Pt nanoparticles on (Ni0.5Co0.5)2P/S-doped carbon nanofibers as electrocatalysts for an efficient hydrogen evolution reaction

Abstract

Owing to the clean and environment friendly advantages, electrochemical water splitting stands out among various hydrogen production strategies. Electrocatalysts play an important role in the hydrogen evolution reaction (HER). Hence, Pt-(Ni_0.5Co_0.5)₂P/S-carbon fibers as electrocatalysts for highly efficient HER were prepared through the structural designing of CNF and heteroatom doping (sulfur (S) or boron (B)). First, three composites of the (Ni_0.5Co_0.5)₂P/carbon fiber ((Ni_0.5Co_0.5)₂P/CNF), (Ni_0.5Co_0.5)₂P/porous carbon fiber ((Ni_0.5Co_0.5)₂P/PCNF), and (Ni_0.5Co_0.5)₂P/hollow porous carbon fiber ((Ni_0.5Co_0.5)₂P/HPCNF) were fabricated via a facile electrospinning with a solvothermal method. (Ni_0.5Co_0.5)₂P/PCNFs showed the smallest overpotential at a current density of 10 mA cm⁻² among the three structures. (Ni_0.5Co_0.5)₂P nanosheets loaded on the porous CNF with a large active surface area may expose active sites and shorten the ion transport channel. To improve the catalytic performance of (Ni_0.5Co_0.5)₂P/PCNF, Pt nanoparticles were anchored on (Ni_0.5Co_0.5)₂P/heteroatom doped-PCNF by the chemical reduction method. Pt-(Ni_0.5Co_0.5)₂P/S doped-PCNF exhibited a small overpotential of 64 mV for the HER with 74.9 mV dec⁻¹ Tafel slope and a good stability, which was attributed to the conductive S-doped PCNF facilitating electron transport, accompanying the synergistic effect between the bimetallic phosphide and Pt nanoparticles, thus providing a facile method for an efficient HER electrocatalysis.