We begin to introduce herein, or to reintroduce with an attempt to use proper terminology, a technical concept, or pathway, for the solar-powered conversion of Carbon Dioxide, as we could recover from the flue gases of our economically essential Coal-fired electric power generation plants, or, even from the atmosphere itself, into liquid and gaseous hydrocarbon fuels and chemicals.
In broad terms, the technology might be thought of as "artificial photosynthesis", as we've touched on in a few previous reports, such as, for two examples:
ARCO CO2 to Methanol Photosynthesis | Research & Development | News; concerning: "United States Patent 4,427,508 - Light Driven Photocatalytic Process; 1984; Assignee: Atlantic Richfield Company, CA;
Claims: A method for the light driven photocatalytic reduction of carbon dioxide or the bicarbonate ion to at least one compound which comprises contacting silicon with a hydrogen containing material and at least one of carbon dioxide and the bicarbonate ion in the absence of separate physical electrolyte and electrodes, and conducting said contacting in the presence of light so that the energy of reduction is essentially supplied by said light. (And) wherein said light is one of artificial light, sunlight, or a combination thereof (and) wherein said compounds are carbon monoxide, alcohols, aldehydes, hydrocarbons, esters, and carboxylic acids ... (which are specified to include) methanol, formaldehyde, formic acid, and methane. There is provided, according to this invention, a method for the light driven photocatalytic reduction of carbon dioxide or the bicarbonate ion to at least one organic compound which comprises contacting silicon (elemental silicon) with at least one of carbon dioxide and the bicarbonate ion in the presence of light so that the energy of reduction is essentially supplied by said light"; and:
California Efficient CO2 to Methanol Photoelectric Conversion | Research & Development | News; concerning: "United States Patent 4,521,499 - Photoelectrochemical Electrodes and Uses Thereof; 1985; Assignee: Union Oil Company of California, Los Angeles; Abstract: A photoelectrode, containing a highly conductive coating material having a band gap (as specified)on a substrate containing a semiconductor material, is utilized in photovoltaic cells, photoelectrosynthesis and photoelectrocatalysis. ... The invention relates to photoelectrochemical electrodes and, more particularly, to the utilization of photoelectrochemical electrodes for producing electricity from semiconductor liquid junction photovoltaic cells and for producing stored energy products from photoelectrosynthetic and photoelectrocatalytic cells. ... Photoelectrosynthetic cells employing the photoelectrode of the invention may convert essentially any organic reactant in the presence of water to an oxidized organic product and hydrogen. Other examples of typical photoelectrosynthetic conversion reactions employing the photoelectrode of the invention include hydrogen chloride converted to hydrogen and chlorine, hydrogen bromide converted to hydrogen and bromine, hydrogen iodide converted to hydrogen and iodine, water and propylene converted to propylene oxide and hydrogen, and water and carbon dioxide converted to methanol and oxygen".
There are two chemical components to such light-driven, and other related, Carbon Dioxide utilization processes:
One is the chemical "reduction" of Carbon Dioxide, to form a more reactive compound, typically identified as Carbon Monoxide, although the chemistry can be more complex than that and different terms can be used to describe a chemically "activated", so to speak, Carbon Dioxide molecule, or fragment thereof.
The second is called, chemically, the "oxidation" of Water, H2O, in order to form, specifically, in addition to byproduct Oxygen, and instead of molecular Hydrogen, the Hydrogen "cation", abbreviated as "H+". See:
Hydrogen ion - Wikipedia, the free encyclopedia; When hydrogen loses its electron ... cations can be formed (such as) "H+".
Such Hydrogen ions, cations, are so reactive that they can then serve to effect the nearly automatic, and concurrent, chemical reduction of Carbon Dioxide, with final reaction products including alcohols and hydrocarbons.
Thus, the potential exists to design photosynthetic systems that - - arising from perhaps less-sophisticated earlier developments like those disclosed in the above-referenced "US Patent 4,427,508 - Light Driven Photocatalytic Process" and "US Patent 4,521,499 - Photoelectrochemical Electrodes and Uses Thereof" - - much more efficiently, through an initial light-driven "water oxidation", with immediately subsequent or concurrent CO2 "reduction", convert blends of Carbon Dioxide and Water into Hydrogen-Carbon compounds, such as various hydrocarbons and alcohols.
