Cobalt-Ruthenium Nanoalloys Parceled in Porous Nitrogen-Doped Graphene as Highly Efficient Difunctional Catalysts for Hydrogen Evolution Reaction and Hydrolysis of Ammonia Borane

The development of clean fuels for hydrogen utilization will benefit from low-cost and active catalysts to produce hydrogen via hydrolytic dehydrogenation by electrochemical and chemical means. Herein, we designed and synthesized a high-efficiency and stable catalyst with low-ruthenium content CoRu alloy nanoparticles supported on porous nitrogen-doped graphene layers (CoRux@N-C) via pyrolysis of small organic metal molecules. The amount of ruthenium in the catalyst that showed the highest activity was only 5.07 wt %. CoRu0.25@N-C can efficiently catalyze the hydrogen evolution reaction (HER) with a wide pH range and low overpotential to drive current densities of 10 mA·cm–2 of only 27 mV (1.0 M KOH) and 94 mV (0.5 M H2SO4). CoRu0.25@N-C also showed decent durability with negligible degradation after 1000 cyclic-voltammetry cycles in both acidic and alkaline solutions. It also has excellent catalytic activity and can easily sustain ammonia borane hydrolysis with an initial turnover frequency (TOF) of 457....