US2014058961 ELECTROCHEMICAL REDUCTION OF CO2 AT COPPER NANOFOAMS

The international, or "world", patent application, for an electrochemical process that converts Carbon Dioxide, as recovered from whatever convenient source, into the polymer, or plastics, raw material "propylene", we report on herein, is actually a republication of a United States Patent Application originating from the state of Rhode Island, from Brown University specifically - - a United States Patent Application submitted last year by Brown University which hasn't yet been published on the web by the United States Government.

What makes that especially strange is that the United States Government actually paid Brown University to develop this process, a technology which uses and consumes CO2 in the synthesis of a hydrocarbon compound, "propylene", that, as seen separately in:  

Propene - Wikipedia, the free encyclopedia; (Propene, also known as propylene) "is the second most important starting product in the petrochemical industry after ethylene. It is the raw material for a wide variety of products. Manufacturers of the plastic polypropylene account for nearly two thirds of all demand. Polypropylene is, for example, needed for the production of films, packaging, caps and closures as well as for other applications. Propene is also used for the production of important chemicals such as propylene oxide, acrylonitrile, cumene, butyraldehyde, and acrylic acid. In the year 2013 about 85 million tonnes of propene were processed worldwide".

Since propylene/propene can, as above, be used in the synthesis of "propylene oxide", in addition to it's use in "polypropylene", it might be important to note, that, as seen in:

Propylene oxide - Wikipedia, the free encyclopedia; "Propylene oxide is an organic compound with the molecular formula CH3CHCH2O. This colourless volatile liquid is produced on a large scale industrially, its major application being its use for the production of polyether polyols for use in making polyurethane plastics".

And, such "polyurethane" is, as well, an immensely valuable polymer with broad application in a wide range of products. If it's production could be freed from links to petroleum-based raw materials, the market would certainly expand, and the demand for propylene would grow. 

In any case, as a result of research paid for with our tax dollars, Brown University has developed the technology whereby Carbon Dioxide can be used and consumed as a valuable raw material resource, a raw material which can serve in the synthesis of the basic polymer, propylene.

As seen in excerpts from the initial and following links in this dispatch to very recent:

"Electrochemical Reduction of CO2 at Copper Nanofoams

World Patent Application: WO/2015/051211; International Application: PCT/US2014/0589

Publication Date: April 9, 2015

Applicant: Brown University, Providence, Rhode Island, USA

Inventors: G. Palmore, et. al., USA

Abstract: This invention includes a catalytic copper electrode is selected from the group comprising copper nanofoam, copper aerogel, and copper nanoparticles. Particular note is made of the catalytic copper electrode (as described) being a copper nanofoam electrode. This invention further includes a method for the reduction of CO2by the steps of:

(i) providing a membrane divided electrochemical cell comprising an anode in a first cell compartment, a catalytic-copper electrode in a second cell compartment containing an aqueous electrolyte in contact with the anode and cathode;

(ii) introducing CO2 to said second cell compartment;

(iii) exposing said CO2 to said catalytic-copper electrode at a step potential between about -0.8 and preferably about -1.0 and about -1.8 V versus the reference electrode;

(iv) electrochemically reducing said CO2and solution by the catalytic-copper electrode in the second cell;

(v) thereby producing propylene and:

(vi) extracting said propylene from said second compartment.

US2014058961 ELECTROCHEMICAL REDUCTION OF CO2 AT COPPER NANOFOAMS

Statement of Government Rights: This invention was made with government support under CHE-1240020 awarded by National Science Foundation. The government has certain rights in the invention.

Field of the Invention: The three dimension structure of copper nanofoams provide for electrocataclytic chemical reduction of CO2. In some embodiments, copper nanofoam with hierarchical porosity is disclosed. Both the distribution of products formed from this reaction and their faradaic efficiencies differ significantly from that obtained at smooth electropolished copper electrodes with particular reference to the production of propylene. Without being bound by any particular theory, high surface roughness, hierarchical porosity, and confinement of reactive species promotes CO2 reduction.

Background of the Invention: Electrochemical reduction of CO2 has been investigated at a variety of metallic electrodes and a number of reports and reviews have been published on this subject.

