https://www.ideals.illinois.
We've made previous reports concerning the work of University of Illinois system professors Richard Masel and Paul Kenis in the development of processes and technologies for the energy-efficient conversion, the recycling, of Carbon Dioxide into, especially, liquid and gaseous hydrocarbon fuels.
Sadly, our too-casual system of labeling and head-lining our dispatches leaves us unable to find and reference for you any of our past reports concerning them and their CO2-recycling achievements, as they are no doubt resident somewhere in the West Virginia Coal Association's Research and Development archives.
Since there have been some more recent developments concerning the CO2-recycling technologies established more specifically by Dr. Masel, we wanted herein to begin re-introducing his, and his colleagues' and his students', work in the field of the catalyzed conversion of Carbon Dioxide into hydrocarbons.
Their work in that arena, as will be seen, has been noteworthy enough to garner financial support from the United States Department of Energy, as part of the USDOE's backing of "artificial photosynthesis" Carbon Dioxide utilization efforts, as exemplified in our recent report of;
West Virginia Coal Association | USDOE 2013 Solar CO2 + H2O = Methanol + Methane | Research & Development; concerning; "United States Patent Application 20130256147 - Solar Fuels Generator; 2013; Inventors: Nathan S. Lewis and Joshua Spurgeon, CA; (California Institute of Technology); Abstract: The solar fuels generator (as descibed). 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 invention relates to solar generators, and more particularly, to solar fuels generators. (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, to warrant the founding of a company to further develop and commercialize it, and presumably to take it to market.
That said, herein we submit a doctoral thesis composed by one of their graduate students at the University of Illinois at Urbana-Champaign which should provide good introduction to the themes of their CO2-recycling efforts, and an overview of the technology involved.
Comment follows excerpts from the initial link in this dispatch to:
"Amine Promotion Of Hydrogen Evolution Reaction Suppression And CO2 Conversion For Artificial Photosynthesis
Wei Zhu
Dissertation: Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemical Engineering in the Graduate College of the University of Illinois at Urbana-Champaign, 2011
Doctoral Committee: Professor Richard I. Masel, Professor Paul Kenis, et. al.Recycling CO2 back into fuels or other useful products is critically important (and, the) electrochemical method is regarded as a promising means to do this because it has the advantage that water can be used as the proton source. However, the overpotential for electrolysis of water is low, whereas the overpotential of electrochemical conversion of CO2 is too high. Increasing the overpotential of water decomposition and lowering the overpotential of CO2 reduction is considered one of the grand challenges for catalysis.
Choline based products are chosen as ideal electrolytes to achieve both hydrogen evolution reaction suppression and lowering of CO2 reduction overpotential of. Experiments combining both electrochemical methods and surface enhanced Raman spectroscopy (SERS) techniques obtain a fairly complete picture of hydrogen evolution reaction and CO2 reduction in choline products.
Based on the experimental data, we have discovered that if we conduct CO2 reduction in choline based quaternary ammonium salts, the overpotential decreases and the starting potential of hydrogen evolution increases. This can be contributed to the fact that amine from choline based electrolyte initiates the suppression of the hydrogen evolution reaction and also acts like a co-catalyst to stabilize intermediates of CO2 reduction.
In particular, we discovered that:
1. Choline based quaternary ammonium salts achieve hydrogen evolution reaction suppression because a thin layer of choline ions forms on the catalyst surface and blocks the protons from getting close to the surface.
2. Different reaction products are forming during CO2 reduction in choline based electrolytes: CO mainly on gold, platinum and platinum/ruthenium; formic acid on palladium.
3. CO2 reduction happens in a variety of catalysts with much lower overpotential because the thin layer of choline ions on the catalyst surface will form lower energy intermediates with CO2, which will make the carbon dioxide reduction process easier.
4. Different anions in choline based electrolytes have little effect on CO2 reduction as well as hydrogen evolution reaction.
