scholarly journals Highly Photoactive Titanium Dioxide Supported Platinum Catalyst: Synthesis Using Cleaner Ultrasound Approach

Catalysts ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 78
Author(s):  
Shital B. Potdar ◽  
Chao-Ming Huang ◽  
BVS Praveen ◽  
Sivakumar Manickam ◽  
Shirish H. Sonawane
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Surface Area ◽  
Noble Metals ◽  
Platinum Catalyst ◽  
Reaction Rates ◽  
Metal Catalysts ◽  
Size Analysis ◽  
Bet Analysis ◽  
Tio2 Support

Catalysts increase reaction rates; however, the surface area to volume ratio of catalysts has a vital role in catalytic activity. The noble metals such as platinum (Pt) and gold (Au) are expensive; despite this, they have proven their existence in catalysis, motivating the synthesis of supported metal catalysts. Metal catalysts need to be highly dispersed onto the support. In this investigation, an ultrasound approach has been attempted to synthesise highly photoactive titanium dioxide (TiO2) nanoparticles by the hydrolysis of titanium tetraisopropoxide in an acetone/methanol mixture. To enhance its photocatalytic activity, TiO2 was doped with Pt. The synthesised photocatalyst was characterised by techniques such as particle size analysis (PSA), XRD, FE-SEM, TEM, and EDX. The enhancement in the surface characteristics of Pt-doped TiO2 compared with bare TiO2 support was confirmed with Brunauer–Emmett–Teller (BET) analysis. The enhanced surface area and uniformity in particle size distribution at the nanoscale level were due to the effects of ultrasonic irradiation. The obtained results corroborated the size and composition of the synthesised catalysts. The size of the catalysts is in the nanometre range, and good dispersion of Pt catalysts over the TiO2 support was observed. The UV-Visible spectroscopy analysis was performed to study the optical properties of the synthesised TiO2 and Pt/TiO2 photocatalysts. An increase in the absorbance was noted when Pt was added to TiO2, which is due to the decrease in the band gap energy.

Synthesis and Characterization of Titanium Dioxide Nanoparticles for Application in Enhanced Oil Recovery

2019 ◽  
Vol 391 ◽  
pp. 74-81 ◽  
Author(s):  
Hasnah Mohd Zaid ◽  
Hanan Fakhruldi ◽  
Foo Yoong Yow ◽  
Norzafirah Razali ◽  
Yaleeni Kanan Dasan
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Titanium Dioxide ◽  
Surface Area ◽  
Calcination Temperature ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Titanium Dioxide Nanoparticles ◽  
Average Particle ◽  
Bet Analysis

In this study, titanium dioxide nanoparticles were synthesized for possible application in enhanced oil recovery. Sol-gel method was employed with titanium (IV) isopropoxide as the precursor. The prepared materials were characterized using Powder X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), High-Resolution Transmission electron microscopy (HRTEM) and Brunauer–Emmet–Teller (BET) techniques. Reaction parameter such as calcination temperature was varied during the preparation to obtain the uniform TiO2 nanoparticles with the smallest particle size and high surface area. The results of study revealed that 400 °C is the optimum calcination temperature in preparing TiO2 nanoparticles producing the smallest crystallite and particle sizes. XRD results indicated that the nanoparticles have formed anatase phase at 400 °C and achieved low crystallite size of 7.27 nm with the smallest average particle size of 19.53 nm through FESEM and HRTEM observations. BET analysis had achieved the highest surface area 103.64 m2/g.

scholarly journals Combination of mesoporous titanium dioxide with MoS2 nanosheets for high photocatalytic activity

2017 ◽  
Vol 19 (2) ◽  
pp. 56-60 ◽  
Author(s):  
Loghman Karimi
Keyword(s):  
Electron Microscopy ◽  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Dye Degradation ◽  
Hydrothermal Process ◽  
Bet Analysis ◽  
Mesoporous Titanium Dioxide

