Electrochemical Deposition of Cr from Cr³⁺ in the Mixed Electrolyte of [BMIM]OAc/H₂O

Authors

Wei LUO, State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China;
Dong-fang NIU, State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China;
Rong-bin DU, Collaborative Innovation Center for Petrochemical New Materials, Anqing 246011, Anhui, China;
Jun-wei WANG, Collaborative Innovation Center for Petrochemical New Materials, Anqing 246011, Anhui, China;
Zhu-qing WANG, Collaborative Innovation Center for Petrochemical New Materials, Anqing 246011, Anhui, China;
Heng XU, Collaborative Innovation Center for Petrochemical New Materials, Anqing 246011, Anhui, China;
Xin-sheng ZHANG, State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China;Follow

Corresponding Author

Xin-sheng ZHANG(xszhang@ecust.edu.cn)

Abstract

The electrochemical reduction of trivalent chromium ion (Cr³⁺) to Cr in 1-butyl-3-methylimidazolium acetate ([BMIM]OAc)-H₂O mixed electrolyte was investigated. The cyclic voltammograms showed that the electroreduction of Cr³⁺ in the mixed electrolyte occurred in a two-step process, namely, Cr³⁺ + e → Cr²⁺ and Cr²⁺ + 2e→ Cr⁰, controlled by the diffusion of Cr³⁺ to the electrode. The diffusion coefficient of Cr³⁺ was 1.2×10^-8 cm²/s at 40 ℃ obtained by Rendle-Sevcik equation. The chronoamperomograms of the Cr³⁺ electrodeposition confirmed the three-dimensional instantaneous nucleation mechanism of Cr. The XRD and SEM characterizations on the Cr coating after calcining in argon atmosphere at 600℃ revealed that the coating was composed of Cr and chromium oxide (Cr₂O₃) nanoparticles with an average particle size of 0.48 μm. The elements of Cr and O were obviously detected from the coating obtained at 40℃ and -3.0V by EDX and the mass fraction of Cr reached 83.8%. Comparison in the qualities of coating layers prepared by Cr electrodepositions in [BMIM]OAc, [BMIM]BF₄ and [BMIM]PF₆ electrolytes indicated that the OAc^- was presented in favor of Cr³⁺ reduction.

Graphical Abstract

Keywords

electrodeposition, 1-butyl-3-methylimidazolium acetate, trivalent chromium ion, Cr coating

DOI Link

https://doi.org/10.13208/j.electrochem.161053

Publication Date

2017-06-29

Online Available Date

2017-03-01

Revised Date

2017-02-07

Received Date

2016-11-25

Recommended Citation

Wei LUO, Dong-fang NIU, Rong-bin DU, Jun-wei WANG, Zhu-qing WANG, Heng XU, Xin-sheng ZHANG. Electrochemical Deposition of Cr from Cr³⁺ in the Mixed Electrolyte of [BMIM]OAc/H₂O[J]. Journal of Electrochemistry, 2017 , 23(3): 332-339.
DOI: 10.13208/j.electrochem.161053
Available at: https://jelectrochem.xmu.edu.cn/journal/vol23/iss3/10