Panasonic Solar Energy Converts More CO2 into Methane

United States Patent: 8617375

One introductory, or explanatory, and extended, note seems demanded of us:

We've been reporting over the past however many years that Carbon Dioxide, as can now be efficiently recovered from either our industrial exhaust gases or even the atmosphere itself, is a valuable raw material resource, no matter what the opponents, whatever their true motivations, of our essential use of Coal in the generation of truly abundant and truly affordable electric power would prefer to have everyone believe.

 

Once we've recovered Carbon Dioxide, we can use it as the basic ingredient in processes that lead to the synthesis of substitute natural gas Methane, fuel alcohols like Methanol, and, even, as seen in:

USDOE Converts Atmospheric CO2 into Gasoline | Research & Development | News; concerning:

"United States Patent Application 20100205856 - Method of Producing Synthetic Fuels and Organic Chemicals from Atmospheric Carbon Dioxide; 2010; Inventors: William Kubic and Jeffrey Martin, Los Alamos, NM; Assignee: Los Alamos National Security LLC, NM (USDOE Los Alamos National Laboratory); Abstract: The present invention is directed to providing a method of producing synthetic fuels and organic chemicals from atmospheric carbon dioxide. Carbon dioxide gas is extracted from the atmosphere, hydrogen gas is obtained by splitting water, a mixture of the carbon dioxide gas and the hydrogen gas (synthesis gas) is generated, and the synthesis gas is converted into synthetic fuels and/or organic products (including) diesel fuel, jet fuel, gasoline ... and mixtures thereof";

according to our own United States Department of Energy, some perhaps more intriguing stuff, as well.    

We've also specifically documented, in a number of reports over the course of the last few years, that Japan's well-known Panasonic Corporation has been at work developing a complete technology for the electrochemical conversion of Carbon Dioxide, as recovered from whatever handy source, and Hydrogen, as concurrently in many of their processes extracted from the water molecule, into various simple hydrocarbons, which hydrocarbons include, as the predominant example, substitute natural gas Methane.

Further, the electrochemical CO2-to-Hydrocarbon processes designed by Panasonic are facilitated by specific catalysts; which catalysts lower the energy needed to effect the Carbon Dioxide conversion so much that the lower-voltage electricity which can be generated from sunlight, that is, photo-voltaic electricity, is sufficient, and is most often specified by Panasonic, to drive the needed chemical reactions.

Technical experts in the employ of our United States Government confirmed the practicability of one of Panasonic's solar-driven CO2-to-Hydrocarbon technologies nearly a year ago through their issuance, as can be learned via:

Panasonic 2013 CO2 to Methane, Formic Acid and Carbon Monoxide | Research & Development | News;

of: "United States Patent 8,414,758 - Method for Reducing Carbon Dioxide; April 9, 2013; Inventors: Masahiro Deguchi, Satoshi Yotsuhashi, and Yuka Yamada, Japan; Assignee: Panasonic Corporation, Osaka; Abstract: A device for reducing carbon dioxide includes a cathode chamber including a cathode electrolyte solution and a cathode electrode, an anode chamber including an anode electrolyte solution and an anode electrode, and a solid electrolyte membrane. The anode electrode includes a nitride semiconductor region on which a metal layer is formed. The metal layer includes at least one of nickel and titanium. A method for reducing carbon dioxide by using a device for reducing carbon dioxide includes steps of providing carbon dioxide into the cathode solution, and irradiating at least part of the nitride semiconductor region and the metal layer with a light having a wavelength of 250 nanometers to 400 nanometers, thereby reducing the carbon dioxide contained in the cathode electrolyte solution. The method ... wherein the first electrolyte solution is a potassium bicarbonate aqueous solution (and) wherein the second electrolyte solution is a sodium hydroxide aqueous solution or a potassium hydroxide aqueous solution. The method ... wherein ... the device is left at a room temperature and under atmospheric pressure. The method ... wherein ... formic acid (and/or) carbon monoxide (and/or) methane is obtained".

The Honorable Masahiro Deguchi, as above, seems to be a primary innovator of Panasonic's Carbon Dioxide utilization technologies, as he is most often, though not always, named as the first, or lead, inventor in patent documents disclosing those Panasonic technologies.

