Karl Foger

FTIR investigations of the adsorption and disproportionation of NO on Cu-exchanged silicoaluminophosphate of type 34

Novel copper exchanged silicoaluminophosphates of chabazite type catalyst have been prepared. Conventional techniques such as elemental analysis, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, nitrogen sorption capacity (BET) have been employed for the characterization of the materials. X-Ray photoelectron spectroscopy results identified the presence of both CuI and CuII species on the catalyst. A detailed FTIR study was carried out on the disproportionation reaction of nitric oxide over the Cu-SAPO-34 catalyst. The spectra indicated the formation of nitrous oxide, mono- and di-nitrosyl complexes of CuI and of CuII and nitrate species. The types of NO sites on the Cu-SAPO-34 are similar to those seen on other copper exchanged zeolites, in particular Cu-ZSM-5. Effects of the pressure, temperature and evacuation on these nitric oxide species have been studied. The concentration and distribution of NO complexes varies with the NO pressure, reaction temperature and evacuation. The adsorption of nitric oxide on the copper exchanged silicoaluminophosphate have been compared with the copper exchanged high silica pentasil zeolite catalyst under identical experimental conditions.

Formation and thermal decomposition of rare-earth carbonates

The preparation of carbonate-containing rare-earth compounds and their thermal decomposition in 0%–17% CO2/N2 gas streams has been studied. Three types of rare-earth carbonate or hydroxycarbonate were produced by precipitation; with ammonium bicarbonate as the precipitant, La2 (CO3)3,CeOCO3 and Ln (OH)x (CO3)y (Sm, Tb, and Yb) were obtained, whereas with Na2CO3, only the normal carbonate, Ln2(CO3)3 (La, Sm, Tb, Er and Yb) was found. Temperature programmed decomposition studies revealed that the normal carbonate decomposed stepwise via a dioxocarbonate, Ln2O2CO3, to the oxide. In contrast, the hydroxycarbonates decomposed directly to the oxide. The presence of CO2 during heating had minimal effect on the decomposition of Ln2(CO3)3 to La2O2CO3 but raised significantly the decomposition temperature of Ln2O2CO3 to the oxide. As CO2 is a major product of the rare-earth oxide catalysed oxidative coupling of methane, these observations indicate that the state of catalyst carbonation will be dependent on the reaction temperature, overall catalyst selectivity and preparative method.

Deposition of chromium species on Sr-doped LaMnO3 cathodes in solid oxide fuel cells

Abstract The system of chromia-forming alloy/Sr-doped LaMnO3 (LSM) electrode/3 mol%Y2O3–ZrO2 (TZ3Y) electrolyte has been investigated at 900°C in air under cathodic polarization conditions. Deposition of chromium species was found to occur preferentially at the TZ3Y electrolyte surface, forming a deposit ring around the edge of the LSM electrode coating. The width of the ring was about 60 μm for an LSM electrode polarized for about 50 h. Overpotential (η) increases with polarization time. In contrast to η, electrode interface resistance (RE) measured under open circuit conditions decreases initially after passing the current and remains almost constant with polarization. The results indicate that the deposition process of chromium species may not be dominated by electrochemical reduction processes in competition with O2 reduction at an early stage of polarization.

Planar solid oxide fuel cells: the Australian experience and outlook

Abstract Since 1992, Ceramic Fuel Cells (CFCL) has grown to what is now the largest focussed program globally for development of planar ceramic (solid oxide) fuel cell, SOFC, technology. A significant intellectual property position in know-how and patents has been developed, with over 80 people involved in the venture. Over

Effects of air pollutants on the cerium exchanged high silica zeolite catalyst: a Fourier transform infrared study

A60 million in funding for the activities of the company has been raised from private companies, government-owned corporations and government business-support programs, including from energy — particularly electricity — industry shareholders that can facilitate access to local markets for our products. CFCL has established state-of-the-art facilities for planar SOFC R&D, with their expansion and scaling-up to pilot manufacturing capability underway. We expect to achieve commercial introduction of our market-entry products in 2002, with prototype systems expected to be available from early 2001.

FT-IR studies of the NO adsorption on rare earth (Eu/Gd/Tb) exchanged new generation silicoaluminophosphate catalysts of chabazite type

Abstract The interaction of air pollutants such as nitric oxide (NO) and carbon monoxide (CO) gases on the cerium exchanged ZSM-5 material was studied by FT-IR spectroscopy. Highly crystalline and pure H-ZSM-5 was used for preparing the cerium exchanged material. The cerium exchanged ZSM-5 material was characterised by conventional techniques such as ICP-OES, nitrogen sorption capacity (BET), XRD and XPS. X-ray photoelectron spectroscopy identified the presence of both Ce III and Ce IV species on the surface of the prepared catalysts. The in situ interaction of NO and CO on the cerium exchanged ZSM-5 was studied using an FT-IR Pyrex/quartz cell. The adsorption of NO gas led to the formation of nitrous oxide, mono- and dinitrosyl complexes of cerium, nitrogen dioxide and nitrate species. The adsorption of CO gas led to the formation of mono-, di- and tricarbonyl complexes of cerium and carbon dioxide and carbonate species. The types of NO and CO sites on the Ce-ZSM-5 catalyst are similar to those observed on copper exchanged catalysts, in particular Cu-SAPO-34 and Cu-ZSM-5.