Introduction: Artificial photosynthetic systems offer the possibility of producing fuels and chemicals from CO2 and sunlight in fewer steps and with higher efficiencies than is possible in natural photosynthesis. There are several ways to reduce carbon dioxide:
(1) homogeneous photochemical reduction of CO2,
(2) heterogeneous photochemical reduction of CO2,
(3) photoelectrochemical CO2 fixation, and:
(4) electrochemical reduction of CO2 using solar electric power.
(Concerning the above use of light, "photo" and/or "solar" energies to drive Carbon Dioxide recycling and conversion processes, see our reports of:
which report is centered on an introduction to the USDOE's "Joint Center for Artificial Photosynthesis"; and:
http://www.solar-fuels.org/; "SOFI's goal is the development of efficient, cost-effective photocatalytic systems that use the energy of sunlight to produce liquid fuels";
wherein it's seen that our USDOE participates in the international Solar Fuels Institute. As far as differentiating "heterogeneous" and "homogeneous" Carbon Dioxide reduction processes, those are terms that have been used in our previous reports, but, providing an explanation of what they actually imply is beyond both our scope herein and, absent the educated opinion of some accomplished folks who used to advise us, our sadly limited capabilities.)
This work was supported by the US Department of Energy under grant DE-SC0004453.
Introduction: For reducing greenhouse gases, natural photosynthesis, which involves the photo- generation of carbon compounds and oxygen from abundant raw materials (carbon dioxide and water), cannot meet the need to mass-reduce the carbon dioxide in the atmosphere.
The use of biomass to produce energy is based on natural photosynthesis that generates energy directly using sunlight and CO2 in the atmosphere. However, it is still unlikely that the natural production of biomass will be able to meet all our needs for fuels and chemicals in the foreseeable future.
Artificial photosynthetic systems offer the possibility of producing fuels and chemicals from CO2 and sunlight in fewer steps and with higher efficiencies than is possible in natural photosynthesis. There are several ways to reduce carbon dioxide (as noted above and as explained further).
The long term goal of our research is to develop better electrochemical systems for CO2 reduction in room-temperature electrolyte that could lead to efficient processes for the large-scale conversion of CO2 into formic acid or other products.
(There currently) is no commercially viable process for large scale CO2 recycling into synfuels or other products because CO2 is difficult to activate.
(The above is no longer true. As seen, for two examples, in our reports of:
West Virginia Coal Association | Audi is Using Renewable Energy to Convert CO2 into Methane | Research & Development; concerning, in part: "'Audi E-Gas Plant Uses CO2, Renewables to Make Fuel'; Audi is building an industrial plant in Werlte, Germany, which will use renewable energy and carbon dioxide to make synthetic methane fuel. The plant will use power-to-gas technology to make so-called e-gas for vehicles, such as the new Audi A3 Sportback TCNG. E-gas made at the plant can be distributed to compressed natural gas stations via Germany’s natural gas network and will power vehicles starting next year, Audi said. The e-gas plant, which has the capacity to convert six MW of power, will use renewable electricity for electrolysis. The process splits water molecules into oxygen and hydrogen ... . (The) plant takes the hydrogen and reacts it with CO2 in a methanation unit to generate renewable synthetic methane, or e-gas"; and:
West Virginia Coal Association | Sweden Makes Public Report of CO2 to Motor Fuel Recycling | Research & Development; concerning, in part, the Swedish newspaper article: "'Iceland As A Green Saudi Arabia'; March 12, 2013; Recently, they shipped the first load to oil company Argos in Holland, for low level blending in gasoline. Vulcanol is just a name for methanol, regular wood spirit. It is the production method which makes this fuel especially interesting. It is made using renewable electricity, water and captured CO2 from the nearby geothermal power plant HS Orka. CRI sees it as a breakthrough for renewable transport fuels which are of non-biological origin. The name Vulcanol refers to the fact that the whole process is driven by geothermal energy, but of course other energy sources could also work well";at least a few industrial-scale, and "commercially viable", Carbon Dioxide recycling facilities are up and running in other places in the world.)
The free energy change of the reaction to compose an original organic compound from CO2 and H2O is positive and does not proceed spontaneously.
