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Conference Review Vol. 60, No.2 p. 36-41

Carbon Dioxide Reduction Technologies:
A Synopsis of the Symposium at TMS 2008

Neale R. Neelameggham

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Figure 1
K. Tatenuma’s reduction process for atmospheric CO2. (Image courtesy of Tatenuma.)



Figure 2
K. Ogura’s scheme of C2H4 by electrolysis of CO2 and H2O.



Figure 3
A ten-cell stack and manifolding. (Courtesy of Ceramatec.)












Questions? Contact
2008 The Minerals, Metals & Materials Society


Common fuels—whether they are simple hydrocarbons or oxygenated hydrocarbons or carbohydrates—can be economically produced from the respective oxides of carbon and hydrogen by simple chemical reductions. These reactions are efficiently carried out by applying fundamentals of the reduction process.


…describe the overall significance of this paper?

CO2 reduction in the atmosphere can be carried out by chemical reduction of CO2 and/or H2O into fuels (by applying extractive metallurgy knowhow for reducing oxides) as well as reduction of usage, as discussed in the papers forming the symposium.

…describe this work to a materials science and engineering professional with no experience in your technical specialty?

Extractive metallurgists know how to reduce oxide ores into metals. This knowledge can be used to reduce oxides of carbon and hydrogen into non-global-warming matter. This approach is as beneficial as minimizing reducing agent carbon and hydrogen consumption.

…describe this work to a layperson?

Some metal ores are converted to metals using energy other than carbon-based fuels—such as electricity, CO2, and H2O—which are similar to metal ores and can be modified to non-global-warming forms by known techniques by extractive metallurgists.

When converting minerals into metals, energy is consumed. Even though energy in various forms can be used in achieving this conversion, or reduction, typically a reductant that can carry the anion of the mineral away from the desired element is used. The potential for economic production of common fuels from the respective oxides of carbon and hydrogen by simple chemical reductions1 was the inspiration for the CO2 Reduction Metallurgy Symposium at the TMS 2008 Annual Meeting. The TMS Reactive Metals Committee initiated the symposium, as carbon’s reactivity is well known to all.

The world needs fuels in all three states of matter: solid, liquid, and gaseous. Naturally available solar, wind, and hydro-energy can be converted into the mobile forms of fuel by using carbon dioxide and water. When such conversions can be affordably achieved, perhaps one cause of global warming— carbon emissions—will be minimized.


Most of the gaseous emissions from the use of fuels are emitted at temperatures higher than ambient temperature. This mass of gases, when mixed with ambient atmosphere, increases the atmospheric air mass temperature. Present-day fuels release both CO2 and H2O, along with hot air, in their exhaust. Of these, the non-condensible CO2 (under atmospheric conditions) continues to increase and is easily measured. In addition, these tri-atomic molecules participate in the radiative heat transfer in the atmosphere.

Unless another cooling medium can dissipate this thermal emission by some other mechanism, global warming will persist. We can only minimize the rate of global warming and not eliminate it as long as the energy conversion from one form to another happens with certain uncontrolled emission of heat. This necessitates the reduction of thermal emission and its constituents. Minimizing the temperature of gaseous emissions by simple methods will go a long way toward minimizing the rate of increase in atmospheric temperatures.


Extractive metallurgists can reduce any oxide compound to its elemental form. Examples of this are the making of iron from iron oxides, aluminum from aluminum oxides, and hydrogen from hydrogen oxide (or water). Carbon dioxide is just like any other oxide and can be reduced to its respective elements by applied energy, a process that could minimize the amount of CO2 released in the air and result in improved fuel self sufficiency. During the CO2 Reduction Metallurgy Symposium at the TMS 2008 Annual Meeting, metallurgists will discuss how to accomplish these goals in a cost-effective manner using all available energy sources, including solar and stored energy in the form of presently land-filled municipal wastes.

