United States Patent Application: 0130118906
In fact, it wasn't the United States Department of Defense itself, as per the headline, but, the US Air Force, the US Army, and the US Navy who, through separate grants and contracts, supported the University of Southern California in their development of technology that uses simple Sunlight to power the conversion of Carbon Dioxide - - as is co-produced in a small way, relative to some all-natural and un-taxable sources of CO2 emission, such as the Earth's inexorable processes of planetary volcanism, from our economically essential use of Coal in the generation of truly abundant and truly affordable electric power - - into substitute, fracking-free, natural gas Methane.
The concept of such "artificial photosynthesis", wherein sunlight is used to convert Carbon Dioxide and Water into substitute natural gas Methane, presuming you to have followed our posts thus far, shouldn't be new to you, since, as seen for one example in our report of:
West Virginia Coal Association | Penn State Solar CO2 + H2O = Methane | Research & Development; concerning: "'High-Rate Solar Photocatalytic Conversion of CO2 and Water Vapor to Hydrocarbon Fuels'; Oomman K. Varghese, Maggie Paulose, Thomas J. LaTempa, and Craig A. Grimes; Materials Research Institute, The Pennsylvania State University; American Chemical Society, January 2009; Efficient solar conversion of carbon dioxide and water vapor to methane";
it has been under development in Coal Country environs for a number of years now.
Further, such "artificial photosynthesis", "solar fuel", CO2-to-Methane technology has been of interest in other academic centers, as well, as seen for one example in our report of:
West Virginia Coal Association | New York City CO2 to Methane via Artificial Photosynthesis | Research & Development; concerning: "United States Patent Application 20120208903 - Conversion of Carbon Dioxide to Methane Using Visible Light; August, 2012; Inventor: Harry D. Gafney, NY; Assignee: Research Foundation of City University of New York, NYC; Abstract: The invention relates to a method for converting carbon dioxide to methane. The method comprises exposing carbon dioxide adsorbed on a nanoporous silicate matrix to light in the presence of a source of carbon dioxide and a source of hydrogen for a time and under conditions sufficient to convert carbon dioxide to methane. In one embodiment, the invention relates to a method for converting carbon dioxide to methane (and) comprises exposing carbon dioxide adsorbed on a nanoporous silicate matrix to light in the presence of a source of carbon dioxide and a source of hydrogen for a time and under conditions sufficient to convert carbon dioxide to methane. Solar energy, e.g., sunlight, is preferred. Source of Hydrogen: ... A preferred source of hydrogen is water";and, has also captured the interest of our United States Department of Energy, as seen in:
West Virginia Coal Association | USDOE Sunlight Converts CO2 into Methane | Research & Development; concerning: "US Patent Application 20130079577 - Synthesis of Photocatalysts for Solar Fuel Generation; March 28, 2013; Inventor: Brian Ingram, et. al., IL and TN'; Assignee: UChicago Argonne, LLC, Chicago; (USDOE Argonne National Laboratory); Abstract: In one preferred embodiment, a photocatalyst for conversion of carbon dioxide and water to a hydrocarbon and oxygen ... . Government Interests: The United States Government has rights in this invention pursuant to Contract No. DE-AC02-06CH11357 between the United States Government and UChicago Argonne, LLC representing Argonne National Laboratory.The photocatalyst (and) method of converting carbon dioxide and water into a hydrocarbon and oxygen comprising exposing a gaseous mixture of carbon dioxide and water to sun light in the presence of a photocatalyst ... . This invention relates to the energy efficient photocatalytic conversion of carbon dioxide gas and water vapor to methane and other hydrocarbon fuels, particularly promoted by sunlight (referred to herein as "solar-derived fuel" or "solar fuel")".