(Brown University lists a small catalogue of technical references that relate to the electrochemical conversion of Carbon Dioxide into hydrocarbons. We haven't yet reported on any of those specifically cited by Brown, but just a few of our prior reports concerning similar and related technology can be accessed via: 

More New Jersey CO2 to High-Energy Alcohol | Research & Development | News; concerning: "United States Patent 8,961,774 - Electrochemical Production of Butanol from Carbon Dioxide and Water; 2015; Inventors: Emily Barton Cole, Kyle Teamey, Andrew Bocarsly, and Narayanappa Sivasankar; Assignee: Liquid Light, Inc., Monmouth, NJ"; and:

USDOE 1976 Atmospheric CO2 to Methanol | Research & Development | News; concerning: "United States Patent 3,959,094 - Electrolytic Synthesis of Methanol from CO2; 1976; Inventor: Meyer Steinberg, NY; Assignee: The USA as represented by the USDOE; Abstract: A method and system for synthesizing methanol from the CO2 in air using electric power. The CO2 is absorbed by a solution of KOH to form K2CO3 which is electrolyzed to produce methanol, a liquid hydrocarbon fuel". Summary: In accordance with a preferred embodiment of this invention, a solution of KOH is employed to absorb CO2 from air forming an aqueous solution of K2CO3, the solution is then electrolyzed to produce CH3OH (i.e., Methanol) and reform KOH in solution, the CH3OH is then removed, and make-up water is then added prior to repeating the aforementioned steps. Other products ... are also formed which can be separated and recovered as valuable products. By the process described above, it is seen that any source of electrical power may be employed, such as coal-fired power plants. However, from an environmental point of view ... solar energy generated power, would be preferred".

This is, in sum, a concept that has been worked with and improved upon over a number of decades.)

Summary of the Invention: This invention includes a catalytic copper electrode is selected from the group comprising copper nanofoam, copper aerogel, and copper nanoparticles. Particular note is made of the catalytic copper electrode having at least about 5 times and preferably about 10 times the electrochemically accessible surface area as determined by the Randles-Sevcik equation at 50 mV/s. Particular note is made of the catalytic coper electrode being a copper nanofoam electrode.

This invention further includes a method for the reduction of CO2 by the steps of:

(a) providing a membrane divided electrochemical cell comprising an anode in a first cell compartment, a catalytic-copper electrode in a second cell compartment containing an aqueous electrolyte in contact with the anode and cathode;

(b) introducing CO2 to said second cell compartment

(c) exposing said CO2 to said catalytic-copper electrode at a step potential between about -0.8 and preferably about -1 .0 and about -1 .8 V versus the reference electrode {e.g., Ag/AgCI);

(d) electrochemically reducing said CO2 and solution by the catalytic-copper electrode in the second cell compartment;

(e) thereby producing propylene; and,

(f) extracting said propylene.

Mention of the Ag/AgCI reference electrode is cited solely to establish voltages of the method. A variety of reference electrodes are known in the art and suitable.

In some embodiments of the method the catalytic copper electrode is selected from the group comprising copper nanofoam, copper aerogel, and coper nanoparticles. In further embodiments of the method the copper nanofoam electrode has at least about 5 times and preferably about 10 times the electrochemically accessible surface area as determined by the Randles-Sevcik equation at 50 mV/s. In particular embodiments the method of employs the electrolyte KHCO3..

Detailed Description of the Invention: Electrocatalytic chemical reduction of CO2 at copper nanofoams yields formic acid at a lower onset potential with faradaic efficiencies that are 10-20% higher than other reported values. In comparison to smooth copper electrodes, the faradaic efficiencies of CO, methane, and ethylene are reduced significantly while C2 and C3 products such as ethane and propylene are produced. Ethane and propylene production has been observed in the instant copper nanofoam system. Without being bound by any particular theory, it is believed that presence of ethane and propylene suggests that copper nanofoams employed as electrocatalysts provide both the nanostructured surfaces and cavities that facilitate the reaction between adsorbed CO2 and hydrogen species to generate higher order hydrocarbons during the electrochemical reduction of CO2.

