Electrodeposition of MoS2 for Charge Storage in Electrochemical Supercapacitors

Mo sulfide thin films were cathodically electrodeposited onto glassy carbon electrodes (GCE) from aqueous electrolytes containing 10 mM (NH4)2MoS4 and 0.2 M KCl. Film adhesion was adequate only for electrodes pretreated by potential cycling in 1.0 M HNO3 and 0.1 M NaF to enhance the surface roughness and partially oxidize the GCE. Previous studies report direct cathodic electrodeposition of MoS2, but energy dispersive x-ray spectroscopy and x-ray diffraction suggest that the as-deposited film is closer in stoichiometry to MoS3, which can be converted to MoS2 by annealing in Ar at 600°C for one hour. The charge storage capability of electrodeposited Mo sulfide films is studied here for the first time in 1.0 M Na2SO4 over the thickness range 50 nm to 5 µm, and before and after high temperature annealing. The highest capacitance is obtained for 50 nm thick MoS2 films is 330 F/g measured by galvanostatic charge discharge at 0.75 A/g, and 360 F/g measured by cyclic voltammetry at 10 mV/sec. The capacitance per unit mass decreases with increasing film thickness due to reduced electrochemical accessibility. MoS2 film formed by high temperature annealing in Ar have a charge storage capability about 40x higher than the as-deposited Mo sulfide films

Qualifications of Candle Filters for Combined Cycle Combustion Applications

The direct firing of coal produces particulate matter that has to be removed for environmental and process reasons. In order to increase the current advanced coal combustion processes, under the U.S. Department of Energy's auspices, Siemens Westinghouse Power Corporation (SWPC) has developed ceramic candle filters that can operate at high temperatures. The Coal Research Center of Southern Illinois University (SIUC), in collaboration with SWPC, developed a program for long-term filter testing at the SIUC Steam Plant followed by experiments using a single-filter reactor unit. The objectives of this program funded by the U.S. Department of Energy were to identify and demonstrate the stability of porous candle filter elements for use in high temperature atmospheric fluidized-bed combustion (AFBC) process applications. These verifications were accomplished through extended time slipstream testing of a candle filter array under AFBC conditions using SIUC's existing AFBC boiler. Temperature, mass flow rate, and differential pressure across the filter array were monitored for a duration of 45 days. After test exposure at SIUC, the filter elements were characterized using Scanning Electron Microscopy and BET surface area analyses. In addition, a single-filter reactor was built and utilized to study long term filter operation, the permeability exhibited by a filter element before and after the slipstream test, and the thermal shock resilience of a used filter by observing differential pressure changes upon rapid heating and cooling of the filter. The data acquired during the slipstream test and the post-test evaluations demonstrated the suitability of filter elements in advanced power generation applications

FUEL-FLEXIBLE GASIFICATION-COMBUSTION TECHNOLOGY FOR PRODUCTION OF H2 AND SEQUESTRATION-READY CO2

It is expected that in the 21st century the Nation will continue to rely on fossil fuels for electricity, transportation, and chemicals. It will be necessary to improve both the process efficiency and environmental impact performance of fossil fuel utilization. GE Energy and Environmental Research Corporation (GE EER) has developed an innovative fuel-flexible Unmixed Fuel Processor (UFP) technology to produce H{sub 2}, power, and sequestration-ready CO{sub 2} from coal and other solid fuels. The UFP module offers the potential for reduced cost, increased process efficiency relative to conventional gasification and combustion systems, and near-zero pollutant emissions including NO{sub x}. GE EER was awarded a Vision 21 program from U.S. DOE NETL to develop the UFP technology. Work on this Phase I program started on October 1, 2000. The project team includes GE EER, California Energy Commission, Southern Illinois University at Carbondale, and T. R. Miles, Technical Consultants, Inc. In the UFP technology, coal/opportunity fuels and air are simultaneously converted into separate streams of (1) pure hydrogen that can be utilized in fuel cells, (2) sequestration-ready CO{sub 2}, and (3) high temperature/pressure oxygen-depleted air to produce electricity in a gas turbine. The process produces near-zero emissions and, based on process modeling work, has an estimated process efficiency of 68%, based on electrical and H{sub 2} energy outputs relative to the higher heating value of coal, and an estimated equivalent electrical efficiency of 60%. The Phase I R&D program will determine the operating conditions that maximize separation of CO{sub 2} and pollutants from the vent gas, while simultaneously maximizing coal conversion efficiency and hydrogen production. The program integrates lab-, bench- and pilot-scale studies to demonstrate the UFP technology. This is the ninth quarterly technical progress report for the Vision 21 UFP program supported by U.S. DOE NETL (Contract No. DE-FC26-00FT40974). This report summarizes program accomplishments for the period starting October 1, 2002 and ending December 31, 2002. The report includes an introduction summarizing the UFP technology, main program tasks, and program objectives; it also provides a summary of program activities and accomplishments covering progress in tasks including lab- and bench-scale experimental testing, pilot-scale design and assembly, and program management

