Enhanced catalytic performance of the carbon-supported Ru ammonia synthesis catalyst by an introduction of oxygen functional groups via gas-phase oxidation

Carbon-supported ruthenium catalysts are very promising application in ammonia synthesis. Here we show that the oxygen functional groups can be introduced into carbon preloaded with Ru species by HNO3 gas-phase oxidation treatment. The results reveal that the presence of oxygen functional groups facilitates the desorption of hydrogen species. Moreover, the decomposition of barium nitrate is accelerated, and the ill effects of carbon methanation and hydrogen poisoning are effectively alleviated. The combination of the change in the existing form of Ba promoter, the acceleration in the desorption and exchange of hydrogen species accounts for the superior ammonia synthesis activity of Ru catalyst with HNO3 gas-phase treatment. Understanding the role of oxygen functional groups provides design rules for the rational design of carbon-supported Ru catalyst with highly activity and stability for ammonia synthesis or other hydrogen-involved reactions.