Another Deguchi-led Panasonic development in the artificial photosynthetic conversion of Carbon Dioxide, into stuff like substitute natural gas Methane, was disclosed  most recently in our report of:

Panasonic Solar CO2 to Methane | Research & Development | News; concerning:

"United States Patent 8,597,488 - Method for Reducing Carbon Dioxide; December 3, 2013; Inventors: Masahiro Deguchi, et. al., Japan; Assignee: Panasonic Corporation, Osaka; Abstract: The method for reducing carbon dioxide of the present disclosure includes a step (a) and a step (b) as follows. A step (a) of preparing an electrochemical cell. The electrochemical cell comprises a working electrode, a counter electrode and a vessel. The vessel stores an electrolytic solution. The working electrode contains at least one nitride selected from the group consisting of titanium nitride, zirconium nitride, hafnium nitride, tantalum nitride, molybdenum nitride and iron nitride. The electrolytic solution contains carbon dioxide. The working electrode and the counter electrode are in contact with the electrolytic solution. A step (b) of applying a negative voltage and a positive voltage to the working electrode and the counter electrode, respectively, to reduce the carbon dioxide".

All of that said, we confess to you that the sheer volume of the CO2 utilization and Hydrogen generation technologies developed and being developed by Panasonic Corporation isn't just astonishing - - given the fact that they are clearly demonstrating that Carbon Dioxide can, on a practical basis, be converted into hydrocarbons via processes of artificial photosynthesis - - but, it is, for us, with our admitted limitations,  overwhelming.

There is much, much more to follow on Panasonic's development of - - and, as we've learned, stated commitment to - - artificial photosynthesis CO2-to-Hydrocarbon technologies.

We will do our best to keep up with it, and present it, and all the other Coal and Coal byproduct utilization technologies and practices we've been treating, to you in as orderly and coherent a fashion as we are capable of. But, you, anyone who is genuinely interested in the economic health and vitality of US Coal Country, anyone who is genuinely concerned with the prosperity and the energy security of the United States of America, anyone who is genuinely committed to the Truth, will have to bear with us, work with us, and attempt to meet us half-ways, so to speak, as we, with the singular, even courageous, help of the West Virginia Coal Association, continue in our efforts to bring you the Truth. 

To that end, herein, we submit for your consideration another example of  those Panasonic artificial photosynthesis technologies, the practicability of which was confirmed by our own US Government experts even more recently than the above, and identically-titled, "United States Patent 8,597,488 - Method for Reducing Carbon Dioxide".

Comment follows, and is inserted within, excerpts from the initial link in this dispatch to:

"United States Patent 8,617,375 - Method for Reducing Carbon Dioxide

Patent US8617375 - Method for reducing carbon dioxide - Google Patents

Method for reducing carbon dioxide - Panasonic Corporation

December 31, 2013

Inventors: Yugi Zenitani, Masahiro Deguchi, Satoshi Yotsuhashi, Reiko Taniguchi, Japan

(Those names will be difficult for native English speakers to remember. But, if you've followed our dispatches over just the past few years, you've seen them before. If you continue to follow our dispatches, you will, we assure you, see them all again.)

Assignee: Panasonic Corporation, Osaka

Abstract: The method for reducing carbon dioxide of the present invention includes a step (a) and a step (b) as follows. A step (a) of preparing an electrochemical cell. The electrochemical cell comprises a working electrode, a counter electrode and a vessel. The vessel stores an electrolytic solution. The working electrode contains boron carbide. The electrolytic solution contains carbon dioxide. The working electrode and the counter electrode are in contact with the electrolytic solution. A step (b) of applying a negative voltage and a positive voltage to the working electrode and the counter electrode, respectively, to reduce the carbon dioxide.

(Note that this process is closely similar to that of "United States Patent 8,597,488 - Method for Reducing Carbon Dioxide", but, it employs a Carbide, "boron carbide", catalyst, as opposed to the various metal "nitride"s specified in Panasonic's USP 8,597,488.

Further, as can be learned separately via:

"United States Patent Application: 0120318680 - Device and Method for Reducing Carbon Dioxide; 2012;

Patent US20120318680 - Device and method for reducing carbon dioxide - Google Patents

Inventors: Yuji Zenitani, et. al., Japan; Abstract: A device for reducing carbon dioxide includes a vessel for holding an electrolyte solution including carbon dioxide, a working electrode and a counter electrode. The working electrode contains boron particles";

Panasonic's Yugi Zenitani and colleagues have been at work developing and designing the actual "Device" for implementing the boron-catalyzed "Method" of our subject, USP 8,617,375. Records indicate that "United States Patent Application 20120318680" has undergone revision since it's initial publication: and, we would expect that final decision on it will soon be made. If and when it issues as a separate and formal United States patent, we will bring report of it to you.)

Claims: A method for reducing carbon dioxide, comprising: a step (a) of preparing an electrochemical cell, wherein the electrochemical cell comprises a working electrode, a counter electrode and a vessel, the vessel stores an electrolytic solution, the working electrode contains boron carbide, the electrolytic solution contains carbon dioxide, the working electrode is in contact with the electrolytic solution, and the counter electrode is in contact with the electrolytic solution; a step (b) of applying a voltage between the working electrode and the counter electrode with an external power supply; and a step (c) of reducing the carbon dioxide at the working electrode with the applied voltage and using the boron carbide as a catalyst, wherein the electrochemical cell further comprises a tube, one end of the tube is disposed in the electrolytic solution, and in the step (c), the carbon dioxide is supplied to the electrolytic solution through the tube. 

