Surface phosphorsulfurization of NiCo2O4 nanoneedles supported on carbon cloth with enhanced electrocatalytic activity for hydrogen evolution

Highlights: • NiCo₂O₄/CC with nanoneedles was used as precursor for the phosphosulphide. • The phosphosulphide can provide the suitable ΔG_H* for hydrogen evolution. • The synergistic effect between phosphosulphide and carbon support contributes to the enhanced activity. The suitable hydrogen-binding free energy (ΔG_H*) of active sites for hydrogen evolution reaction (HER) is the key for enhancing the electrocatalytic performances of transition metal based electrocatalysts. Usually metal/nonmetal elemental doping and unique nanostructure can be used to adjust the MH bonding energy for accelerating both generation and departure of H₂. Herein, a simple in-situ phosphorsulfurization method has been used to synthesized nickel cobalt phosphosulphide (NiCoP|S/CC) nanoneedles grown on the surface of carbon cloth (CC) at low temperature as electrocatalyst for hydrogen evolution reaction (HER) in both acid (0.5 M H₂SO₄) and alkaline (1.0 M KOH) electrolyte solution. Typically, NiCo₂O₄/CC with nanoneedles structure is used as precursor. And NaH₂PO₂ and H₂S is used as phosphorus and sulfur source, respectively. Compared with single metal phosphophides, the enhanced electrocatalytic performance of NiCoP|S/CC for HER can be attributed to the formation of new specie phosphosulphide and synergistic effect between phosphosulphide and carbon support CC. This work provide a new method with adjusting ΔG_H* of active sites for preparing the excellent electrocatalysts for water splitting.