(We'll note in passing, that, as seen in:
West Virginia Coal Association | NASA Improves CO2 to Methane Conversion | Research & Development; concerning: "United States Patent Application 20120029095 - Sabatier Process and Apparatus for Controlling Exothermic Reaction; 2012; Inventors: Christian Junaedi, et. al., Connecticut; Abstract: A Sabatier process involving contacting carbon dioxide and hydrogen in a first reaction zone with a first catalyst bed at a temperature greater than a first designated temperature; feeding the effluent from the first reaction zone into a second reaction zone, and contacting the effluent with a second catalyst bed at a temperature equal to or less than a second designated temperature, so as to produce a product stream comprising water and methane. The first and second catalyst beds each individually comprise an ultra-short-channel-length metal substrate. An apparatus for controlling temperature in an exothermic reaction, such as the Sabatier reaction, is disclosed. Government Interests: 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";a "reaction" that forms an "organic compound from CO2" and elemental, molecular Hydrogen, on the other hand, will "proceed spontaneously" when properly catalyzed; so much so that exothermic heat generated by the hydrocarbon synthesis reaction has to be removed from the reaction zone.)
The objective of our work is to learn how to use artificial electrochemical synthesis to create materials for renewable fuels. Specifically, we will be examining the mechanism of CO2 conversion on different catalysts in one choline based quaternary ammonium salt. We project using electricity generated from solar power plant to convert CO2 and water into CO, H2 and formic acid, one useful product of CO2 reduction. Over the globe, the demand of formic acid is growing. Significant amounts of formic acid are produced as a byproduct in the manufacturing of other chemicals, especially acetic acid. When methanol and carbon monoxide are combined with the presence of a strong base, the formic acid is produced. However, these processes are neither straightforward nor environmentally friendly.
We have been exploring the use of amines to suppress water electrolysis and enhance CO2 electrolysis. We find that the presence of choline ion raises the onset of hydrogen evolution, and lowers the overpotential for CO2 conversion. The result shows that there is a region of potential where CO2 electrolysis is more rapid than hydrogen evolution. The products vary with the catalysts. Based on SERS data, we suggest that hydrogen evolution reaction is suppressed because choline ions formed a layer on the catalyst surface and blocked the adsorption of the protons. Moreover, CO2 reduction happens at such a modest potential because choline cations in the electrolyte are forming a complex with key anionic intermediates of the CO2 reduction reaction such as (CO2)-. The stabilization of the anionic intermediates leads to the substantial reduction in the required potential for CO2 reduction.
In this work, experiments combining both electrochemical conversion methods and surface enhanced Raman spectroscopy (SERS) obtained a fairly complete picture of CO2 reduction in choline products. Particularly, we discovered that:
1. Choline based quaternary ammonium salts achieve hydrogen evolution reaction suppression because a thin layer of choline ions forms on the catalyst surface and blocks the protons from coming close to the surface.
2. Different reaction products form during CO2 reduction in choline electrolyte: CO mainly on gold, platinum and platinum/ruthenium; formic acid on palladium.
3. CO2 reduction happens in various catalysts with much lower overpotential because the thin layer of choline ions on the catalyst surface will form lower energy intermediates with CO2, which will make the CO2 reduction process easier.
4. Different anions in choline based electrolytes have little effect on CO2 reduction as well as hydrogen evolution reaction.
(The author includes lengthy and highly technical explanations of CO2 reduction technologies that have been demonstrated by others. The intent is to find ways in which the needed electrical potential, the amount of energy required to effect the electrochemical reduction of CO2, can be reduced, while at the same time Hydrogen evolution is suppressed.)
(One) key long-term question that we are to consider in our work is: What does the choline based electrolyte contribute to the conversion of CO2 that allows the reaction to proceed at such modest potentials? In particular, we wish to test the hypothesis that imidazolium cation of the choline ion is the factor that interacts with the catalyst surface. Because of the interaction, the hydrogen evolution reaction is suppressed and CO2 reduction occurs at a much less negative potential than before.
