Efficient hydrogen production from ammonia over Ru-Co/SiC catalysts

This study provides a valuable insight into the influence of the order impregnation of ruthenium and cobalt on β-SiC support as catalysts for efficient green hydrogen production from ammonia. The catalysts were characterized using different techniques such as Temperature Programmed Reduction, X-Ray Diffraction, Transmission Electron Microscopy and Scanning Electron Microscopy. The addition of Ru clearly changed the reduction profile, decreasing the temperature to obtain metallic species. The catalyst prepared by co-impregnation inhibited the formation of Co silicates, which are very difficult to reduce. Additionally, the metal size was also affected by the order of impregnation, with the co-impregnation method showing the smallest crystallite sizes and the highest hydrogen production. On the other hand, it was found that the 2.5 wt.% total metal content catalyst improved the hydrogen production rate by 41% compared to 5 wt.% total metal content at 350 ºC, justifying the use of a lower metal loading. Therefore, the highest activity was achieved with a Ru/Co co-impregnation with a 50/50 weight ratio and a metal loading of 2.5 wt.%, which exhibited excellent activity and stability with 95% conversion over 50 hours of reaction. • Bimetallic Ru-Co catalyst supported on β-SiC is promising for NH 3 decomposition. • Co-impregnation yields the smallest crystal size and prevents Co-silicate formation. • Catalytic properties are enhanced by replacing ~50% of Co with Ru. • The 2.5 wt.% bimetallic catalyst exhibits boosted NH 3 activity compared to the 5 wt.% one.