Investigation of electrochemical reduction of GeO2 to Ge in molten CaCl2-NaCl

Rong, Liangbin; He, Rui; Wang, Zhiyong; Peng, Junjun; Jin, Xianbo; Chen, George Z.

Abstract

Electrochemical reduction of solid GeO2 has been investigated in the mixed CaCl2-NaCl melt at 1023 K for developing a more efficient process for preparation of Ge. Cyclic voltammetry and potentiostatic electrolysis were applied to study the GeO2-loaded metallic cavity electrode. In addition, porous GeO2 pellets were reduced by potentiostatic and constant cell voltage electrolysis with a graphite anode, and the electrolysis products were analyzed by powder X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectrometry, focusing on understanding the reduction mechanism and the impact of electrode potential on the product purity. It was found that the reduction of GeO2 to Ge occurred at a potential of about -0.50 V (vs. Ag/Ag+), but generating various calcium germanates simultaneously, whose reduction was a little more difficult and needed a potential more negative than -1.00 V. However, if the cathode potential exceeded -1.60 V, Ca (or Na) - Ge intermetallic compounds might form. These results gave an appropriate potential range between -1.10 and -1.40 V for the production of pure germanium. Rapid electrolysis of GeO2 to pure Ge has been realized at a cell voltage of 2.5 V with a current efficiency of about 92%.

Citation

Rong, L., He, R., Wang, Z., Peng, J., Jin, X., & Chen, G. Z. (2014). Investigation of electrochemical reduction of GeO2 to Ge in molten CaCl2-NaCl. Electrochimica Acta, 147, 352-359. https://doi.org/10.1016/j.electacta.2014.09.107

• Journal Article Type: Article
• Acceptance Date: Sep 22, 2014
• Online Publication Date: Sep 28, 2014
• Publication Date: Nov 20, 2014
• Deposit Date: Jun 25, 2023
• Journal: Electrochimica Acta
• Print ISSN: 0013-4686
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 147
• Pages: 352-359
• DOI: https://doi.org/10.1016/j.electacta.2014.09.107
• Public URL: https://nottingham-repository.worktribe.com/output/3213660
• Publisher URL: https://www.sciencedirect.com/science/article/abs/pii/S0013468614019380?via%3Dihub