Reductions require some form of energy to overcome the negative free energy of formation of the compound oxides. Such reductions into fuels are better than just capturing CO2 and pushing it back into the ground. The second option of CO2 reduction metallurgy is using energy from various alternate sources in making materials. In addition, the process development in improving energy efficiency minimizes CO2 emissions by reducing the use of carbonaceous fuel. Energy efficiency improvements also include recycling the oxidative abilities of contained oxygen in CO2. All these approaches are complimentary to each other.


Worldwide commitments to reduce CO2 emissions to pre-1990 levels in the next 12 to 13 years pose a formidable challenge. To make this goal economically feasible, new technologies such as those that may come from this symposium are essential.

Approaches to CO2 emission reductions in metal production by improved energy efficiency in life-cycle fuel use, reduction in carbonate based flux/raw material usage, and thermodynamically feasible reactions leading to lower emissions are all part of this program. The symposium attracted the following members of the scientific community as co-sponsors: the National Materials Advisory Board; the Metallurgical Society of the Canadian Institute of Mining Metallurgy and Petroleum; the American Iron and Steel Institute (AISI); the TMS Light Metals and Extraction & Processing Divisions, Reactive Metals Committee, and Recycling and Environmental Technologies Committee.

This symposium, the first of its kind in applying extractive metallurgy techniques, is complimentary to several international conferences on CO2 utilization (there have been eight such symposia so far, the last of which was held in Oslo, Norway in 2005),2 and minor symposia on the subject by the American Chemical Society, American Institute of Chemical Engineers, Electrochemical Society, etc., in promoting pertinent know-how in solving these global concerns. Study of the conversion of CO2 to other chemicals started in the 19th century and was revived several times. Considerable research work has been reported related to space travel and CO2 conversion.

The upcoming symposium is divided into three major sessions: mechanisms, ferrous metallurgy, and electrolytic approaches. Typically, TMS symposia are reviewed in JOM after the fact, with summaries of the papers presented. This article provides a view of the planned presentations, compiled from the abstracts and extracts from the papers submitted by the authors. The symposium proceedings in CD and book form will be available during the conference.3

The organizing team started with four and is down to the following three: Neale Neelameggham, US Magnesium LLC; Masao Suzuki, AI Tech Associates; and Ramana Reddy, University of Alabama. (The organizers are sorry to note the unexpected and unfortunate demise of our fourth organizer, Ralph Harris, McGill University, during July 2007. Harris facilitated the co-sponsorship of the Metallurgical Society of the Canadian Institute of Mining Metallurgy and Petroleum.) One of the three sessions related to ferrous metallurgy is geared toward addressing the CO2 reduction issues in the largest tonnage metal—iron. The AISI co-sponsorship was facilitated by Pinakin Chaubal, Mittal Steel and Larry Kavanaugh, AISI.

These CO2 reduction topics will alternate between chemical reduction of CO2 as an oxide as well as physical reduction of the emission by using less carbon—thus less CO2, and/or less energy utilization.


Keynote Address
The symposium will begin with a keynote address by Meyer Steinberg, who is retired from Brookhaven National Laboratory. He is the co-author of a detailed treatise Greenhouse Gas Carbon Dioxide Mitigation: Science and Technology,4 based on more than 30 years each of expertise in this field by him and his co-author M. Halmann. Steinberg, who started his career as a Manhattan Project scientist, notes that mitigating global greenhouse effect while maintaining a fossil fuel economy requires improving the efficiency of conversion and utilization of fossil fuels, use of high-hydrogen-content fossil fuels, decarbonization of fossil fuels, and sequestration of carbon and CO2 applied to all energy-consuming sectors of the economy including electric power generation, industrial domestic heating, materials production, and transportation.

Steinberg’s review will cover the principles of removal and recovery from power plant stacks, the oceanographic and geological disposal of CO2, and the conversion of CO2 to gaseous and liquid transportation fuels.

The keynote speech will be followed by five papers from the session on mechanisms, co-chaired by Ray Peterson, Aleris International, and Mahesh Jha, Department of Energy.

