We've reported now many times on the Carbon Dioxide utilization technologies founded, as seen for only the most recent example in our report of:
Princeton University March, 2014, CO2 to Methanol | Research & Development | News; concerning: "United States Patent 8,663,447 - Conversion of Carbon Dioxide to Organic Products; March 4, 2014; Inventors: Andrew Bocarsly, NJ, and Emily Barton Cole, TX; Assignee: Princeton University, NJ; Abstract: The invention relates to various embodiments of an environmentally beneficial method for reducing carbon dioxide. The methods in accordance with the invention include electrochemically or photoelectrochemically reducing the carbon dioxide in a divided electrochemical cell ... to produce therein a reduced organic product. Government Interests: This invention was made with United States government support from National Science Foundation Grant No. CHE-0616475. The United States Government has certain rights in this invention. Claims: An environmentally beneficial method of producing methanol by electrochemical reduction of any available source of carbon dioxide";
in the Princeton University labs of Professor Andrew Bocarsly; and, as seen for one example in our report of:
The USDOE and New Jersey Convert CO2 into Ethanol | Research & Development | News; concerning: "United States Patent Application 20130199937 - Reducing Carbon Dioxide to Products; August 8, 2013; Inventors: Emily Barton Cole, et. al., Texas and New Jersey; Assignee: Liquid Light, Inc., NJ; Abstract: A method reducing carbon dioxide to one or more products ... .Government Interests: This invention was made with government support under Grant DE-SC0006201 awarded by the Department of Energy. The government has certain rights in the invention. Claims: A method for reducing carbon dioxide to one or more products (and) wherein said products comprise one or more of ... ethane, ethanol, ... methane, methanol, (etc.)";
by the New Jersey company, Liquid Light, Incorporated - -:
LIQUID LIGHT; "Liquid Light develops electrocatalytic technology to make major chemicals from low-cost, globally abundant carbon dioxide (CO2)"
- - which company has been described as a commercial "spin-off" from Princeton University, intended to commercialize and further develop the CO2-recycling technology first developed by Princeton.
Another Liquid Light technology for the similar productive utilization of Carbon Dioxide, which gas is so fortuitously co-produced - - but only in a small way, relative to some all-natural and un-taxable sources of it's emission, such as the Earth's inexorable processes of planetary volcanism - - during our essential use of Coal in the generation of truly abundant and truly affordable electric power, is that seen in our report of:
New Jersey Recycles More Carbon Dioxide | Research & Development | News; concerning: "United States Patent Application 20110114504 - Electrochemical Production of Synthesis Gas from Carbon Dioxide; May, 2011; Inventors: Narayanappa Sivasankar, Emily Barton Cole and Kyle Teamy, NJ and DC; Abstract: A method for electrochemical production of synthesis gas from carbon dioxide is disclosed".
As we explained and documented via separate reference included in that report, such "synthesis gas", also called "syngas", is a blend of gases which primarily "contains varying amounts of carbon monoxide and hydrogen" and which can be used to produce "synthetic natural gas (,) methanol (and) synthetic petroleum".
Since before many of us were born, as seen for one example in:
Texaco 1951 Coal + CO2 + H2O + O2 = Syngas | Research & Development | News; concerning: "United States Patent 2,558,746 - Carbon Monoxide and Other Gases from Carbonaceous Materials; July 3, 1951; Assignee: The Texas Company; Abstract: This invention relates to a process and apparatus for the generation of gases comprising carbon monoxide from carbonaceous materials. In one of its more specific aspects it relates to a process and apparatus for the generation of a mixture of carbon monoxide and hydrogen, suitable as a feed for the synthesis of hydrocarbons, from powdered coal";
it has been known, but unfortunately not to the Coal Country public, that we can also make such hydrocarbon synthesis gas, or syngas", out of our abundant Coal.
In any case, just yesterday, independent technical experts in the employ of our United States Government confirmed the validity and practicability of the Carbon Dioxide-to-syngas technology disclosed in our earlier report concerning Liquid Light's "United States Patent Application 20110114504", through their allowance, as excerpted from the initial link in this dispatch, of:
"United States Patent 8,721,866- Electrochemical Production of Synthesis Gas from Carbon Dioxide
Electrochemical production of synthesis gas from carbon dioxide - Liquid Light, Inc.
