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 wt ratio and a metal loading of 2.5 wt%, which exhibited excellent activity and stability with 95 % conversion over 50 hours of reaction.