MoS₂-Coated Ni₃S₂ Nanorods with Exposed {110} High-Index Facets As Excellent CO-Tolerant Cocatalysts for Pt: Ultradurable Catalytic Activity for Methanol Oxidation

Abstract

Methanol oxidation reaction (MOR) efficiency is lowered by poor COads-tolerance and structural stability of Pt-based catalysts. Herein, single crystal Ni3S2 nanorods (with exposed {110} high-index facets) coated with MoS2 particles are grown on nickel foam (MoS2/Ni3S2-nrs/NF) as a low-loading Pt support/cocatalyst (Pt, 0.5 wt %), which not only enhances anti-COads poisoning capacity but also extremely improves the structure stability of the catalyst. Pt/MoS2/Ni3S2-nrs/NF catalyst exhibits a mass activity of 805.4 mA mgPt–1, which is 1.97 times higher than that of commercial Pt/C (10 wt %). It also shows an excellent cyclic durability with 4.6% decline (Pt/C, 40.2%) after 28 h. Electrochemcial tests and theoretical calculations (DFT) reveal that the excellent MOR activity and durability of Pt/MoS2/Ni3S2-nrs/NF are primarily attributed to the close binding effects among Pt, MoS2, and Ni3S2-nrs. Theoretical calculations show that, when Pt nanoparticles deposit on the preconstructed MoS2/Ni3S2-nrs hybrid, they preferentially attach to the single crystal Ni3S2-nrs rather than MoS2 particles. These heterostructures can offer sufficient active sites in radial direction, which energetically promote the charge transfer along axial dimension. Sufficient Mo–Sx edge (interface) sites facilitate OHads generation from H2O decomposition. Meanwhile, OHads can fast react with/eliminate CO-species on MoS2/Ni3S2-nrs attracted from Pt active-sites. Therefore, MoS2/Ni3S2-nrs/NF as a promising MOR support/cocatalyst provides unique perspectives for high-efficient utilization of Pt.