Date: May 13, 2014
Inventors: Narayanappa Sivasankar, Emily Barton Cole, Kyle Teamey, NJ and DC
Assignee: Liquid Light, Inc., NJ
Abstract: A method for electrochemical production of synthesis gas from carbon dioxide is disclosed. The method generally includes steps (A) to (C). Step (A) may bubble the carbon dioxide into a solution of an electrolyte and a catalyst in a divided electrochemical cell. The divided electrochemical cell may include an anode in a first cell compartment and a cathode in a second cell compartment. The cathode generally reduces the carbon dioxide into a plurality of components. Step (B) may establish a molar ratio of the components in the synthesis gas by adjusting at least one of (i) a cathode material and (ii) a surface morphology of the cathode. Step (C) may separate the synthesis gas from the solution.
(At this point in United States patents, lists of precedent patented art are provided. The one provided by Liquid Light is extensive, and includes many about which we have already reported, such as:
USDOE 1976 Atmospheric CO2 to Methanol | Research & Development | News; concerning: "United States Patent 3,959,094 - Electrolytic Synthesis of Methanol from CO2; Date: May, 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".
Liquid Light cites many other Carbon Dioxide utilization and conversion technologies, as well, including many established by Nobel Laureate George Olah, and colleagues, at the University of California, and by the scientists at Chicago's Gas Research Institute, and it's precedent and subsequent incarnations. Our citing other examples of our earlier reportage of those technologies here would be an insufferable interruption, but, Liquid Light's extensive list of prior patents here, and their list of associated literature references, speaks to the fact that these folks have done their homework. The technology being disclosed herein is very thoroughly based on, and has evolved from, solid foundations.)
Claims: A method for electrochemical production of synthesis gas from carbon dioxide, comprising the steps of: (A) bubbling carbon dioxide into a solution of an electrolyte and a catalyst, the catalyst selected from the group consisting of an aromatic heterocyclic amine containing oxygen and an aromatic heterocyclic amine containing sulfur, in a divided electrochemical cell, wherein (i) said divided electrochemical cell comprises an anode in a first cell compartment and a cathode in a second cell compartment, (ii) said cathode reducing said carbon dioxide into synthesis gas, the synthesis gas includes a plurality of components; (B) establishing a molar ratio of said components in said synthesis gas by adjusting at least one of (i) a cathode material and (ii) a surface morphology of said cathode; and (C) separating said synthesis gas from said solution.
The method ... wherein said cathode includes at least one of Aluminum, Gold, Silver, Carbon, Cadmium, Cobalt, Chromium, Copper (and, etc., and( wherein the electrolyte includes one of Potassium Chloride, Sodium Nitrate (and, etc.).
The method ...wherein said synthesis gas includes said plurality of components, the plurality of components include carbon monoxide and hydrogen.
A method for electrochemical production of synthesis gas from carbon dioxide, comprising the steps of: (A) bubbling carbon dioxide into a solution of an electrolyte and a catalyst, the catalyst selected from the group consisting of a quinolone, adenine, benzimidazole, 1-10-phenanthroline, thiazole and oxazole, in a divided electrochemical cell, wherein (i) said divided electrochemical cell comprises an anode in a first cell compartment and a cathode in a second cell compartment, (ii) said cathode reducing said carbon dioxide into synthesis gas, the synthesis gas includes a plurality of components; (B) establishing a molar ratio of said components in said synthesis gas by adjusting at least one of (i) a cathode material and (ii) a surface morphology of said cathode; and (C) separating said synthesis gas from said solution.
The method .. wherein the electrolyte includes one of Potassium Chloride (and, etc., in specified concentrations).
Background and Field: The present invention relates to chemical reduction generally and, more particularly, to a method and/or apparatus for implementing electrochemical production of synthesis gas from carbon dioxide.
The combustion of fossil fuels in activities such as electricity generation, transportation and manufacturing produces billions of tons of carbon dioxide annually. ... Countries around the world, including the United States, are seeking ways to mitigate emissions of carbon dioxide.
A mechanism for mitigating emissions is to convert carbon dioxide into economically valuable materials such as fuels and industrial chemicals.
