United States Patent Application: 0150064105
There are without doubt many good people, honest United States citizens, even brave patriots who have served, or would serve if called, in uniform, who have become convinced that Carbon Dioxide is accumulating in the atmosphere due to our use of fossil fuels; that such CO2 accumulation results in dangerous "global warming"; and, that to prevent calamitous climate change we must somehow limit our use of fossil fuels, with most fingers pointing at Coal as the CO2-emitting culprit-in-chief.
However, not nearly all of those thumping the CO2 drum do so for honest and altruistic reasons. The primary "solution" to our Carbon Dioxide "problem" has always it seems been the imposition of a Carbon "tax" on our Coal-fired electric power generation industries, with the result being higher rates paid by the consumers of Coal-based electricity, and a back-door price support for the much more expensive electricity generated from so-called "renewable" energy resources and from supposedly less carbon intense alternative fossil fuels, like shale gas.
But, the real reason behind some government bureaucrats', some politicians', and some activists' "push" for a tax on emissions of Carbon Dioxide, a tax to be levied onto the backs of those common citizens reliant on our nation's most cost-competitive electricity, that electricity generated from Coal, was, perhaps inadvertently, laid bare by a former United States Secretary of the treasury in:
Oil’s swoon creates the opening for a carbon tax - The Washington Post; "'Oil’s swoon creates the opening for a carbon tax'; By Lawrence Summers, January 4, 2015; (Lawrence Summers was Secretary of the Treasury from 1999 to 2001) The case for carbon taxes has long been compelling. With the recent steep fall in oil prices and associated declines in other energy prices, it has become overwhelming. There is room for debate about the size of the tax and about how the proceeds should be deployed. But there should be no doubt that, given the current zero tax rate on carbon, increased taxation would be desirable. ... (Even) with the substantial recent increases in U.S. oil production, we remain a net importer. Any increase in our consumption raises our dependence on Middle East producers. All of us, when we drive our cars, heat our homes or use fossil fuels in more indirect ways, create (costs) without paying for them. It follows that we overuse (fossil) fuels. Advocating a carbon tax is not some kind of argument for government planning; it is the logic of the market: That which is not paid for is overused. Even if the government had no need or use for revenue, it could make the economy function better by levying carbon taxes and rebating the money to taxpayers. While the recent decline in energy prices is a good thing in that it has, on balance, raised the incomes of Americans, it has also exacerbated the problem of energy overuse. The benefit of imposing carbon taxes is therefore enhanced. ... (There) has always been the concern that a carbon tax would place an unfair burden on some middle- and low-income consumers. Those who drive long distances to work, say, or who have homes that are expensive to heat would be disproportionately burdened. Now that these consumers have received a windfall from the fall in energy prices, it would be possible to impose substantial carbon taxes without them being burdened relative to where things stood six months ago. The price of gasoline has fallen by more than a dollar. A $25-a-ton tax on carbon that would raise far more than $1 trillion over the next decade would lift gasoline prices by only about 25 cents".
To sum up and paraphrase what we might now reasonably presume to be the position and attitude of some in our government: Since we've had a "recent decline in energy prices", it would now be pretty much okay to screw "middle- and low-income consumers" since they have, after all, "received a windfall", and they might not notice being "burdened" as much as they previously would have, and, the federal government could consequently reap an extra "$1 trillion", by imposing a CO2 tax, to do pretty much what it wanted with, such as "rebating the money" - - that is, redistributing the money collected via carbon taxes to those the government deems worthy.
But: We have it in our power now to lay that contentious issue to rest; to thwart the avarice of government social engineers, and, at the same time, to make our economically unhealthy reliance on OPEC oil nothing but a chapter in the history books concerning unhappy and dangerous times for our nation.
Carbon Dioxide, as is co-produced 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 - - by our economically essential use of Coal in the generation of abundant, reliable and affordable electric power, is a valuable raw material resource.