That explanation is overly simplistic, and it's inadequacy reflects our own lack of education and sophistication in such matters. Certainly, there are qualified folks around in our Coal Country colleges and universities, and in some of our Coal Country chemical corporations, who could much more cogently and completely describe the concepts involved, if anyone happens to be genuinely interested enough to seek them out. Thankfully, there are also folks in the employ of our United States Department of Energy who do understand the meaning, and value, of such Solar-driven "Water Oxidation", for the generation of reactive Hydrogen ions, and the consequent, "CO2 Reduction", using the Hydrogen ions, to form hydrocarbons.
And, as seen in our reports of:
USDOE 2013 Solar CO2 + H2O = Methanol + Methane | Research & Development | News; concerning: "United States Patent Application 20130256147 - Solar Fuels Generator; 2013; Inventors: Nathan S. Lewis and Joshua Spurgeon, CA; (Presumed eventual Assignee of rights: the California Institute of Technology); Abstract: The solar fuels generator includes an ionically conductive separator between a gaseous first phase and a second phase. A photoanode uses one or more components of the first phase to generate cations during operation of the solar fuels generator. A cation conduit is positioned provides a pathway along which the cations travel from the photoanode to the separator. The separator conducts the cations. A second solid cation conduit conducts the cations from the separator to a photocathode. Government Interests: This invention was made with government support under DE-SC000493/T-105066 awarded by the Department of Energy. The government has certain rights in the invention. ... The generator ... wherein the photoanode includes an oxidation catalyst (and) wherein the pathway extends from the oxidation catalyst to the separator (and) wherein: the photoanode extends outward from a first side of a separator; and a photocathode extends outward from a second side of the separator, the second side being opposite from the first side (and) wherein the cation conduit is in direct physical contact with the separator. The generator ... wherein the first phase is a gas that includes water vapor, the second phase is a gas, and the photoanode is configured to use the water vapor to generate the cations. ... Another method of generating solar fuels includes using cations to generate the solar fuel (with) a photocathode in a gaseous second phase (and, a) separator being between the first phase and the second phase. The supply stream and/or the second phase can also include or consist of a reactant (in addition to water). (And, in some embodiments) CO2 serves as the reactant that is delivered to the photocathodes. Examples of the fuels that can be produced using this reaction in combination with the disclosed solar fuels generator include ... methanol, methane, ethanol"; and:
USDOE and California Solar Hydrogen for CO2-to-Fuel Conversion | Research & Development | News; concerning: "United States Patent Application 20130092549 - Proton Exchange Membrane Electrolysis Using Water Vapor as a Feedstock; 2013; Inventors: Joshua Spurgeon, Nathan Lewis and Philip Marcus; Assignee: California Institute of Technology, Pasadena; Abstract: A light-driven electrolytic cell that uses water vapor as the feedstock and that has no wires or connections whatsoever to an external electrical power source of any kind. In one embodiment, the electrolytic cell uses a proton exchange membrane (PEM) with an IrRuOx water oxidation catalyst and a Pt black water reduction catalyst to consume water vapor and generate molecular oxygen and a chemical fuel, molecular hydrogen. The operation of the electrolytic cell using water vapor supplied by a humidified carrier gas has been demonstrated under varying conditions of the gas flow rate, the relative humidity, and the presence or absence of oxygen. The performance of the system with water vapor was also compared to the performance when the device was immersed in liquid water. Government Interests: This invention was made with government support under DE-SC0004993/T-105066 awarded by the Department of Energy. The government has certain rights in the invention. Claims: An illumination-driven apparatus, comprising: a separator having a first side and a second side opposite said first side, said separator configured to be permeable to an ionic reaction moiety and configured to be substantially impermeable to molecular moieties so as to separate a first molecular moiety present on said first side from a second molecular moiety present on said second side; an oxidation catalyst present on said first side of said separator, said oxidation catalyst configured to oxidize H2O to produce molecular oxygen; a reduction