CoNi alloy catalyst supported on Zr-modified Y2O3 for ammonia decomposition to COx-free hydrogen

The increasing focus on renewable energy has led to the exploration of alternative hydrogen carriers, with NH3 emerging as a promising option due to its ability to overcome storage and transportation challenges, as well as its high hydrogen storage capacity. Co and Ni have been identified as effective catalysts in the decomposition of NH3, owing to their affordability and favorable catalytic properties. In this study, Zr-modified Y2O3 carriers were synthesized using the hydrothermal method. Additionally, mesoporous monometallic and bimetallic catalysts were prepared via the co-precipitation method. The study aimed to investigate the impact of active metal loading, specifically loading Co, Ni, and Co-Ni bimetallic on catalyst activity. The study demonstrated that the CoNi(1:2)/5 %Zr-Y2O3 catalyst exhibited the best catalytic performance and stability, achieving a conversion rate of 90.9 % at 550 °C and GHSV = 9000 mL h-1 gcat-1. The catalytic properties of the catalysts were analyzed using XRD, XPS, SEM, EDX, TEM, and H2-TPR characterization. The results showed that the catalysts prepared using co-precipitation had a large specific surface area and a large number of mesoporous. These catalysts also had CoNi alloy particles on their surface, which resulted in a higher catalytic activity than single metal catalysts due to the synergistic interaction between Co and Ni. The suitable bonding energy also enhanced the stability of the catalysts.