Electrolytic cell anode structures containing cobalt spinels
AssigneeThe Dow Chemical Company
InventorsMark Jonathan Hazelrigg, Jr., Donald Lee Caldwell
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Abstract
Anodes particularly suitable for use in electrolytic cells are prepared by coating an electrically-conductive substrate with a bimetallic oxide having a spinel structure of the formula M.sub.x Co.sub.3-x O.sub.4 where O<X.ltoreq.1 and where M is a metal of Periodic Group IB, IIA or IIB. Also the coating contains therein, optionally, a modifier oxide, such as ZrO.sub.2.
Claims20
An anode material for use in electrolytic cells, said material comprising
- an electroconductive substrate having coated thereon an effective amount of a bimetal oxide spinel having the formula M.sub.x Co.sub.3-x O.sub.4 where O<X.ltoreq.1 and M is a metal selected from Groups IB, IIA, and IIB of the Periodic Table of the Elements.
In electrolytic chlorine cells containing anodes and cathodes separated by aqueous NaCl electrolyte, said electrolyte being divided into catholyte and anolyte sections by membrane or diaphragm means, the improvement which comprises anode embodiments characterized as being electroconductive substrates having coated thereon an effective amount of bimetal spinel, M.sub.x Co.sub.3-x O.sub.4, where X has a value of from about 0.1 to 1.0 and where M is a metal selected from the group consisting of metals of Groups IB, IIA, and IIB.
The method of preparing electrolytic cell anodes, said anodes consisting of an electroconductive substrate having coated thereon an effective amount of a bimetal spinel of the formula M.sub.x Co.sub.3-x O.sub.4 where the value of X is in the range of about 0.1 to 1.0 and where M is a metal selected from the group consisting of metals of Groups I-B, II-A, and II-B, the said method comprising, in sequence,
- cleaning an electroconductive substrate to remove surface oxides and contaminants,
- applying to the substrate a coating mixture of a thermally decomposable, oxidizable inorganic cobalt compound and a thermally decomposable, oxidizable M-metal compound said M-metal being selected from the group consisting of Groups I-B, II-A, and II-B, said mixture containing molar ratio of Co:M-metal, based on metal, in the range of about 29:1 to 2:1,
- heating the so-coated substrate at a temperature in the range of about 200.degree. C to about 450.degree. C for a period of time of from about 1.5 to about 60 minutes, with the shorter heating times being employed with the higher temperatures over the said ranges, thereby decomposing said mixture of cobalt compound and M-metal compound to form a bimetal spinel of the formula M.sub.x Co.sub.3-x O.sub.4,
- cooling the so-formed spinel-coated substrate,
- repeating, a plurality of times, the steps of applying the coating mixture, heating the so-coated substrate, and cooling the spinel-coated substrate, and
- performing a final baking of the spinel-coated substrate at a temperature in the range of about 350.degree.-450.degree. C for about 0.5 to about 2.0 hours.
In a process for electrolyzing aqueous NaCl electrolyte to form chlorine and NaOH, and where such electrolyzing is done by passing electric current through the aqueous NaCl electrolyte and between a cathode and an anode, and where such electrolyte is divided into a catholyte section and an anolyte section by a diaphragm or membrane,
- the improvement wherein the anode is a titanium structure having a coating thereon of a bimetal spinel of the formula M.sub.x Co.sub.3-x O.sub.4 where X is a value of from about 0.1 to 1.0 and M is a metal of Group I-B, II-A, or II-B.
Dependencies are inferred from the claim text.