Partially oxidized Ni nanoparticles supported on Ni-N co-doped carbon nanofibers as bifunctional electrocatalysts for overall water splitting

The development of efficient and low-cost bifunctional electrocatalysts for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is crucial for the successful implementation of water splitting technologies, which represents a promising and appealing solution to the sustainable-energy conversion. In this work, a nanocomposite electrocatalyst based on partially oxidized Ni nanoparticles supported on Ni-N co-doped carbon nanofibers (PO-Ni/Ni-N-CNFs) was developed using low-cost hydrothermal carbonaceous nanofibers, pyrrole, and NiCl2 as precursors. Benefiting from effective active sites, mesoporous structure, and interlinked nanofiber network, the as-obtained nanocomposite electrocatalyst exhibited superior catalytic activity and durability for both HER and OER in alkaline media. Furthermore, the practical application of PO-Ni/Ni-N-CNFs as a bifunctional catalyst for overall water splitting was demonstrated, with a current density of 10 mA cm−2 achieved at the voltage of 1.69 V.