Comparison of Nanocrystalline and Polycrystalline Oxide Supports for Catalytic Oxidation of Methane

1997 ◽  
Vol 497 ◽  
Author(s):  
Horst H. Hahn ◽  
Heiko Hesemann ◽  
William S. Epling ◽  
Gar B. Hoflund
Keyword(s):  
Catalytic Oxidation ◽  
Methane Oxidation ◽  
Weight Basis ◽  
Oxide Supports ◽  
Oxidation Of Methane ◽  
Better Than

ABSTRACTNanocrystalline and polycrystalline ZrO2, CeO2 and Mn3O4 without and with 5 wt% Pd have been tested for methane oxidation. The nanocrystalline catalysts perform better than the polycrystalline catalysts on a weight basis. Nanocrystalline (n)-CeO2 performs much better than n-ZrO2, and both perform much better than polycrystalline (P)-CeO2 and P-ZrO2. 5 wt% Pd/n-ZrO2 is the best catalyst tested, but 5 wt% Pd/n-CeO2 performs nearly as well. A 20 wt% Ag/p-ZrO2 and a 20 wt% Ag/n-ZrO2 catalyst were also tested. The Ag yields a significant improvement over the bare supports, but not as much so as Pd.

Study of Catalytic Methane Oxidation Over Pd Supported on Nanocrystalline CeO2: Effects of Calcination and Pd Loading

2001 ◽  
Vol 676 ◽  
Author(s):  
Seung H. Oh ◽  
Michael L. Everett ◽  
Gar B. Hoflund ◽  
Johannes Seydel ◽  
Horst W. Hahn
Keyword(s):  
Catalytic Oxidation ◽  
Methane Oxidation ◽  
Catalyst Activity ◽  
Pd Catalyst ◽  
Oxidation Of Methane ◽  
Heating And Cooling ◽  
Enhanced Activity ◽  
Nanocrystalline Ceria ◽  
Catalytic Methane Oxidation

ABSTRACTThe catalytic oxidation of methane was studied over palladium supported on nanocrystalline ceria. Three palladium weight loadings (1, 5, and 10 wt%) were tested after calcining at 500 °C, at 280 °C and after no calcination at all. For the 5 and 10 wt% loadings, the 280 °C-calcined and non-calcined catalysts exhibit enhanced activity after several heating and cooling cycles. Calcining these same catalysts at 500 °C results in a systematic decline in activity. For all pretreatments the 1 wt% Pd catalyst exhibits decreasing activity. For the 5 and 10 wt% Pd loadings, the non-calcined catalysts are more active than the 280 °C-calcined catalysts, which are more active than the 500 °C-calcined catalysts. For the 1 wt% Pd catalyst, the opposite is true. The catalyst activity improves as the Pd loading is increased.

scholarly journals Catalytic Oxidation of Methane

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 944
Author(s):  
Anil C. Banerjee
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Catalytic Oxidation ◽  
Energy Sources ◽  
Oxidation Of Methane

Methane (the major component of natural gas) is one of the main energy sources for gas-powered turbines for power generation, and transport vehicles [...]

scholarly journals Electron donation of non-oxide supports boosts O2 activation on nano-platinum catalysts

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tao Gan ◽  
Jingxiu Yang ◽  
David Morris ◽  
Xuefeng Chu ◽  
Peng Zhang ◽  
...  
Keyword(s):  
Catalytic Oxidation ◽  
Pt Nanoparticles ◽  
Catalytic Performance ◽  
Nitrogen Vacancy ◽  
Innovative Strategy ◽  
Oxide Supports ◽  
Heterogeneous Catalytic ◽  
Highly Active ◽  
Electron Sink ◽  
Nitrogen Vacancies

AbstractActivation of O2 is a critical step in heterogeneous catalytic oxidation. Here, the concept of increased electron donors induced by nitrogen vacancy is adopted to propose an efficient strategy to develop highly active and stable catalysts for molecular O2 activation. Carbon nitride with nitrogen vacancies is prepared to serve as a support as well as electron sink to construct a synergistic catalyst with Pt nanoparticles. Extensive characterizations combined with the first-principles calculations reveal that nitrogen vacancies with excess electrons could effectively stabilize metallic Pt nanoparticles by strong p-d coupling. The Pt atoms and the dangling carbon atoms surround the vacancy can synergistically donate electrons to the antibonding orbital of the adsorbed O2. This synergistic catalyst shows great enhancement of catalytic performance and durability in toluene oxidation. The introduction of electron-rich non-oxide substrate is an innovative strategy to develop active Pt-based oxidation catalysts, which could be conceivably extended to a variety of metal-based catalysts for catalytic oxidation.

scholarly journals Lanthanum modified Fe-ZSM-5 zeolites for selective methane oxidation with hydrogen peroxide

2021 ◽  
Author(s):  
Songmei Sun ◽  
Alexandra Barnes ◽  
Xiaoxiao Gong ◽  
Richard Lewis ◽  
Nicholas F. Dummer ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Methane Oxidation ◽  
Partial Oxidation ◽  
Partial Oxidation Of Methane ◽  
Ambient Conditions ◽  
Oxidation Of Methane

Selective partial oxidation of methane to methanol under ambient conditions is a great challenge in chemistry. Iron modified ZSM-5 catalysts are shown to be effective for this reaction using H2O2...

scholarly journals Unraveling reaction networks behind the catalytic oxidation of methane with H2O2 over a mixed-metal MIL-53(Al,Fe) MOF catalyst

