Download or read book The Partial Oxidation of Ammonia in Ceramic Electrochemical Reactors written by Nigel M. Sammes and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The partial oxidation of ammonia in a ceramic electrochemical reactor written by Nigel M. Sammes and published by . This book was released on 1988 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrochemical and Partial Oxidation of written by Rahul Singh and published by . This book was released on 2008 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrogen has been the most common fuel used for the fuel cell research but there remains challenging technological hurdles and storage issues with hydrogen fuel. The direct electrochemical oxidation of CH4 (a major component of natural gas) in a solid oxide fuel cell (SOFC) to generate electricity has a potential of commercialization in the area of auxiliary and portable power units and battery chargers. They offer significant advantages over an external reformer based SOFC, namely, (i) simplicity in the overall system architecture and balance of plant, (ii) more efficient and (iii) availability of constant concentration of fuel in the anode compartment of SOFC providing stability factor. The extreme operational temperature of a SOFC at 700-1000 °C provides a thermodynamically favorable pathway to deposit carbon on the most commonly used Ni anode from CH4 according to the following reaction (CH4 = C + 2H2), thus deteriorating the cell performance, stability and durability. The coking problem on the anode has been a serious and challenging issue faced by the catalyst research community worldwide. This dissertation presents (i) a novel fabricated bi-metallic Cu-Ni anode by electroless plating of Cu on Ni anode demonstrating significantly reduced or negligible coke deposition on the anode for CH4 and natural gas fuel after long term exposure, (ii) a thorough microstructural examination of Ni and Cu-Ni anode exposed to H2, CH4 and natural gas after long term exposure at 750 °C by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction and (iii) in situ electrochemical analysis of Ni and Cu-Ni for H2, CH4 and natural gas during long term exposure at 750 °C by impedance spectroscopy. A careful investigation of variation in the microstructure and performance characteristics (voltage-current curve and impedance) of Ni and Cu-Ni anode before and after a long term exposure of CH4 and natural gas would allow us to test the validation of a negligible coke formation on the novel fabricated anode by electroless plating process. Hydrogen is an environmentally cleaner source of energy. The recent increase in the demand of hydrogen as fuel for all types of fuel cells and petroleum refining process has boosted the need of production of hydrogen. Methane, a major component of natural gas is the major feedstock for production of hydrogen. The route of partial oxidation of methane to produce syngas (CO + H2) offers significant advantages over commercialized steam reforming process for higher efficiency and lower energy requirements. Partial oxidation of methane was studied by pulsing O2 into a CH4 flow over Rh/Al2O3 in a sequence of in situ infrared (IR) cell and fixed bed reactor at 773 K. The results obtained from the sequence of an IR cell followed by a fixed bed reactor show that (i) adsorbed CO produced possesses a long residence time, indicating that adsorbed oxygen leading to the formation of CO is significantly different from those leading to CO2 and (ii) CO2 is not an intermediate species for the formation of CO. In situ IR of pulse reaction coupled with alternating reactor sequence is an effective approach to study the primary and secondary reactions as well as the nature of their adsorbed species. As reported earlier, hydrogen remains to be the most effective fuel for fuel cells, the production of high purity hydrogen from naturally available resources such as coal, petroleum, and natural gas requires a number of energy-intensive steps, making fuel cell processes for stationary electric power generation prohibitively uneconomic. Direct use of coal or coal gas as the feed is a promising approach for low cost electricity generation. Coal gas solid oxide fuel cell was studied by pyrolyzing Ohio #5 coal to coal gas and transporting to a Cu anode solid oxide fuel cell to generate power. The study of coal-gas solid oxide fuel cell is divided into two sections, i.e., (i) understanding the composition of coal gas by in situ infrared spectroscopy combined with mass spectrometry and (ii) evaluating the performance of coal gas for power generation based on the composition on a Cu-SOFC. The voltage-current performance curve for coal gas suggests that hydrogen and methane rich coal gas performed better than CO2 or D2O concentrated coal gas. A slow rate of reforming reaction of D2O than CO2 with coal and coal gas was observed during pyrolysis reaction. The coal and coke (by-product of pyrolysis) were characterized by Raman spectrometer to reveal the effect of pyrolysis on the structural properties of coal.

Download or read book Selectivity Control Using Electrochemical Oxygen written by K. Hellgardt and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Microsectioned Electrochemical Reactors for Selective Partial Oxidation written by Michael Matlosz and published by . This book was released on 1998 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrochemical Oxidation and Characterization of U oxo Tetra t butylphthalocyaninato Silicon written by David C. Gale and published by . This book was released on 1989 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electrocatalysis written by Minhua Shao and published by Springer. This book was released on 2021-03-21 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience.Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.

