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Journal of Electrochemistry ›› 2017, Vol. 23 ›› Issue (3): 332-339.doi: 10.13208/j.electrochem.161053

• Special issue: 15th National Symposium on organic electrochemistry and electrochemical industry • Previous Articles     Next Articles

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

LUO Wei1, NIU Dong-fang1, DU Rong-bin2, WANG Jun-wei2, WANG Zhu-qing2, XU Heng2, ZHANG Xin-sheng1*   

  1. 1.State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China; 2. Collaborative Innovation Center for Petrochemical New Materials, Anqing 246011, Anhui, China
  • Received:2016-11-25 Revised:2017-02-07 Online:2017-06-29 Published:2017-03-01
  • Contact: ZHANG Xin-sheng E-mail: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.

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

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