Preparation of Nanoporous Ni and NiO and Their Electrocatalytic Activities for Oxygen Evolution Reaction

Nanoporous Ni was prepared by a combined method of rapid quenching and dealloying, and then the prepared samples were heat-treated to synthesize the nanoporous NiO. The phase, morphology, microstructure and pore-size distribution of nanoporous Ni and NiO were analyzed by X-ray diffraction ( XRD) , scanning electron microscopy (SEM) , transmission electron microscopy (TEM ) and N-2 adsorption-desorption analysis , respectively. Their electrochemical performance was investigated by cyclic voltammetry , electrochemical stea-dy-state polarization and electrochemical impendence spectroscopy (EIS). The results show that the nanoporous Ni obtained from Ni-30 Al-70 has multi-stage nanoporous structure, when the current density is 10 mA/cm(2), the oxygen evolution overpotential is only 224 mV, the exchange current density is 0. 63297 mA/cm(2), and the apparent activation free energy is 40. 297 kJ/mol; after 1000 cycles of voltammetry , the overpotential decreases by 5 mV( j= 10 mA/cm(2)) , showing fine catalysis stability and durability.