2018 ◽  
Vol 9 (33) ◽  
pp. 6765-6773 ◽  
Author(s):  
Ágnes Szécsényi ◽  
Guanna Li ◽  
Jorge Gascon ◽  
Evgeny A. Pidko
Keyword(s):  
Dft Calculations ◽  
Catalytic Oxidation ◽  
Metal Organic Framework ◽  
Reaction Networks ◽  
Reaction Paths ◽  
Mixed Metal ◽  
Oxidation Of Methane ◽  
Metal Organic ◽  
Periodic Dft Calculations ◽  
Periodic Dft

Reaction paths underlying the catalytic oxidation of methane with H2O2 over an Fe containing MIL-53(Al) metal–organic framework were studied by periodic DFT calculations.

scholarly journals Subgroup Characteristics of Marine Methane-Oxidizing ANME-2 Archaea and Their Syntrophic Partners as Revealed by Integrated Multimodal Analytical Microscopy

2018 ◽  
Vol 84 (11) ◽  
Author(s):  
Shawn E. McGlynn ◽  
Grayson L. Chadwick ◽  
Ariel O'Neill ◽  
Mason Mackey ◽  
Andrea Thor ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Methane Oxidation ◽  
Three Dimensional ◽  
Fluorescence Labeling ◽  
Anaerobic Oxidation Of Methane ◽  
Methane Seep ◽  
Bacterial Populations ◽  
Symbiotic Associations ◽  
Iron Mineral ◽  
Oxidation Of Methane

ABSTRACTPhylogenetically diverse environmental ANME archaea and sulfate-reducing bacteria cooperatively catalyze the anaerobic oxidation of methane oxidation (AOM) in multicelled consortia within methane seep environments. To better understand these cells and their symbiotic associations, we applied a suite of electron microscopy approaches, including correlative fluorescencein situhybridization-electron microscopy (FISH-EM), transmission electron microscopy (TEM), and serial block face scanning electron microscopy (SBEM) three-dimensional (3D) reconstructions. FISH-EM of methane seep-derived consortia revealed phylogenetic variability in terms of cell morphology, ultrastructure, and storage granules. Representatives of the ANME-2b clade, but not other ANME-2 groups, contained polyphosphate-like granules, while some bacteria associated with ANME-2a/2c contained two distinct phases of iron mineral chains resembling magnetosomes. 3D segmentation of two ANME-2 consortium types revealed cellular volumes of ANME and their symbiotic partners that were larger than previous estimates based on light microscopy. Polyphosphate-like granule-containing ANME (tentatively termed ANME-2b) were larger than both ANME with no granules and partner bacteria. This cell type was observed with up to 4 granules per cell, and the volume of the cell was larger in proportion to the number of granules inside it, but the percentage of the cell occupied by these granules did not vary with granule number. These results illuminate distinctions between ANME-2 archaeal lineages and partnering bacterial populations that are apparently unified in their ability to perform anaerobic methane oxidation.IMPORTANCEMethane oxidation in anaerobic environments can be accomplished by a number of archaeal groups, some of which live in syntrophic relationships with bacteria in structured consortia. Little is known of the distinguishing characteristics of these groups. Here, we applied imaging approaches to better understand the properties of these cells. We found unexpected morphological, structural, and volume variability of these uncultured groups by correlating fluorescence labeling of cells with electron microscopy observables.

scholarly journals Anaerobic oxidation of methane in grassland soils used for cattle husbandry

2012 ◽  
Vol 9 (10) ◽  
pp. 3891-3899 ◽  
Author(s):  
A. Bannert ◽  
C. Bogen ◽  
J. Esperschütz ◽  
A. Koubová ◽  
F. Buegger ◽  
...  
Keyword(s):  
Methane Oxidation ◽  
Enrichment Culture ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
Incubation Experiment ◽  
Nutrient Source ◽  
Oxidation Activity ◽  
Oxidation Of Methane ◽  
Cattle Husbandry

Abstract. While the importance of anaerobic methane oxidation has been reported for marine ecosystems, the role of this process in soils is still questionable. Grasslands used as pastures for cattle overwintering show an increase in anaerobic soil micro-sites caused by animal treading and excrement deposition. Therefore, anaerobic potential methane oxidation activity of severely impacted soil from a cattle winter pasture was investigated in an incubation experiment under anaerobic conditions using 13C-labelled methane. We were able to detect a high microbial activity utilizing CH4 as nutrient source shown by the respiration of 13CO2. Measurements of possible terminal electron acceptors for anaerobic oxidation of methane were carried out. Soil sulfate concentrations were too low to explain the oxidation of the amount of methane added, but enough nitrate and iron(III) were detected. However, only nitrate was consumed during the experiment. 13C-PLFA analyses clearly showed the utilization of CH4 as nutrient source mainly by organisms harbouring 16:1ω7 PLFAs. These lipids were also found as most 13C-enriched fatty acids by Raghoebarsing et al. (2006) after addition of 13CH4 to an enrichment culture coupling denitrification of nitrate to anaerobic oxidation of methane. This might be an indication for anaerobic oxidation of methane by relatives of "Candidatus Methylomirabilis oxyfera" in the investigated grassland soil under the conditions of the incubation experiment.

scholarly journals Catalytic oxidation of methane over PdO in wire microcalorimetry

2013 ◽  
Vol 160 (1) ◽  
pp. 149-154 ◽  
Author(s):  
Taichang Zhang ◽  
Yuxuan Xin ◽  
Zhuyin Ren ◽  
Fei Qi ◽  
Chung K. Law
Keyword(s):  
Catalytic Oxidation ◽  
Oxidation Of Methane
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