Preparation and Pretreatment Effects on Co/SiO2 Catalysts for Fischer-Tropsch Synthesis

1994 ◽  
Vol 368 ◽  
Author(s):  
Kent E. Coulter ◽  
Allen G. Sault
Keyword(s):  
Surface Properties ◽  
Photoelectron Spectroscopy ◽  
Cobalt Catalysts ◽  
Volatile Components ◽  
Cobalt Metal ◽  
Nitrate Hexahydrate ◽  
Incipient Wetness Impregnation ◽  
Supported Metal Catalysts ◽  
Drying Procedures ◽  
Wide Range

ABSTRACTCatalyst drying procedures are often given little attention in the experimental section of papers on supported metal catalysts. In general, drying appears to be regarded as a method to remove water and other volatile components prior to calcining or reduction, but not as a method to affect the surface properties of the catalyst. This study uses x-ray photoelectron spectroscopy (XPS) to examine the surface properties of silica supported cobalt catalysts, prepared using incipient wetness impregnation of cobalt nitrate hexahydrate, and finds a wide range of cobalt distributions, extent of nitrate decomposition, and reducibility for various drying procedures. After UHV annealing and subsequent reduction, the final cobalt surface properties are found to depend on the length of heating and the environment during the drying process. Maximum cobalt metal surface area is obtained for samples exposed to limited amounts of air and dried under conditions where gas phase species generated during the precursor decomposition are rapidly removed from the surface of the sample.

scholarly journals Surface Properties of Halloysite-Carbon Nanocomposites and Their Application for Adsorption of Paracetamol

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5647
Author(s):  
Beata Szczepanik ◽  
Dariusz Banaś ◽  
Aldona Kubala-Kukuś ◽  
Karol Szary ◽  
Piotr Słomkiewicz ◽  
...  
Keyword(s):  
Surface Properties ◽  
Photoelectron Spectroscopy ◽  
Adsorption Model ◽  
Xps Spectra ◽  
Carbon Nanocomposites ◽  
Wide Range ◽  
Intra Particle Diffusion ◽  
Pseudo Second Order ◽  
Energy Survey ◽  
Photoelectron Peak

Analysis of surface properties of halloysite-carbon nanocomposites and non-modified halloysite was carried out with surface sensitive X-ray photoelectron spectroscopy (XPS) and inverse gas chromatography (IGC). The XPS spectra were measured in a wide range of the electron binding energy (survey spectra) and in the region of C 1s photoelectron peak (narrow scans). The IGC results show the changes of halloysite surface from basic for pure halloysite to acidic for carbon-halloysite nanocomposites. Halloysite-carbon nanocomposites were used as adsorbents of paracetamol from an aqueous solution. The adsorption mechanism was found to follow the pseudo-second-order and intra-particle diffusion models. The Langmuir multi-center adsorption model described well the obtained experimental data. The presence of carbon increased significantly the adsorption ability of halloysite-carbon nanocomposites for paracetamol in comparison to the non-modified halloysite.

Aromatic Volatile Composition of Celery and Celeriac Cultivars

HortScience ◽  
1990 ◽  
Vol 25 (5) ◽  
pp. 556-559 ◽  
Author(s):  
Fredy Van Wassenhove ◽  
Patrick Dirinck ◽  
Georges Vulsteke ◽  
Niceas Schamp
Keyword(s):  
Volatile Compounds ◽  
Chromatographic Method ◽  
Apium Graveolens ◽  
Volatile Components ◽  
Two Dimensional ◽  
Qualitative Composition ◽  
Volatile Composition ◽  
Wide Range ◽  
Gas Chromatographic Method ◽  
Identification And Quantification

A two-dimensional capillary gas chromatographic method was developed to separate and quantify aromatic volatiles of celery in one analysis. The isolation, identification, and quantification of the volatile compounds of four cultivars of blanching celery (Apium graveolens L. var. dulce) and six cultivars of celeriac (Apium graveolens L. var. rapaceum) are described. The qualitative composition of Likens-Nickerson extracts of both cultivars is similar. The concentration of terpenes and phthalides, the key volatile components, found in various cultivars of both celery and celeriac varied over a wide range.

scholarly journals Tunable Crystalline Phases in UV-Curable PEG-Grafted Ladder-Structured Silsesquioxane/Polyimide Composites