University of Utah professors Michael Moats, Jan Miller, and Wlodzimierz Zmierczak will consider chemical utilization of sequestered CO2 as a booster of the hydrogen economy. It is noted that hydrogen in a pure hydrogen economy would be like natural gas in today’s energy economy. Unfortunately, hydrogen’s physical properties are unsuited to the energy market’s requirements in terms of packaging, storage, transfer, and delivery.

Comparison of Energy Management Approaches



Technology only
Technology only
People Only

In this paper, a hybrid energy economy that packages hydrogen chemically on carbon atoms from various sources including recycled CO2 is introduced and discussed. For this new hybrid energy economy to become a sustainable reality, the ability to recycle CO2 and attach hydrogen to create a usable energy product, such as dimethyl ether, is needed. Dimethyl ether is recognized as a potential next-generation, environmentally benign material for energy storage and distribution. To maximize the sustainability of the proposed hybrid energy economy, green hydrogen will be utilized, created by the electrolysis of water powered by renewable energy sources, such as solar, wind, or geothermal heat.

Phillip A. Armstrong and Charles A. Lewinsohn of Air Products (Allentown, Pennsylvania) and John Gordon, Ceramatec Inc. (Salt Lake City, Utah), will discuss systems based on mixed conductive ceramics. In particular, ceramics conductive to oxygen ions and electrons, for reducing CO2 emissions from metallurgical production. Membranes based on these mixed conducting properties enable commercial viability of several attractive metallurgical processes. One of these processes utilizes modular, ceramic-membrane structures for the generation of pure oxygen, in tonnage quantities. It is noted that membrane-based systems offer significant capital savings and operating efficiencies in various metallurgical processes.

Katsuyoshi Tatenuma, Kaken Inc. (Ibaraki, Japan), proposes to reduce global atmospheric CO2 by isolating surplus CO2 from the biosphere, permanently fixing it as an insoluble mineral onto the sea bottom. This method is based on the concept that an insoluble carbonate mineral (CaCO3) can be formed by direct electrolysis of the seawater,

Ca2+ + 2HCO3- + OH-
= CaCO3(insoluble) + CO32-(soluble)
+ H+ + H2O

(this is not the coral reef reaction), and is directly disposed by itself onto the sea bottom. By this treatment, a concentration of carbonate is reduced in the seawater. The absorption capacity of atmospheric CO2 is therefore increased as a result of chemical equilibrium between the ocean surface and the atmosphere. The proposed method, without any additives or generation of secondary wastes or CO2 itself, and disturbance of the environmental balance has potential as a green-oriented method with an ability to resolve fundamentally the problem of global warming. The schematic of the process is shown in Figure 1.

Maria Salazar-Villalpando and Todd Gardner, National Energy Technology Laboratory (NETL), will talk on CO2 reduction by dry methane reforming over hex aluminates. Methane reforming using CO2 has been of interest for many years because CO2 provides a source of clean oxygen. Coal power or metallurgical plants have wasted heat streams that can be utilized in CO2 reduction. The product of this reaction is syngas, which could generate electrical power in a single-oxide fuel cell or used in the production of synthetic fuels. Hexaluminate catalysts prepared at NETL may represent a product that can be utilized for the conversion of CO2 to syngas. A series of BaNixAl12–y O19–z catalysts were prepared by coprecipitation followed by calcination at 1,400°C. Reactions were carried out to determine catalyst performance and catalyst characterization was conducted to determine surface area, pore size, catalyst phases, and structures. Moreover, catalyst characterization analysis of three samples (y = 0.2, 0.6, and 1.0 in BaNixAl12–y O19–z) was performed by extended x-ray absorption fine structure and temperature programmed reduction.

