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 457.8 molH2 min–1 molcat–1 under ambient conditions. CoRu0.25@N-C can readily perform both NH3BH3 hydrolytic dehydrogenation and electrochemical hydrogen evolution as a result of its highly specific surface area, carbon layer protection, metal vacancies, and a porous carbon matrix doped with heteroatoms. The creation of a multifunctional composite/hybrid by the use of small metal organic molecules can lead to cost-effective and highly efficient catalysts for energy conversion.