Glycerol oxidation by fluorinated and platinized Titania

In this work, fluorinated and platinized TiO2 was evaluated in the glycerol oxidation. Fluorination led to increase the specific surface area of titania, and platinization treatment led to obtain the highest absorption in the visible region of the electromagnetic spectrum; thus, 0.5 wt.% Pt-F-TiO2 was the best catalyst in the obtention of highest yield and selectivity to glyceraldehyde (GAL). It was also found that 2wt.% of Pt content had a detrimental effect in the glycerol conversion. Fluorination and platinum addition led to modify the reaction mechanism and selectivity.

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Simultaneous deposition of Au nanoparticles during flame synthesis of TiO2 and SiO2

Journal of Materials Research ◽

10.1557/jmr.2003.0017 ◽

2003 ◽

Vol 18 (1) ◽

pp. 115-120 ◽

Cited By ~ 61

Author(s):

L. Mädler ◽

W. J. Stark ◽

S. E. Pratsinis

Keyword(s):

Metal Oxide ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Au Nanoparticles ◽

Visible Region ◽

Gold Deposits ◽

Absorption Bands ◽

Oxide Support ◽

Metal Oxide Support

Nanostructured gold/titania and gold/silica particles with up to 4 wt% Au were made by a single-step process in a spray flame reactor. Gold(III)-chloride hydrate and titania- or silica-based metalorganic precursors were mixed in a liquid fuel solution, keeping concentrations in the flame and overall combustion enthalpy constant. The powders were characterized by x-ray diffraction, transmission electron microscopy, Brunauer–Emmett–Teller, and ultraviolet–visible analysis. The titania or silica specific surface area and the crystalline structure of titania were not affected by the presence of gold in the flame. Furthermore the size of the gold deposits was independent of the metal oxide support (TiO2 or SiO2) and its specific surface area (100 and 320 m2/g, respectively). The gold nanoparticles were nonagglomerated, spherical, mostly single crystalline, and well dispersed on the metal oxide support. Depending on the Au weight fraction (1, 2, and 4 wt%) the Au nanoparticles' mass mean diameter was 3, 7, and 15 nm, respectively, on both titania and silica. The particles showed surface plasmon absorption bands in the ultraviolet–visible region, which is typical for nano-sized gold. This absorption band was red shifted in the case of the titania support, while no shift occurred with the silica support.

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Nanoscale Multidimensional Pd/TiO2/g-C3N4 Catalyst for Efficient Solar-Driven Photocatalytic Hydrogen Production

Catalysts ◽

10.3390/catal11010059 ◽

2021 ◽

Vol 11 (1) ◽

pp. 59

Author(s):

Ting-Han Lin ◽

Yin-Hsuan Chang ◽

Kuo-Ping Chiang ◽

Jer-Chyi Wang ◽

Ming-Chung Wu

Keyword(s):

Hydrogen Production ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Visible Region ◽

Green Energy ◽

Solar Irradiation ◽

Xenon Lamp ◽

Tio2 Nanofibers ◽

Photocatalytic Hydrogen Production

Solar-to-fuel conversion is an innovative concept for green energy, attracting many researchers to explore them. Solar-driven photocatalysts have become an essential solution to provide valuable chemicals like hydrogen, hydrocarbon, and ammonia. For sustainable stability under solar irradiation, titanium dioxide is regarded as an acceptable candidate, further showing excellent photocatalytic activity. Incorporating the photo-sensitizers, including noble metal nanoparticles and polymeric carbon-based material, can improve its photoresponse and facilitate the electron transfer and collection. In this study, we synthesized the graphitic carbon nitride (g-C3N4) nanosheet incorporated with high crystalline TiO2 nanofibers (NF) as 1D/2D heterostructure catalyst for photocatalytic water splitting. The microstructure, optical absorption, crystal structure, charge carrier dynamics, and specific surface area were characterized systematically. The low bandgap of 2D g-C3N4 nanosheets (NS) as a sensitizer improves the specific surface area and photo-response in the visible region as the incorporated amount increases. Because of the band structure difference between TiO2 and g-C3N4, constructing the heterojunction formation, the superior separation of electron-hole is observed. The detection of reactive oxygen species and photo-assisted Kelvin probe microscopy are conducted to investigates the possible charge migration. The highest photocatalytic hydrogen production rate of Pd/TiO2/g-C3N4 achieves 11.62 mmol·h−1·g−1 under xenon lamp irradiation.

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

International Journal of Photoenergy ◽

10.1155/2012/767905 ◽

2012 ◽

Vol 2012 ◽

pp. 1-7 ◽

Cited By ~ 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.