If the carbon dioxide is converted using energy from renewable sources, both mitigation of carbon dioxide emissions and conversion of renewable energy into a chemical form that can be stored for later use will be possible.
Electrochemical and photochemical pathways are techniques for the carbon dioxide conversion.
Copper, silver and gold have been found to reduce carbon dioxide to various products. However, the electrodes are quickly "poisoned" by undesirable reactions on the electrode and often cease to work in less than an hour. Similarly, gallium-based semiconductors reduce carbon dioxide, but rapidly dissolve in water. Many cathodes make a mix of organic products. For instance, copper produces a mix of gases and liquids including methane, formic acid, ethylene and ethanol.
Summary: The present invention concerns a method for electrochemical production of synthesis gas from carbon dioxide. The method generally includes steps (A) to (C). Step (A) may bubble the carbon dioxide into a solution of an electrolyte and a catalyst in a divided electrochemical cell. The divided electrochemical cell may include an anode in a first cell compartment and a cathode in a second cell compartment. The cathode generally reduces the carbon dioxide into a plurality of components. Step (B) may establish a molar ratio of the components in the synthesis gas by adjusting at least one of (i) a cathode material and (ii) a surface morphology of the cathode. Step (C) may separate the synthesis gas from the solution.
The objects, features and advantages of the present invention include providing a method and/or apparatus for implementing electrochemical production of synthesis gas from carbon dioxide that may provide (i) cathode combinations for simultaneous evolution of carbon monoxide and hydrogen gas using carbon dioxide and water as feedstock, (ii) combinations of cathode materials, electrolytes, electrical potentials, pH levels, carbon dioxide flow rates and/or heterocycle catalysts, used to get a desired molar ratios of carbon monoxide and hydrogen gas, (iii) specific process conditions that optimize the carbon dioxide conversion to carbon monoxide while optimizing hydrogen gas evolution, (iv) a choice of specific configurations of heterocyclic amine catalysts with engineered functional groups, (v) process conditions that may facilitate long life electrode and cell cycling and/or (vi) process conditions that may provide long-term product recovery.
In accordance with some embodiments of the present invention, an electro-catalytic system is provided that generally allows carbon dioxide to be converted at modest overpotentials to highly reduced species in an aqueous solution. Some embodiments generally relate to an evolution of carbon monoxide and hydrogen gas from carbon dioxide and water. Carbon-carbon bonds and/or carbon-hydrogen bonds may be formed in the aqueous solution under mild conditions utilizing a minimum of energy.
In some embodiments, the energy used by the system may be generated from an alternative energy source or directly using visible light, depending on how the system is implemented.
The reduction of carbon dioxide may be suitably catalyzed by aromatic heterocyclic amines (e.g., pyridine, imidazole and substituted derivatives.) Simple organic compounds have been found effective and stable homogenous electrocatalysts and photoelectrocatalysts for the aqueous multiple electron, multiple proton reduction of carbon dioxide to organic products, such as formic acid, formaldehyde and methanol. High faradaic yields for the reduced products have generally been found in both electrochemical and photoelectrochemical systems at low reaction overpotentials.
Some embodiments of the present invention thus relate to environmentally beneficial methods for reducing carbon dioxide. The methods generally include electrochemically and/or photoelectrochemically reducing the carbon dioxide in an aqueous, electrolyte-supported divided electrochemical cell that includes an anode (e.g., an inert conductive counter electrode) in a cell compartment and a conductive or p-type semiconductor working cathode electrode in another cell compartment. A catalyst of one or more substituted or unsubstituted aromatic heterocyclic amines may be included to produce a reduced organic product. Carbon dioxide may be continuously bubbled through the cathode electrolyte solution to saturate the solution.
The catalyst for conversion of carbon dioxide electrochemically or photoelectrochemically may be a substituted or unsubstituted aromatic heterocyclic amine. Suitable amines are generally heterocycles which may include, but are not limited to, heterocyclic compounds that are 5-member or 6-member rings with at least one ring nitrogen. For example, pyridines, imidazoles and related species with at least one five-member ring, bipyridines (e.g., two connected pyridines) and substituted derivatives were generally found suitable as catalysts for the electrochemical reduction and/or the photoelectrochemical reduction. Amines that have sulfur or oxygen in the rings may also be suitable for the reductions. Amines with sulfur or oxygen may include thiazoles or oxazoles. Other aromatic amines (e.g., quinolines, adenine, benzimidazole and 1,10-phenanthroline) may also be effective electrocatalysts.
