Solid oxide membrane-assisted controllable electrolytic fabrication of metal carbides in molten salt

Abstract

Silicon carbide (SiC), titanium carbide (TiC), zirconium carbide (ZrC), and tantalum carbide (TaC) have been electrochemically produced directly from their corresponding stoichiometric metal oxides/carbon (MOx/C) precursors by electrodeoxidation in molten calcium chloride (CaCl2). An assembled yttria stabilized zirconia solid oxide membrane (SOM)-based anode was employed to control the electrodeoxidation process. The SOM-assisted controllable electrochemical process was carried out in molten CaCl2 at 1000 °C with a potential of 3.5 to 4.0 V. The reaction mechanism of the electrochemical production process and the characteristics of these produced metal carbides (MCs) were systematically investigated. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy analyses clearly identify that SiC, TiC, ZrC, and TaC carbides can be facilely fabricated. SiC carbide can be controlled to form a homogeneous nanowire structure, while the morphologies of TiC, ZrC, and TaC carbides exhibit porous nodular structures with micro/nanoscale particles. The complex chemical/electrochemical reaction processes including the compounding, electrodeoxidation, dissolution-electrodeposition, and in situ carbonization processes in molten CaCl2 are also discussed. The present results preliminarily demonstrate that the molten salt-based SOM-assisted electrodeoxidation process has the potential to be used for the facile and controllable electrodeoxidation of MOx/C precursors to micro/nanostructured MCs, which can potentially be used for various applications.

EIS study of oxidation heat‐treatment effects on corrosion behavior of Ni10Cu11Fe6Al metallic inert anode inside molten calcium chloride salt

“…So, with the failure of the surface, chloride ions penetrate through the pores and existing defects on the surface to the alloy and then cause further corrosion in the oxidized alloys. The kinetics study and the negative effect of nickel‐based alloy oxidation have been discussed in detail in reference . However with oxidation in electrolysis in calcium chloride salt for the unoxidized alloys, the protective surface is gently created.…”

“…Oxygen gas that is environment‐friendly instead of the greenhouse gases like carbon monoxide and carbon dioxide can be obtained when an inert anode is used during electrolysis . Research on inert anodes was concentrated on ceramic, metallic, and cermet inert anodes . Various materials as inert anodes in molten calcium chloride salts were widely studied in the past such as nickel, platinum, calcium ruthenate, tin oxide, yttria‐stabilized zirconia, titania doped with niobium, nickel ferrite cermet …”

Electrochemical Reduction of TiO2/Al2O3/C to Ti3AlC2and Its Derived Two-Dimensional (2D) Carbides

“…The 22 reaction mechanism of the electroreduction of TiO 2 /Al 2 O 3 /C mixture precursor has 23 2 been discussed based on the time-and position-dependent phase constitution analysis. 24 In addition, two-dimensional (2D) Ti 3 AlC 2 -derived carbides, i.e., Ti 3 C 2 T x and TiC x 25 have been successfully prepared from the electrosynthesized Ti 3 AlC 2 by a chemical 26 etching process and an electrochemical etching process, respectively. Both derived 27 carbides exhibit the similar layered structure, in which single layer carbides are 28 composed of plentiful nanometer carbides.…”

Direct Extraction of Titanium Alloys/Composites from Titanium Compounds Ores in Molten CaCl₂

“…Therefore, the anodic products-related side reactions can be avoided during the SOM-assisted electroreduction process. 44) In our previous work, 44,45,[47][48][49][50][51] various refractory metals/alloys/composites have been successfully prepared from their corresponding oxides/compounds precursors by using the SOM-based anode electrolysis process. In particular, the SOM process has the potential to be used to extract alloys/ composites from complex multicomponent compounds in molten salts.…”

“…[41][42][43][44][45][46][47][48][49][50][51] During the SOM-assisted electroreduction process, the anodic reaction area can be separated from molten electrolyte by the SOM due to its selective permeability for only oxygen ions. Therefore, the anodic products-related side reactions can be avoided during the SOM-assisted electroreduction process.…”