Mark Berkley, Jim Sarvinis, Jason Berzansky, and David Clarry, of Hatch Associates (Brisbane, Australia), give an in-depth overview of existing methods in the CO2 capture and sequestration implications for the metals industry. Technologies developed to sequester CO2 or use CO2 for enhanced fossil fuel recovery are currently in operation. Taxation regimes and CO2 credit trading are becoming drivers for a number of projects. Some mining companies have also identified an opportunity to sequester CO2 in their by-products; recent work by Alcoa in using by-product alkalinity is a prime example. In addition to process plant emissions, mining companies are becoming increasingly aware of their overall carbon footprint, including CO2 generated during the production of power they use. New power plant designs in various stages of development include CO2 separation and sequestration techniques. This paper summarizes the state-of-the-art for these technologies, including integrated gasification combined cycle power plants. A concept to use the gasification products as reductants in metallurgical processes is also described. The relevance of technology from power plant designs with post-combustion capture to the processing of off-gas generated in metallurgical facilities is also reviewed.

The authors touch upon several physical and chemical methods of concentrating and separating CO2 from the flue gas, assuming state-of-the-art methods. This is still a fertile field for metallurgists.

Ferrous Metallurgy
The ferrous metallurgy session on CO2 reduction metallurgy, co-chaired by Larry Kavanaugh (AISI) and K. Mondal (Southern Illinois University), will feature the following topics.

Jean-Pierre Birat, Arcelor-Mittal Research (Maizicres-les-Metz, France) will present the EU work on CO2 in the steel industry and the ultra-low CO2 steelmaking program. The European steel industry has been engaged since 2004 in an extensive, five-year, 50 million euro program to develop breakthrough process technologies to produce steel with a reduction of specific CO2 emissions by at least a factor of 2. This program, called ultra-low CO2 steelmaking, will deliver several process route concepts that meet this target and are ready for scaling up to a commercial size pilot by 2009. After screening a large number of potential routes in extensive future studies, the program now focuses on five concepts. The oxygen blast furnace with top gas recycling and carbon capture and sequestration (CCS); a bath smelting reduction process, also using pure oxygen and CCS; a new direct reduction, also oxygen and CCS-based, and two processes to carry out the electrolysis of iron ore; they will now be tested at fairly large scales. The approach may be of interest to other metallurgies than steelmaking.

Standard ΔG° and E° Values for Several Electrode Reactions of Carbon Dioxide in Aqueous Solutions

ΔG° (kJ/mol)


CO2 + 2 H+ + 2 e → HCOOH
CO2 + 2 H+ + 2 e → CO + H2O
CO2 + 4 H+ + 4 e → HCHO + H2O
CO2 + 6 H+ + 6 e → CH3OH + H2O

*CO2 and CO are gases. All other substances are aqueous solutions.

R. Malti Goel, special advisor, Department of Science and Technology, Government of India, will talk about the recent developments in technology management for reducing of CO2 emissions in the metal industry. The ferrous and non-ferrous industries in India are undergoing a transition to meet growing demand and a new thrust toward R&D is mounting. This paper describes the recent developments in technology management, the importance of R&D, and case studies on adoption of energy efficient and CO2 reduction technologies in the metal industry in India.

James Evans, University of California, Berkeley, and Brian Wildey, Pacific Consolidated Industries (Riverside, California) will present the impact on greenhouse gas emissions of a switch from carbon to hydrogen as the principal reducing agent in producing metals. The authors point out that carbon has been the principal reducing agent in producing metals for centuries. Carbon has been an inexpensive reducing agent, but also an effective one, as any undergraduate who knows his or her Ellingham diagrams is aware. Even in the production of aluminum, an electrolytic process, carbon consumed at the anodes serves to reduce the voltage of the Hall–Héroult cell. The interest in reducing the amount of anthropogenic CO2 has led to this examination of whether a switch to hydrogen as a major reductant is feasible and economical. The main source of hydrogen is natural gas and its production entails the generation of CO2; however, that CO2 is more easily captured than, say, the CO2 leaving an iron blast furnace. Calculations and speculations lead to conclusions about whether there is significant benefit to be obtained from such a radical change in our way of producing metals and the approximate cost of such change.