The USDOE is so enthused about the prospects for using Sunlight to synthesize Methane and other hydrocarbon fuels from Water and Carbon Dioxide that it has, in fact, established a consortium, "The Joint Center for Artificial Photosynthesis", with itself as the core and a number of university research laboratories as partners, as explained in our report of:
West Virginia Coal Association | CO2 a "Powerful Option" for US Hydrocarbon Fuel Independence | Research & Development; "The Joint Center for Artificial Photosynthesis (JCAP) is the nation's largest research program dedicated to the development of an artificial solar-fuel generation technology. Established in 2010 as a U.S. Department of Energy (DOE) Energy Innovation Hub, JCAP aims to find a cost-effective method to produce fuels using only sunlight, water, and carbon dioxide as inputs".However, as we've seen in other reports, such as, for just two examples:
West Virginia Coal Association | More US Air Force 1965 CO2 Recycling | Research & Development; concerning:"Investigation of Catalytic Reactions for CO2 Reduction; Part II; Technical Documentary Report No. FDL-TDR 64-22: April, 1965; Edward Thompson; Air Force Flight Dynamics Laboratory; Wright-Patterson AFB, Ohio; Abstract: Several base metal and base metal oxide CO2 reduction catalysts were selected for investigation as Part II of an in-house research program to determine catalytic effectiveness in promoting the reduction of carbon dioxide by hydrogen to methane and water"; and:
West Virginia Coal Association | US Navy 2008 CO2 to Synfuel | Research & Development; concerning: "United States Patent 7,420,004 - Producing Synthetic Liquid Hydrocarbon Fuels; 2008; Inventors: Dennis Hardy and Timothy Coffey, VA; Assignee: The USA, as represented by the Secretary of the Navy; Abstract: A process for producing synthetic hydrocarbons that reacts carbon dioxide, obtained from seawater or air, and hydrogen obtained from water, with a catalyst in a chemical process such as reverse water gas shift combined with Fischer Tropsch synthesis. The hydrogen is produced by ... ocean thermal energy conversion, or any other source that is fossil fuel-free, such as wind or wave energy. The process can be either land based or sea based";
the United States Department of Defense, through various of it's armed forces branches, has, as well, been promoting the development of technologies that, in some cases specifying the use of environmental energy to drive the processes, convert Carbon Dioxide into "synthetic hydrocarbons", including "methane".
And, herein, we learn that our United States Armed Forces have come together to sponsor research at a major university that has furthered the development of Artificial Photosynthesis technology, wherein Solar light energy is used to drive the conversion of Carbon Dioxide into substitute natural gas Methane.
As seen in excerpts from the initial link in this dispatch to:
"US Patent Application 20130118906 - Method and System for Enhancing Catalytic and Photocatalytic Processes
May 16, 2013
Inventors: Stephen Cronin, et. al., California
Assignee: University of Southern California, Los Angeles
(Concerning the above University of Southern California, we remind you of the many Carbon Dioxide utilization technologies developed there by their resident Nobel Prize-winning chemist, George Olah; as in, for just one out of many examples, our report of:
West Virginia Coal Association | California July 2012 Efficient CO2 to Methanol | Research & Development; concerning: "United States Patent 8,212,088 - Efficient and Selective Chemical Recycling of Carbon Dioxide toMethanol, Dimethyl Ether and Derived Products; July 3, 2012; Inventors: George Olah and G.K. Surya Prakash;Assignee: University of Southern California, Los Angeles; Abstract: An efficient and environmentally beneficial method of recycling and producing methanol from varied sources of carbon dioxide including flue gases of fossil fuel burning powerplants, industrial exhaust gases or the atmosphere itself. Converting carbon dioxide by chemical or electrochemical reduction seconardy treatment to produce essentially methanol, dimethyl ether and derived products". )
Abstract: A system for solar energy conversion includes a photoelectric cell. The photoelectric cell includes a cathode and an anode comprising a nanostructure array. The nanostructure array includes a semiconductor photocatalyst; and a plasmon resonant metal nanostructure film arranged on the semiconductor photocatalyst. The system is used in a method to produce methane by placing a photocatalytic cell in an environment containing CO2; and exposing the photocatalytic cell to visible light thereby allowing the CO2 to be converted to methane.