Download or read book Developing Methods to Inform Catalyst Design for the Electrochemical Oxidation of Methane and Alcohols written by Michael James Boyd and published by . This book was released on 2021 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the production of natural gas and agricultural biomass/energy crops increases, new efficient and sustainable technologies will be required to convert these feedstock molecules into the same fuels and chemical we get from conventional petroleum today. Electrochemistry is a possible tool for the conversion of these species that can be coupled to renewable electricity. The discovery and development of selective and active electrocatalysts is one of the primary challenges in utilizing natural gas and biomass resources. But first there is a lack of fundamental understanding in (1) the reaction mechanism and (2) how operating conditions such as potential, electrolyte pH, mass transport, and time affect the the activity and selectivity of catalysts. To this end platinum was used as a model system to study electrochemical methane oxidation at room temperature and pressure. The experimental results on platinum combined with density functional theory calculations show that methane is first thermally activated at Pt (211) like step sites, then the resulting methyl intermediate is electrochemically oxidized to CO* which is in equilibrium with the final product CO2. The equilibrium can be shifted to favor complete oxidation by adjusting the applied electrochemical potential, specifically at potentials below 0.5 V vs. RHE CO* is the most thermodynamically stable species along the reaction pathway whereas above 0.5 V vs. RHE CO2 is now the most stable species. Important to note however is that since the kinetics for methane activation are very slow (barrier of ~0.95 eV) the platinum surface must be free of other adsorbed species, namely protons or hydroxides. Based on reaction mechanism for electrochemical methane oxidation on platinum it is unlikely that partial oxidation of methane on metallic electrodes well occur. For this reason we probed the activity of several transition metal oxide materials with the hope that they may be active for methane oxidation. Unfortunately our initial results suggest no significant methane oxidation occurs on these materials. In the case of biomass oxidation 1st row transition metal oxides have recently been shown to be quite selective in the conversion of alcohols to their corresponding carboxylic acids. Benzyl alcohol was used as a model molecule to study the reaction mechanism for alcohol oxidation on Ni(OH)2 electrodes as a function of potential and electrolyte pH. It was found that the active phase for alcohol oxidation is the metal oxy-hydroxide. The activity and selectivity were found to be heavily dependent on the electrolyte pH. Under strong alkaline conditions (> pH 13) high current densities and complete oxidation of benzyl alcohol to benzoate was favored whereas at more moderately alkaline conditions low current densities and partial oxidation to benzaldehyde was favored. Based on these results we hypothesize that a significant concentration of OH- in solution is required to activated the intermediate product benzaldehyde. The activity of several novel Ni materials was also probed for benzyl alcohol oxidation. Ni-doped nitrided carbons which have single atom nickel active sites were found to be selective for partial oxidation, however further optimization of the catalyst synthesis is required to increase the activity to compete with the bulk Ni(OH)2 electrodes. In conclusion, this dissertation presents a variety of experimental work focused on identifying the reaction mechanism for several oxidation reactions and provides key understanding that can be used towards the development of new electrocatalysts for the oxidation of hydrocarbons and alcohols.

Download or read book Recent Advances in Electrochemical Promotion of Catalysis written by Philippe Vernoux and published by Springer Nature. This book was released on 2022-10-03 with total page 386 pages. Available in PDF, EPUB and Kindle. Book excerpt: This contributed volume provides a critical review of research in the field of Electrochemical Promotion of Catalysis (EPOC). It presents recent developments during the past decade that have led to a better understanding of the field and towards applications of the EPOC concept. The chapters focus on the implementation of EPOC for developing sinter-resistant catalysts, catalysts for hydrogen production, ammonia production and carbon dioxide valorization. The book also highlights the developments towards electropromoted dispersed catalysts and for self-sustained electrochemical promotion which are currently expanding. This authoritative analysis of EPOC is useful for various scientific communities working at the interface of heterogeneous catalysis, solid state electrochemistry and materials science. It is of particular interest to groups whose research focuses on developments towards a better and more sustainable future.

Download or read book Electrodeposited Transition Metal Oxides as Electrocatalysts for Methane Partial Oxidation written by Yu-Chao Huang and published by . This book was released on 2021 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: The conversion of methane to valuable chemicals via electrochemical approaches is of great interest in the field of catalysis. Conventional catalytic processes utilize extreme conditions (high temperatures or pressures) to provide the energy required to achieve methane activation and require sophisticated heat integration networks to be economically viable. In contrast, catalytic processes via electrification or electrocatalysis offers direct routes of methane activation under ambient conditions, with lower energy requirements and simplified configurations. However, electrochemical oxidation of methane using current electrocatalysts remains challenging due to low energy efficiencies and a seemingly unavoidable trade-off between conversion and selectivity. In this regard, many research efforts have been devoted to the development of efficient and selective electrocatalysts for the activating and transformation of methane into valuable chemicals. Over the last decade, researchers have shown that composite transition metal oxides such as NiO/ZrO2 and Co3O4/ZrO2 can catalyze the electrochemical partial oxidation of methane to value-added chemicals such as methanol, ethanol, and propanol in a carbonate electrolyte. Chemical co-precipitation has been utilized predominantly for the preparation of metal oxide catalysts which involves multiple steps such as centrifugation, collection, drying, and annealing, and result in oxide materials with poor conductivity which are not amenable to electrocatalysis. In this work, a one-step electrodeposition method has been developed for the preparation of CoZrOx electrocatalysts. The electrodeposited CoZrOx material was found to be an active electrocatalyst for the partial oxidation of methane with a simple fabrication method. Furthermore, different electrodeposited unary transition metal oxides (CoOx, NiOx, MnOx, FeOx, and CuOx) were prepared through the same electrodeposition method, and were also studied for the electrochemical oxidation of methane. CoOx, NiOx, CuOx, and the CoZrOx electrocatalysts have been discovered to catalyze the conversion of methane to methanol. The preliminary results in this work demonstrate an additional approach among the available strategies for catalyst fabrication and may provide an efficient strategy of catalyst preparation for further studies of the electrochemical oxidation of methane under ambient conditions.