In the following description of methods, process steps may be carried out over a range of temperatures (e.g., approximately 10 degrees Celsius to 50 degrees C and a range of pressures (e.g., approximately 1 to 10 atmospheres) ... .
A use of electrochemical or photoelectrochemical reduction of carbon dioxide, tailored with certain electrocatalysts, may produce carbon monoxide and/or hydrogen gas in a high yield of 0% to about 100%. Relative yields may be controlled by changing the cathode materials, catalysts and various aspects of reaction conditions such as pH and carbon dioxide flow rate.
The overall reaction for the evolution of synthesis gas from carbon dioxide may be represented as follows: CO2 + H2O =.CO + H2 + O2
The reduction of the carbon dioxide may be suitably achieved efficiently in a divided electrochemical or photoelectrochemical cell in which (i) a compartment contains an anode that is an inert counter electrode and (ii) another compartment contains a working cathode electrode and one or more substituted or unsubstituted aromatic heterocyclic amines. The compartments may be separated by a porous glass frit or other ion conducting bridge. Both compartments generally contain an aqueous solution of an electrolyte. Carbon dioxide gas may be continuously bubbled through the cathodic electrolyte solution to saturate the solution.
In the working electrode compartment, carbon dioxide may be continuously bubbled through the solution. In some embodiments, if the working electrode is a conductor, an external bias may be impressed across the cell such that the potential of the working electrode is held constant. In other embodiments, if the working electrode is a p-type semiconductor, the electrode may be suitably illuminated with light. An energy of the light may be matching or greater than a bandgap of the semiconductor during the electrolysis. Furthermore, either no external source of electrical energy may be used or a modest bias (e.g., about 500 millivolts) may be applied. The working electrode potential is generally held constant relative to a saturated calomel electrode (SCE). The electrical energy for the electrochemical reduction of carbon dioxide may come from a normal energy source, including nuclear and alternatives (e.g., hydroelectric, wind, solar power, geothermal, etc.), from a solar cell or other nonfossil fuel source of electricity, provided that the electrical source supply at least 1.6 volts across the cell. Other voltage values may be adjusted depending on the internal resistance of the cell employed.
Advantageously, the carbon dioxide may be obtained from any sources (e.g., an exhaust stream from fossil-fuel burning power or industrial plants, from geothermal or natural gas wells or the atmosphere itself).
The carbon dioxide may be obtained from concentrated point sources of generation prior to being released into the atmosphere. For example, high concentration carbon dioxide sources may frequently accompany natural gas in amounts of 5% to 50%, exist in flue gases of fossil fuel (e.g., coal, natural gas, oil, etc.) burning power plants and nearly pure carbon dioxide may be exhausted of cement factories and from fermenters used for industrial fermentation of ethanol.
(Note, in the above, as we have previously documented and reported, the large amounts of Carbon Dioxide that are associated with what have been presented as our various "Clean Energy Alternative"s.)
Certain geothermal steams may also contain significant amounts of carbon dioxide. The carbon dioxide emissions from varied industries, including geothermal wells, may be captured on-site. Separation of the carbon dioxide from such exhausts is known. Thus, the capture and use of existing atmospheric carbon dioxide in accordance with some embodiments of the present invention generally allow the carbon dioxide to be a renewable and unlimited source of carbon.
For electrochemical conversions, the carbon dioxide may be readily reduced in an aqueous medium with a conductive electrode. Faradaic efficiencies have been found high, some reaching about 100%.
Carbon dioxide may be efficiently converted to value-added gases, using either a minimum of electricity (that could be generated from an alternate energy source) or directly using visible light.
Some processes described above may generate high energy density fuels that are not fossil-based as well as being chemical feedstock that are not fossil or biologically based. Moreover, the catalysts for the processes may be substituents-sensitive and provide for selectivity of the value-added gases.