It can, as seen for just one out of now many examples in our report of:
USDOE 2012 Coal Power Plant CO2 to Gasoline | Research & Development | News; concerning: "United States Patent 8,226,909 - Systems Including Catalysts in Porous Zeolite Materials Within a Reactor for Use In Synthesizing Hydrocarbons; 2012; Inventors: Harry Rollins, et. al., Idaho; Assignee: Battelle Energy Alliance, LLC, Idaho Falls (USDOE Idaho National Laboratory); Abstract: Catalytic structures include a catalytic material disposed within a zeolite material. The catalytic material may be capable of catalyzing a formation of methanol from ... carbon dioxide, and the zeolite material may be capable of catalyzing a formation of hydrocarbon molecules from methanol. ... Government Interests: This invention was made with government support under Contract No. DE-AC07-05ID14517 awarded by the United States Department of Energy. The government has certain rights in the invention. ... A system for synthesizing hydrocarbon molecules having two or more carbon atoms from hydrogen and ... carbon dioxide ... . Carbon dioxide gas (CO2) may be converted into liquid fuels such as, for example, hydrocarbon molecules of between about 5 carbon atoms and about 12 carbon atoms per molecule (e.g., gasoline) through multi-step reactions. ... (The) catalytic structures, systems, and methods described herein may facilitate economic utilization of carbon dioxide from stationary carbon dioxide sources, such as coal-powered and hydrocarbon-powered electricity generation plants, which otherwise may be vented to atmosphere";
be harvested from the exhaust gases of our "coal-powered ... electricity generation plants", and then be "converted into liquid fuels such as, for example" non-OPEC "gasoline".
Sadly, and suspiciously, though, not only has that seemingly joyous news NOT been publicly, openly and fully reported to anyone in United States Coal Country, or anywhere else in the United States of America, neither has the ominous news, that, as seen for just one example in:
Saudi Arabia February 24, 2015, CO2 to Hydrocarbon Fuel | Research & Development | News; concerning both:
"United States Patent 8,961,829 - Catalytic Hydrogenation of Carbon Dioxide into Syngas Mixture; 2015; Inventors: Agaddin Mamedov, et. al.; Assignee: Saudi Basic Industries Corporation, Riyadh; Abstract: The invention relates to a process of making a syngas mixture containing hydrogen, carbon monoxide and carbon dioxide, comprising a step of contacting a gaseous feed mixture containing carbon dioxide and hydrogen with a catalyst, which catalyst substantially consists of Mn oxide and an oxide of at least one member selected from the group consisting of Cr, Ni, La, Ce, W, and Pt. This process enables hydrogenation of carbon dioxide into carbon monoxide with high selectivity, and good catalyst stability over time and under variations in processing conditions. a The process can be applied separately, but can also be integrated with other processes, both up-stream and/or down-stream; ... synthesis processes for making products like alkanes, aldehydes, or alcohols";nd:
"United States Patent 8,962,702 - Mixed Oxide Based Catalyst for the Conversion of Carbon Dioxide to Syngas and Method of Preparation and Use; 2015; Inventors: Aghaddin Mamedov, et. al.; Assignee: Saudi Basic Industries Corporation, Riyadh, Saudi Arabia; Abstract: The invention relates to a catalyst and process for making syngas mixtures including hydrogen, carbon monoxide and carbon dioxide. The process comprises contacting a gaseous feed mixture containing carbon dioxide and hydrogen with the catalyst, where the catalyst comprises Mn oxide and an auxiliary metal oxide selected from the group consisting of La, Ca, K, W, Cu, Al and mixtures or combinations thereof. The process enables hydrogenation of carbon dioxide into carbon monoxide with high selectivity, and good catalyst stability over time and under variations in processing conditions. The process can be applied separately, but can also be integrated with other processes, both up-stream and/or down-stream ... synthesis processes for making products like alkanes, aldehydes, or alcohols";
Saudi Arabia, that is, OPEC, has developed related and similar technology for using and consuming Carbon Dioxide in the synthesis of a range of products which could, as in "alkanes (and) alcohols" include both gaseous and liquid hydrocarbon fuels. We'll note in passing, without documenting via citation of any of our past reports concerning the matter, that "alcohols", such as ethanol and methanol, can be directly and efficiently converted into Gasoline via any one of several known and established technologies such as, for example, ExxonMobil's "MTG"(r), methanol-to-gasoline, process.
In any case, to effect the conversion of Carbon Dioxide into hydrocarbon fuels, via either the USDOE's process of the above-cited "United States Patent 8,226,909 - Systems Including Catalysts in Porous Zeolite Materials Within a Reactor for Use In Synthesizing Hydrocarbons" or one of Saudi Arabia's technologies cited above, a supply of elemental, molecular Hydrogen is required. And, herein we see that Saudi Arabia has developed the technology to obtain that Hydrogen by extracting it both from a noxious gaseous pollutant that is likely co-produced during refinery operations that convert their crude petroleum into hydrocarbon fuels and other products, and, from plain old water, H2O, in a process powered only by some of their abundant desert sunshine.
