An In Situ Dealloying and Oxidation Route to Co3O4 Nanosheets and their Ambient-Temperature CO Oxidation Activity

ChemCatChem ◽  
2011 ◽  
Vol 3 (2) ◽  
pp. 399-407 ◽  
Author(s):  
Caixia Xu ◽  
Yunqing Liu ◽  
Ce Zhou ◽  
Lin Wang ◽  
Haoran Geng ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Co Oxidation ◽  
Oxidation Activity

scholarly journals Catalytic Behaviour of Flame-Made CuO-CeO2 Nanocatalysts in Efficient CO Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 256 ◽  
Author(s):  
Feng Zhao ◽  
Shuangde Li ◽  
Xiaofeng Wu ◽  
Renliang Yue ◽  
Weiman Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Water Vapor ◽  
Co Oxidation ◽  
Photoelectron Spectroscopy ◽  
Co Adsorption ◽  
Synergistic Interaction ◽  
Flame Spray ◽  
Oxidation Activity ◽  
X Ray

CuO-CeO2 nanocatalysts with varying CuO contents (1, 5, 9, 14 and 17 wt %) were prepared by one-step flame spray pyrolysis (FSP) and applied to CO oxidation. The influences of CuO content on the as-prepared catalysts were systematically characterized by X-ray diffraction (XRD), N2 adsorption-desorption at −196 °C, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and hydrogen-temperature programmed reduction (H2-TPR). A superior CO oxidation activity was observed for the 14 wt % CuO-CeO2 catalyst, with 90% CO conversion at 98 °C at space velocity (60,000 mL × g−1 × h−1), which was attributed to abundant surface defects (lattice distortion, Ce3+, and oxygen vacancies) and high reducibility supported by strong synergistic interaction. In addition, the catalyst also displayed excellent stability and resistance to water vapor. Significantly, in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS) showed that in the CO catalytic oxidation process, the strong synergistic interaction led readily to dehydroxylation and CO adsorption on Cu+ at low temperature. Furthermore, in the feed of water vapor, although there was an adverse effect on the access of CO adsorption, there was also a positive effect on the formation of fewer carbon intermediates. All these results showed the potential of highly active and water vapor-resistive CuO-CeO2 catalysts prepared by FSP.

CO oxidation activity of Pt, Zn and ZnPt nanocatalysts: a comparative study by in situ near-ambient pressure X-ray photoelectron spectroscopy

Nanoscale ◽  
2018 ◽  
Vol 10 (14) ◽  
pp. 6566-6580 ◽  
Author(s):  
Ahmed Naitabdi ◽  
Anthony Boucly ◽  
François Rochet ◽  
Robert Fagiewicz ◽  
Giorgia Olivieri ◽  
...  
Keyword(s):  
Comparative Study ◽  
Co Oxidation ◽  
Chemical Reactions ◽  
Photoelectron Spectroscopy ◽  
Ambient Pressure ◽  
Oxidation Activity ◽  
X Ray

NAP-XPS allows the monitoring of chemical reactions on nanocatalysts.

In situ spectroscopic investigation of a Pd local structure over Pd/CeO2 and Pd/MnOx–CeO2 during CO oxidation

2017 ◽  
Vol 5 (25) ◽  
pp. 12998-13008 ◽  
Author(s):  
Erdem Sasmaz ◽  
Chao Wang ◽  
Michael J. Lance ◽  
Jochen Lauterbach
Keyword(s):  
Fourier Transform ◽  
Co Oxidation ◽  
Local Structure ◽  
Diffuse Reflectance ◽  
Oxidation Activity ◽  
X Ray ◽  
Low Temperature Co Oxidation ◽  
Diffuse Reflectance Infrared ◽  
X Ray Absorption

In situ X-ray absorption fine structure (XAS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) experiments were performed to elucidate the effect of the Pd local structure on low temperature CO oxidation activity of Pd/CeO2 and Pd/MnOx–CeO2.

Active yet extremely durable Co3O4 spheroids of different texture without/with Au deposition for CO oxidation

2015 ◽  
Vol 5 (2) ◽  
pp. 1065-1075 ◽  
Author(s):  
Y. Yao ◽  
Q. Su ◽  
X. Z. Feng ◽  
B. Sun ◽  
W. J. Ji ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Oxidation Activity ◽  
Highly Active ◽  
Shell Type

Co3O4 spheroids of different texture without/with Au deposition were highly active yet very durable at 60–90 °C for CO oxidation. The calcined Co3O4-based catalysts and the yolk–shell type one were even more durable. The catalysts encountered obvious enhancement in CO oxidation activity via in situ pretreatment.

The solid-state in situ construction of Cu2O/CuO heterostructures with adjustable phase compositions to promote CO oxidation activity

CrystEngComm ◽  
2020 ◽  
Vol 22 (45) ◽  
pp. 7808-7815
Author(s):  
Baolin Liu ◽  
Yizhao Li ◽  
Kun Wang ◽  
Yali Cao
Keyword(s):  
Solid State ◽  
Co Oxidation ◽  
Oxidation Activity ◽  
Catalytic Activities ◽  
State Technology

Cu2O/CuO heterojunctions were fabricated via in situ solid-state technology. Tuning the ratio of reactants enables optimization of the components of the Cu2O/CuO heterostructures and their catalytic activities for CO oxidation.

