A conductive oxide as an O2 evolution anode for the electrolytic reduction of metal oxides

Kim, Sung-Wook; Choi, Eun-Young; Park, Wooshin; Im, Hun Suk; Hur, Jin‐Mok

doi:10.1016/j.elecom.2015.03.005

Cited by 23 publications

(8 citation statements)

References 18 publications

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“…Fray et al studied the electrode properties of CaRuO 3 in calcium chloride (CaCl 2 )-calcium oxide (CaO), 12 and Hur et al reported the electrode properties of La 0.33 Sr 0.67 MnO 3 in lithium chloride (LiCl)-lithium oxide (Li 2 O). 17 We previously reported the electrode properties of controlled valency La 1−x Sr x FeO 3−δ in LiCl-potassium chloride (KCl)-Li 2 O at 723 K. 10 In this study, we investigated the electrode properties of the La-based perovskite-type oxides prepared by combining various metal oxides in LiCl-CaCl 2 melts at 873 K: La 0.7 Sr 0.3 FeO 3−δ , La 0.7 Ca 0.3 FeO 3−δ , La 0.7 Sr 0.3 Fe 0.95 Ni 0.05 O 3−δ , La 0.6 Sr 0.4 CoO 3−δ and LaCo 0.5 Ni 0.5 O 3−δ . One of the applications of the inert anodes is the electrolytic reduction of CO 2 .…”

Section: → + / [ ] Xmentioning

confidence: 99%

Electrolytic Reduction of CO₂ Using Perovskite-Type La-Based Oxide Anodes in Chloride Molten Salts

Kimura,

Tanaka,

Suzuki

et al. 2024

J. Electrochem. Soc.

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CO2 decomposition in molten salt is an attractive process as a new method for achieving carbon neutrality, for which the development of inert anodes and electrolytic bath suitable for CO2 decomposition is essential. Previous studies focused on the electrode material but did not investigate the relationship between the electrolysis bath and electrode reaction. The effects of the electrolytic bath on anode reaction and the development of inert anode material with high current density were investigated in this study. Electrolytic bath of LiCl–CaCl2 and NaCl–CaCl2 with similar oxide solubilities were compared, finding that LiCl–CaCl2 melts exhibited higher oxidation current density in cyclic voltammetry and more stable potential transition in galvanostatic electrolysis. Among the five anodes with a perovskite-type La-based oxide were investigated, La0.6Sr0.4CoO3−δ showed the highest electrical conductivity and the largest increase in oxidation current density. CO2 decomposition tests were performed in LiCl–CaCl2 with CaO and CaCO3 added as a CO2 source at 873 K using La0.6Sr0.4CoO3−δ anode. Only C and O2 were recovered from CO2 by electrolysis test. The current efficiencies were 78.3% and 54.4%, respectively. The La0.6Sr0.4CoO3−δ anode exhibited excellent corrosion resistance, demonstrating its potential as a promising inert anode for CO2 decomposition.

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Section: → + / [ ] Xmentioning

confidence: 99%

Electrolytic Reduction of CO₂ Using Perovskite-Type La-Based Oxide Anodes in Chloride Molten Salts

Kimura,

Tanaka,

Suzuki

et al. 2024

J. Electrochem. Soc.

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“…50,51 Alternative anode materials have been proposed, however none have been widely adopted. 48,[52][53][54][55][56][57][58][59] Pt → Pt 2+ + 2e − [3] 2Li…”