Von Richards, Simon Lekakh, Charles Rawlins, and Kent Peaslee, of the University of Missouri at Rolla, will discuss the subject of sequestration of CO2 by steelmaking slag—inclusive of the process phenomena and reactor study. Steelmaking processes generate CO2 air emissions and a slag co-product. This project developed a functional sequestration system using steelmaking slag to permanently capture CO2 emitted in steelmaking offgas. A possible parallel benefit of this process would be rapid chemical stabilization of the slag minerals with reducing swelling or leaching. The authors will be presenting the results of the project, including mineralogical and structural features of carbon sequestration with steelmaking slag, mathematical modeling of reaction phenomena using a modified shrinking core model, Metsim modeling of several possible industrial applications, a thermo-gravimetrical study of the reaction between slags and different gases, and design and testing for a lab-scale apparatus consisting of two reactors.

Jon Feldman, Edmund Smith, Stephen Gale, and David Clarry of Hatch present a management technique used at a Canadian steel plant leading to impressive results. In 2006, independent steelmaker Algoma Steel Inc. (Ontario, Canada) embarked on an ambitious initiative to become “Best in Class in Energy Management.” The initiative focused on identifying energy/greenhouse gas management improvements leading to low-implementation cost approaches to energy savings.

The authors note that the key components of the approach were: review site energy management practices and benchmark internationally; review best technical practices and benchmark against public energy intensity data; conduct a site-wide energy assessment and physical review of operating areas; facilitate on-site workshops with staff to prioritize savings opportunities and identify and remove implementation barriers; and develop an energy management action plan for implementation of improvements.

Most organizations can produce, with relative ease, a list of ideas for saving energy, but implementing them is the challenge. This paper addresses these issues as well as the profitability of the energy efficiency improvements and the consequences for greenhouse gas emissions. Table I shows the range of benefits accrued from differing levels of project approaches.

Chenguang Bai, Liangying Wen, and Feng Xia from Chongqing University, China, present a technique for the reduction of Ti-V-magnetite with microwave energy, which effectively minimizes CO2 emissions in the process. The relationship between carbon consumption and microwave energy consumption for the magnetite reduction process was studied. At different microwave power levels, the carbon usage per unit of ore is different. While the output of power and irradiation time increase, carbon consumption decreases. The results prove that microwave energy is a good resource that can be used in magnetite extraction to reduce CO2 emission.

Electrolytic Methods
The use of electrolytic methods is the logical and thermodynamically analyzed choice for CO2 reduction metallurgy. This session is co-chaired by D. Sadoway of the Massachusetts Institute of Technology (MIT) and J. Hryn (Praxair; Danbury, Connecticut).

This session will start with a discussion by Sadoway of carbon-free metals extraction by molten oxide electrolysis. He notes that molten oxide electrolysis (MOE), which is the electrolytic decomposition of molten metal-oxide into liquid metal and oxygen gas, represents an improvement over today’s carbon-intensive thermochemical reduction processes for metal production. For MOE, the feedstock can be concentrate derived from ore or from hazardous waste (such as chromate sludge). The process avoids the use of consumable carbon anodes and thus eliminates greenhouse-gas emissions as the by-product of the metal-recovery step. The concept applies to a variety of chemistries including titanium, iron, and ferroalloys. The electrochemistry of multi-component oxide melts from the family FeO–SiO2–TiO2–Al2O3–MgO– CaO has been studied by voltammetry at temperatures up to 1,750°C. Galvanostatic electrolysis in laboratory-scale cells operating with a variety of feedstocks has demonstrated the extraction of liquid iron, ferrosilicon, and titanium with the simultaneous co-generation of oxygen.

The rest of this session will cover effects of electrolytic reduction of CO2 using electron transfers of two to eight electrons making different combinations of (alloys of) carbon, hydrogen, and oxygen from CO2 and H2O.

