Cobalt-Induced PdO Formation in Low-Loading Pd/BEA Catalysts for CH4 Oxidation

ACS Catalysis ◽  
2021 ◽  
pp. 13066-13076
Author(s):  
Junjie Chen ◽  
Kevin Giewont ◽  
Eric A. Walker ◽  
Jungkuk Lee ◽  
Yubiao Niu ◽  
...  
Keyword(s):  
Ch4 Oxidation

Optimized Landfill Biocover for CH4 Oxidation II: Implications of Spatially Heterogeneous Fluxes for Monitoring and Emission Prediction

2016 ◽  
Vol 3 (2) ◽  
pp. 94-106 ◽  
Author(s):  
Inga Ute-Röwer ◽  
Jan Streese-Kleeberg ◽  
Heijo Scharff ◽  
Eva-Maria Pfeiffer ◽  
Julia Gebert
Keyword(s):  
Ch4 Oxidation

scholarly journals Influence of CO on Dry CH4 Oxidation on Pd/Al2O3 by Operando Spectroscopy: A Multitechnique Modulated Excitation Study

ACS Catalysis ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 4791-4804
Author(s):  
Valentina Marchionni ◽  
Maarten Nachtegaal ◽  
Davide Ferri
Keyword(s):  
Ch4 Oxidation ◽  
Operando Spectroscopy

Characterization of plasma catalytic decomposition of methane: role of atomic O and reaction mechanism

2021 ◽  
Author(s):  
Yudong Li ◽  
Jingkai Jiang ◽  
Michael Hinshelwood ◽  
Shiqiang Zhang ◽  
Peter Bruggeman ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Gas Phase ◽  
Vibrational Frequency ◽  
Catalyst Surface ◽  
Atmospheric Pressure Plasma ◽  
Catalytic Decomposition ◽  
Fold Increase ◽  
Co2 Absorption ◽  
Ch4 Oxidation ◽  
Frequency Changes

Abstract In this work, we investigated atmospheric pressure plasma jet (APPJ)-assisted methane oxidation over a Ni-SiO2/Al2O3 catalyst. We evaluated possible reaction mechanisms by analyzing the correlation of gas phase, surface and plasma-produced species. Plasma feed gas compositions, plasma powers, and catalyst temperatures were varied to expand the experimental parameters. Real-time Fourier-transform infrared spectroscopy (FTIR) was applied to quantify gas phase species from the reactions. The reactive incident fluxes generated by plasma were measured by molecular beam mass spectroscopy (MBMS) using an identical APPJ operating at the same conditions. A strong correlation of the quantified fluxes of plasma-produced atomic oxygen with that of CH4 consumption, and CO and CO2 formation implies that O atoms play an essential role in CH4 oxidation for the investigated conditions. With the integration of APPJ, the apparent activation energy was lowered and a synergistic effect of 30% was observed. We also performed in-situ diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) to analyze the catalyst surface. The surface analysis showed that surface CO abundance mirrored the surface coverage of CHn at 25 oC. This suggests that CHn adsorbed on the catalyst surface as an intermediate species that was subsequently transformed into surface CO. We observed very little surface CHn absorbance at 500 oC, while a ten-fold increase of surface CO and stronger CO2 absorption were seen. This indicates that for a nickel catalyst at 500 oC, the dissociation of CH4 to CHn may be the rate-determining step in the plasma-assisted CH4 oxidation for our conditions. We also found the CO vibrational frequency changes from 2143 cm-1 for gas phase CO to 2196 cm-1 for CO on a 25 oC catalyst surface, whereas the frequency of CO on a 500 oC catalyst was 2188 cm-1. The change in CO vibrational frequency may be related to the oxidation of the catalyst.

The effects of acid nitrogen and acid sulphur deposition on CH4 oxidation in a forest soil: a laboratory study

2001 ◽  
Vol 33 (12-13) ◽  
pp. 1695-1702 ◽  
Author(s):  
M.A Bradford ◽  
P Ineson ◽  
P.A Wookey ◽  
H.M Lappin-Scott
Keyword(s):  
Forest Soil ◽  
Laboratory Study ◽  
Ch4 Oxidation ◽  
Sulphur Deposition

Support effect on the catalytic performance of Au/Co3O4–CeO2 catalysts for CO and CH4 oxidation

