Temperature‐compensated, differential tensimeter for measuring gas adsorption by low surface area solids

1982 ◽  
Vol 53 (7) ◽  
pp. 1061-1066 ◽  
Author(s):  
Isao Suzuki
Keyword(s):  
Surface Area ◽  
Gas Adsorption

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

Probing the performance of imide linked micro-porous polymers for enhanced CO2 gas adsorption applications

2021 ◽  
Author(s):  
Narendran Rajendran ◽  
Ali A. Husain ◽  
Saad Makhseed
Keyword(s):  
Surface Area ◽  
Gas Adsorption ◽  
Oxidative Polymerization ◽  
Porous Polymers ◽  
Bet Surface Area ◽  
Co2 Gas

Three new carbazole containing cross-linked polymers namely AH-Poly, TM-PDA-Poly and TMB-PDA-Poly were designed and successfully synthesized by an oxidative polymerization protocol. The prepared AH-Poly showed a specific BET surface area...

Hydrothermal Treatment of Coprecipitated YSZ Powders

2010 ◽  
Vol 660-661 ◽  
pp. 983-988 ◽  
Author(s):  
Alexander Rodrigo Arakaki ◽  
Walter Kenji Yoshito ◽  
Valter Ussui ◽  
Dolores Ribeiro Ricci Lazar
Keyword(s):  
Surface Area ◽  
Hydrothermal Treatment ◽  
Gas Adsorption ◽  
X Ray Diffraction ◽  
Electronic Microscopy ◽  
Immersion Method ◽  
Cubic Symmetry ◽  
X Ray ◽  
Granulometric Analysis ◽  
Symmetry Surface

Zirconia stabilized with 8.5 mol% yttria (YSZ) were synthesized by coprecipitation and resulting gels were hydrothermallly treated at 200°C and 220 PSI for 4, 8 and 16 hours. Products were oven dried at 70°C for 24 hours, isostatically pressed as pellets and sintered at 1500 °C for 1 hour. Powders were characterized for surface area with N2 gas adsorption, X-ray diffraction, laser diffraction granulometric analysis and scanning and transmission electronic microscopy. Density of ceramics was measured by an immersion method based on the Archimedes principle. Results showed that powders dried at 70°C are amorphous and after treatment has tetragonal/cubic symmetry. Surface area of powders presented a significant reduction after hydrothermal treatment. Ceramics prepared from hydrothermally treated powders have higher green density but sintered pellets are less dense when compared to that made with powders calcined at 800°C for 1 hour due to the agglomerate state of powders. Solvothermal treatment is a promising procedure to enhance density.

The Effect of Hydrothermal Treatment on Samaria and Gadolinia Doped Ceria Powders Synthesized by Coprecipitation

2010 ◽  
Vol 660-661 ◽  
pp. 959-964
Author(s):  
Alexander Rodrigo Arakaki ◽  
Walter Kenji Yoshito ◽  
Valter Ussui ◽  
Dolores Ribeiro Ricci Lazar
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Hydrothermal Treatment ◽  
Specific Surface Area ◽  
Gas Adsorption ◽  
Fluorite Structure ◽  
High Specific Surface Area ◽  
Powder Synthesis ◽  
Laser Scattering ◽  
The One

One of the main applications of ceria-based (CeO2) ceramics is the manufacturing of Intermediate Temperature Solid Oxide Fuel Cells electrolytes. In order to improve ionic conductivity and densification of these materials various powder synthesis routes have been studied. In this work powders with composition Ce0.8(SmGd)0.2O1.9 have been synthesized by coprecipitation and hydrothermal treatment. A concentrate of rare earths containing 90wt% of CeO2 and other containing 51% of Sm2O3 and 30% of Gd2O3, both prepared from monazite processing, were used as precursor materials. The powders were characterized by X-ray diffraction, scanning and transmission electron microscopy, agglomerate size distribution by laser scattering and specific surface area by gas adsorption. Ceramic sinterability was evaluated by dilatometry and density measurements by Archimedes method. High specific surface area powders (~100m2/g) and cubic fluorite structure were obtained after hydrothermal treatment around 200°C. Ceramic densification was improved when compared to the one prepared from powders calcined at 800°C.

