Co–Co₂B, Ni–Ni₃B and Co–Ni–B nanocomposites catalyzed ammonia–borane methanolysis for hydrogen generation

Abstract

Co–Co₂B and Ni–Ni₃B nanocomposites were synthesized by the reduction of Co²⁺ and Ni²⁺ ions using ammonia–borane in methanol. The Co–Ni–B nanocomposite was synthesized by the co-reduction of Co²⁺ and Ni²⁺ ions. The catalytic activities of these metal nanocomposites were studied for the dehydrogenation of ammonia–borane in methanol. Three moles of H₂ were liberated in 2.5 min and 4.2 min in case of Co–Co₂B and Ni–Ni₃B nanocomposites, respectively (catalyst/AB = 0.2). The Co–Ni–B nanocomposite showed greater activity compared to individual metal–metal boride nanocomposites: 3 moles of H₂ were liberated in 1.5 min (catalyst/AB = 0.2). The catalysts were highly recyclable and the activities remained almost unchanged even after several cycles.