NiCoP fibers as novel catalysts for hydrogen evolution in alkali and acidic environment

Abstract

NiCoP transition metal phosphide has been recognized as a most promising candidate to alternate the noble metals in hydrogen evolution reaction. Herein, it is first time presented the facile preparation of NiCoP electrocatalyst in form of fibers with dominant 1D structure formed by needle-less electrospinning technology and finalized by defined heat treatment process. The study provides a precise method for the preparation of NiCoP or similar phosphide fibers, together with an experimental proof of their excellent electrocatalytic performance in alkali and acidic environments. The as-prepared fibrous NiCoP electrocatalyst sintered in air at 900 °C followed by sintering at 700 °C in Ar/H2 exhibits low hydrogen evolution reaction overpotential (η10) of 141 mV in alkali and 146 mV in acidic environment corresponding with low Tafel slopes of 53 and 97.8 mV/dec, respectively. The bimetallic phosphide also shows superior oxygen evolution reaction activity in alkaline medium 1 M KOH with satisfying durability in long-term stability tests. The highly innovative fibrous form of the material not only plays a significant role in regulation of the electronic structure and boosting the electrochemical active sites and thus the electrocatalytic performance in water splitting technology, but also allows tuning of the electrode electric conductivity, occurrence of the active sites probability and thus utilisation of the electrode, together with its permeability and mechanical stability.