scholarly journals Structure Sensitivity and Hydration Effects in Pt/TiO2 and Pt/TiO2–SiO2 Catalysts for NO and Propane Oxidation

2021 ◽  
Author(s):  
Sara Viéitez-Calo ◽  
David J. Morgan ◽  
Stan Golunski ◽  
Stuart H. Taylor ◽  
Martyn V. Twigg
Keyword(s):  
Pt Nanoparticles ◽  
Propane Oxidation ◽  
Ionic Form ◽  
Support Material ◽  
Surface Characterisation ◽  
Total Oxidation ◽  
Oxidation Activity ◽  
Support Materials ◽  
Pre Treatment ◽  
Composition Changes

AbstractThe NO and propane oxidation activities of a series of 1%Pt/TiO2–SiO2 catalysts show different underlying trends as the support composition changes. Surface characterisation of the catalysts indicates that the trend for NO conversion is consistent with the oxidation rate being dependent on the degree of metallic character of the Pt nanoparticles, rather than their morphology. Although a similar correlation is expected for the total oxidation of propane, it is masked by the effects of adventitious ions originating during manufacture of the support materials. When residual chloride is present in the support, most of the exposed Pt is stabilised in its low-activity ionic form; while support materials containing W or oxidised-S ions give rise to catalysts with much higher activity than expected from their measured Pt0 content. When a Cl-containing, but SiO2-free, TiO2 support material is pre-treated hydrothermally, the propane-oxidation activity of the resultant Pt/TiO2 catalyst is substantially improved, so that it matches the performance of highly-metallic Pt supported on TiO2 containing 16 wt% SiO2. The hydrothermal pre-treatment removes residual chloride from the support material, but it also leaves the catalyst in a hydrated state. We show that, by controlling the metallic content of Pt nanoparticles, understanding the promoting and inhibiting effects of adventitious ions, and optimising the degree of catalyst hydration, the activity of 1%Pt/TiO2–SiO2 catalysts can be made to exceed that of a benchmark 2%Pt/γ-Al2O3 formulation for both NO and propane oxidation.

Effects of Support Material and Sulfation on Propane Oxidation Activity over Platinum

1993 ◽  
Vol 144 (2) ◽  
pp. 484-494 ◽  
Author(s):  
C.P. Hubbard ◽  
K. Otto ◽  
H.S. Gandhi ◽  
K.Y.S. Ng
Keyword(s):  
Propane Oxidation ◽  
Support Material ◽  
Oxidation Activity

ChemInform Abstract: Effects of Support Material and Sulfation on Propane Oxidation Activity Over Platinum

ChemInform ◽  
2010 ◽  
Vol 25 (10) ◽  
pp. no-no
Author(s):  
C. P. HUBBARD ◽  
K. OTTO ◽  
H. S. GANDHI ◽  
K. Y. S. NG
Keyword(s):  
Propane Oxidation ◽  
Support Material ◽  
Oxidation Activity

Employing Exfoliated Graphite as Novel Support Material for Heterogeneous Model Catalysts

2019 ◽  
Author(s):  
Moritz Wolf ◽  
Nico Fischer ◽  
Michael Claeys
Keyword(s):  
Surface Area ◽  
Graphite Powder ◽  
Model Catalysts ◽  
Model Systems ◽  
Exfoliated Graphite ◽  
Support Material ◽  
Heterogeneous Model ◽  
Support Materials ◽  
Metal Support Interaction ◽  
Catalyst Systems

<p>The inert nature of graphitic samples allows for characterisation of rather isolated supported nanoparticles in model catalysts, as long as sufficiently large inter-particle distances are obtained. However, the low surface area of graphite and the little interaction with nanoparticles result in a challenging application of conventional preparation routes in practice. In the present study, a set of graphitic carbon materials was characterised in order to identify potential support materials for the preparation of model catalyst systems. Various sizes of well-defined Co<sub>3</sub>O<sub>4</sub> nanoparticles were synthesised separately and supported onto exfoliated graphite powder, that is graphite after solvent-assisted exfoliation <i>via</i> ultrasonication resulting in thinner flakes with increased specific surface area. The developed model catalysts are ideally suited for sintering studies of isolated nano-sized cobaltous particles as the graphitic support material does not provide distinct metal-support interaction. Furthermore, the differently sized cobaltous particles in the various model systems render possible studies on structural dependencies of activity, selectivity, and deactivation in cobalt oxide or cobalt catalysed reactions.</p>

scholarly journals Surface characterisation of PET modified using a p-DC or HIPIMS reactive sputter pre-treatment

2012 ◽  
Vol 44 (8) ◽  
pp. 1063-1067
Author(s):  
S. J. Hinder ◽  
M. Audronis ◽  
V. Bellido-Gonzalez ◽  
P. Mack ◽  
M. A. Baker
Keyword(s):  
Surface Characterisation ◽  
Pre Treatment

Theoretical exploration of novel catalyst support materials for fuel cell applications