Fuel-Flexible Gasification-Combustion Technology for Production of H2 and Sequestration-Ready CO2

GE Global Research is developing an innovative energy technology for coal gasification with high efficiency and near-zero pollution. This Unmixed Fuel Processor (UFP) technology simultaneously converts coal, steam and air into three separate streams of hydrogen-rich gas, sequestration-ready CO{sub 2}, and high-temperature, high-pressure vitiated air to produce electricity in gas turbines. This is the draft final report for the first stage of the DOE-funded Vision 21 program. The UFP technology development program encompassed lab-, bench- and pilot-scale studies to demonstrate the UFP concept. Modeling and economic assessments were also key parts of this program. The chemical and mechanical feasibility were established via lab and bench-scale testing, and a pilot plant was designed, constructed and operated, demonstrating the major UFP features. Experimental and preliminary modeling results showed that 80% H{sub 2} purity could be achieved, and that a UFP-based energy plant is projected to meet DOE efficiency targets. Future work will include additional pilot plant testing to optimize performance and reduce environmental, operability and combined cycle integration risks. Results obtained to date have confirmed that this technology has the potential to economically meet future efficiency and environmental performance goals

Removal of non-CO2 greenhouse gases by large-scale atmospheric solar photocatalysis

Large-scale atmospheric removal of greenhouse gases (GHGs) including methane, nitrous oxide and ozone-depleting halocarbons could reduce global warming more quickly than atmospheric removal of CO2. Photocatalysis of methane oxidizes it to CO2, effectively reducing its global warming potential (GWP) by at least 90%. Nitrous oxide can be reduced to nitrogen and oxygen by photocatalysis; meanwhile halocarbons can be mineralized by red-ox photocatalytic reactions to acid halides and CO2. Photocatalysis avoids the need for capture and sequestration of these atmospheric components. Here review an unusual hybrid device combining photocatalysis with carbon-free electricity with no-intermittency based on the solar updraft chimney. Then we review experimental evidence regarding photocatalytic transformations of non-CO2 GHGs. We propose to combine TiO2-photocatalysis with solar chimney power plants (SCPPs) to cleanse the atmosphere of non-CO2 GHGs. Worldwide installation of 50,000 SCPPs, each of capacity 200 MW, would generate a cumulative 34 PWh of renewable electricity by 2050, taking into account construction time. These SCPPs equipped with photocatalyst would process 1 atmospheric volume each 14–16 years, reducing or stopping the atmospheric growth rate of the non-CO2 GHGs and progressively reducing their atmospheric concentrations. Removal of methane, as compared to other GHGs, has enhanced efficacy in reducing radiative forcing because it liberates more °OH radicals to accelerate the cleaning of the troposphere. The overall reduction in non-CO2 GHG concentration would help to limit global temperature rise. By physically linking greenhouse gas removal to renewable electricity generation, the hybrid concept would avoid the moral hazard associated with most other climate engineering proposals

Catalytic reduction of SO{sub 2} with methane over molybdenum catalyst. Quarterly report, 1 December 1994--28 February 1995

One of the primary concerns in coal utilization is the emission of sulfur compounds, especially SO{sub 2}. This project deals with catalytic reduction of SO{sub 2} with methane using molybdenum sulfide catalyst supported on different activated carbons: Darco TRS, Norit ROZ-3, and an activated carbon prepared from Illinois coal IBC-110. The work conducted during this quarter has concentrated on continuation of the synthesis of activated carbon derived from Illinois coal IBC-110, modification and improvement of the apparatus for the catalyst testing, ESCA (XPS) analysis of the catalyst (10% MoS{sub 2} on Darco TRS activated carbon), and experiments in the temperature range of 450{degree}C--600{degree}C for the S0{sub 2}:CH{sub 4} ratio equal 1:1. XPS study confirmed that Mo is present in the form of Mo+4 and S in the form of S-2. The catalytic experiments of SO{sub 2} reduction with CH{sub 4} showed that for both Darco TRS and ROZ-3 supports, S0{sub 2} conversion increases with the temperature. Also, the catalyst having 20% loading of MoS{sub 2} on Darco TRS support shows the highest S0{sub 2} conversion over 10% or 15% loadings on Darco TRS. In contrast, for the ROZ-3 support, the catalyst having a 15% loading shows the highest activity. Additionally, it was observed that conversions of S0{sub 2} at 600{degree}C for both supports are comparable to each other when catalysts with 20% loadings are used; at lower temperatures, the activities are quite different with the conversions being higher for Darco TRS support