2008 ◽  
Vol 139 (3) ◽  
pp. 174-179 ◽  
Author(s):  
L.F. Liotta ◽  
G. Di Carlo ◽  
A. Longo ◽  
G. Pantaleo ◽  
A.M. Venezia
Keyword(s):  
Catalytic Performance ◽  
Support Effect ◽  
Ch4 Oxidation

scholarly journals Biogeochemistry of manganese in ferruginous Lake Matano, Indonesia

2011 ◽  
Vol 8 (10) ◽  
pp. 2977-2991 ◽  
Author(s):  
C. Jones ◽  
S. A. Crowe ◽  
A. Sturm ◽  
K. L. Leslie ◽  
L. C. W. MacLean ◽  
...  
Keyword(s):  
Water Column ◽  
Transport Modeling ◽  
Ch4 Oxidation ◽  
X Ray ◽  
Lake Matano ◽  
Sinking Particles ◽  
Modern Analogue ◽  
Reaction Transport ◽  
Kinetics Of ◽  
Mn Oxides

Abstract. This study explores Mn biogeochemistry in a stratified, ferruginous lake, a modern analogue to ferruginous oceans. Intense Mn cycling occurs in the chemocline where Mn is recycled at least 15 times before sedimentation. The product of biologically catalyzed Mn oxidation in Lake Matano is birnessite. Although there is evidence for abiotic Mn reduction with Fe(II), Mn reduction likely occurs through a variety of pathways. The flux of Fe(II) is insufficient to balance the reduction of Mn at 125 m depth in the water column, and Mn reduction could be a significant contributor to CH4 oxidation. By combining results from synchrotron-based X-ray fluorescence and X-ray spectroscopy, extractions of sinking particles, and reaction transport modeling, we find the kinetics of Mn reduction in the lake's reducing waters are sufficiently rapid to preclude the deposition of Mn oxides from the water column to the sediments underlying ferruginous water. This has strong implications for the interpretation of the sedimentary Mn record.

scholarly journals Trace gas fluxes of CO<sub>2</sub>, CH<sub>4</sub> and N<sub>2</sub>O in a permanent grassland soil exposed to elevated CO<sub>2</sub> in the Giessen FACE study

2011 ◽  
Vol 11 (17) ◽  
pp. 9333-9342 ◽  
Author(s):  
M. Kaleem Abbasi ◽  
C. Müller
Keyword(s):  
Elevated Co2 ◽  
15N Tracer ◽  
Organic N ◽  
N2o Emissions ◽  
Ch4 Oxidation ◽  
N2o Production ◽  
N Application ◽  
Oxidation Rates ◽  
Controlled Conditions ◽  
N2o Fluxes

Abstract. Long-term field observations showed that N2O fluxes observed shortly after N application were not significantly affected by elevated CO2 in the Giessen Free Air Carbon dioxide Enrichment (FACE) study. To further investigate this unexpected result a 15N tracer study was carried out under controlled conditions where in parallel treatments either the NH4+ pool (15NH4NO3) or the NO3− pool (NH415NO3) was enriched with 15N. Fluxes of CO2, CH4, and N2O as well as the 15N enrichment of the N2O were measured. Denitrifying Enzyme Activity (DEA), total denitrification (N2 + N2O) and N2-to-N2O ratios were quantified in separate experiments. Over the 57 day incubation, N2O fluxes averaged 0.090 ng N2O-N g−1 h−1 under ambient and 0.083 ng N2O-N g−1 h−1 under elevated CO2 (not significantly different). The N2O production processes were identified by a two-source model. Results showed that N2O must have also been produced by a third source – possibly related to organic N transformation – which was stimulated by elevated CO2. Soil CO2 fluxes were approximately 20 % higher under elevated CO2 than soil from ambient but the differences were not significant. CH4 oxidation rates were on average −1.75 ng CH4-C g−1 h−1 in the elevated and −1.17 ng CH4-C g−1 h−1 in the ambient indicating that elevated CO2 increased the CH4 oxidation by 49 % compared to ambient CO2 under controlled conditions. N fertilization increased CH4 oxidation by 3-fold in both CO2 treatments. CO2 did not have any significant effect on DEA while total denitrification and N2-to-N2O ratios increased by 36 and 33 %, respectively. The results indicate that shortly after N application elevated CO2 must have stimulated both the N2O production and reduction to N2 to explain the increased N2-to-N2O ratio and at the same time explain the non-responsiveness of the N2O emissions. Thus, the observed variation of the CO2 effect on N2O emissions throughout the year is possibly governed by the dynamics of the N2O reductase activity.

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