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2295 ◽  
Author(s):  
Ryung Il Kim ◽  
Ju Ho Shin ◽  
Jong Suk Lee ◽  
Jung-Hyun Lee ◽  
Albert S. Lee ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Surface Properties ◽  
Weight Ratio ◽  
Hybrid Polymer ◽  
Water Contact ◽  
Uv Curable ◽  
Wide Range ◽  
Drastic Increase ◽  
Polyimide Composites ◽  
Crystalline Polyethylene

A series of UV-curable hybrid composite blends containing a carboxylic acid functionalized polyimidewith varying amounts of high molecular weight (~1 K) PEG-grafted ladder-structured polysilsesquioxanes copolymerized with methacryl groups were fabricated and their structural, thermal, mechanical, and surface properties characterized. At a composite weight ratio of polyimide above 50 wt.%, a stark shift from amorphous to crystalline polyethylene glycol (PEG) phases were observed, accompanied by a drastic increase in both surface moduli and brittleness index. Moreover, fabricated composites were shown to have a wide range water contact angle, 9.8°–73.8°, attesting to the tunable surface properties of these amphiphilic hybrid polymer composites. The enhanced mechanical properties, combined with the utility of tunable surface hydrophilicity allows for the possible use of these hybrid polymer composites to be utilized as photosensitive polyimide negative photoresists for a myriad of semiconductor patterning processes.

scholarly journals Reactivity and Chemical Sintering of Carey Lea Silver Nanoparticles

Nanomaterials ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1525
Author(s):  
Sergey Vorobyev ◽  
Elena Vishnyakova ◽  
Maxim Likhatski ◽  
Alexander Romanchenko ◽  
Ivan Nemtsev ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Silver Nanoparticles ◽  
Flexible Electronics ◽  
Photoelectron Spectroscopy ◽  
Colloidal Solutions ◽  
Ag Nps ◽  
Wide Range ◽  
Carboxylic Groups ◽  
The Media ◽  
Sulfide Ions

Carey Lea silver hydrosol is a rare example of very concentrated colloidal solutions produced with citrate as only protective ligands, and prospective for a wide range of applications, whose properties have been insufficiently studied up to now. Herein, the reactivity of the immobilized silver nanoparticles toward oxidation, sulfidation, and sintering upon their interaction with hydrogen peroxide, sulfide ions, and chlorocomplexes of Au(III), Pd(II), and Pt(IV) was investigated using SEM and X-ray photoelectron spectroscopy (XPS). The reactions decreased the number of carboxylic groups of the citrate-derived capping and promoted coalescence of 7 nm Ag NPs into about 40 nm ones, excluding the interaction with hydrogen peroxide. The increased nanoparticles form loose submicrometer aggregates in the case of sulfide treatment, raspberry-like micrometer porous particles in the media containing Pd(II) chloride, and densely sintered particles in the reaction with inert H2PtCl6 complexes, probably via the formation of surface Ag-Pt alloys. The exposure of Ag NPs to HAuCl4 solution produced compact Ag films along with nanocrystals of Au metal and minor Ag and AgCl. The results are promising for chemical ambient temperature sintering and rendering silver-based nanomaterials, for example, for flexible electronics, catalysis, and other applications.

scholarly journals A Highly Sensitive Room Temperature CO2 Gas Sensor Based on SnO2-rGO Hybrid Composite

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 522
Author(s):  
Zhi Yan Lee ◽  
Huzein Fahmi bin Hawari ◽  
Gunawan Witjaksono bin Djaswadi ◽  
Kamarulzaman Kamarudin
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Gas Sensor ◽  
Photoelectron Spectroscopy ◽  
Hybrid Composite ◽  
Room Temperature ◽  
Co2 Gas ◽  
X Ray ◽  
Wide Range ◽  
Co2 Gas Sensor