catalyst present on said second side of said separator, said reduction catalyst configured to reduce a substance to produce a chemical fuel (and) wherein said chemical fuel is a carbonaceous fuel (and, the) illumination-driven apparatus ... wherein said light absorber configured to absorb illumination is configured to absorb ... terrestrial solar illumination. A method of generating a chemical fuel and molecular oxygen from a reaction medium containing water vapor, comprising the steps of: providing an illumination-driven apparatus (with an) oxidation catalyst configured to oxidize H2O to produce molecular oxygen; a reduction catalyst present on said second side of said separator, said reduction catalyst configured to reduce a substance to produce a chemical fuel (and) wherein said reduction catalyst is a catalyst that reduces CO2 to produce a carbonaceous fuel. The method of generating a chemical fuel and molecular oxygen from a reaction medium containing water vapor (and) a reagent containing CO2 ... . In the issue of Chemical Reviews published on Nov. 10, 2010, Arthur J. Nozik and John Miller wrote in an editorial that "[t]he direct conversion of solar photons to fuels produces high-energy chemical products that are labeled as solar fuels; these can be produced through nonbiological approaches, generally called artificial photosynthesis. The feedstocks for artificial photosynthesis are H2O and CO2, either reacting as coupled oxidation-reduction reactions, as in biological photosynthesis, or by first splitting H2O into H2 and O2 and then reacting the solar H2 with CO2 (or CO produced from CO2) in a second step to produce fuels through various well-known chemical routes involving syngas, water gas shift, and alcohol synthesis";
our United States Department of Energy has begun to fund the development of light-driven, combined Water Oxidation and Carbon Dioxide reduction technologies, wherein a process of "artificial photosynthesis" powered by "terrestrial solar illumination" can generate "solar fuels", like "methanol, methane (and) ethanol" from inputs of Water and Carbon Dioxide.
More information is becoming, and waiting to become, available about the USDOE's Artificial Photosynthesis, Carbon Dioxide and Water-to-fuels, program. For example, full reports of the USDOE contract work performed under the above-cited "DE-SC0004993/T-105066" have not yet been published; and, other, related contracts have been let by the USDOE, about which reports are also still pending. And, there is yet more background information we will be documenting for you in future reports.
But, herein, we submit yet another example of USDOE-sponsored Artificial Photosynthesis development efforts leading to yet another catalytic technology that enables the solar-driven extraction of Hydrogen from the Water, H2O, molecule, and which Hydrogen - - -
(as the full Disclosure of the technology admits, first, in the exposition of "Background":
"Hydrogen is one of the most promising alternative energy sources. It can be obtained by electrolysis of water, which is environmentally friendly and efficient. However, the electrolysis of water is an energy intensive process, which is very expensive. On the other hand, photolysis, the splitting of water by light, presents an attractive alternative method of obtaining hydrogen. Additionally, light driven reduction of carbon dioxide by water to provide hydrocarbons or methanol may be another promising alternative to alternate energy sources. For both types of reactions, coupled water oxidation to oxygen is required. In order to facilitate the photolysis of water by light in either type of reaction, a catalyst is required for the reaction";
and, then, near the end of the "Detailed Description" segment of the full Disclosure:
"Another aspect of the present invention provides methods of generating hydrocarbons, methanol and/or oxygen (O2) gases by photo-electrolyzing water. The method comprises providing a catalyst described herein and adding the catalyst to a electrolytic media under an effective condition to generate methanol/hydrocarbons and/or oxygen (O2). In one embodiment, the method further comprises exposing the reaction media which contain the catalyst to light radiation to generate methanol, hydrocarbons and/or oxygen (O2). In another embodiment, the method comprises exposing the photo-electrochemical cell described herein to light radiation without the requirement of applying an external electrical potential";)
- - - enables - via the reverse water gas shift reaction/reverse conversion - or proceeds in conjunction with, the concomitant "light-driven" chemical "reduction of carbon dioxide" and, with additional Hydrogen produced via the disclosed "photolysis, the splitting of water by light", the subsequent synthesis of "hydrocarbons or methanol".