Critical Influence of Redox Pretreatments on the CO Oxidation Activity of BaFeO3−δ Perovskites: An in-Depth Atomic-Scale Analysis by Aberration-Corrected and in Situ Diffraction Techniques

ACS Catalysis ◽  
2017 ◽  
Vol 7 (12) ◽  
pp. 8653-8663 ◽  
Author(s):  
Achraf el Hadri ◽  
Isabel Gómez-Recio ◽  
Eloy del Río ◽  
Juan C. Hernández-Garrido ◽  
Raquel Cortés-Gil ◽  
...  
Keyword(s):  
Co Oxidation ◽  
Atomic Scale ◽  
Scale Analysis ◽  
Oxidation Activity ◽  
In Situ Diffraction ◽  
Aberration Corrected

Effect of crystallite size on the performance and phase transformation of Co3O4/Al2O3 catalysts during CO-PrOx – an in situ study

2017 ◽  
Vol 197 ◽  
pp. 269-285 ◽  
Author(s):  
Thulani M. Nyathi ◽  
Nico Fischer ◽  
Andy P. E. York ◽  
Michael Claeys
Keyword(s):  
Co Oxidation ◽  
Crystallite Size ◽  
Surface Area ◽  
Oxidation Activity ◽  
Temperature Range ◽  
Reformate Gas ◽  
Crystallite Sizes ◽  
Average Size ◽  
Water Gas

The preferential oxidation of carbon monoxide has been identified as an effective route to remove trace amounts of CO (approx. 0.5–1.0 vol%) in the H2-rich reformate gas stream after the low-temperature water–gas shift. Instead of noble metal-based catalysts, Co3O4-based catalysts were investigated in this study as cheaper and more readily available alternatives. This study aimed at investigating the effect of crystallite size on the mass- and surface area-specific CO oxidation activity as well as on the reduction behaviour of Co3O4. Model Co3O4 catalysts with average crystallite sizes between 3 and 15 nm were synthesised using the reverse micelle technique. Results from the catalytic tests revealed that decreasing the size of the Co3O4 crystallites increased the mass-specific CO oxidation activity in the 50–200 °C temperature range. On the other hand, the surface area-specific CO oxidation activity displayed a volcano-type behaviour where crystallites with an average size of 8.5 nm were the most active within the same temperature range. In situ characterisation in the magnetometer revealed that the Co3O4 crystallites are partially reduced to metallic Co above 225 °C with crystallites larger than 7.5 nm showing higher degrees of reduction under the H2-rich environment of CO-PrOx. In situ PXRD experiments further showed the presence of CoO concurrently with metallic fcc Co in all the catalysts during the CO-PrOx runs. In all experiments, the formation of fcc Co coincided with the formation of CH4. Upon decreasing the reaction temperature below 250 °C under the reaction gas, both in situ techniques revealed that the fcc Co previously formed is partially re-oxidised to CoO.

In situ growth of small Au nanoparticles on ZnO nanorods via ultrasonic irradiation toward super-enhanced catalytic activity

RSC Advances ◽  
2016 ◽  
Vol 6 (109) ◽  
pp. 107433-107441 ◽  
Author(s):  
Xueling Song ◽  
Xiao Zhang ◽  
Ping Yang
Keyword(s):  
Catalytic Activity ◽  
Co Oxidation ◽  
Ultrasonic Irradiation ◽  
Photocatalytic Performance ◽  
Au Nanoparticles ◽  
Zno Nanorods ◽  
Sonochemical Method ◽  
In Situ Growth ◽  
Oxidation Activity

Au/ZnO NRs created via a sonochemical method exhibit superior photocatalytic performance and enhanced CO oxidation activity.

SEM of non-coated hepatocellular cytoskeleton of perfused livers

1984 ◽  
Vol 42 ◽  
pp. 306-307
Author(s):  
S.W. French ◽  
N.C. Benson ◽  
C. Davis-Scibienski
Keyword(s):  
Ambient Temperature ◽  
Critical Point ◽  
Protease Inhibitors ◽  
Metal Deposition ◽  
Heat Damage ◽  
Detergent Extraction ◽  
Cytoskeletal Elements ◽  
Triton X ◽  
Excised Tissue

Previous SEM studies of liver cytoskeletal elements have encountered technical difficulties such as variable metal coating and heat damage which occurs during metal deposition. The majority of studies involving evaluation of the cell cytoskeleton have been limited to cells which could be isolated, maintained in culture as a monolayer and thus easily extracted. Detergent extraction of excised tissue by immersion has often been unsatisfactory beyond the depth of several cells. These disadvantages have been avoided in the present study. Whole C3H mouse livers were perfused in situ with 0.5% Triton X-100 in a modified Jahn's buffer including protease inhibitors. Perfusion was continued for 1 to 2 hours at ambient temperature. The liver was then perfused with a 2% buffered gluteraldehyde solution. Liver samples including spontaneous tumors were then maintained in buffered gluteraldehyde for 2 hours. Samples were processed for SEM and TEM using the modified thicarbohydrazide procedure of Malich and Wilson, cryofractured, and critical point dried (CPD). Some samples were mechanically fractured after CPD.

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