A tin oxide (SnO2) and reduced graphene oxide (rGO) hybrid composite gas sensor for high-performance carbon dioxide (CO2) gas detection at room temperature was studied. Since it can be used independently from a heater, it emerges as a promising candidate for reducing the complexity of device circuitry, packaging size, and fabrication cost; furthermore, it favors integration into portable devices with a low energy density battery. In this study, SnO2-rGO was prepared via an in-situ chemical reduction route. Dedicated material characterization techniques including field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) were conducted. The gas sensor based on the synthesized hybrid composite was successfully tested over a wide range of carbon dioxide concentrations where it exhibited excellent response magnitudes, good linearity, and low detection limit. The synergistic effect can explain the obtained hybrid gas sensor’s prominent sensing properties between SnO2 and rGO that provide excellent charge transport capability and an abundance of sensing sites.

scholarly journals Improved H2 utilization by Pd doping in cobalt catalysts for reductive amination of polypropylene glycol

RSC Advances ◽  
2020 ◽  
Vol 10 (73) ◽  
pp. 45159-45169
Author(s):  
Kyungjun Kim ◽  
Dong Woo Kang ◽  
Youngheon Choi ◽  
Wanggyu Kim ◽  
Hyunjoo Lee ◽  
...  
Keyword(s):  
Cobalt Oxide ◽  
Reductive Amination ◽  
Cobalt Catalysts ◽  
Cobalt Metal ◽  
Polypropylene Glycol ◽  
Hydrogen Dissociation ◽  
Pd Doping ◽  
P Addition

Addition of Pd into Co helped remarkably to reduce cobalt oxide and nitride to cobalt metal by enhanced hydrogen dissociation and desorption.

Surface properties of ZrO2thin film under Cl2/Ar plasma using angle-resolved X-ray photoelectron spectroscopy

2014 ◽  
Vol 53 (8S3) ◽  
pp. 08NB05 ◽  
Author(s):  
Jong-Chang Woo ◽  
Chang-Auck Choi ◽  
Woo-Seok Yang ◽  
Yoon-Soo Chun ◽  
Chang-Il Kim
Keyword(s):  
Surface Properties ◽  
Photoelectron Spectroscopy ◽  
X Ray ◽  
Ar Plasma

Direct probing of the surface properties of alkali-treated aluminas by infrared and x-ray photoelectron spectroscopy

1981 ◽  
Vol 85 (10) ◽  
pp. 1406-1412 ◽  
Author(s):  
P. O. Scokart ◽  
A. Amin ◽  
C. Defosse ◽  
P. G. Rouxhet
Keyword(s):  
Surface Properties ◽  
Photoelectron Spectroscopy ◽  
X Ray

scholarly journals Application of fungal copper carbonate nanoparticles as environmental catalysts: organic dye degradation and chromate removal

Microbiology ◽  
2021 ◽  
Vol 167 (12) ◽  
Author(s):  
Feixue Liu ◽  
Dinesh Singh Shah ◽  
Laszlo Csetenyi ◽  
Geoffrey Michael Gadd
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Properties ◽  
Dye Degradation ◽  
Antibacterial Properties ◽  
Toxic Metal ◽  
Catalytic Efficiency ◽  
Methyl Red ◽  
Copper Carbonate ◽  
Wide Range ◽  
Organic Dye Degradation

Biomineralization is a ubiquitous process in organisms to produce biominerals, and a wide range of metallic nanoscale minerals can be produced as a consequence of the interactions of micro-organisms with metals and minerals. Copper-bearing nanoparticles produced by biomineralization mechanisms have a variety of applications due to their remarkable catalytic efficiency, antibacterial properties and low production cost. In this study, we demonstrate the biotechnological potential of copper carbonate nanoparticles (CuNPs) synthesized using a carbonate-enriched biomass-free ureolytic fungal spent culture supernatant. The efficiency of the CuNPs in pollutant remediation was investigated using a dye (methyl red) and a toxic metal oxyanion, chromate Cr(VI). The biogenic CuNPs exhibited excellent catalytic properties in a Fenton-like reaction to degrade methyl red, and efficiently removed Cr(VI) from solution due to both adsorption and reduction of Cr(VI). X-ray photoelectron spectroscopy (XPS) identified the oxidation of reducing Cu species of the CuNPs during the reaction with Cr(VI). This work shows that urease-positive fungi can play an important role not only in the biorecovery of metals through the production of insoluble nanoscale carbonates, but also provides novel and simple strategies for the preparation of sustainable nanomineral products with catalytic properties applicable to the bioremediation of organic and metallic pollutants, solely and in mixtures.

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