And, as will be seen, the recycling of Carbon Dioxide into hydrocarbons is, in fact, what this is all about.
Comment follows and is inserted within excerpts from the initial link in this dispatch to:
"United States Patent Application 20150064105 - Tethered Transition Metals Promoted Photocatalytic System for Efficient Hydrogen Evolutions
Tethered Transition Metals Promoted Photocatalytic System for Efficient Hydrogen Evolutions - KING ABDULLAH UNIVERSITY OF SCIE
March 5, 2015
Inventors: Kazuhiro Takanabe, et. al., Saudi Arabia
Assignees: King Abdullah University of Science and Technology and Saudi Arabian Oil Company
(Keep in mind that we have cited the above Saudi Arabian Oil Company, and their development of complete, integrated, and somewhat different solar-powered Carbon Dioxide utilization technologies previously, as in our report of:
Saudi July 10, 2014 Sunshine Converts CO2 into Hydrocarbon Fuel | Research & Development | News; concerning: "United States Patent Application 20140194539 - Carbon Dioxide Conversion to Hydrocarbon Fuel via Syngas Production Cell Harnessed from Solar Radiation; 2014; Inventors: Ahmad D. Hammad, et. al., Saudi Arabia; Assignee: Saudi Arabian Oil Company, Dhahran; Abstract: A process for converting carbon dioxide to hydrocarbon fuels using solar energy harnessed with a solar thermal power system to create thermal energy and electricity, using the thermal energy to heat a fuel feed stream, the heated fuel feed stream comprising carbon dioxide and water, the carbon dioxide captured from a flue gas stream, converting the carbon dioxide and water in a syngas production cell, the syngas production cell comprising a solid oxide electrolyte, to create carbon monoxide and hydrogen, and converting the carbon monoxide and hydrogen to hydrocarbon fuels in a catalytic reactor. In at least one embodiment, the syngas production cell is a solid oxide fuel cell. In at least one embodiment, the syngas production cell is a solid oxide electrolyzer cell".)
Abstract: The present invention is directed, at least in part, to a process for improving the efficiency of a photocatalyst (a semiconductor photocatalyst) by tethering (depositing) a metal (e.g., metal ions of a late transition metal, such as nickel) to the semiconductor (photocatalyst) surface through the use of an organic ligand. More specifically, 1,2-ethanedithiol (EDT) functions as an excellent molecular linker (organic ligand) to attach a transition metal complex (e.g., nickel (Ni2+ ions)) to the semiconductor surface, which can be in the form of a cadmium sulfide surface. The photocatalyst has particular utility in generating hydrogen from H2S (Hydrogen Sulfide).
Claims: A process for producing a photocatalyst comprising the steps of: forming an initial semiconductor photocatalyst material; exposing the initial photocatalyst material to a first solution containing an organic ligand resulting in the formation of a photocatalyst material having the organic ligand deposited on a surface thereof; and suspending the photocatalyst material which has the organic ligand deposited thereon in a metal aqueous solution to form a photocatalyst material that has a metal-organic ligand species deposited thereon (and) wherein the initial photocatalyst material comprises CdS (and) wherein the initial CdS photocatalyst material comprises synthesized CdS nanocrystals (and) wherein the metal aqueous solution comprises a transition metal (and) wherein the transition metal comprises Ni2+.
The process ... wherein the photocatalyst is capable of: (1) hydrogen evolution from H2S; (2) water splitting and (3) CO2 reduction.
(We interrupt our excerpts from the "Claims" segment of this United States Patent Application here to emphasize that the above acquisition of Hydrogen, from either "H2S" or "water", and the subsequent and/or concurrent use of that Hydrogen in a "CO2 reduction" process is what this is actually all about.)
A process for producing a photocatalyst that is capable of converting H2S into hydrogen and sulfur comprising the steps of: preparing a photocatalyst material; and using an organic ligand to attach a transition metal species to a surface of the photocatalyst material without the formation of a dopant layer.
(Keep in mind that the above emphasis on "H2S" as a starting material, although H2O can be used as well, in this photocatalytic process for the production of Hydrogen is much like that seen in our report of:
Florida Hydrogen and Sulfur from H2S | Research & Development | News; concerning: "United States Patent 6,572,829 - Photocatalytic Process for Decomposing Hydrogen Sulfide; 2003; Inventors: Clovis Linkhouse and Nazim Muradov, FL; Assignee: University of Central Florida, Orlando; Abstract: System for separating hydrogen and sulfur from hydrogen sulfide (H2S) gas produced from oil and gas waste streams";
and, it is, in fact, "oil and gas waste streams" to which the "Saudi Arabian Oil Company" would wish to apply the technique. However, as in another above claim, it can also, or instead, entail solar-drive "water splitting and ... CO2 reduction" in one integrated, contiguous operation, as in our report of: .
