Comparative Study of Mono- and Bimetallic (Ni–Co–Fe) Catalysts Supported on LaCeO3 for Ammonia Decomposition

Ammonia decomposition over non-precious metal thermos-catalysts offers a viable and cost-effective pathway for sustainable hydrogen production. In this study, LaCeO3 perovskite was synthesized using a citric acid complexation method and employed as a support for mono- and bimetallic catalysts prepared by incipient wetness impregnation, maintaining a total metal loading of 10 wt%. Structural and surface properties were systematically investigated using BET, XRD, H2-TPR, SEM, TEM, and CO2-TPD. Among the monometallic catalysts (Ni, Co, and Fe), 10%Ni/LaCeO3 exhibited the highest activity, which is attributed to its enhanced reducibility and optimal surface basicity, facilitating NH3 activation. Bimetallic systems (Ni-Co, Ni-Fe, and Co-Fe) with equal metal loadings (5 wt% each) showed better activity compared to their monometallic counterparts following the order: 5%Ni–5%Co/LaCeO3 > 5%Ni–5%Fe/LaCeO3 > 5%Co–5%Fe/LaCeO3. The improved performance of the Ni-Co system is due to structural interactions between Ni and Co, which promote hydrogen desorption and accelerate N–H bond cleavage, while suppressing nitrogen recombination as the rate-limiting step. Further systematic optimization of the Ni/Co ratio showed that 8%Ni–2%Co/LaCeO3 had the highest catalytic activity with consistent performance over 50 h. This optimal composition provides a balanced distribution of active metallic sites and moderate-to-strong basic sites, enhancing NH3 adsorption and intermediate transformation. These findings show that LaCeO3-supported Ni-Co catalysts are promising candidates for efficient hydrogen production from ammonia without using noble metals.