Ni/NiO nanoparticles embedded inporous graphite nanofibers towards enhanced electrocatalytic performance

Abstract

Ni/NiO nanoparticles (NPs) were encapsulated in one dimensional (1D) graphitic nanofibers using a two-step calcination route. The precursor fibers obtained by electrospinning were heated in air at a low temperature firstly, followed by calcination at high temperature in Ar. With changing the amount of Ni precursors and preparation conditions, the morphology of resulting samples were adjusted from porous nanofiber to nanotube-loaded bulky material. The sizes and distribution of Ni/NiO NPs also changed. These NPs were in and on the nanofibers or located on the top of nanotubes. Electrochemistry test results indicate that resulting sample revealed enhanced electrocatalytic hydrogen evolution reaction (HER) when the precursor contained 0.5 mmol Ni. In an alkaline medium, the current density of samples could reach up to 280 mA cm−2. This is ascribed to the homogeneous distribution of Ni/NiO NPs and the porous structure of nanofibers with a large surface area of 251 m2/g. In contrast, the HER performance of nanotube-loaded bulky material get worse due to the disadvantage of specific surface area.