A method for reducing carbon dioxide (as above) wherein: the vessel comprises a solid electrolyte membrane, the solid electrolyte membrane is interposed between the working electrode and the counter electrode, and a negative voltage is applied to the working electrode and a positive voltage is applied to the counter electrode. 

The method ... wherein: the voltage is equal to or greater than 0.9 V in the counter electrode based on a silver/silver chloride electrode as a reference electrode in contact with the electrolytic solution, and the electrolytic solution is in contact with the working electrode.

(Panasonic's USP 8,597,488, the subject of our prior report, in the full Disclosure, though not in the specific Claims, identifies a range of voltage from 0.7 V to a little over 2 V, depending on the specific catalyst selected, to operate the process. That, like the above "0.9 V", doesn't sound like a lot, and isn't. But, it's not the full picture, either. The needed amperage, or, in other words, the actual amount, of electricity needed to effect some specific volume of Carbon Dioxide conversion and Methane synthesis, isn't really defined, insofar as we've been able to determine. If we think of the voltage as the "pressure" of the electricity we're feeding to the reaction, we don't need a lot. But, the amperage would be related to just how much CO2 we actually convert, how much Methane we actually produce. The full Disclosure of our subject, and other Panasonic literature, describes how the processes can be operated on smaller scales, at sites with limited space and/or solar exposure, so the efficiency must be pretty good; we just can't yet define it with any certainty. Some specifics are no doubt available in the supporting documents associated with the patent, and they might be accessible via some of the auxiliary links associated with the main paten publication. But, the needed calculations would be far, far beyond our capabilities. In honesty, we're pretty certain those calculations and considerations would need to be made before the true value of this technology could be accurately assessed or estimated, at least in terms of the technology's worth in larger-scale industrial settings.)

Background and Field: The present invention relates to a method for reducing carbon dioxide. 

A carbon dioxide (CO2) reduction technique using a catalyst is expected as a technique for fixing CO2 and producing useful substances.

As the CO2 reduction techniques using a catalyst, a catalytic hydrogenation method and an electrochemical method (electrolytic reduction method) have been studied so far. In the catalytic hydrogenation method, CO2 reacts catalytically with hydrogen (H2) to be reduced under a high temperature and high pressure gas phase condition. The catalytic hydrogenation method allows CO2 to be converted into highly useful substances such as methanol. 

(As just one example of CO2 "catalytic hydrogenation" technology, as above, see our report of:

The University of Oxford Converts CO2 into Methanol | Research & Development | News; concerning: "Process For Producing Methanol; Publication No: WO/2011/045605; International Application No: PCT/GB2010/051733; International Filing Date: October 14, 2010; Applicants: Isis Innovation Limited, Great Britain (The University of Oxford); The present invention relates to a novel process for the production of methanol (which) comprises the heterolytic cleavage of hydrogen (from water, as described) and the hydrogenation of CO2 with the heterolytically cleaved hydrogen to form methanol".)


In the electrolytic reduction method, the reducing reaction proceeds even at an ordinary temperature and ordinary pressure. The electrolytic reduction method requires no large-scale equipment. Thus, the electrolytic reduction method is simpler than the catalytic hydrogenation method. Accordingly, the electrolytic reduction method is considered as an effective CO2 reduction method.

Summary: (It) is an object of the present invention to provide a method for reducing carbon dioxide using a highly-durable catalyst that is capable of reducing CO2 at an overvoltage equal to or lower than overvoltages required for conventional catalysts to produce highly useful substances (such as formic acid (HCOOH), methane (CH4), ethylene (C2H4), and ethane (C2H6)). 

A method for reducing carbon dioxide according to the present invention includes: a step (a) of preparing an electrochemical cell, wherein the electrochemical cell comprises a working electrode, a counter electrode and a vessel, the vessel stores an electrolytic solution, the working electrode contains boron carbide, 
the electrolytic solution contains carbon dioxide, the working electrode is in contact with the electrolytic solution, and the counter electrode is in contact with the electrolytic solution; and a step (b) of applying a negative voltage and a positive voltage to the working electrode and the counter electrode, respectively, to reduce the carbon dioxide. 

The electrochemical cell is used in the method for reducing carbon dioxide of the present invention. The electrochemical cell comprises the working electrode for reducing carbon dioxide. The working electrode contains boron carbide. Boron carbide is capable of reducing carbon dioxide at an overvoltage equal to or lower than overvoltages required for conventional catalysts for reducing carbon dioxide. Therefore, the method of the present invention makes it possible to produce highly useful substances, such as HCOOH, CH4, C2H4 and C2H6, at an overvoltage equal to or lower than overvoltages required in conventional methods. Furthermore, the high durability of boron carbide allows the working electrode to achieve high durability. 