Abstract This study presents a facile approach for the preparation of MoS2 nanosheet decorated by porous titanium dioxide with effective photocatalytic activity. Mesoporous titanium dioxide nanostructures first synthesized by a hydrothermal process using titanium (III) chloride and then the MoS2/TiO2 were prepared through mixing of MoS2 nanosheet with mesoporous titanium dioxide under ultrasonic irradiation. The synthesized nanocomposite was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), and Brunauer-Emmett-Teller (BET) analysis. The results showed that the nanocomposite has mesoporous structure with specific surface area of 176.4 m2/g and pore diameter of 20 nm. The as-prepared MoS2/TiO2 nanocomposites exhibited outstanding photocatalytic activity for dye degradation under sunlight irradiation, which could be attributed to synergistic effect between the molybdenum disulfide nanosheet and mesoporous titanium dioxide. The photocatalytic performance achieved is about 2.2 times higher than that of mesoporous TiO2 alone. It is believed that the extended light absorption ability and the large specific surface area of the 2D MoS2 nanosheets in the nanocomposite, leading to the enhanced photocatalytic degradation activity.

scholarly journals PHYSICOCHEMICAL PROPERTIES AND POZZOLANIC PERFORMANCE OF ULTRAFINE TREATED RICE HUSK ASH (UFTRHA) AS ADDITIVE IN CONCRETE

2018 ◽  
Vol 16 ◽  
Author(s):  
Siti Asmahani Saad ◽  
Nasir Shafiq ◽  
Maisarah Ali
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Rice Husk Ash ◽  
High Energy ◽  
Size Analysis ◽  
Pre Treatment

Rice husk ash (RHA) contains high amount of amorphous silica that is ubiquitous in the pozzolanic reaction of SCM in concrete. However, usage of conventional RHA is currently unfavourable in concrete industry due to its properties inconsistency. In this regard, improvement on the RHA properties by introduction of thermochemical pre-treatment prior to burning procedure is seen as an excellent way to reach the goal. In this paper, raw rice husk was pre-treated using 0.1N hydrochloric acid (HCl) and heated at 80oC. It was then mechanically activated by high energy planetary ball mill for 15 minutes at speed of 300rpmand ball-to-powder ratio (BPR) of 15:1. The chemical composition, mineralogical properties, particle size analysis, specific surface area as well as microstructure properties of ultrafine treated rice husk ash (UFTRHA) were determined accordingly. As for amorphous silica content of the optimum sample was recorded as 98.60% incinerated at 600oC with four hours of pre-treatment soaking duration. In terms of particle size and specific surface, it was also observed that, burning temperature of 600oC, pre-treated at four hours were recorded to produce finest size of UFTRHA where d(0.1), d(0.5) and d(0.9) were obtained as 1.416?m, 4.364 ?m and 14.043 ?m respectively. Largest specific surface area value was obtained at 219.58 m2/g with the similar pre-treatment conditions. Meanwhile, the strength activity of UFTRHA from the optimum pre-treatment process was measured by testing the compressive strength of mortars. The highest compression value obtained was 50.17MPa with 3% UFTRHA replacement at 28 days.

scholarly journals Unexpected reactivity related to support effects during xylose hydrogenation over ruthenium catalysts

2021 ◽  
Author(s):  
Léa Vilcocq ◽  
Ana Maria Paez ◽  
Victoria Freitas ◽  
Laurent Veyre ◽  
Pascal Fongarland ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Kinetic Constant ◽  
Reaction Rates ◽  
Ruthenium Catalysts ◽  
Side Reactions ◽  
Strong Impact ◽  
Reaction Products ◽  
Tio2 Support