USDOE and California Solar Hydrogen for CO2-to-Fuel Conversion | Research & Development | News; concerning: ; 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) 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";
wherein Carbon Dioxide and Water are converted together into hydrocarbon synthesis gas, i.e., Carbon Monoxide and Hydrogen, and byproduct Oxygen.)
A process for hydrogen evolution from H2S comprising the steps of: using a photocatalyst that has a Nickel (and) 1,2-ethanedithiol (EDT) complex deposited on a surface of a substrate of the photocatalyst to generate hydrogen from H2S.
Background and Field: The present invention relates to a photocatalyst material (semiconductor photocatalyst) and more specifically, to a process for tethering the photocatalyst surface with a metal (e.g., nickel ions or other transition metal ions) by a linker (organic ligand) to improve the performance of the photocatalyst, thereby providing improved photocatalytic systems for efficient hydrogen evolutions as well as other for use in other photocatalytic applications.
Natural gas operations and hydrodesulfurization processes at refineries produce large quantities of hydrogen sulfide (H2S).
Some sour gas wells can contain greater than 30% of H2S.
(So much for "America's Clean Energy Alternative".)
H2S is corrosive in nature and impedes the integrity of pipeline. H2S induces hydrate formation and impacts gas production. H2S is toxic, environmental harmful and therefore, it must be neutralized.
In the step of desulfurizing crude oil which is generally conducted presently, heavy naphtha is subjected to hydrofining during crude oil distillation to recover all of the sulfur ingredients contained in the crude oil as hydrogen sulfide. Currently, the predominant process for converting H2S into non-toxic elemental sulfur is the Claus sulphur recovery process. The Claus process includes a number of different steps that are performed to neutralize the toxic H2S. First, the H2S is separated from the host gas stream using amine extraction. Then, the H2S is fed to a Claus unit, where it is converted in the following two steps. The first step is a thermal step in which the H2S is partially oxidized with air. This is done in a reaction furnace at high temperatures (1000-1400 C). Sulfur is formed, but some H2S remains unreacted, and some SO2 is made. The second step is a catalytic step in which the remaining H2S is reacted with the SO2 at lower temperatures (about 200-350 C) over a catalyst to make more sulfur. A catalyst is needed in the second step to help the components react with reasonable speed. Unfortunately, the reaction does not go to completion even with an optimal catalyst. For this reason, two or three stages are used, with sulfur being removed between the stages. Inevitably, a small amount of H2S remains in the tail gas and this residual quantity, together with other trace sulfur compounds, is usually dealt with in a tail gas unit.
While the Claus process can yield high conversion rates, there are a number of deficiencies associated with this sulfur recovery process. In particular, the Claus process necessitates an enormous amount of energy because of not only the catalytic reaction of sulfurous acid gas with hydrogen sulfide but also repetitions of heating and condensation. The process has further problems, for example, that the management of sulfurous acid gas is costly. In addition, the process cannot recover the energy contents of H2S and cannot produce highly demanded H2.
Catalysis is the process in which a substance participates in modifying the rate of a chemical transformation of the reactants without being altered or consumed in the end. This substance is known as the catalyst which increases the rate of a reaction by reducing the activation energy. Generally speaking, photocatalysis is a reaction which uses light to activate a substance which modifies the rate of a chemical reaction without being involved itself. The photocatalyst is the substance which can modify the rate of chemical reaction using light irradiation.
A semiconductor photocatalyst has an energy band structure in which the conduction band and the valence band structure are separated by a forbidden band. When a photocatalyst is irradiated with light having energy equal to or higher than a band gap, electrons in the valence band are excited to the conduction band, while holes are generated in the valence band. The electrons excited to the conduction band have higher reducing power than that when the electrons are present in the valence band, and the holes have higher oxidizing power.
Thus, photocatalysis can be in the form of a process that involves light absorption by a semiconductor, particularly, in the form of particulates and generation of excitons to be separated to make redox reactions. The process allows the free-energy positive reaction (a thermodynamically unfavored reaction) to happen utilizing photon energy incident to a reactor (device), which can be utilized for solar energy conversion to chemical energy.