Investigations of nitric oxide and carbon monoxide adsorption on the new generation cerium exchanged silico-aluminophosphate of type 18 catalyst

Novel rare earth exchanged silicoaluminophosphate catalysts (small pore, 0.43 nm) of chabazite type have been prepared. The rare earth elements europium (Eu), gadolinium (Gd) and terbium (Tb) were used for preparing the cation exchanged chabazite type SAPO-18 catalysts. Routine and sophisticated instrumental techniques were used for the material characterisation. The FT-IR technique was used to study the in situ interaction of NO on the rare earth exchanged SAPO-18 catalysts. The adsorption of NO on the Eu-, Gd-, Tb-exchanged SAPO-18 samples led to the formation of nitrous oxide, mono- and dinitrosyl complexes of Eu, Gd and Tb, nitrogen dioxide and nitrate species.

Chemical interactions between strontium-doped praseodymium manganite and 3 mol% yttria-zirconia

Abstract Cerium exchanged SAPO-18 material showed adsorptivity for NO and CO molecules. In situ adsorption of nitric oxide and carbon monoxide on cerium exchanged SAPO-18 materials was studied by FT-IR spectroscopy. The cerium exchanged SAPO-18 samples were prepared using the highly crystalline and pure H-SAPO-18 material. The SAPO-18 and cerium exchanged SAPO-18 materials were characterised by routine and sophisticated instrumental techniques. The presence of both Ce III and Ce IV species on the surface of the Ce-SAPO-18 catalyst were revealed by the XPS technique. The concentration of cerium is higher on the surface of the material than in the bulk. The interaction of NO with Ce-SAPO-18 material led to the formation of nitrous oxide, mono- and di-nitrosyl complexes of cerium, nitrogen dioxide and nitrate species. The formation of mono-, di- and tri- carbonyl complexes of cerium and carbon dioxide species were observed after the carbon monoxide adsorption on the Ce-SAPO-18.

Conveision of natural gas to electricity in fuel cells

The interfacial reaction between (Pr 0.8 Sr 0.2 ) y MnO 3 (PSM, y=0.9, 1.0, 1.05) film and 3 mol% yttria tetragonal zirconia (TZ3Y) substrate has been studied at 1200 and 1400°C in air. A diffusion layer of Pr and Mn in zirconia, which was identified to be a cubic phase of zirconia, was detected in all specimens. When the solubility limit of Pr ions in the cubic zirconia was reached, a pyrochlore phase, Pr 2 Zr 2 O 7 , was formed. A delay for the formation of pyrochlore phase was observed for the A-site sub-stoichiometric and stoichiometric PSM at 1200°C. For the A-site over-stoichiometric PSM, a Pr-rich (Pr,Zr)O x phase was detected at the interface besides the pyrochlore phase. At 1400°C, a relatively thick layer of pyrochlore phase was formed after 24 hour heat treatment in all specimens. The amount of the pyrochlore phase formed at the interface depends on the A-site stoichiometry of perovskite in the initial stage. The growth of the pyrochlore layer after the initial stage, however, appears to be determined by contact area between PSM and the substrate.

Activation of Methane under Mild Conditions

Publisher Summary The current discussions on atmospheric pollution and greenhouse warming have focused on the use of more environmentally friendly fuels and technologies for electricity generation, and natural gas may develop into the preferred fuel for power stations as pollutant output from gas fired power stations are substantially lower compared to coal fired ones. For example, particulate and SO x emissions are small and NO x emissions only in the range 150 ppm. Similarly, efficiencies of natural gas fired power systems are higher resulting in lower emissions of the greenhouse gas CO 2 . Central station power generation with a long distance distribution grid has further disadvantages such as (i) substantial losses during transmission resulting in decreased efficiencies at the user site and (ii) complex and difficult load demand management. Dispersed power generation at the user site overcomes these problems, but this option is severely limited with current generation technologies because of cost, size, and scaling constraints and pollution aspects. Fuel cells overcome these constraints and are low polluting. They are modular in construction and thus easy to scale, have high electric efficiencies—for some future advanced fuel cells, systems efficiencies up to 75% have been predicted—and they lower pollutant output by several magnitudes. Therefore, they are ideal for dispersed power generation and have the potential to revolutionize future electricity generation, but substantial development effort is still required to bring this technology to the market place.