Section: Experience With the Reduction Processmentioning

confidence: 99%

Review—Metallic Lithium and the Reduction of Actinide Oxides

Merwin

Williamson

Willit

et al. 2017

J. Electrochem. Soc.

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Extensive research and process development has been conducted on the electrolytic reduction of actinide oxides in molten LiCl-Li 2 O. It is now accepted that the reduction of these metal oxides occurs via two separate reduction mechanisms: direct electro-chemical reduction and mediated chemical reduction by metallic lithium. The deposition of metallic lithium at the cathode (mediated chemical reduction mechanism) during the process is known to be essential in order to achieve high process throughputs and reduction yields, and yet a knowledge gap exists regarding the nature of metallic lithium in this system. This review summarizes the formation of lithium during the process and its dispersion into the molten salt electrolyte. Previously reported aspects of the physical chemistry of the LiCl-Li 2 O-Li system are presented with a specific focus on the dispersion of Li in the solution. Finally, issues regarding the effect of the presence of lithium on the electrolytic reduction process are discussed. Evidence shows that electrochemically generated metallic lithium is likely a significant source of experimental uncertainty, low current efficiency and Li 2 O consumption in the oxide reduction process. The reduction of uranium, plutonium and minor actinide oxides to a metallic form is an important nuclear fuel cycle process.2-9 The ability of metallic lithium to reduce various uranium oxides, importantly UO 2 and U 3 O 8 , has been known for many years.10 A molten salt metalothermic reduction process employing metallic lithium (Li) as a reductant dissolved in molten LiCl was first developed by Argonne National Laboratory (ANL) to consolidate a variety of forms of actinide oxides for integration into a single electrometallurgical reprocessing system. 11-13 An electrolytic process, often referred to as electro-deoxidation or simply oxide reduction, was subsequently developed as a more controllable method of reducing metal oxides. A feasibility study conducted by Poa et al. demonstrated that oxides of uranium and plutonium could be reduced electrochemically in molten salts as long as the reduction potential of the metal oxide in question was more noble than the cation of the electrolyte.14,15 This approach was further developed by Gourishankar et al. to better understand processes chemistry and develop the electrolytic cell technology. 13,[16][17][18][19][20] Independent research conducted by Fray, Farthing, and Chen (FFC) applied the principles of electrochemical reduction in molten salt electrolytes to a variety of metal oxide reduction processes. 21,22 The FFC process has been the subject of several literature reviews.23-25 While these review articles address the processes associated with the reduction of nuclear fuel in LiCl, they focus on the electro-deoxidation phenomena and the CaCl 2 -CaO system. Additionally, the process engineering of the electrolytic reduction of nuclear fuel, and experience in incorporating oxide fuel into pyroprocessing, has been the focus of a recent review article. 26 The current review wi...

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“…Some ceramics are known to be stable in molten chlorides. However, the ceramic materials are poor electrical conductors, although some exhibit semiconducting properties that allow conduction at high temperatures [7,8,13,14].…”

Section: Introductionmentioning

confidence: 99%

Oxygen Evolution Behavior of La1−xSrxFeO3−δ Electrodes in LiCl−KCl Melt

Kimura

Fukumoto

Suzuki

et al. 2023

Preprint

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Electrochemical reduction processes of oxides in molten salt have been proposed as the carbon free technology in order to achieve carbon neutral. The anodic behavior of La1−xSrxFeO3−δ as an oxygen-evolution anode in LiCl−KCl at 723 K is investigated. Data suggests that at 723 K, the electrical conductivity of La1−xSrxFeO3−δ tends to increase as the extent of Sr doping. The anodic reactions of La1−xSrxFeO3−δ electrodes are characterized by electrochemical measurements in LiCl−KCl + Li2O at 723 K. Based on the cyclic voltammograms of the La0.7Sr0.3FeO3−δ electrode, oxygen evolution has proceeded between 2.7 V and 3.6 V. The potential of La0.7Sr0.3FeO3−δ electrode during galvanostatic electrolysis has conducted at 39 mA cm-2 for 15 h has remained stable at 2.8 V, indicating that the stable evolution of oxygen gas is monitored. The corrosion rate is estimated to have the low value of 8.6 × 10−4 g cm−2 h−1. Electrode surface data collect after electrolysis indicate that La0.7Sr0.3FeO3−δ electrode has excellent chemical and physical stability in LiCl−KCl at 723 K. Evidence thus indicates that La0.7Sr0.3FeO3−δ electrode is a promising candidate material as inert anodes for oxides decomposition. As one of application of the La0.7Sr0.3FeO3−δ electrode, the electrolysis reduction of CO2 was also successfully achieved.

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A conductive oxide as an O2 evolution anode for the electrolytic reduction of metal oxides

Cited by 23 publications

References 18 publications

Electrolytic Reduction of CO₂ Using Perovskite-Type La-Based Oxide Anodes in Chloride Molten Salts

Electrolytic Reduction of CO₂ Using Perovskite-Type La-Based Oxide Anodes in Chloride Molten Salts

Review—Metallic Lithium and the Reduction of Actinide Oxides

Oxygen Evolution Behavior of La1−xSrxFeO3−δ Electrodes in LiCl−KCl Melt

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A conductive oxide as an O2 evolution anode for the electrolytic reduction of metal oxides

Cited by 23 publications

References 18 publications

Electrolytic Reduction of CO2 Using Perovskite-Type La-Based Oxide Anodes in Chloride Molten Salts

Electrolytic Reduction of CO2 Using Perovskite-Type La-Based Oxide Anodes in Chloride Molten Salts

Review—Metallic Lithium and the Reduction of Actinide Oxides

Oxygen Evolution Behavior of La1−xSrxFeO3−δ Electrodes in LiCl−KCl Melt

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Product

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Electrolytic Reduction of CO₂ Using Perovskite-Type La-Based Oxide Anodes in Chloride Molten Salts

Electrolytic Reduction of CO₂ Using Perovskite-Type La-Based Oxide Anodes in Chloride Molten Salts