Ammonia decomposition for carbon-free hydrogen production over Ni/Al-Ce catalysts: Synergistic effect between Al and Ce

To deeply understand the synergistic effect between Al and Ce in the composite support of Ni-based catalysts for ammonia decomposition, a series of Ni/Al-Ce catalysts with 10 wt% Ni loading were prepared combining coprecipitation and impregnation methods. The activity test results showed that the Ni/Al0.1Ce0.9Ox catalyst exhibited significantly improved activity for ammonia decomposition in the temperature range of 450–600 ℃ compared with Ni/Al2O3, Ni/CeO2, and other Ni/Al-Ce catalysts. Systematic characterization results showed that appropriate ratio of Al and Ce formed an Al-Ce-O solid solution and increased the number of oxygen vacancies on the surface, which induced synergistic effect and played a vital role in the improved activity. Such synergistic effect not only promoted the dispersion of Ni species, facilitated the activation of NH3, but also enhanced the interaction between metal and support. This work provided a new strategy for designing efficient Ni-based catalysts for ammonia decomposition and deepened the understanding of the synergistic effect between Al and Ce in the composite support.