Hydrogen production by ammonia decomposition over ruthenium supported on SiC catalyst

Abstract

A series of ruthenium catalysts using β-SiC as a support was synthesized with different metal loading (1−5 wt.% of Ru). Catalysts were characterized and tested with hydrogen production by catalytic ammonia decomposition. Additionally, the influence of calcination conditions as well as reduction temperatures (673 K and 873 K) was studied. Ru dispersion and metallic particle size were found to greatly influence catalytic activity. Moreover, calcination in a nitrogen atmosphere could remove a higher proportion of chlorine species derived from the precursor, thereby enhancing catalytic activity. Furthermore, a lower reduction temperature resulted in smaller particle sizes of ruthenium, which were more active in ammonia decomposition. Maximum intrinsic activity was obtained for a Ru size of around 5 nm. The catalyst containing 2.5 wt.% Ru, calcined in a N2 atmosphere and reduced at 673 K resulted in excellent H2 production from ammonia decomposition, with ammonia conversion close to 100% at 623 K was obtained. Porous SiC proved to be a suitable support for the nanosized Ru catalyst and was highly active in hydrogen production from ammonia decomposition. Moreover, this support provided good performance stability after one day of reaction.