Effect of Fe²⁺/Fe³⁺Interconvertion on Reduction Behavior of Fe³⁺ in Acidic Electrolytes

Authors

Jian-xin QIN, Guangxi Key Laboratory of super-hard material, National Special Mineral Materials Engineering Technology Research Center, China Nonferrous Metals (Guilin) Geology and Mining Co., Ltd. Guilin 541004, China;Follow
Feng LIN, Guangxi Key Laboratory of super-hard material, National Special Mineral Materials Engineering Technology Research Center, China Nonferrous Metals (Guilin) Geology and Mining Co., Ltd. Guilin 541004, China;
Wen-ping LIU, Guangxi Key Laboratory of super-hard material, National Special Mineral Materials Engineering Technology Research Center, China Nonferrous Metals (Guilin) Geology and Mining Co., Ltd. Guilin 541004, China;
Chao CHEN, Guangxi Key Laboratory of super-hard material, National Special Mineral Materials Engineering Technology Research Center, China Nonferrous Metals (Guilin) Geology and Mining Co., Ltd. Guilin 541004, China;
Meng-de REN, Guangxi Key Laboratory of super-hard material, National Special Mineral Materials Engineering Technology Research Center, China Nonferrous Metals (Guilin) Geology and Mining Co., Ltd. Guilin 541004, China;

Corresponding Author

Jian-xin QIN(qdqinjianxin@163.com)

Abstract

The influences of ferrous/ferric (Fe²⁺/Fe³⁺) interconvertion on electrochemical reduction and electrode reaction of Fe³⁺ were investigated by using linear sweep voltammetry, potentiostatic method and cyclic voltammetry (CV) in acidic electrolytes containing chloride ion (Cl^- ) and sulfate ion (SO₄^2-). It was shown that the reduction process of Fe³⁺/Fe²⁺ would take place in two independent stages: (1) the reduction of Fe³⁺ to Fe²⁺ at E=0.35V and (2) the co-precipitation of Fe²⁺ by forming Fe(OH)₂ (E≤-0.3 V) instead of Fe. The major effect of Fe²⁺/Fe³⁺ interconvertion on the reduction is the |ipa/ipc| of quasi-reversible and equilibrium potential in the first stage. Practically speaking, the |ipa/ipc| values increased with the increase of c(Fe³⁺ )/c(Fe²⁺ ), and the values of |ipa/ipc| at fast sweep rates were less strongly affected than those at slow sweep rates. The least variation in |ipa/ipc| (|i_pa/i_pc|≈1.20) with sweep rate was observed in 0.50 mol·L^-1 Fe²⁺ and 0.50 mol·L^-1 Fe³⁺ solutions. Meanwhile, the equilibrium potential was also affected by c(Fe³⁺ )/c(Fe²⁺ ). The equilibrium potential shifted more positively from E₁=0.501 V in No. ① to E₅=0.565 V in No. ⑤ among the five samples studied in this work.

Graphical Abstract

Keywords

Fe2+/Fe3+ interconvertion, cyclic voltammetry, polarization curve, reduction behavior

DOI Link

https://doi.org/10.13208/j.electrochem.161129

Publication Date

2017-12-28

Online Available Date

2017-03-30

Revised Date

2017-03-03

Received Date

2016-11-29

Recommended Citation

Jian-xin QIN, Feng LIN, Wen-ping LIU, Chao CHEN, Meng-de REN. Effect of Fe²⁺/Fe³⁺Interconvertion on Reduction Behavior of Fe³⁺ in Acidic Electrolytes[J]. Journal of Electrochemistry, 2017 , 23(6): 702-707.
DOI: 10.13208/j.electrochem.161129
Available at: https://jelectrochem.xmu.edu.cn/journal/vol23/iss6/8