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

Abstract

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.