Limited Accessibility to Surface Area Generated by Thermal Pretreatment of Electrodes Reduces Its Impact on Redox Flow Battery Performance

2021 ◽  
Author(s):  
Katharine Greco ◽  
Jude Bonesteel ◽  
Nicolas Chanut ◽  
Charles Wan ◽  
Yet- Ming Chiang ◽  
...  
Keyword(s):  
Pore Size ◽  
Surface Area ◽  
Gas Adsorption ◽  
Active Species ◽  
Model Material ◽  
Carbon Paper ◽  
Thermal Pretreatment ◽  
Flow Battery ◽  
Redox Species ◽  
Physical Surface

Thermal oxidation of carbon electrodes is a common approach to improving flow battery performance. Here, we investigate how thermal pretreatment increases electrode surface area and the effect this added surface area has on electrode performance. Specifically, we rigorously analyze the surface area of Freudenberg H23 carbon paper electrodes, a binder-free model material, by systematically varying pretreatment temperature (400, 450, and 500 °C) and time (0 to 24 h) and evaluating changes in the physical, chemical, and electrochemical properties of the electrodes. We compare physical surface area, measured by a combination of gas adsorption techniques, to surface area measured via electrochemical double layer capacitance. We find good agreement between the two at shorter treatment times (0-3 h); however, at longer treatment times (6-24 h), the surface area measured electrochemically is an underestimate of the physical surface area. Further, we use gas adsorption to measure a pore size distribution and find that the majority of pores are in the micropore range (< 2 nm), and ca. 60% of the added surface area are in the sub-nanometer (< 1 nm) pore size range. We postulate that the solvated radii and imperfect wetting of electrochemical species may hinder active species transport into these recessed regions, explaining the discrepancy between electrochemical and physical surface area. These results are supported with in situ flow cell testing, where single-electrolyte polarization measurements show little improvement with increasing surface area. Further, using a simple convection-reaction model to simulate electrode overpotential as a function of surface area, we find that increasing surface area improves the performance to a point, but the mass transport to and the catalytic activity of the reaction sites offer greater comparative impact. Ultimately, this work aims to inform the design of electrodes that offer maximal accessible surface area to redox species.

Limited Accessibility to Surface Area Generated by Thermal Pretreatment of Electrodes Reduces Its Impact on Redox Flow Battery Performance

2021 ◽  
Author(s):  
Katharine Greco ◽  
Jude Bonesteel ◽  
Nicolas Chanut ◽  
Charles Wan ◽  
Yet- Ming Chiang ◽  
...  
Keyword(s):  
Pore Size ◽  
Surface Area ◽  
Gas Adsorption ◽  
Active Species ◽  
Model Material ◽  
Carbon Paper ◽  
Thermal Pretreatment ◽  
Flow Battery ◽  
Redox Species ◽  
Physical Surface

Thermal oxidation of carbon electrodes is a common approach to improving flow battery performance. Here, we investigate how thermal pretreatment increases electrode surface area and the effect this added surface area has on electrode performance. Specifically, we rigorously analyze the surface area of Freudenberg H23 carbon paper electrodes, a binder-free model material, by systematically varying pretreatment temperature (400, 450, and 500 °C) and time (0 to 24 h) and evaluating changes in the physical, chemical, and electrochemical properties of the electrodes. We compare physical surface area, measured by a combination of gas adsorption techniques, to surface area measured via electrochemical double layer capacitance. We find good agreement between the two at shorter treatment times (0-3 h); however, at longer treatment times (6-24 h), the surface area measured electrochemically is an underestimate of the physical surface area. Further, we use gas adsorption to measure a pore size distribution and find that the majority of pores are in the micropore range (< 2 nm), and ca. 60% of the added surface area are in the sub-nanometer (< 1 nm) pore size range. We postulate that the solvated radii and imperfect wetting of electrochemical species may hinder active species transport into these recessed regions, explaining the discrepancy between electrochemical and physical surface area. These results are supported with in situ flow cell testing, where single-electrolyte polarization measurements show little improvement with increasing surface area. Further, using a simple convection-reaction model to simulate electrode overpotential as a function of surface area, we find that increasing surface area improves the performance to a point, but the mass transport to and the catalytic activity of the reaction sites offer greater comparative impact. Ultimately, this work aims to inform the design of electrodes that offer maximal accessible surface area to redox species.

