Preparation of Co/SiC catalyst and its catalytic activity for ammonia decomposition to produce hydrogen

Abstract

SiC was first synthesized using the sol-gel method and subsequent carbothermal reduction method, then xCo/SiC-700 and 30%Co/SiC-T catalysts were prepared by hydrothermal method and thermal treatment. The structure of the catalysts was characterized by XRD, SEM/TEM, XPS, H2-TPR, CO2-TPD, etc. Their catalytic activities for ammonia decomposition to produce hydrogen were investigated in a fixed-bed reactor. The results showed that the synthesized SiC had a high specific surface area and could evenly disperse Co3O4 nanoparticles, which increased the exposure of active sites and improved the adsorption capacity on the catalyst surface. N2-TPD indicates that 30%Co/SiC-700 has a high N2 adsorption capacity, effectively preventing hydrogen reduction of Co3O4 nanoparticles in the catalyst during ammonia decomposition. CO-TPD shows that Co has the best dispersion on 30%Co/SiC-700 catalyst. CO2-TPD shows the higher the catalyst's basicity, the stronger ammonia's decomposition ability. Among the synthesized catalysts, 30% Co/SiC-700 showed the best catalytic activity for ammonia decomposition, with the ammonia conversion of 78.3% and hydrogen production of 25.0 mmol H2 gcat−1 min−1 at 550 °C under 30,000 mL gcat−1 h−1.