2016 ◽  
Vol 4 (39) ◽  
pp. 15181-15188 ◽  
Author(s):  
Xin Xia ◽  
Jane L. R. Yates ◽  
Glenn Jones ◽  
Misbah Sarwar ◽  
Ian Harkness ◽  
...  
Keyword(s):  
Material Selection ◽  
Catalyst Support ◽  
Oxygen Adsorption ◽  
Oxygen Binding ◽  
Support Material ◽  
Support Materials ◽  
Wetting Ability ◽  
Orr Activity ◽  
Novel Catalyst ◽  
Ability Parameter

(Left) The atomic model of oxygen adsorption on the MX supported Pt overlayer film. (Right) Support material selection through the Pt wetting ability parameter δ and oxygen binding energy, ΔE*[O]. The dashed line corresponds to the wetting parameter δ0 of the unsupported Pt(111) surface. The red line denotes the apex of ORR activity.

Structural Characterization and CO Oxidation Activity of Nanostructured LaMnO3 Catalysts

2002 ◽  
Vol 55 (12) ◽  
pp. 757 ◽  
Author(s):  
Min Chen ◽  
Huai-Qing Huang ◽  
Xiao-Ming Zheng ◽  
Michael A. Morris
Keyword(s):  
Co Oxidation ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Total Oxidation ◽  
Oxidation Activity ◽  
Preparation Methods ◽  
Synthesis Conditions ◽  
Nanostructured Particles ◽  
Transmission Electron ◽  
Perovskite Type

Perovskite-type LaMnO3 catalysts were prepared by three different methods and tested for CO oxidation. The structural character of the catalysts was investigated by using powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). All three different preparation methods resulted in nanostructured particles forming in the LaMnO3 catalysts. The crystallite size was in the range of 20 to 80 nm depending on the synthesis conditions. It was possible to synthesize the smallest particle size and a pure phase of perovskite-type LaMnO3 oxide by using a sol–gel method. The results also indicated that the CO total oxidation activity was related to the size of LaMnO3 particle and the structure formed.

Optimisation of the hydrogen peroxide pre-treatment of titanium: surface characterisation and protein adsorption

2008 ◽  
Vol 19 (12) ◽  
pp. 1317-1326 ◽  
Author(s):  
M. E. Nagassa ◽  
A. E. Daw ◽  
W. G. Rowe ◽  
A. Carley ◽  
D. W. Thomas ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Protein Adsorption ◽  
Titanium Surface ◽  
Surface Characterisation ◽  
Pre Treatment

Batch experiment on H2S degradation by bacteria immobilised on activated carbons

2004 ◽  
Vol 50 (4) ◽  
pp. 299-308 ◽  
Author(s):  
R. Yan ◽  
Y.L. Ng ◽  
X.G. Chen ◽  
A.L. Geng ◽  
W.D. Gould ◽  
...  
Keyword(s):  
Activated Carbons ◽  
Enrichment Culture ◽  
Future Research ◽  
Support Material ◽  
Support Materials ◽  
Biological Treatments ◽  
Pore Blockage ◽  
The Media ◽  
Biofilm Development ◽  
Optimum Balance

Biological treatments of odorous compounds, as compared to chemical or physical technologies, are in general ecologically and environmentally favourable. However, there are some inefficiencies relative to the media used in biofiltration processes, such as the need for an adequate residence time; the limited lifetime, and pore blockage of media, which at present render the technology economically non-viable. The aim of the study is to develop novel active media to be used in performance-enhanced biofiltration processes, by achieving an optimum balance and combination of the media adsorption capacity with the biodegradation of H2S through the bacteria immobilised on the media. An enrichment culture was obtained from activated sludges in order to metabolise thiosulphate. Batch-wise experiments were conducted to optimise the bacteria immobilisation on activated carbon, so as to develop a novel “biocarbon”. Biofilm was mostly developed through culturing the bacteria with the presence of carbons in mineral media. SEM and BET tests of the carbon along with the culturing process were used to identify, respectively, the biofilm development and biocarbon porosity. Breakthrough tests evaluated the biocarbon performance with varying gas resistance time, inlet H2S concentration, and type of support materials. Fundamental issues were discussed, including type of support material, mode of bacteria immobilisation, pore blockages, and biodegradation kinetics, etc. This batch-wise study provides a basis for our future research on optimisation of the biofiltration process using a bio-trickling reactor.

scholarly journals Low temperature total oxidation of toluene by bimetallic Au–Ir catalysts

2017 ◽  
Vol 7 (13) ◽  
pp. 2886-2896 ◽  
Author(s):  
Laura Torrente-Murciano ◽  
Benjamín Solsona ◽  
Saïd Agouram ◽  
Rut Sanchis ◽  
José Manuel López ◽  
...  
Keyword(s):  
Low Temperature ◽  
Synergetic Effect ◽  
Total Oxidation ◽  
Intimate Contact ◽  
Oxidation Activity ◽  
Iridium Nanoparticles ◽  
Voc Oxidation

Intimate contact between gold and iridium nanoparticles supported on TiO2 provides a synergetic effect leading to low temperature VOC oxidation activity.

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