One-step Nanoporous Structure Formation Using NiO Nanoparticles: Pore Size Control and Pore Size Dependence of Hydrogen Evolution Reaction

A nanoporous nickel with tunable pore size was prepared with a one-step annealing method using nickel oxide nanoparticles. The in situ formation of nanoporous structures occurs by the sequential cooperation of reduction of nickel oxide on the surface and anisotropic reconstruction of reduced nickel under a hydrogen reductive atmosphere. The nickel oxide skeleton inside the nanoporous structures plays an important role to suppress coarsening of nanoporous structures. The resulting tunable nanoporous nickel provides good understanding of pore size dependence in the hydrogen evolution reaction in electrolysis of water. One-step synthesis of nanoporous non-precious metal using NiO nanoparticles has been developed to tune morphology and catalytic abilities. During annealing under hydrogen atomosphere, the NiO skeleton inside nanoporous structures suppress rapid pore growth, controlling pore diameter from 10 to 250 nm. The smallest nanoporous Ni demonstrates excellent catalytic activities in electrolysis of water as precious metal-free electrodes.