Highly Active Ruthenium Catalyst Supported on Barium Hexaaluminate for Ammonia Decomposition to CO_<i>x</i>-Free Hydrogen

Abstract

Barium hexaaluminate (BHA) obtained from a reverse microemulsion-mediated route is used as a support for Ru nanoparticles to catalyze the NH3 decomposition reaction, and the relationships between the structure and the catalytic performance over Ru/BHA have been disclosed based on the results of various characterization techniques. Ru/BHA is found to be the most active catalyst among all of the tested Ru catalysts supported on conventional MgO, Al2O3, and CNTs used commonly in NH3 decomposition. Moreover, the activation energy over Ru/BHA is 65.0 kJ/mol; this value is about 1/2 of that for Ru/Al2O3 (121.7 kJ/mol) and Ru/MgO (102.8 kJ/mol). It is also found that the presence of electronic interactions between Ru and BHA would improve the electron density and enhance the rate of recombinative desorption of nitrogen over the Ru surface, leading to excellent catalytic activity. Additionally, alleviation of hydrogen poisoning is also preferable for ammonia decomposition.