Catalytic reduction of SO{sub 2} with methane over molybdenum catalyst. Technical report, March 1--May 31, 1995

One of the primary concerns in coal utilization is the emission of sulfur compounds, especially SO{sub 2}. This project deals with catalytic reduction of SO{sub 2} with methane using molybdenum sulfide catalyst supported on different activated carbons: Darco TRS, ROZ-3, and an activated carbon prepared from Illinois coal IBC-110. The work conducted during this quarter included preparation of activated carbons from Illinois coal, preparation of the catalysts on these supports, and experiments on SO{sub 2} reduction with methane at different feed ratio SO{sub 2}: CH{sub 4}. It was found that at the feed ratio 1:1, 10% MoS{sub 2} supported on Darco TRS catalyst has highest activity at low temperatures; at higher temperatures, the catalysts 15% and 20% MoS{sub 2} supported on Darco TRS exhibit high activity in both SO{sub 2} conversion (> 90%) and yield of elemental sulfur (97.4% for 20% MoS{sub 2} at 600 C). For catalyst supported on ROZ-3, this having 10% of MOS{sub 2} showed high activity in the reaction. To determine the effect of feed ratio on the reaction, the catalysts with 15% loading of MoS{sub 2} supported on Darco TRS and ROZ-3 were used. For catalyst supported on ROZ-3 activated carbon, the effect of feed ratio is dramatic, especially at the higher temperatures at which the conversion of SO{sub 2} increases more than twice when the feed contains excess of methane. For catalyst supported on Darco TRS activated carbons, there is practically no difference in SO{sub 2} conversion for feed ratios 1:1 and 1:2 (with respect for methane)

Qualifications of Candle Filters for Combined Cycle Combustion Applications

The direct firing of coal produces particulate matter that has to be removed for environmental and process reasons. In order to increase the current advanced coal combustion processes, under the U.S. Department of Energy's auspices, Siemens Westinghouse Power Corporation (SWPC) has developed ceramic candle filters that can operate at high temperatures. The Coal Research Center of Southern Illinois University (SIUC), in collaboration with SWPC, developed a program for long-term filter testing at the SIUC Steam Plant followed by experiments using a single-filter reactor unit. The objectives of this program funded by the U.S. Department of Energy were to identify and demonstrate the stability of porous candle filter elements for use in high temperature atmospheric fluidized-bed combustion (AFBC) process applications. These verifications were accomplished through extended time slipstream testing of a candle filter array under AFBC conditions using SIUC's existing AFBC boiler. Temperature, mass flow rate, and differential pressure across the filter array were monitored for a duration of 45 days. After test exposure at SIUC, the filter elements were characterized using Scanning Electron Microscopy and BET surface area analyses. In addition, a single-filter reactor was built and utilized to study long term filter operation, the permeability exhibited by a filter element before and after the slipstream test, and the thermal shock resilience of a used filter by observing differential pressure changes upon rapid heating and cooling of the filter. The data acquired during the slipstream test and the post-test evaluations demonstrated the suitability of filter elements in advanced power generation applications

Catalytic reduction of SO{sub 2} with methane over molybdenum catalyst. Quarterly technical report, September 1, 1994--November 30, 1994

One of the primary concerns in coal utilization is the emission of sulfur compounds, especially SO{sub 2}. This project deals with catalytic reduction of SO{sub 2} with methane using molybdenum sulfide catalyst supported on different activated carbons: Darco TRS, Norit ROZ-3, and an activated carbon prepared from Illinois coal IBC-110. The work conducted during this quarter has concentrated on catalyst preparation and characterization along with synthesis of activated carbon from IBC-110 coal, as well as, construction of the apparatus for catalytic tests of SO{sub 2} reduction with methane. It was found that Darco TRS supported catalysts have larger surface area than the pure activated carbon, whereas the impregnation of Norit ROZ-3 did not significantly change the BET surface area. Also, the synthesis of activated carbon support from IBC-110 is in progress