(As revealed, but almost only in passing, further on, the CO2 is to be in an "aqueous solution"; or, the process is to be performed on "CO2 saturated water vapor", and includes the "photocatalytic splitting of water". The Water, H2O, is the source of the Hydrogen needed for the synthesis of the Methane, CH4.
Further, concerning what a "plasmon resonant metal" might be, and what it means, have a look at the full article accessible via:
Surface plasmon resonance - Wikipedia, the free encyclopedia; "Surface plasmon resonance (SPR) is the collective oscillation of electrons in a solid orliquid stimulated by incident light".
We would be lying if we told you we fully understood it. But, there are people who do understand it; and, the materials which exhibit the needed "plasmon resonance" aren't uncommon. )
Government Interests: This invention was made with government support under Grant No. FA9550-08-1-0019, awarded by the Air Force Office of Scientific Research (AFOSR); under Grant No. N00014-08-1-0132, awarded by the Office of Naval Research (ONR); under Grant No. W911NF-09-1-0240, awarded by the Army Research Office (ARO); and under Grant No. CBET-0846725, awarded by the National Science Foundation (NSF). The Government has certain rights in the invention.
Claims: A system for solar energy conversion comprising: a photoelectric cell comprising: a cathode; and an anode comprising a nanostructure array, wherein the nanostructure array comprises: a semiconductor photocatalyst; and a plasmon resonant metal nanostructure film arranged on the semiconductor photocatalyst.
The system for solar energy conversion ... wherein the semiconductor photocatalyst is at least one selected from the group consisting of TiO2, YbO, PbO, Fe2O3, ZnO, CdS, SiC, WO3, and GaP, and any combination thereof.
(The above Titanium Oxide, TiO2, is frequently specified in these sorts of photocatalytic CO2 and H2O conversion technologies. It's pretty common stuff; and, only one or two of the specified photocatalysts could be considered genuinely rare or exotic.)
The system for solar energy conversion ... wherein the plasmon resonant metal nanostructure film has (dimensions and shapes as specified, and) is comprised of at least one selected from the group consisting of Gold, Silver, Aluminum, Copper and Platinum, and any combination thereof.
The system for solar energy conversion ... wherein the plasmon resonant metal nanostructure film is arranged on a surface of the semiconductor photocatalyst (and) wherein the absorption spectrum of the anode is in the visible region.
The system for solar energy conversion ... wherein the nanostructure array has a repeating pattern of shapes (such as)dots, rods, triangles, bowties, and crescents (and) wherein the shapes have a size (as specified, and) wherein the semiconductor photocatalyst is doped with a dopant selected from the group consisting of Vanadium, Chromium, Manganese, Iron, Nickel, any ion thereof and any combination thereof.
A method for producing methane comprising the steps of: placing a photocatalytic cell in an environment containing CO2; and exposing the photocatalytic cell to visible light thereby allowing the CO2 to be converted to methane, wherein the photoelectric cell comprises: a cathode; and an anode comprising a nanostructure array, and the nanostructure array comprises: a semiconductor photocatalyst; and a plasmon resonant metal nanostructure film arranged on the semiconductor photocatalyst
The method ... wherein the absorption spectrum of the anode is in the visible region.
Background: Utilizing solar electricity for large scale energy generation presents several problems. First, as an intermittent energy source (night and day), there is no way to effectively store this enormous amount of electricity each day to be used during the night. Batteries give the option of storing limited amounts of energy, but suffer from finite lifetimes and contain significantly toxic chemicals that are difficult to dispose of. Also, there are huge losses associated with transporting electricity over large distances. Therefore, a method of storing the sun's energy in chemical bonds then releasing it without harmful byproducts is indeed the "Holy Grail" in solar energy conversion.
(Some discussion is devoted to explanation of what a "plasmon" is, and, why plasmons are good things to include in a process like this, that is, how they enhance the absorption of light in various wavelengths, and make the light energy available for use in the reactions. Again, they are understood by those skilled in these arts, and can be formed of common elements.)
