Heterointerface engineering of Ni/Ni_(3)N hierarchical nanoarrays for efficient alkaline hydrogen evolution

Ni-based transition metal nitrides(TMNs)have been regarded as promising substitutes for noble-metal electrocatalysts towards the hydrogen evolution reaction(HER)due to their low cost,excellent chemical stability,high electronic conductivity,and unique electronic structure.However,facile green synthesis and rational microstructure design of Ni-based TMNs electrocatalysts with high HER activity remain challenging.In this work,we report the fabrication of Ni/Ni_(3)N heterostructure nanoarrays on carbon paper via a one-step magnetron sputtering method under low temperature and N2 atmosphere.The Ni/Ni_(3)N hierarchical nanoarrays exhibit an excellent HER catalytic activity with a low overpotential of 37 mV at 10 mA·cm^(−2)and robust long-term durability over 100 h.Furthermore,the Ni/Ni_(3)N||NiFeOH(NiFeOH=NiFe bimetallic hydroxide)electrolyzer requires a small voltage of 1.54 V to obtain 10 mA·cm^(−2)for water electrolysis.Density functional theory(DFT)calculations reveal that the heterointerface between Ni and Ni_(3)N could directly induce electron redistribution to optimize the electronic structure,which accelerates the dissociation of water molecules and the subsequent hydrogen desorption,and thus boosting the HER kinetics.