Melvin Miles of the University of La Verne (La Verne, California) will cover the subject of an electrochemical reduction of CO2 with a six electron transfer. He notes that considerable research has been conducted on the anodic oxidation of methanol in fuel cells. The electrochemical reduction of CO2 in aqueous solutions to form methanol is the same reaction in reverse (i.e., CO2 + 6 H+ + 6 e- = CH3OH + H2O). The same catalysts and conditions may operate for both reaction directions. This CO2 reduction reaction, however, must be able to compete with the electrochemical reduction of water to form hydrogen gas. Thermodynamically, the reduction of CO2 to form CH3OH is slightly more favorable than the reduction of water. Kinetically, CO2 reduction can be favored by electrodes that are poor catalysts for water reduction such as Mo, Cu, In, Sn, and Sb. The use of nearly neutral electrolytes rather than acidic electrolytes makes the reduction of CO2 kinetically more favorable. The thermodynamics of various reaction steps will be presented.

The author provides the electromagnetic fields of varying CO2–H2O electrolytic reactions, as shown in Table II. Neale Neelameggham of US Magnesium LLC (Salt Lake City, Utah) will discuss the fundamentals of soda fuel cycle metallurgy. Processes for generating alloys of carbon and hydrogen by reducing the CO2 and water mixture (carbonated water or water vapor) called soda, to easily stored fuels are normally endothermic. The processes are similar to the generation of hydrogen alone from water, which is also endothermic. But hydrogen is more difficult to store than compounds (or alloys) of carbon and hydrogen. This recycling of CO2 and water is possible by using other forms of energy by innovative carbon capture methods.

Thermodynamic diagrams developed for soda (CO2 and H2O)–metal reactions provide hints for using low-cost stored energy in un-recycled metallic waste for thermal conversion. The soda-to-fuel using metals reaction is written as

m CO2 + n H2O + p M
= CmH2nOy + MpO(2m + n – y)

Choices for conditions for the electrochemical approaches (using solar, wind, and hydropower) are also discussed. The product mix will be a function of the reactant stoichiometry between CO2 and H2O. It is pointed out that this stoichiometric control may be better in non-aqueous electrolytes. Kotaro Ogura of Yamaguchi University discusses his solution of how to carry out the electrocatalytic reduction of CO2 to C2H4 at a gas/solution/metal interface. He proposes that the problem of greenhouse effect can be largely mitigated if CO2 can be recycled for use as fuels or chemicals. Although various processes for converting CO2 to valuable compounds have been proposed, it is important that the conversion process be feasible under mild conditions. This is because the secondary generation of CO2 is feared if high energy is required and supplied with a fossil fuel. Ogura’s research developed the electrochemical reduction process of CO2 to C2H4 which occurs at a three-phase (gas/solution/ metal) interface in concentrated potassium halide solutions. The input energy required for this process was supplied by a solar cell or a commercial power source. In the closed circulation system, the conversion efficiency of CO2 increased with an increase of input electric charge to reach 100%, and the maximum selectivity for the formation of C2H4 was more than 80%. Ogura’s mechanism of CO2–H2O electrolysis making ethylene is shown in Figure 2.

Mingming Zhang and Ramana Reddy, from the University of Alabama, have been pioneering the advantages of green production of light metals in ionic liquid electrolytes. Carbon dioxide is one of the most common by-products of present-day light metals production. The authors propose a novel light metals production process using ionic liquid electrolytes. This process has significant advantages compared with traditional high-temperature processes, such as zero CO2 and CF4 emission; low energy consumption due to the low temperature operation; and nonconsumable electrodes. Two types of anode materials (graphite and extruded carbon) were assessed in an electrolysis experiment. The results showed that both anode materials were stable (negligible weight loss). However, the extruded carbon was found to be superior to graphite in terms of facilitating higher current density and current efficiency. The calculated energy consumption for aluminum production was less than 5 kWh/kg at up to 350 A/m2.

Joseph Hartvigsen, S. Elangovan, Lyman Frost, and Anthony Nickens of Ceramatec (Salt Lake City, Utah), and Carl Stoots, James O’Brien, and J. Herring of Idaho National Laboratory (INL) will present their work on CO2 recycling by high-temperature coelectrolysis and hydrocarbon synthesis. The raw material for synfuel production is syngas, a mixture of H2 and CO. Ceramatec and INL have demonstrated conversion of CO2 and steam to syngas by high-temperature solid oxide co-electrolysis, followed by catalytic conversion of the syngas to a hydrocarbon fuel. This is a controlled electrolysis without using much excess CO2 or excess H2O in making synthesis gas followed by demonstrated conversion into hydrocarbon fuel. Carbon dioxide recovered from concentrated sources, such as metallurgical reduction furnaces, cement kilns, and fossil fuel power plants can provide a valuable feedstock for a synthetic fuels industry based on energy from nuclear, solar, wind, and hydropower sources. This electrolysis technology is the reverse mechanism of conventional solid oxide fuel cell technology.

