Enhanced NH3 decomposition for H2 production over bimetallic M(M=Co, Fe, Cu)Ni/Al2O3

Ammonia (NH 3 ) has been regarded as an attractive energy source for hydrogen production via catalytic decomposition , especially over non-noble metal catalysts . Owing to the decent performance and low cost, nickel (Ni) based catalysts have been widely studied for catalytic decomposition of NH 3 where the decomposition rates, can be further tailored by adding other metals. Herein, we synthesized bimetallic M(M = Co, Fe, Cu)Ni/Al 2 O 3 catalysts delivering superior catalytic performance at a wide temperature range of 350–750 °C. Co-Ni/Al 2 O 3 demonstrated nearly 100% conversion of NH 3 decomposition to H 2 at 700 °C and the gas hourly space velocity of 30,000 ml g −1  min −1 , which was ~20.85% higher than that of intrinsic Ni/Al 2 O 3 . The structural characterizations indicated that Co could decrease the particle size and enhance the dispersion of active sites. The density functional theory calculations substantiated that the associative decomposition of N to generate N 2 was the rate-determining step of the NH 3 decomposition reactions . NH 3 Temperature Programmed Desorption (TPD) results suggested that the enhanced catalytic performance was predominantly attributed to the Co that decreases the energy barrier for the associative decomposition of N to form N 2 . This study provides new insights in designing diverse catalysts for efficient NH 3 decomposition for controllable H 2 production.