Development of highly active Co/Mo2C catalysts for green H2 production from NH3

The development of cost-effective catalysts with excellent catalytic performance is of great interest for ammonia cracking. In this work, an innovative and stable cobalt catalyst supported on a commercial molybdenum carbide material was prepared. The influence of pre-activation treatment on the catalytic activity of a 5Co/Mo 2 C catalyst for ammonia decomposition was investigated using H 2 /Ar and NH 3 /Ar at 400 °C. Both activations resulted in a high ammonia conversion (~ 90%) at 500 °C. XPS analysis revealed that H 2 pre-activation resulted in greater surface Co/Mo ratio and enhanced charge transfer, contributing to increase active cobalt and hence better catalytic activity. The effect of cobalt loading (2.5-10 wt.%) was further optimized, with 7.5Co/Mo 2 C achieving the highest conversion (93.7% at 450 °C), attributed to optimal Co dispersion and crystallite size (~16.8 nm). The addition of a secondary metal (K, Cs or La) to the 7.5Co/Mo 2 C catalyst showed that lanthanum significantly improved the catalytic activity by increasing the basicity, cobalt dispersion, and surface Co/Mo ratio. In contrast, K and Cs had a negative effect, causing agglomeration and reduction of active sites by blocking. These findings indicate that H 2 pre-activation and La promotion were key factors for enhancing ammonia decomposition efficiency on Co/Mo 2 C catalyst. • Cobalt supported on Mo 2 C is a promising catalyst for NH 3 decomposition. • H 2 /Ar pre-activation improves Co reduction, boosting catalytic activity. • The 7.5Co/Mo 2 C catalyst achieves the highest ammonia conversion. • The 7.5Co-La/Mo 2 C catalyst exhibited 95% of conversion for 50 hours of reaction.