Comment follows excerpts from the initial link in this dispatch to:
"US Patent 8,524,903 - Ruthenium or Osmium Complexes and Their Uses as Catalysts for Water Oxidation
Date: September 3, 2013
Inventors: Javier Jesus Concepcion Corbea, et. al., North Carolina
Assignee: The University of North Carolina at Chapel Hill
Abstract: The present invention provides ruthenium or osmium complexes and their uses as a catalyst for catalytic water oxidation. Another aspect of the invention provides an electrode and photo-electrochemical cells for electrolysis of water molecules.
Government Interests: This invention was made, in-part, with United States government support under grants numbered DE-FG02-06ER15788 and DE-SC0001011 from the Department of Energy. The U.S. Government has certain rights to this invention..
Claims: A complex having the structure of formula (specified and defined, and containing): ruthenium (Ru) or osmium (Os) ... .
A catalyst comprising a complex having a structure selected from the group (identified and specified).
(We are editing the Claims section in the extreme. It is replete with chemical jargon intelligible only to the initiated, and makes reference to figures and formulas that require access to the full patent Disclosure and supporting documents, links to all of which are available on the US Patent and Trademark Office electronic record of this patent.)
An electrode comprising (a) a complex (of) ruthenium (Ru) or osmium (Os) (as specified), and (b) a supporting substrate on which said catalyst is supported (and) wherein (b) the supporting substrate comprises fluorine-doped (Tin Oxide).
(Note: The "fluorine-doped (Tin Oxide)" is no problem, but, the "ruthenium" and "osmium" are rare and expensive Platinum Group metals. However, they act in a way as catalysts in this process, and aren't used up or consumed in any appreciable way by the reactions. They would, thus, represent a, for practical purposes, one-time investment in physical plant more than anything else. And, our close allies in Canada are quite able to supply all that would be needed from known, and mined, deposits in Ontario, where they exist in association with ores of Nickel.)
A photoelectrolytic device comprising a catalyst comprising a complex (as defined and described, and) wherein the complex has a structure (as defined, and) further comprising a proton acceptor base (as chemically defined).
Background and Field: The present invention generally relates to catalysts for water oxidation.
Hydrogen is one of the most promising alternative energy sources. It can be obtained by electrolysis of water, which is environmentally friendly and efficient. However, the electrolysis of water is an energy intensive process, which is very expensive. On the other hand, photolysis, the splitting of water by light, presents an attractive alternative method of obtaining hydrogen.
Additionally, light driven reduction of carbon dioxide by water to provide hydrocarbons or methanol may be another promising alternative to alternate energy sources.
For both types of reactions, coupled water oxidation to oxygen is required.
In order to facilitate the photolysis of water by light in either type of reaction, a catalyst is required for the reaction.
Therefore, there is a need in the industry for an efficient catalyst for the electrolysis or photo electrolysis of water to obtain hydrogen or water reduction of carbon dioxide to obtain affordable and sustainable alternative source of energy.
Summary: Some aspects of the present invention provide complexes comprising formula (referenced and described in full documentation).
According to another aspect of the invention, the complexes described above may be used as a catalyst for catalytic water oxidation.
A further aspect of the invention provides an electrode comprising a complex descried herein.
Another aspect of the present invention provides photo-electrochemical cells comprising a catalyst described herein.
Another aspect of the invention provides photoelectrolytic devices comprising a catalyst described herein and a supporting substrate on which said catalyst is supported.
A further aspect of the invention describes methods of generating hydrogen (H2) and/or oxygen (O2) gases. The method comprises providing a catalyst described herein and adding the catalyst to an electrolytic media under a condition effective to generate hydrogen and/or oxygen.
Another aspect of the invention describes methods of generating methanol, hydrocarbons and/or oxygen (O2). The method comprises: providing a catalyst described herein and adding the catalyst to an electrolytic media under a condition effective to generate methanol, hydrocarbons and/or oxygen (O2).
