Phosphorus-doped nickel selenides nanosheet arrays as highly efficient electrocatalysts for alkaline hydrogen evolution

Earth-abundant transition-metal dichalcogenides are considered as promising electrocatalysts to accelerate the hydrogen evolution reaction (HER). Among them, the pyrite nickel diselenide (NiSe2) has been received special attention due to its low cost and high conductivity, but it suffers a poor HER performance in alkaline media possibly attributed to its inadequate hydrogen adsorption free energies. Here, we report a novel P-doped NiSe2 nanosheet arrays anchored on the carbon cloth with an obviously optimized HER performance. The catalyst only needs a low overpotential of 86 mV at a current density of 10 mA cm(-2) and a Tafel slop of 61.3 mV dec(-1),as well as maintains a long-term durability for 55 h in 1.0 M KOH, which is superior to the pristine NiSe2 (135 mV@10 mA cm(-2)) and most recently reported non-noble metal electrocatalysts. The XRD, EDS, TEM and XPS results validated the successful doping of P element into NiSe2 nanosheet, while the density functional theory (DFT) calculation demonstrated the P doping can optimize the electronic structures and the hydrogen adsorption free energy of NiSe2. This work thus opens up new ways for rationally designing high-efficient HER electrocatalysts and beyond. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

A novel P-doped NiSe2 nanosheet arrays anchored on the carbon cloth show significantly optimized HER performance, with low overpotential, high catalytic activity and long-term durability in alkaline media. The successful P doping enhances the electronic structures and hydrogen adsorption free energy of NiSe2, providing new ways for designing high-efficient HER electrocatalysts.