Cited 19 time in webofscience Cited 20 time in scopus

Atomic-Layer-Deposited MoN x Thin Films on Three-Dimensional Ni Foam as Efficient Catalysts for the Electrochemical Hydrogen Evolution Reaction

Title
Atomic-Layer-Deposited MoN x Thin Films on Three-Dimensional Ni Foam as Efficient Catalysts for the Electrochemical Hydrogen Evolution Reaction
Authors
Ramesh, RahulNandi, Dip K.Kim, Tae HyunCheon, TaehoonOh, JihunKim, Soo-Hyun
Issue Date
2019-05
Citation
ACS Applied Materials and Interfaces, 11(19), 17321-17332
Type
Article
Article Type
Article
Author Keywords
molybdenum nitrideatomic layer depositionNi foamconformalityoptimum thicknesshydrogen evolution reaction
Keywords
AmmoniaAtomsCoatingsElectrocatalystsElectrolytesFilm thicknessHigh resolution transmission electron microscopyMolybdenum compoundsNanocrystalsNickelPotassium hydroxideScanning electron microscopyThin filmsX ray photoelectron spectroscopyConformalityHydrogen evolution reactionsMolybdenum nitrideNi foamOptimum thicknessAtomic layer deposition
ISSN
1944-8244
Abstract
Future realization of a hydrogen-based economy requires a high-surface-area, low-cost, and robust electrocatalyst for the hydrogen evolution reaction (HER). In this study, the MoN x thin layer is synthesized on to a high-surface-area three-dimensional (3D) nickel foam (NF) substrate using atomic layer deposition (ALD) for HER catalysis. MoN x is grown on NF by the sequential exposure of Mo(CO) 6 and NH 3 at 225 °C. The thickness of the thin film is controlled by varying the number of ALD cycles to maximize the HER performance of the MoN x /NF composite catalyst. The scanning electron microscopy and transmission electron microscopy (TEM) images of MoN x /NF highlight that ALD facilitates uniform and conformal coating. TEM analysis highlights that the MoN x film is predominantly amorphous with the nanocrystalline MoN grains (4 nm) dispersed throughout it. Moreover, the high-resolution (HR)-TEM analysis shows a rough surface of the MoN x film with an overall composition of Mo 0.59 N 0.41 . X-ray photoelectron spectroscopy depth-profile analysis reveals that oxygen contamination is concentrated at the surface because of surface oxidation of the MoN x film under ambient conditions. The HER activity of MoN x is evaluated under acidic (0.5 M H 2 SO 4 ) and alkaline (0.1 M KOH) conditions. In an acidic electrolyte, the sample prepared with 700 ALD cycles exhibits significant HER activity and a low overpotential (Ε) of 148 mV at 10 mA cm -2 . Under an alkaline condition, it achieves 10 mA cm -2 with βof 125 mV for MoN x /NF (700 cycles). In both electrolytes, the MoN x thin film exhibits enhanced activity and stability because of the uniform and conformal coating on NF. Thus, this study facilitates the development of a large-area 3D freestanding catalyst for efficient electrochemical water-splitting, which may have commercial applicability. © 2019 American Chemical Society.
URI
http://hdl.handle.net/20.500.11750/9900
DOI
10.1021/acsami.8b20437
Publisher
American Chemical Society
Files:
There are no files associated with this item.
Collection:
Center for Core Research Facilities1. Journal Articles


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