Influence of Acid Treatment on the Loading and Release Behavior of Halloysite with 2-Mercaptobenzothiazole

2019 ◽  
Vol 19 (11) ◽  
pp. 7178-7184 ◽  
Author(s):  
Xuteng Xing ◽  
Jihui Wang ◽  
Qiushi Li ◽  
Wenbin Hu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Acid Treatment ◽  
Gas Adsorption ◽  
Treatment Time ◽  
Halloysite Nanotubes ◽  
Tubular Structure ◽  
Internal Diameter ◽  
Release Behavior

Halloysite nanotubes (HNTs) are natural clay minerals with a tubular structure. They have attracted considerable attention as a potential nanocontainer due to their abundance, biocompatibility and nontoxicity. In this study, HNTs were handled with H2SO4 at 70 °C. The morphology and structure of these acid-treated and original HNTs were investigated by scanning electron microscopy (SEM), energy dispersion spectrum (EDS), transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR), and their specific surface area was determined by automatic gas adsorption analyzer. The loading efficiency and release behavior of acid-treated HNTs for 2-Mercaptobenzothiazole (MBT) were investigated by UV-vis spectrophotometer. Results show that acid-treated HNTs retained their tubular structure, but their internal diameter expanded by 35–37 nm after 32 h of acid treatment. After 72 h of acid treatment, HNTs can be transferred into amorphous silica nanotubes. Moreover, the specific surface area of these HNTs samples initially increased with the increase in acid treatment time but then started to decrease after 32 h. The specific surface area of acid-treated HNTs at 32 h can reach 251.6 m2/g, which was much higher than that for untreated HNTs (55.3 m2/g). In addition, the loading capacity of acid-treated HNTs can reach 32.1% for HNTs-32, which is about three times higher than that of original HNTs. The acid treatment has slight effect on the release behavior.

Surface area and microstructure of microwave activated crumb rubber modifier and its influence on high temperature properties of crumb rubber modifier binders

2020 ◽  
Vol 10 (2) ◽  
pp. 272-277 ◽  
Author(s):  
Bo Li ◽  
Xuwei Zhu ◽  
Xingjun Zhang ◽  
Xiaolong Yang ◽  
Xiuli Su
Keyword(s):  
High Temperature ◽  
Surface Area ◽  
Gas Adsorption ◽  
Treatment Time ◽  
Particle Surface ◽  
Microwave Treatment ◽  
Crumb Rubber ◽  
Adsorption Method ◽  
Temperature Performance ◽  
Mechanism Of Interaction

Crumb rubber pretreatment by microwave before blending with an asphalt matrix can address and improve the modification problem of of crumb rubber modifier (CRM) asphalt plant. In this research, the surface area and microstructure of microwave activated CRM and high-temperature performance of CRM asphalt were investigated to characterize the mechanism of interaction between activated CRM blends added and base asphalt. The surface area and microstructure of CRM were measured by gas adsorption method and the scanning electron microscopy (SEM) respectively when CRM was activated using microwave treatment time (30 s, 60 s, 90 s, 120 s and 150 s). The complex shear modulus (G*) and the phase angle (δ) of the CRM asphalt were measured by Dynamic Shear Rheometer (DSR) test. The results indicated that microwave treatment produced more porous structure and agglomeration phenomenon than control one for a given activated time of CRM. The flocculent structure was the most obvious one and agglomeration phenomenon was the most significant one for the particle surface microwave activated 90 s. The δ decreased and G* increased as CRM blends activated time increased before a certain time using the same frequency of microwave treatment. The G*/sinδ of CRM blends was the maximum when CRM activated for 90 s using microwave treatment. Both surface area and microstructure of the CRM influenced the high-temperature performance of CRM binders.

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