Xylose is a major component of hemicelluloses. In this paper, its hydrogenation to xylitol in aqueous medium was investigated with two Ru/TiO2 catalysts prepared with two commercial TiO2 supports. A strong impact of support on catalytic performances was evidenced. Ru/TiO2-R led to fast and selective conversion of xylose (100 % conversion in 2 h at 120°C with 99 % selectivity) whereas Ru/TiO2-A gave a slower and much less selective transformation (58 % conversion in 4 h at 120°C with 17 % selectivity) with the formation of several by-products. Detailed characterization of catalysts with ICP, XRD, FTIR, TEM, H2 chemisorption, N2 porosimetry, TPR and acid-base titration were performed to elucidate the role of each support. TiO2-R has a small specific surface area with large ruthenium nanoparticles in weak interaction with TiO2 support and no acidity, whereas TiO2-A is a mesoporous material with a large specific surface area, mildly acidic, and bears small ruthenium particles in strong interaction with TiO2 support. The former was very active and selective for xylose hydrogenation to xylitol whereas the latter was less active and poorly selective. Moreover, careful analysis of reaction products also revealed that TiO2 anatase can catalyze undesired side-reactions such as xylose isomerisation to various pentoses, and therefore the corresponding unexpected polyols (arabitol, ribitol) were produced during xylose conversion by hydrogenation. In a first approach of the kinetics, a simplified kinetic model was built to compare quantitatively intrinsic reaction rates of both catalysts. The kinetic constant for hydrogenation was 20 times higher for Ru/TiO2-R at 120°C.

The influence of titanium dioxide (TiO2) nanoparticles on the structure, optical and dielectric properties of polyvinyl chloride (PVC)

2020 ◽  
Vol 34 (28) ◽  
pp. 2050310
Author(s):  
M. A. Ramazanov ◽  
A. M. Rahimli ◽  
F. V. Hajiyeva
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Dielectric Properties ◽  
Surface Area ◽  
Titanium Dioxide Nanoparticles ◽  
Inorganic Nanoparticles ◽  
Nanocomposite Films ◽  
Slight Reduction ◽  
Insulation Systems ◽  
Nanoparticle Content

The tendency to improve the properties of insulating materials by incorporating inorganic nanoparticles has become necessary in order to design new insulation systems. In this study, PVC/TiO2-based nanocomposites with different loadings (3, 5 and 10 wt.%) of TiO2 nanoparticles were prepared by the solution mixing method. The morphology of the prepared nanocomposites was studied by Atomic Force Microscope (AFM). Experimentally, it was found that as the concentration increases, the size of the surface structural elements and particle size increases. Photoluminescence (PL) analysis of samples shows improvement compared to the pristine polymer. Furthermore, PL intensity for nanocomposites increases depending on the concentration and saturation occurs at a certain amount of titanium dioxide nanoparticles. The increase in luminescence intensity till a certain nanoparticle content is due to the growth of the luminescent surface area. Further saturation is explained by the increase in particle size with no increase or a slight reduction in surface area. Dielectric properties of nanocomposites were studied. It was found that dielectric permittivity of the materials increases as the nanoparticle volume content increases and it reaches at its highest value for the nanocomposites with 3% nanoparticle content. The optical properties of the polymer and nanocomposite films were studied in the region 200 nm to 600 nm. It was found that the PVC/TiO2 nanocomposites showed enhancement in the absorbance intensities which was more significant for the nanocomposites with higher nanoparticle content compared to the pristine polymer. Furthermore, absorption spectra were used to calculate the optical bandgap of the prepared nanocomposite films and redshift observed in the calculated values of bandgap for nanocomposites. Consequently, it was proved that by incorporating TiO2 nanoparticles into the polymer matrix, the spectral region of the samples can be expanded resulting in broadened application of such systems in various fields of science and technology.

scholarly journals PHYSICOCHEMICAL PROPERTIES AND POZZOLANIC PERFORMANCE OF ULTRAFINE TREATED RICE HUSK ASH (UFTRHA) AS ADDITIVE IN CONCRETE

2018 ◽  
Vol 16 (6) ◽  
Author(s):  
Siti Asmahani Saad ◽  
Nasir Shafiq ◽  
Maisarah Ali
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Rice Husk Ash ◽  
High Energy ◽  
Size Analysis ◽  
Pre Treatment

