Self‐Templated Fabrication of MoNi₄/MoO_3‐x Nanorod Arrays with Dual Active Components for Highly Efficient Hydrogen Evolution

Abstract

A binder-free efficient MoNi /MoO nanorod array electrode with 3D open structure is developed by using Ni foam as both scaffold and Ni source to form NiMoO precursor, followed by subsequent annealing in a reduction atmosphere. It is discovered that the self-templated conversion of NiMoO into MoNi nanocrystals and MoO as dual active components dramatically boosts the hydrogen evolution reaction (HER) performance. Benefiting from high intrinsic activity, high electrochemical surface area, 3D open network, and improved electron transport, the resulting MoNi /MoO electrode exhibits a remarkable HER activity with extremely low overpotentials of 17 mV at 10 mA cm and 114 mV at 500 mA cm , as well as a superior durability in alkaline medium. The water-alkali electrolyzer using MoNi /MoO as cathode achieves stable overall water splitting with a small cell voltage of 1.6 V at 30 mA cm . These findings may inspire the exploration of cost-effective and efficient electrodes by in situ integrating multiple highly active components on 3D platform with open conductive network for practical hydrogen production.

Fabrication of NiC/MoC/NiMoO4 Heterostructured Nanorod Arrays as Stable Bifunctional Electrocatalysts for Efficient Overall Water Splitting

“…The schematic procedure for the fabrication of 3D NiC/MoC/NiMoO 4 heterostructured nanorod arrays is illustrated in Scheme . Through a facile hydrothermal process, NiMoO 4 nanorods were initially synthesized on NF (first step) . In the second hydrothermal process, the as‐synthesized NiMoO 4 nanorods were partially converted into NiC/MoC by introducing a dopamine source and annealing treatment to form NiC/MoC/NiMoO 4 heterostructured nanorod arrays (second step).…”

“…There is a stronger peak at 286.3 eV, corresponding to C 1 s in NiC/MoC/NiMoO 4 ‐30, than that of the same peak in NiMoO 4 , which further confirms the existence of MoNiC x . As shown in Figure c, the HR Mo 3 d signal of NiC/MoC/NiMoO 4 samples could be deconvoluted into three typical components at 228.4, 231.4, and 234.7 eV, corresponding to Mo 2+ , Mo 4+ , and Mo 6+ , respectively . The two peaks at 231.4 and 234.7 eV in the spectrum of NiMoO 4 are attributed to Mo 4+ 3 d 3/2 and Mo 6+ 3 d 3/2 , respectively.…”

Prereduction of Metal Oxides via Carbon Plasma Treatment for Efficient and Stable Electrocatalytic Hydrogen Evolution

“…Also the reduction is still unstable and obvious degradation of HER catalytic activity is observed for the H 2 ‐annealed NiMoO 4 , Co 3 O 4 , and NiO (see Figure S1d, Supporting Information). Zhang et al and Chen et al treated NiMoO 4 nanorods by reducing under an H 2 atmosphere. While the electrodes after H 2 reduction show good catalytic performance in both studies, the nanorod surfaces were directly exposed and might be subject to oxidation during operation in the KOH electrolyte.…”

Network‐Like Ni1−xMox Nanosheets: Multi‐Functional Electrodes for Overall Water Splitting and Supercapacitor

“…[44][45][46][47][48][49] The corresponding satellite peaks are located at the higher binding energies . [50][51][52][53][54][55][56] The oxidation states of Ni and Mo are commonly observed in the XPS spectra because of oxidization in air. [50][51][52][53][54][55][56] The oxidation states of Ni and Mo are commonly observed in the XPS spectra because of oxidization in air.…”