Download or read book Voltammetric and NMR Studies of the Electrochemical Oxidation of Methanol on Platinum Nanoparticles written by Patrick Brian McGrath and published by . This book was released on 2007 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effects of Partial Oxidation of PMAN Carbon on Their Performance as Anodes in 1M LiPF6 written by and published by . This book was released on 1996 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was undertaken to examine the effects of partial oxidation on the electrochemical performance of carbons derived from poly(methylacrylonitrile) (PMAN)-divinylbenzene (DVB) co-polymers. Mild oxidation was examined as a possible technique to increase the reversible capacity, improve cycleability, and reduce the amount of irreversible capacity associated with the formation of the passivation layer during the first reduction. Oxidizing conditions involved treatment of the PMAN carbon prepared at 700 C with dry CO2 or with steam at 600 C for one hour. The effects on the performance in 1M LiPF6/ethylene carbonate (EC)-dimethyl carbonate (DMC) solutions were evaluated by galvanostatic cycling tests, complex-impedance spectroscopy, and, to a more limited extent, cyclic voltammetry. Partial oxidation of PMAN carbon showed little or no overall beneficial effects in performance relative to the control.

Download or read book Electrochemical Advanced Oxidation Process Utilizing Nb doped TiO2 Electrodes written by and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An electrochemical advanced oxidation process has been developed, utilizing electrodes which generate hydroxyl free radical (HO) by oxidizing water. All substrates tested are oxidized, mostly with reaction rates proportional to the corresponding rate constants for reaction with hydroxyl. All substrates tested in the process have been destroyed. Complete oxidation of substrate molecules is the rule, and products of partial oxidation are rarely detected. Because relatively large current efficiencies can be achieved, this process is attractive in regard to energy cost. No hydrogen peroxide or ozone is required.

Download or read book Energy and Electrochemical Processes for a Cleaner Environment written by Christos Comninellis and published by The Electrochemical Society. This book was released on 2001 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Materials for Electrochemical Energy Conversion and Storage written by Arumugam Manthiram and published by John Wiley & Sons. This book was released on 2012-03-28 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: This new volume covers the latest developments in the field of electrochemistry. It addresses a variety of topics including new materials development, materials synthesis, processing, characterization, property measurements, structure-property relationships, and device performance. A broader view of various electrochemical energy conversion devices make this book a critical read for scientists and engineers working in related fields. Papers from the symposium at the 102nd Annual Meeting of The American Ceramic Society, April 29-May 3, 2000, Missouri and the 103rd Annual Meeting, April 22-25, 2001, Indiana.

Download or read book Environmental Analysis by Electrochemical Sensors and Biosensors written by Ligia Maria Moretto and published by Springer. This book was released on 2014-10-31 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses in detail the analysis and monitoring of the most important analytes in the environmental field. It also reviews the implementation, realization and application of sensor designs mentioned in the first volume of this set, dividing the coverage into global parameters, sensors of organics and sensors of inorganics.

Download or read book PERFORMANCE IMPROVEMENT OF SOLID OXIDE ELECTROLYSIS CELL SYSTEM INTEGRATED PARTIAL OXIDATION written by Nuttawut Visitdumrongkul and published by . This book was released on 2014 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid oxide electrolysis cell (SOEC) is a hydrogen production technology based on an electrochemical principle. In order to reduce an electrical energy demand, a thermal energy can be applied to the SOEC for separating steam into hydrogen and oxygen. Partial oxidation reaction (POX) is an exothermic reaction that can produce high thermal energy. Thus, the SOEC integrated with the POX process would lead to an improved, high efficient process to produce hydrogen energy. In this study, modeling of the SOEC and POX integrated process is performed. Effect of operating parameters in the POX process, i.e., oxygen to carbon ratio, operating temperature and pressure, on the SOEC performance is studied. The simulation results show that the efficiency of the SOEC can be improved from 69.65% to 84.97% when it is integrated with the POX process run at the oxygen to carbon ratio of 0.645, temperature of 1373 K and pressure of 5 atm. Energy and exergy analyses of the proposed process are carried out with respect to changes in key operating parameters. The results indicate that the POX reactor is the unit having the highest exergy destruction.