Rice husk ash (RHA) contains high amount of amorphous silica that is ubiquitous in the pozzolanic reaction of SCM in concrete. However, usage of conventional RHA is currently unfavourable in concrete industry due to its properties inconsistency. In this regard, improvement on the RHA properties by introduction of thermochemical pre-treatment prior to burning procedure is seen as an excellent way to reach the goal. In this paper, raw rice husk was pre-treated using 0.1N hydrochloric acid (HCl) and heated at 80oC. It was then mechanically activated by high energy planetary ball mill for 15 minutes at speed of 300rpmand ball-to-powder ratio (BPR) of 15:1. The chemical composition, mineralogical properties, particle size analysis, specific surface area as well as microstructure properties of ultrafine treated rice husk ash (UFTRHA) were determined accordingly. As for amorphous silica content of the optimum sample was recorded as 98.60% incinerated at 600oC with four hours of pre-treatment soaking duration. In terms of particle size and specific surface, it was also observed that, burning temperature of 600oC, pre-treated at four hours were recorded to produce finest size of UFTRHA where d(0.1), d(0.5) and d(0.9) were obtained as 1.416?m, 4.364 ?m and 14.043 ?m respectively. Largest specific surface area value was obtained at 219.58 m2/g with the similar pre-treatment conditions. Meanwhile, the strength activity of UFTRHA from the optimum pre-treatment process was measured by testing the compressive strength of mortars. The highest compression value obtained was 50.17MPa with 3% UFTRHA replacement at 28 days.

scholarly journals Synthesis and Characterization of Mn–C–CodopedTiO2Nanoparticles and Photocatalytic Degradation of Methyl Orange Dye under Sunlight Irradiation

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Wei Xin ◽  
Duanwei Zhu ◽  
Guanglong Liu ◽  
Yumei Hua ◽  
Wenbing Zhou
Keyword(s):  
Particle Size ◽  
Methyl Orange ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Visible Region ◽  
High Specific Surface Area ◽  
Size Analysis ◽  
Manganese Acetate ◽  
Sunlight Irradiation

Novel visible-light-active Mn–C–TiO2nanoparticles were synthesized by modified sol-gel method based on the self-assembly technique using polyoxyethylenes orbitan monooleate (Tween 80) as template and carbon precursor and manganese acetate as manganese precursor. The samples were characterized by XRD, FTIR, UV-vis diffuse reflectance, XPS, and laser particle size analysis. The XRD results showed that Mn–C–TiO2sample exhibited anatase phase and no other crystal phase was identified. High specific surface area, small crystallite size, and small particle size distribution could be obtained by manganese and carbon codoped and Mn–C–TiO2exhibited greater red shift in absorption edge of samples in visible region than that of C–TiO2and pure TiO2. The photocatalytic activity of synthesized catalyst was evaluated by photocatalytic oxidation of methyl orange (MO) solution under the sunlight irradiation. The results showed that Mn–C–TiO2nanoparticles have higher activity than other samples under sunlight, which could be attributed to the high specific surface area, smaller particle size, and lower band gap energy.

Microstructural properties and pozzolanic activity of calcined kaolins as supplementary cementing materials

2012 ◽  
Vol 39 (12) ◽  
pp. 1274-1284 ◽  
Author(s):  
Erhan Güneyisi ◽  
Mehmet Gesoǧlu ◽  
Turan Özturan ◽  
Kasım Mermerdaş
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Thermo Gravimetric Analysis ◽  
Particle Size Analysis ◽  
Pozzolanic Activity ◽  
Area Measurement ◽  
Size Analysis ◽  
Gravimetric Analysis

In this study, the utilization of unprocessed kaolins calcined at various temperatures as supplementary cementing material was investigated experimentally. The current work deals with four kaolin deposits existing in the western region of Turkey that have not yet been investigated for this purpose. Thermal properties of the unprocessed kaolins were examined by means of differential thermal and thermo gravimetric analysis. After determination of the thermal behavior, pozzolanic activity indices of the kaolins were determined according to ASTM C311. Based on the pozzolanic activity test results, calcination temperatures were assigned for kaolins and the changes in the mineralogical composition and the formation of amorphous structures were examined by X-ray diffraction analysis. The changes in particle size and specific surface area of the calcined kaolin minerals were observed through, particle size analysis with laser diffractometer, Scanning electron microscopy image analysis, and Brunauer-Emmett-Teller specific surface area measurement. The results showed that a complete kaolinite to metakaolinite conversion was achieved by the calcination procedure adopted.

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