In-situ growth of carbon nanotubes on Ni/NiO nanofibers as efficient hydrogen evolution reaction catalysts in alkaline media

Abstract

Abstract A novel hierarchical structure of carbon nanotubes grown on Ni/NiO composite nanofiber has been in-situ fabricated by electrospinning and following low-temperature (500 °C) vacuum thermal treatment. During vacuum thermal treatment, decomposition of electrospun nickel acetate/polyvinylpolypyrrolidone precursor nanofibers generate gases as a function of both reducing agents and carbon sources for NiO reduction and carbon nanotubes growth. The thermal treatment processing parameter, i.e. heating rate, controls the morphology and composition of the resulting Ni nanofibers or Ni/NiO‑carbon nanotubes composite nanofibers. This proposed method avoid the usual extra introduction of reducing agents and carbon source. It is a low cost, high yield and safe no-hazard technique. Then, these non-noble metal-based nanofibers are applied as efficient electrocatalysts for the hydrogen evolution reaction in alkaline solution. The Ni/NiO‑carbon nanotubes (10 °C min−1) can drive 10 mA cm−2 at an overpotential of 98 mV in 1 M KOH, which is 52 mV less than for Ni nanofibers. This work offers promising novel catalyst materials in water-splitting devices for large-scale production of hydrogen fuel.