higher Ru-N coordination, leading to the formation of more positively charged Ru species. These species can promote the decomposition of hydrazine with a lower energy barrier. This study provides valuable insights for the rational design of highly efficient catalysts for the low-temperature anhydrous hydrazine decomposition.