By way of example, a fixed cathode may be used in an electrochemical system where the electrolyte and/or catalyst are altered to change the gas mix. In a modular electrochemical system, the cathodes may be swapped out with different materials to change the gas mix. In a photoelectrochemical system, the anode and/or cathode may use different photovoltaic materials to change the gas mix.
(Concerning the above several statements, the full Disclosure goes into great detail, and extended explanation, concerning the various electrode materials, catalysts, and cell configurations which can be used, whether in conjunction with light, for photo-electric reduction of CO2, or, with what seem very low levels of electricity supplied by alternative sources. Different products can be made, but, with the design and combinations directed to the production of synthesis gas, efficiencies can approach 100%.)
Some embodiments of the present invention generally provide for new cathode combinations for simultaneous evolution of carbon monoxide and hydrogen gas using carbon dioxide and water as feedstock.
Specific combinations of cathode materials, electrolytes, catalysts, pH levels and/or electrical potentials may be established that optimize the carbon dioxide conversion to carbon monoxide while also optimizing hydrogen gas evolution.
Choice of specific configurations of heterocyclic amine catalysts with engineered functional groups may be utilized in the system. Process conditions described above may facilitate long life (e.g., improved stability), electrode and cell cycling and product recovery.
Various process conditions disclosed above, including electrolyte choice, cell voltage, and manner in which the carbon dioxide is bubbled, generally improve control of the reaction so that precise molar ratios within synthesis gas may be maintained with little or no byproducts. Greater control over the reaction generally opens the possibility for commercial systems that are modular and adaptable to make different gases. The new materials and process conditions combinations generally have high faradaic efficiency and relatively low cell potentials, which allows an energy efficient cell to be constructed".
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The full Disclosure, as we indicated via our few inserted comments, is lengthy and complex; and, it much more fully specifies the various materials which can be used for the electrodes, catalysts, etc., and, how those choices affect both the mix of products obtained and the energies, whether sunlight or low-level electricity from alternative sources, which can be used to drive the Carbon Dioxide utilization process.
As we read it, hydrocarbon synthesis gas, a blend of Carbon Monoxide and Hydrogen which can, using various techniques and catalysts, be chemically condensed into a full range of both gaseous and liquid hydrocarbons, is the product which can be made, as herein, from Carbon Dioxide and Water with the greatest efficiency and at the lowest energy demand.
But, again, the technicalities are complex, and the explanation of them extended.
The essence of it all, though, is this:
Carbon Dioxide, as recovered from whatever source might be most convenient to us, and Water, in processes that can be powered by various forms of low-level environmental, renewable energy, can be converted at a rate of nearly 100% into Carbon Monoxide and Hydrogen, with Oxygen a likely byproduct.
The product blend of Carbon Monoxide and Hydrogen can subsequently be chemically condensed, via processes that have been known and practiced, and further developed and refined, since before WWII, into a full range of liquid and gaseous hydrocarbon fuels and organic chemical manufacturing raw materials.
Some brilliant, and very hard-working, very thorough, folks in New Jersey have - - as officially confirmed herein just yesterday by our United States Government - - demonstrated that to be true and have established valid and practicable methods by which it all can be accomplished.
An old West Virginia Coal miner among our number here, who actually spent a little time as an honorary New Jersey "sand hog", helping them figure out how to drive some of their urban subway tunnels through difficult ground, thinks it's far past time someone in Coal Country qualified to do so gave these blue-collar scientists in Jersey a call, got the full story, and brought it home to the rest of us.
Not only could we expose the concepts of Cap & Trade Carbon taxes and mandated geologic sequestration of CO2 in leaky old oil wells - all done at the expense of consumers of Coal-based electricity and intended to subsidize the profits of the oil well owners by enabling secondary recovery of residual petroleum - as counterproductive, somewhat predatory schemes, we could lay the foundations for a new industry to be founded in US Coal Country: An industry targeted on the production of hydrocarbon fuels and chemicals, via the intermediate production of synthesis gas, Carbon Monoxide and Hydrogen, from Water and, what should now be seen as a valuable byproduct arising from our economically essential use of Coal in the generation of abundant and affordable electric power: Carbon Dioxide.