Electrochemical Behavior of Co(II) Reduction for Preparing Nanocrystalline Co Catalyst for Hydrogen Evolution Reaction from 1-ethyl-3-methylimidazolium Bisulfate and Ethylene Glycol System
| Autor: | Zhengyang Sun, Luye Wu, Xinkuai He, Qingtian Zou, Jianbing Jiang |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Renewable Energy Sustainability and the Environment 020209 energy Nucleation 02 engineering and technology Glassy carbon Chronoamperometry Condensed Matter Physics Nanocrystalline material Surfaces Coatings and Films Electronic Optical and Magnetic Materials Catalysis chemistry.chemical_compound chemistry Chemical engineering Ionic liquid 0202 electrical engineering electronic engineering information engineering Materials Chemistry Electrochemistry Cyclic voltammetry Ethylene glycol |
| Zdroj: | Journal of The Electrochemical Society. 166:D57-D64 |
| ISSN: | 1945-7111 0013-4651 |
| DOI: | 10.1149/2.0981902jes |
| Popis: | The electrochemical behavior of Co(II) reduction and Co nucleation/growth process on glassy carbon (GC) electrode in 1-ethyl-3-methylimidazolium bisulfate ([EMIM]HSO4) ionic liquid (IL) and ethylene glycol (EG) system is investigated. Cyclic voltammetry (CV) measurements indicate that Co(II) reduction occurs by a one-step process, Co(II) to Co(0), and it is an irreversible reaction. The diffusion coefficient of Co(II) is 2.24 × 10−6 cm2 s−1 at 323 K in the system. Chronoamperometry measurements show that the growth/nucleation process of Co on GC electrode in [EMIM]HSO4-EG is a three-dimensional (3D) progressive nucleation at lower overpotentials and instantaneous nucleation at higher overpotentials under diffusion controlled growth process. These effects of electrodepositing potential, current density and temperature on Co coating thickness are also investigated. The Co coatings are observed by energy dispersive spectrometer (EDS), scanning electron microscope (SEM) and X-ray diffractometer (XRD). SEM micrographs confirm that the Co coatings are relatively loose with a fibrous surface morphology. XRD pattern of the prepared coating reveals the characteristic peak of crystalline Co with a preferred orientation direction and the average size of Co grains is 11 nm. The nanocrystalline Co coating exhibits an excellent catalytic activity and stability for hydrogen evolution reaction (HER) in alkaline medium. |
| Databáze: | OpenAIRE |
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