Fabrication of superparamagnetic permalloy nanostructures in ZnO matrix by ion beam sputtering

Mahendra, Anmol; Gupta, Prasanth; Murmu, Peter P.; Trompetter, W.J.; Kennedy, John

doi:10.1016/j.matpr.2020.05.475

Cited by 3 publications

(3 citation statements)

References 21 publications

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“…Tungsten thin films were sputtered onto silicon (100) substrates using ion beam sputtering at ambient temperature. 21 Prior to sputtering, the silicon substrates were ultrasonically washed for 5 min in acetone, ethanol, and finally deionized water (18.2 MΩ cm resistivity). Ion beam sputtering was performed at 4 × 10 −6 mbar using an argon ion beam (15 kV, 0.3 mA) directed toward a tungsten target (99.99% pure) inclined at a 45°angle to the beam.…”

Section: Methodsmentioning

confidence: 99%

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Grain Boundary-Rich Tungsten Carbide Nanoparticle Films Exhibit High Intrinsic Activity Toward Hydrogen Evolution

Malone,

Fiedler,

Mitchell

et al. 2024

ACS Appl. Nano Mater.

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Tungsten carbides have an electronic density of states near the Fermi level similar to platinum and are predicted to exhibit high intrinsic activity toward the hydrogen evolution reaction (HER). However, traditional fabrication routes typically require high synthesis temperatures, resulting in undesirable agglomeration and losses in electrocatalytic performance. Herein, we demonstrate the use of thermal spikes, a high-energy transient phenomenon resulting from ion implantation, to synthesize tungsten carbide nanoparticle films without thermal annealing. By precisely controlling the carbon fluence implanted into smooth tungsten thin-film substrates, β-W 2 C, γ-WC, and δ-WC were selectively synthesized. Despite their low surface area, the tungsten carbide films possessed a high density of grain boundaries resulting in excellent intrinsic HER activity and stability (TOF = 11 H 2 s −1 , 10 mA cm −2 for 12 h). These results confirm that ion implantation is a promising approach for synthesizing tungsten carbide nanoparticle films with high intrinsic activity toward HER.

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Section: Methodsmentioning

confidence: 99%

“…Tungsten thin films were sputtered onto silicon (100) substrates using ion beam sputtering at ambient temperature . Prior to sputtering, the silicon substrates were ultrasonically washed for 5 min in acetone, ethanol, and finally deionized water (18.2 MΩ cm resistivity).…”

Section: Experimental Sectionmentioning

confidence: 99%

Grain Boundary-Rich Tungsten Carbide Nanoparticle Films Exhibit High Intrinsic Activity Toward Hydrogen Evolution

Malone,

Fiedler,

Mitchell

et al. 2024

ACS Appl. Nano Mater.

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“…IBS was conducted at 4 × 10 −6 mbar using a Mo target (99.99% purity) and an Ar + beam (15 kV, 0.4 mA). The target and collection angles were 45°and 60°, respectively, following the work of Mahendra et al 21 Ion implantation was conducted using a Penning ion source with carbon monoxide as a precursor gas. 22 Using magnetic mass separation, C + ions were implanted into the Mo films at a pressure of 1 × 10 −7 mbar.…”

Section: Synthesis and Characterizationmentioning

confidence: 99%

High Turnover Frequency for the Hydrogen Evolution Reaction on Molybdenum Carbide Thin Films Synthesized by Ion Implantation

Malone,

Fiedler,

Mitchell

et al. 2023

ACS Appl. Eng. Mater.

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Molybdenum carbides are promising low-cost alternatives to platinum-based catalysts for the hydrogen evolution reaction (HER). In spite of decades of research, scalable and reliable synthetic routes toward electrochemically active molybdenum carbide surfaces have yet to be discovered. Herein, we demonstrate the application of an industrial surface modification technique that is based on low-energy implantation to synthesize films containing the phases γ-MoC, γ′-MoC, η-MoC, β-Mo 2 C, and β′-Mo 2 C with excellent intrinsic HER activity. Smooth molybdenum substrates (<1.5 nm) were selected for the carbon implantation studies. Grazing incidence X-ray diffraction, X-ray photoelectron spectroscopy, and high-resolution scanning transmission electron microscopy results verified the successful formation of molybdenum carbides and the high density of non-aligned phases or grain boundaries in the films. By varying the implantation energy and fluence, selective production of specific molybdenum carbides could be achieved. Specifically, a transition from β-Mo 2 C toward η-MoC was observed with increasing carbon fluence. Despite their small surface area, the molybdenum carbide films were able to efficiently drive HER in 0.5 M H 2 SO 4 with overpotentials as low as 262 mV at 10 mA cm −2 . For the best catalyst, a high turnover frequency (TOF, 18 H 2 s −1 ) and a low Tafel slope (58 mV dec −1 ) were realized. These results encourage the wider use of ion implantation methods for the synthesis of transition metal carbide-based electrocatalysts for HER and other applications.

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Post-deposition heat treatment effect on pH sensing behavior of chemical bath deposited nanostructured zinc oxide

Rosli

Hamid

Zulkefle

et al. 2023

International Journal of Hydrogen Energy

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Fabrication of superparamagnetic permalloy nanostructures in ZnO matrix by ion beam sputtering

Cited by 3 publications

References 21 publications

Grain Boundary-Rich Tungsten Carbide Nanoparticle Films Exhibit High Intrinsic Activity Toward Hydrogen Evolution

Grain Boundary-Rich Tungsten Carbide Nanoparticle Films Exhibit High Intrinsic Activity Toward Hydrogen Evolution

High Turnover Frequency for the Hydrogen Evolution Reaction on Molybdenum Carbide Thin Films Synthesized by Ion Implantation

Post-deposition heat treatment effect on pH sensing behavior of chemical bath deposited nanostructured zinc oxide

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