Ruthenium nanoparticles supported on Ni3N nanosheets as bifunctional electrocatalysts for hydrogen oxidation/evolution reactions

The development of highly efficient catalysts for hydrogen oxidation/evolution reactions (HOR/HER) is an urgent requirement for the acceleration of the development of fuel cells and the technique of hydrogen generation by water electrolysis. In this work, we have successfully synthesized a Ru/Ni3N-NF bifunctional catalyst for HOR and HER. Ultra-small Ru nanoparticles were loaded on Ni3N nanosheets grown on nickel foam. Ru/Ni3N-NF presents outstanding HOR and HER performance, and it achieves a current density of 8.83 mA cm(-2) with an overpotential of 50 mV for HOR. Its ultra-high exchange current density of 15.69 mA cm(-2 )is nearly 2 times that of Pt/C and better than that of most reported HOR catalysts. Meanwhile, Ru/Ni3N-NF needs an overpotential of only 22.6 mV to deliver 10 mA cm(-2) for HER in 0.1 M KOH, lower than that for Pt/C and other Ru-based HER catalysts. The excellent bifunctional properties of Ru/Ni3N-NF are attributed to the synergistic catalysis of Ru and Ni3N due to the charge redistribution. In summary, this work provides an excellent example of the use of the synergistic effects of Ru and Ni3N to develop bifunctional electrocatalysts for HOR/HER.