A further aspect of the present invention provides methods of generating hydrogen (H.2) and/or oxygen (O2) gases. In one embodiment, the method comprises providing a catalyst described herein, and adding the catalyst to an electrolytic media under a condition effective to generate hydrogen and/or oxygen.
In one embodiment, the methods further comprise exposing the reaction media, which contains the catalyst to light radiation to generate hydrogen and/or oxygen gases.
In another embodiment, the method comprises exposing the photo-electrochemical cell described herein to light radiation to generate hydrogen and oxygen gases without the requirement of applying an external electrical potential".
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As in the above "aspect of the invention" which "describes methods of generating methanol, hydrocarbons and/or oxygen (O2). The method comprises: providing a catalyst described herein and adding the catalyst to an electrolytic media under a condition effective to generate methanol, hydrocarbons and/or oxygen (O2)"; Carbon Dioxide would, of course, have to be an additiional component entrained in that "media", so that the "photo-electrochemical cell" could, when exposed to "light radiation", generate, through initial production of Hydrogen cations, stuff like "methanol" and "hydrocarbons".
However, if the implications made by the full Disclosure of our subject herein, the USDOE-sponsored "US Patent 8,524,903 - Ruthenium or Osmium Complexes and Their Uses as Catalysts for Water Oxidation", aren't clear enough in that regard, it is plain that the process of "US Patent 8,524,903 - Ruthenium or Osmium Complexes and Their Uses as Catalysts for Water Oxidation" does enable the efficient generation of Hydrogen from Water by solar light energy. And, once we have the Hydrogen, we could use it in a process like that seen in our report of:
USDOE 2009 CO2 to Gasoline | Research & Development | News; which centers on: "United States Patent 7,592,291 - Method of Fabricating a Catalytic Structure; 2009; Inventors: Harry Rollins, et. al., Idaho; Assignee: Battelle Energy Alliance, LLC, Idaho Falls, ID (United States Department of Energy Idaho National Laboratory); A precursor to a catalytic structure comprising zinc oxide and copper oxide (and, a) method of hydrogenating a carbon oxide using the catalytic structure is also disclosed, as is a system that includes the catalytic structure. Government Interests: The United States Government has certain rights in this invention pursuant to Contract No. DE-AC07-05ID14517 between the United States Department of Energy and Battelle Energy Alliance, LLC. The present invention relates to catalytic materials, systems, and methods. More particularly, the present invention relates to precursor catalytic structures including copper oxide and zinc oxide, catalytic structures including copper and zinc oxide, and to a system and a method for producing alcohols from hydrogen and at least one of carbon monoxide and carbon dioxide using such catalytic structures. ... Carbon dioxide gas (CO2) may be converted into liquid fuels such as, for example, hydrocarbon molecules of between about 5 and about 12 carbon atoms per molecule (e.g., gasoline) through multi-step reactions. For example, carbon dioxide (CO2) gas and hydrogen (H2) may be converted to carbon monoxide (CO) gas and water (H2O) through the Reverse Water-Gas Shift Reaction .... . Synthesis gas, which is a mixture of carbon monoxide gas (CO) and hydrogen gas (H2) then may be produced from the reaction products of the Reverse Water-Gas Shift Reaction by adding additional hydrogen gas (H2) to the reaction products. This synthesis gas may be further reacted through either Fischer-Tropsch (FT) processes, or through methanol synthesis (MS) plus methanol-to-gasoline (MTG) processes, to provide liquid fuels";
where that Hydrogen could be used, as explained by our USDOE, in a reaction sequence wherein "Carbon dioxide gas (CO2) may be converted into liquid fuels such as, for example ... gasoline" through a known and established sequence of reactions between Carbon Dioxide, as recovered from whatever handy source, and, as produced from Water and Sunlight by the process of our tax dollar-funded subject herein, "US Patent 8,524,903 - Ruthenium or Osmium Complexes and Their Uses as Catalysts for Water Oxidation"; elemental Hydrogen obtained from "the photolysis of water by light".