Hierarchical Porous g-C3N4 Coupled Ultrafine RuNi Alloys as Extremely Active Catalysts for the Hydrolytic Dehydrogenation of Ammonia Borane

It is a crucial and urgent task to develop high performance catalysts for the hydrolysis of ammonia borane (NH3BH3, AB), which is presently thought to be an effective strategy for hydrogen generation. In this work, we immobilize the ultrafine RuNi alloy nanoparticles in the network of hierarchical porous g-C3N4 thin sheets with a facile adsorption-in situ reduction method. The structural and physicochemical properties of the as-prepared catalysts are studied using various techniques. The influence of different molar ratios of Ru to Ni in the catalysts on the hydrolytic dehydrogenation rate of AB is investigated to optimize the best one. The detailed reaction kinetics and the enhancing effect of NaOH with different dosages on the hydrolysis rate are studied through a series of experiments. Catalyzed by the optimal catalysts (denoted as Ru0.5Ni0.5/p-g-C3N4), the hydrolysis reaction is first-order and near zero-order relative to the Ru and AB concentrations, respectively. The corresponding turnover frequency reaches 840.3 min(-1), and the apparent activation energy is as low as 14.1 kJ mol(-1), which are greatly superior to many similar or counterpart catalysts previously reported. The results indicate the potential of the bimetallic alloy catalysts for the hydrolytic dehydrogenation of hydrogen storage materials.