Particular note is made of the term electrocatalyst. As used herein, an electrocatalyst is a catalyst that participates in electrochemical reactions. Catalyst materials modify and increase the rate of chemical reactions without being consumed in the process. Electrocatalysts are a specific form of catalysts that function at electrode surfaces or may be the electrode surface itself as embodied in the copper nanofoams disclosed herein. ... The term electrocatalyst is used in distinction from an electrode which is merely an electrical conductor used to make contact with a nonmetallic part of a circuit - but not a catalytic function.

Products from the electro-reduction of CO2 were observed at -1 .0 V, indicating an onset potential that is -200 mV more positive than that required at smooth copper electrodes. This decrease in overpotential may be a consequence of the higher surface orientation in the copper nanofoams (by 22%) compared to smooth copper.

(The full Disclosure goes into highly technical, detail about how the "copper nanofoam" electrodes influence the product distribution, relative to smooth copper electrodes, of Carbon Dioxide "electro-reduction", describing how different electrodes and different applied currents drive the product mix toward or away from simple hydrocarbons, Methane, Ethane, etc., and Formic Acid, and/or the desired "higher order hydrocarbons" such as the specified "propylene".)

Scalability of this method is noted. By way of nonlimiting example, multiple copper nanofoam electrodes can be present in a flow system open to introduction of feed stock and collection of products such a propylene and ethane and formic acid.

(This device can be "sized up", in other words.)

US2014058961 ELECTROCHEMICAL REDUCTION OF CO2 AT COPPER NANOFOAMS

(Claims:)

A catalytic copper electrode is selected from the group comprising copper nanofoam, copper aerogel, and copper nanoparticles (as further described and specified).

The catalytic copper electrode ...  wherein said electrode is a copper nanofoam electrode.

 A method for the reduction of CO2 by the steps of

(a) providing a membrane divided electrochemical cell comprising an anode in a first cell compartment, a catalytic-copper electrode in a second cell compartment containing an aqueous electrolyte in contact with the anode and catalytic-copper electrode;

(b) introducing CO2 to said second cell compartment

(c) exposing said CO2 to said catalytic-copper electrode at a step potential between about -0.8 and about -1.8 V versus the reference electrode;

(d) electrochemically reducing said CO2 and solution by the catalytic- copper electrode in the second cell compartment;

(e) thereby producing propylene; and,

(f) extracting said propylene from said second compartment.

The method ... wherein said electrolyte is KHCO3 (Potassium Bicarbonate)."

--------------------------------

First, if it seems improbable that an east coast university would have interest in developing technologies like this, we remind you of our prior report:

Rhode Island Improves Coal Ash for Market | Research & Development | News; concerning: "United States Patent 6,136,089 - Apparatus and Method for Deactivating Carbon in Fly Ash; 2000; Inventors: Robert Hurt, et. al., RI; Assignee: Brown University Research Foundation, Providence; Abstract: An apparatus and method for improving the properties of carbon-containing fly ash through ozonation is described. The apparatus includes a chamber for containing the fly ash and an ozonator that generates an ozone-containing gas. The ozonator supplies the ozone-containing gas such that it enters the chamber with the fly ash and deactivates carbon within the fly ash. Afterwards, the fly ash will have decreased surfactant absorptivity so that it can be effectively mixed with cement ... . Claims:  A method of deactivating carbon in coal fly ash, said method comprising the steps of: delivering coal fly ash to a reaction zone; and exposing said coal fly ash to ozone-containing gas to deactivate carbon in said coal fly ash; wherein said exposing step passivates carbon within said coal fly ash and operates to reduce surfactant uptake of said coal fly ash";

wherein it was seen that Brown University has done some commendable work in developing processes to improve the commercial value of Coal-fired power plant fly ash.

And, to emphasize, although the plastic/polymer raw material "propylene" is being preferentially synthesized from CO2 in the process of our subject, "Electrochemical Reduction of CO2 at Copper Nanofoams; World Patent Application: WO/2015/051211", other hydrocarbon compounds, as well, such as "methane, and ethylene" and "ethane", could also be viable co-products of this technology, along with the propylene.

In any case, it is demonstrated again herein that Carbon Dioxide, as we might harvest as a byproduct from our economically essential use of Coal in the generation of abundant and affordable electric power, can be seen and treated as a valuable raw material resource, the informed use of which could lead to the creation of new industries and new jobs in United States Coal Country.


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