Photocatalytic evolution (generation) of hydrogen using semiconductor powder materials has gained considerable attention because of the importance of solar energy conversion or recovering energy from waste, such as biomass-related organic wastes and hydrogen sulfide. Utilizing solar energy for photocatalysis requires not only extensive absorption in visible light range but also large scale application with low capital cost. The earth-abundant elements are therefore preferred to be the components of the photocatalyst materials. Noble metal nanoparticles are generally good electrocatalyst materials to reduce water/proton to generate hydrogen molecules, and thus efficient photocatalysts can include noble metal nanoparticles on the surface of semiconductor materials. Finding the alternative of noble metals possessing high electrocatalytic activity is still awaited and is desirable.
For high efficient conversion of photocatalytic water splitting, modification of the photocatalyst surface with a cocatalyst is essential because of enhancement in the charge separation creating new metal-semiconductor electronic structure, and in electrocatalytic properties that catalyze the target redox reactions.
Despite (cited) advances, there is still a need for improvements in solar-based hydrogen production technologies and in particular, there is a need for an improved alternative process for the simultaneous conversion of H2S or its containing gases into valuable hydrogen and sulfur. In other words, there is a desire and need for a method for decomposing hydrogen sulphide with a photocatalyst to yield hydrogen and sulfur and which can be put to practical use, thereby making it possible to decompose hydrogen sulfide as a harmful substance with a smaller amount of energy to produce hydrogen and sulfur as useful substances.
This is particularly true for industries that are located in areas that have high annual solar irradiation, such as Saudi Arabia.
Summary: The present invention is directed, at least in part, to a process for improving the efficiency of a photocatalyst (semiconductor photocatalyst) by tethering (depositing) a metal (e.g., metal ions of a late transition metal, such as nickel) to the semiconductor (photocatalyst) surface through the use of an organic ligand as described herein.
The photocatalyst of the present invention can be used in a number of different applications, including for the generation of hydrogen from H2S, water splitting, CO2 reduction, etc".
As indicated by our excerpts, most of the Disclosure is devoted to discussion of the photocatalytic decomposition of Hydrogen Sulfide, which is produced "in large quantities" by "natural gas operations", into elemental Sulfur, which does have commercial value, and Hydrogen; which Hydrogen can be consequently, or even concurrently, applied to a "CO2 reduction" process, which CO2 reduction with Hydrogen could result in, as in the above citation of our report concerning:
"United States Patent Application 20140194539 - Carbon Dioxide Conversion to Hydrocarbon Fuel via Syngas Production Cell Harnessed from Solar Radiation; 2014; Inventors: Ahmad D. Hammad, et. al., Saudi Arabia; Assignee: Saudi Arabian Oil Company";
hydrocarbon synthesis gas, which syngas can then be catalytically, chemically condensed, as via, for just one nearly ancient example, the Fischer-Tropsch synthesis, into a full range of both liquid and gaseous hydrocarbons.
Or, such CO2 reduction with Hydrogen could, instead, as in our report of:
NASA 2014 CO2 to Methane | Research & Development | News; concerning: "United States Patent 8,710,106 - Sabatier Process and Apparatus for Controlling Exothermic Reaction; 2014; Assignee: Precision Combustion, Inc., CT; Abstract: A Sabatier process involving contacting carbon dioxide and hydrogen ... so as to produce a product stream comprising water and methane. ... Government Support: This invention was made with support from the U.S. government under U.S. Contract No. NNX10CF25P sponsored by the National Aeronautics and Space Administration. The U.S. Government holds certain rights in this invention";
be catalyzed and structured so as to result in the direct synthesis much more specifically of substitute natural gas Methane via the equally ancient, century-old and Nobel Prize-winning, Sabatier process.
In any case, the Saudi Arabian process of our subject, "US Patent Application 20150064105 - Tethered Transition Metals Promoted Photocatalytic System for Efficient Hydrogen Evolutions; 2015; Assignees: King Abdullah University of Science and Technology and Saudi Arabian Oil Company", can actually, as in our above-cited report 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. ... 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 ... 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";
if desired, be configured so as to, in a process driven by sunlight, a process that might be labeled as one of "artificial photosynthesis", first, extract Hydrogen from either "H2S" or "water splitting", and, then, in a contiguous catalyzed function, use that Hydrogen in a process of chemical "CO2 reduction", with the end product being either hydrocarbon synthesis gas or even simple, and perhaps more complex, hydrocarbons.