In order to test that hypothesis, we need to answer several questions:
1. Whether and how will choline based electrolyte achieve hydrogen evolution reaction suppression?
In our research, we pursue the suppression of hydrogen evolution reaction in water solutions. Choline based electrolytes are employed in this research as an electrolyte suppressing the hydrogen evolution reaction. We propose to show the choline based electrolytes suppresses the hydrogen evolution by shifting the reacting potential to lower values. When dissolved in water, choline based electrolytes release amine cation: choline ion. By interfering with the hydrogen adsorption process, the amine cations influence the evolution of hydrogen. In this process, a single layer of choline cations is formed on the surface of the catalyst, which blocks the hydrogen adsorption on the catalyst surface, and therefore blocks the reaction of hydrogen evolution.
2. Whether and why CO2 reduction will happen in various catalysts with much lower overpotentials?
We would like to demonstrate the ability of choline based electrolytes to reduce the overpotential in carbon dioxide reduction process. In choline based electrolytes, the hydrogen evolution reaction was suppressed because choline based electrolytes reduce the hydrogen adsorption. Here, we would like to show it does not only suppress hydrogen evolution reaction but also lowers the overpotential for CO2 conversion. As a result, the overpotential for carbon dioxide reduction was reduced to much lower values in different catalysts, which is very beneficial to efficient large-scale production.
This work was supported by the US Department of Energy under grant DE-SC0004453."
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We'll close there. As might be surmised from our excerpts, the full dissertation is a scholastic treatment of the subject of enhancing the electro-chemical, and photo-electro-chemical transformation of Carbon Dioxide into useful products, by reducing the electrical energy needed to effect the transformation and by narrowing a bit the range of products generated from what is, essentially, the co-electrolysis of Carbon Dioxide and Water, perhaps promoted by light, which, as seen in:
West Virginia Coal Association | USDOE Converts CO2 & H2O into Hydrocarbon Synthesis Gas | Research & Development; concerning: "'High-Temperature Co-Electrolysis of H2O and CO2 for Syngas Production'; 2006 Fuel Cell Seminar; Carl M. Stoots; November 2006; Idaho National Laboratory; United States Department of Energy; Abstract: Worldwide, the demand for light hydrocarbon fuels like gasoline and diesel oil is increasing. To satisfy this demand, oil companies have begun to utilize oil deposits of lower hydrogen content (e.g., Athabasca Oil Sands). Additionally, the higher contents of sulfur and nitrogen of these resources requires processes such as hydrotreating to meet environmental requirements. In the mean time, with the price of oil currently over $70 / barrel, synthetically-derived hydrocarbon fuels (synfuels) have become economical";
can as well be conducted in a way that results in the production of hydrocarbon "Syngas", which can then be catalytically, chemically condensed over one or more of a range of known catalysts for the production of specific ranges of hydrocarbons, with the downside being that higher temperatures and higher electric potentials are needed - - that is, a higher energy input with attendant greater expense is required - - to effect the production of syngas from CO2 and H2O, as opposed to the relatively much milder, less demanding energy requirements discussed in our subject, "Amine Promotion Of Hydrogen Evolution Reaction Suppression And CO2 Conversion For Artificial Photosynthesis", which resulted from work performed under "grant DE-SC0004453" from the US Department of Energy.
There have been additional technical developments in the field of Carbon Dioxide utilization arising from the work done under "grant DE-SC0004453", and related contracts, as we noted in our introductory comments, which we will be making report of in the future
And, we wanted to make this preliminary document available for reference when we get around to composing those reports which serve to further document the now plain fact, that:
Carbon Dioxide - - as it arises in only 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, from our economically essential use of Coal in the generation of abundant and truly-affordable electric power - - is a valuable raw material resource. We can reclaim it from whatever source most convenient to us and, then, under relatively mild conditions, using a variety of energies and catalysts to promote the needed reactions, convert that CO2, along with Hydrogen as extracted from Water, into various reactive chemical intermediaries, such as formic acid and Carbon Monoxide, CO, which themselves are valuable for the further synthesis various hydrocarbon compounds.