Superb Hydrogen Evolution by a Pt Nanoparticle-Decorated Ni3S2 Microrod Array.

Ni3S2 has attracted great interest as a potential alternative catalyst for the oxygen evolution reaction; however, the formation of sulfur-hydrogen bonds on Ni3S2 suppressed the hydrogen evolution reaction (HER), which remains a significant challenge in interface engineering of Ni3S2 structures for enhancing its HER performance. Herein, we demonstrate an efficient strategy for constructing a Pt nanoparticle-decorated Ni3S2 microrod array supported on Ni foam (Pt/Ni3S2/NF) by electrodeposition of Pt nanoparticles on hydrothermally synthesized Ni3S2/NF. The Pt/Ni3S2/NF heterostructure array exhibits an extremely low overpotential of 10 mV at 10 mA cm-2, surpassing that of commercial Pt/C and representing the best alkaline HER catalysts to date. Impressively, at an overpotential of 0.15 V, Pt/Ni3S2/NF displays a Pt mass activity and a normalized current density (against the electrochemical surface area) of 5.52 A mg-1 and 1.84 mA cm-2, respectively, which are 8.8 and 15.3 times higher compared to those of Pt/C, respectively. In addition, this electrode also shows much enhanced catalytic performance and stability in neutral media. Such enhanced HER activities are attributed to the constructed interface in the Pt/Ni3S2 heterostructure array, which synergistically favor water dissociation and subsequent hydrogen evolution, which is supported by density functional theory calculations.