(Boron Carbide) used as a catalyst in reducing CO2 causes the reducing reaction of CO2 only with an external energy from DC power supply at ordinary temperature.

Moreover, the method for reducing CO2 of the present invention can be applied to methods using a solar cell as an external power supply.

The catalyst for reducing CO2 can be applied, by combination with a photocatalyst, to catalysts that can be used with solar energy. 

The method for reducing CO2 using B4C (Boron Carbide) is very simple because it can be carried out by blowing CO2 gas into an electrolytic solution or by forming a three-phase boundary with a gas diffusion electrode. Thus, it can be said that the method for reducing CO2 using B4C is a very promising technique as an energy-saving measure for CO2 in places where large-scale equipment cannot be installed in houses and communities.

The method for reducing CO2 of the present invention can be applied to methods using a solar cell as an external power supply. The catalyst for reducing CO2 can be applied, by combination with a photocatalyst, to catalysts which can be used with solar energy. 

Industrial Applicability: The present invention demonstrates that boron carbide (B4C), which is a highly durable compound, is capable of reducing CO2 electrolytically at an overvoltage lower than overvoltage required for conventional catalysts for reducing CO2. Boron carbide makes it possible to produce CH4 (Methane) ..., etc. from CO2 with less energy. That is, the method for reducing CO2 of the present invention can provide these useful substances from CO2 at lower cost.

The CO2 reduction treatment technique is expected to be useful as a more environmentally-friendly resource recycling method for the future if they are combined with photocatalytic technology and solar power generation technology. "

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As should be apparent, this is another example of the growing body of "artificial photosynthesis" technologies, wherein "solar energy" powers the conversion of Carbon Dioxide into hydrocarbons, especially into substitute natural gas Methane. Panasonic Corporation, in Japan, as we noted above in our introductory comments, seems especially committed in to the concept, and we will have more to offer on their development of such technology in even more reports to follow.

For now, suffice it to say that our own United States Government not long ago confirmed, through issuance and allowance of our subject, "United States Patent 8,617,375 - Method for Reducing Carbon Dioxide", that, "solar energy" can be used on a practicable basis to power the conversion of Carbon Dioxide, along with Hydrogen concurrently extracted from Water, H2O, into simple hydrocarbons, with Methane, CH4, being perhaps the primary, or at least exemplary, product. 

And, we remind you, as seen for only one out of many examples in our report of:

Standard Oil 1949 CO2 + CH4 + H2O = Hydrocarbon Syngas | Research & Development | News; concerning: "United States Patent 2,460,508 - Method and Means for Hydrocarbon Synthesis; 1949; Assignee: Standard Oil Company; Abstract: This invention relates to the synthesis of hydrocarbons having more than one carbon atom in the molecule and it pertains more particularly to an improved method and means for producing normally liquid hydrocarbons by reacting hydrogen and carbon monoxide over catalysts. More specifically it relates to hydrocarbon synthesis with methane as the raw material. When methane ... is reformed by direct combustion with oxygen, a certain amount of excess heat is available (and) Carbon dioxide can be incorporated in the feed gas in quantities sufficient to absorb excess heat by reacting it endothermically with a portion of the (methane). The incorporation of carbon dioxide in the feed gas not only simplifies the design of the reformer by making the operation thermally balanced, but also increases the overall carbon efficiency of the process. Consequently from the standpoint of thermal and carbon efficiency it is desirable to feed to the reforming operation a gas comprising methane, oxygen and carbon dioxide. The basic equations for the gas reforming operation using methane may be somewhat as follows: CH4 + CO2 = 2CO + 2H2 (and, the) proportions of carbon dioxide and steam and/or oxygen containing gas can in any case be so adjusted to give the desired make gas. The process of synthesizing hydrocarbons from hydrogen and carbon monoxide mixtures produced by converting hydrocarbons (specified, as above, to be Methane) with carbon dioxide and oxygen in a substantially thermally balanced reaction";

that it has been known for a very long time, that, once we have Methane, CH4, as synthesized via the "solar energy"-driven process of our subject, "United States Patent 8,617,375 - Method for Reducing Carbon Dioxide", from Carbon Dioxide, we can then react that CO2-derived Methane with even more Carbon Dioxide, and thereby generate a hydrocarbon synthesis gas consisting of Carbon Monoxide, "CO", and Hydrogen, "H2", which can then be catalytically, chemically condensed via nearly-ancient processes, such as Germany's pre-WWII Fischer-Tropsch synthesis, into any and all "normally liquid hydrocarbons".