Effects of Organic Compounds on Ni/AlLaCe Catalysts for Ammonia Decomposition to Hydrogen

Ammonia has attracted extensive attention from scholars due to its high energy density and hydrogen content. In this work, we synthesized a series of Ni-based catalysts by an impregnation method to investigate the influence of organic compounds on Ni/AlLaCe catalysts for NH3 decomposition. The effects of different organic compounds like β-cyclodextrin (β-CD), citric acid (CA), and poly(vinylpyrrolidone) (PVP) on the catalyst structure and performance have been examined through a series of characterizations. Experimental results indicated that citric acid significantly affects the size of the active metal particles and promotes metal–support interaction compared to other organic compounds. At the same time, the introduction of citric acid increased the number of strongly basic sites and oxygen vacancies of the catalyst. Among the catalysts tested, the NALC-60CA sample demonstrated a high conversion of 99.7% for ammonia decomposition at a gas hourly space velocity of 30,000 mL·h–1·g–1 and a temperature of 600 °C. Additionally, NALC-60CA exhibited good stability during a 55 h activity test at a temperature of 525 °C.