Wherever a source of high-temperature process heat is available, such as from an advanced high-temperature nuclear reactor or solar dish concentrator, the endothermic electrolysis reactions can utilize both thermal and electrical inputs in such a way that the conversion efficiency within the cell is 100% followed by conversion to synfuel.

Widespread implementation of such synfuel production from CO2 will enable a much larger reliance on intermittent renewable energy than can be accommodated by conventional electric demand profiles. Their ten cell stack of a solid oxide CO2-steam electrolyzer making syngas is shown in Figure 3.

Kanchan Mondal of Southern Illinois University will present his mechanistic concepts on CO2 reduction by nanoscale galvanic couples. He notes that methanol, lower hydrocarbons, CO, and HCOOH have been formed by the reduction of CO2 with H2. Uncatalyzed electro-reduction requires a significant overvoltage. An alternate route has been conceptualized. Production of hydrogen from water can be achieved by chemical oxidation of a metal in water followed by oxidation of the hydronium ion by the released electrons to form hydrogen radicals. It is hypothesized that circumventing the problem of the formation of hydrogen molecules is essential while having the hydrogen radical react with CO2 forming methanol, etc. This may be possible by a bimetallic catalyst acting as a galvanic couple, wherein one metal acts as the electron donor for the production of hydrogen radicals while the other acts as a catalyst for the reduction of CO2. This may enhance the reaction rates. The concept circumvents the need for an external electric field unlike the electrochemical process.

Kandasamy Subramanian, Krishnasamy Asokan, and Govindarajan Gomathi of Central Electrochemical Research Institute (Karaikudi, India), will discuss their experience in carrying out the two-electron transfer reduction of CO2 to formate ion in an electrochemical membrane reactor in KHCO3 buffer solutions.

An electrochemical reactor with anode and cathode chambers separated by a composite perfluoro polymer cation exchange membrane was designed, fabricated, and used for the reduction of dissolved CO2 to formate under ambient conditions. The flow reactor enhanced the mass transfer of carbon dioxide compared to the batch reactor. Experiments were conducted using two different membranes—Nafion 961 and Nafion 430. Optimum values of flow rate and current density were evaluated for the formation of formate in aqueous KHCO3 buffer solutions. The efficacy of various cathode materials (Cd, Pb, Sn, and Zn plated stainless steel woven mesh) for the electro-reduction of CO2 is also reported.

Each session will end with a panel discussion to get input from other members, whose comments and contributions to this field will be worthwhile. I would like to end this synopsis with a quote (author unknown) “Along the way there were those who knew all the reasons these things couldn’t be done. Fortunately there were those who knew enough not to listen.”


1. R. Neelameggham, “Fossilize CO2–Make Fuels, A Green and Black Paper on Soda-Fuel Cycle” (private communications, August 2006).
2. Eighth International Conference on Carbon Dioxide Utilization (20–23 June 2005, Oslo, Norway),
3. Neale R. Neelameggham and Ramana G Reddy, editors, Proceedings of Carbon Dioxide Reduction Metallurgy Symposium (Warrendale, PA: TMS, 2008).
4. Martin M. Halmann and M. Steinberg, Greenhouse Gas Carbon Dioxide Mitigation: Science and Technology (Boca Raton, FL: CRC Press LLC, 1999).

Neale R. Neelameggham is the technical development scientist, US Magnesium LLC, 238 N 2200 W, Salt Lake City, UT 84116; Dr. Neelameggham is also the JOM advisor from the Reactive Metals Committee of the TMS Light Metals Division.