Ultrasmall Pt Nanoparticles-Loaded Crystalline MoO2/Amorphous Ni(OH)2 Hybrid Nanofilms with Enhanced Water Dissociation and Sufficient Hydrogen Spillover for Hydrogen Generation

Generating hydrogen via the alkali-water electrocatalytic hydrogen evolution reaction (HER) is a prospective avenue, in which the key point is to construct the electrocatalyst with excellent catalytic behavior. Herein, a Pt nanoparticles-loaded crystalline MoO2/amorphous Ni(OH)(2) hybrid nanosheets-composed nanofilm (PtNPs-c-MoO2/a-Ni(OH)(2)NF) on Ni foam was designed via a one-step solution-phase strategy for the alkaline HER. The hydrophilic amorphous Ni(OH)(2) in the hybrid nanosheets accelerated water dissociation, and the spillover effect of H atoms from Pt nanoparticles to MoO2 in the hybrid nanosheets increased the utilization of the dissociated H atoms; moreover, the MoO2 and the Ni(OH)(2) heterostructure in the hybrid nanosheets exposed copious active edge sites, which jointly enhanced the HER performance of the Pt NPs-c-MoO2/a-Ni(OH)(2)NF. The density functional theory (DFT) results showed that the water dissociation at Pt/Ni(OH)(2) (-0.24 eV) is thermodynamically more favored than that on Pt(111) (0.62 eV), and the recombination of one H* on Pt and one H* on MoO2 could significantly reduce the energy barrier to only 0.05 eV. The optimized Pt(1.07%)NPs-c-MoO2/a-Ni(OH)(2)NF with similar to 2 nm ultrasmall Pt nanoparticles can achieve 10 mA cm(-2) at an ultralow overpotential of 18 mV and 500 mA cm(-2) at a low overpotential of 167 mV with superior long-term steadiness. Moreover, the mass activity of Pt(1.07%)NPs-c-MoO2/a-Ni(OH)(2)NF achieved 8.24 mA mu g(Pt)(-1) at an overpotential of 70 mV, nearly 21.7-fold that of commercial Pt/C. Our synthesis strategy can be extended to obtain the Pd or Au nanoparticles-loaded c-MoO2/a-Ni(OH)(2) nanofilm with low noble-metal content for enhanced HER activities.

Automated summary

In this study, a Pt nanoparticles-loaded crystalline MoO2/amorphous Ni(OH)2 hybrid nanosheets-composed nanofilm was successfully designed via a one-step solution-phase strategy for efficient alkaline hydrogen evolution reaction (HER). The hybrid nanosheets structure utilized in the catalyst accelerated water dissociation and optimized the utilization of dissociated H atoms, resulting in enhanced HER performance. The density functional theory results indicated thermodynamically favored water dissociation at Pt/Ni(OH)2 and reduced energy barriers for hydrogen adsorption, showcasing the potential for practical applications in hydrogen generation.