Preparation of Silicon Carbide Supported Iron Catalysts and their Catalytic Activities in Hydrogen Production by Ammonia Decomposition

In this study, silicon carbide (SiC) was prepared from sol–gel process combined with subsequent carbothermal reaction. Then through hydrothermal method synthesized xFe/SiC-700 and 30Fe/SiC-T catalysts. The catalysts were characterized by XRD, SEM/TEM, XPS, and H₂-TPR. The ammonia decomposition performances of the catalysts were assessed in a fixed-bed reactor. Tests revealed that SiC has a high specific surface area and can evenly diffuse Fe₂O₃ nanoparticles, thus exposing more active sites and raising the adsorption capacity of catalysts surface. The interaction of Fe₂O₃ and SiC is stronger, the catalyst activity is better. The surface basicity of catalyst is higher, decomposition ability of ammonia is stronger. 30Fe/SiC-700 catalyst has the best activity among the synthesized catalysts for hydrogen production by ammonia decomposition. The ammonia conversion rate can reach up to 90.16%, and the hydrogen generation can rate reach up to 30.19 mmol·min⁻¹·gcat⁻¹ at 600 °C at 30,000 mL·gcat⁻¹·h⁻¹. Moreover, the catalytic activity is efficient and stable after continuous reaction at 600 °C for 160 h.

Ammonia decomposition: The silicon carbide supported iron oxide catalyst was prepared, which effectively cracked ammonia to produce CO_X-free H₂.