Metal oxides such as TiO2, YbO, PbO may be used as photocatalysts for a number of applications, including solar fuel production, oxidation of pollutants, and anti-fogging/self-cleaning coatings for windows and lenses. When gold is dispersed as fine particles (2-5 nm) over select metal oxides, it may exhibit exceptionally high catalytic activity, far exceeding that of the metal oxide and gold catalysts separately. Examples of this enhanced catalytic activity include ...: hydrogen production from water (and) hydrogenation of CO2 ... . Quite often these reactions occur at low or subambient temperatures.
Summary:The present disclosure is directed toward a system and method to enhance catalytic and photocatalytic processes under solar irradiation by integrating plasmon resonant nanostructures with strongly catalytic materials.
In one embodiment of the present disclosure, a system for solar energy conversion comprises a photoelectric cell. The photoelectric cell comprises a cathode; and an anode comprising a nanostructure array. The nanostructure array may comprise a semiconductor photocatalyst; and a plasmon resonant metal nanostructure film arranged on the semiconductor photocatalyst.
In another embodiment of the present disclosure, a method for producing methane comprises the steps of placing a photocatalytic cell in an environment containing CO2; and exposing the photocatalytic cell to visible light thereby allowing the CO2 to be converted to methane. The photoelectric cell comprises a cathode; and an anode comprising a nanostructure array. The nanostructure array comprises a semiconductor photocatalyst; and a plasmon resonant metal nanostructure film arranged on the semiconductor photocatalyst.
Illustrative examples are now discussed and illustrated. ... Figure 7a shows the product yields of the photoreduction of aqueous CO2 (and) methane is the only product detected ... .
(It) is energetically favorable for electrons from the conduction band of TiO2 to transfer to CO2 to initiate the reduction of CO2 with H2O producing CH4.
Methane is the only favorable product."
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First, in passing, we remind you, that, as seen in our report of:
West Virginia Coal Association | Stanford University Converts CO2 to Methane | Research & Development; concerning: "United States Patent 4,404,068 - Solid State Method for Synthesis Reactions; 1983; Inventors: Robert Huggins and Turgut Gur, California; Assignee: Stanford University; Abstract: A method for synthesizing reaction products, such as hydrocarbons, from fluid reactants is provided by use of a solid state electrochemical cell. A preferred embodiment may be used to produce methane at a substantially enhanced, controllable rate. Claims: A method for synthesizing a reaction product ... wherein reactants are in gaseous form (and) wherein: said first reactant is CO or CO2 and said second reactant is H2 (and) wherein: said reaction product is methane";
this is far from the first technology to emerge from the California university system to define a process for converting Carbon Dioxide into Methane, although our subject, "US Patent Application 20130118906 - Method and System for Enhancing Catalytic and Photocatalytic Processes", does explain how simple Sunlight can be used to drive the needed reactions.
And, in closing, we remind you, that, as seen for one out of now many examples in our report of:
West Virginia Coal Association | Pittsburgh 1941 CO2 + Methane = Hydrocarbon Syngas | Research & Development; concerning:"United States Patent 2,266,989 - Manufacture of a Gas from CO2 and Methane; Date: December 23, 1941; Inventor: Max Radtke, Germany; Assignee: Koppers Company, Pittsburgh, PA; Abstract: The present invention relates to the manufacture of gases suitable for the synthesis of higher hydrocarbons or the like, said gases containing definite volumes of carbon monoxide and hydrogen in a certain proportion, by reacting on methane ... with carbon dioxide or a mixture of carbon dioxide and steam, so that the methane ... is decomposed into hydrogen and carbon monoxide";
once we have Methane, as synthesized herein, via the process of "United States Patent Application 20130118906 - Method and System for Enhancing Catalytic and Photocatalytic Processes", from Water and Carbon Dioxide, in reactions powered by Sunlight, we can then react that CO2-based Methane with even more Carbon Dioxide, as recovered from whatever handy source, and thereby generate a syngas blend of Carbon Monoxide and Hydrogen "suitable for the synthesis of higher hydrocarbons".