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Improvement of Biohydrogen and Usable Chemical Products from Glycerol by Co-Culture of Enterobacter spH1 and Citrobacter freundii H3 Using Different Supports as Surface Immobilization

Fermentation ◽

10.3390/fermentation7030154 ◽

2021 ◽

Vol 7 (3) ◽

pp. 154

Author(s):

Biniam T. Maru ◽

Francisco Lopez ◽

Francesc Medina ◽

Magda Constantí

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

H2 Production ◽

Dark Fermentation ◽

Biodiesel Production ◽

Citrobacter Freundii ◽

Surface Immobilization ◽

Iron Species ◽

Glycerol Conversion

Glycerol is a by-product of biodiesel production in a yield of about 10% (w/w). The present study aims to improve the dark fermentation of glycerol by surface immobilization of microorganisms on supports. Four different supports were used—maghemite (Fe2O3), activated carbon (AC), silica gel (SiO2), and alumina (γ-Al2O3)—on which a newly isolated co-culture of Enterobacter spH1 and Citrobacter freundii, H3, was immobilized. The effect of iron species on dark fermentation was also studied by impregnation on AC and SiO2. The fermentative metabolites were mainly ethanol, 1,3-propanediol, lactate, H2 and CO2. The production rate (Rmax,i) and product yield (Yi) were elucidated by modeling using the Gompertz equation for the batch dark fermentation kinetics (maximum product formation (Pmax,i): (i) For each of the supports, H2 production (mmol/L) and yield (mol H2/mol glycerol consumed) increased in the following order: FC < γ-Al2O3 < Fe2O3 < SiO2 < Fe/SiO2 < AC < Fe/AC. (ii) Ethanol production (mmol/L) increased in the following order: FC < Fe2O3 < γ-Al2O3 < SiO2 < Fe/SiO2 < Fe/AC < AC, and yield (mol EtOH/mol glycerol consumed) increased in the following order: FC < Fe2O3 < Fe/AC < Fe/SiO2 < SiO2 < AC < γ-Al2O3. (iii) 1,3-propanediol production (mmol/L) and yield (mol 1,3PDO/mol glycerol consumed) increased in the following order: γ-Al2O3 < SiO2 < Fe/SiO2 < AC < Fe2O3 < Fe/AC < FC. (iv) Lactate production(mmol/L) and yield (mol Lactate/mol glycerol consumed) increased in the following order: γ-Al2O3 < SiO2 < AC < Fe/SiO2 < Fe/AC < Fe2O3 < FC. The study shows that in all cases, glycerol conversion was higher when the support assisted culture was used. It is noted that glycerol conversion and H2 production were dependent on the specific surface area of the support. H2 production clearly increased with the Fe2O3, Al2O3, SiO2 and AC supports. H2 production on the iron-impregnated AC and SiO2 supports was higher than on the corresponding bare supports. These results indicate that the support enhances the productivity of H2, perhaps because of specific surface area attachment, biofilm formation of the microorganisms and activation of the hydrogenase enzyme by iron species.

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Samarium Promoted Ni/Al2O3 Catalysts for Syngas Production from Glycerol Pyrolys

BULLETIN OF CHEMICAL REACTION ENGINEERING AND CATALYSIS ◽

10.9767/bcrec.11.2.555.238-244 ◽

2016 ◽

Vol 11 (2) ◽

pp. 238 ◽

Cited By ~ 3

Author(s):

Mohd Nasir Nor Shahirah ◽

Bamidele V. Ayodele ◽

Jolius Gimbun ◽

Chin Kui Cheng

Keyword(s):

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Fixed Bed Reactor ◽

Ni Catalyst ◽

Impregnation Method ◽

Glycerol Conversion ◽

Product Ratio ◽

Syngas Production ◽

Bet Specific Surface Area

The current paper reports on the kinetics of glycerol reforming over the alumina-supported Ni catalyst that was promoted with rare earth elements. The catalysts were synthesized via wet impregnation method with formulations of 3 wt% Sm-20 wt% Ni/77 wt% Al2O3. The characterizations of all the as-synthesized catalysts were carried out, viz. BET specific surface area measurements, thermogravimetri analysis for temperature-programmed calcination studies, FESEM for surface imaging, XRD to obtain diffraction patterns, XRF for elemental analysis, etc.. Reaction studies were performed in a stainless steel fixed bed reactor with reaction temperatures set at 973, 1023 and 1073 K employing weight hourly space velocity (WHSV) of 4.5×104 mL g-1 h-1. Agilent GC with TCD capillary column was used to analyze gas compositions. Results gathered showed that the BET specific surface area was 2.09 m2.g-1 for the unpromoted Ni catalyst while for the promoted catalysts, was 2.68 m2.g-1. Significantly, the BET results were supported by the FESEM images which showed promoted catalysts exhibit smaller particle size compared to the unpromoted catalyst. It can be deduced that the promoter can increase metal dispersion on alumina support, hence decreasing the size of particles. The TGA analysis consistently showed four peaks which represent water removal at temperature 373-463 K, followed by decomposition of nickel nitrate to produce nickel oxide. From reaction results for Sm promotion showed glycerol conversion, XG of 27% which was 7% higher than unpromoted catalyst. The syngas productions were produced from glycerol decomposition and created H2:CO product ratio which always lower than 2.0. The H2:CO product ratio of 3 wt% Sm promoted Ni/Al2O3 catalyst was 1.70 at reaction temperature of 973 K and glycerol partial pressure of 18 kPa and suitable enough for Fischer-Tropsch synthesis. Copyright © 2016 BCREC GROUP. All rights reservedReceived: 22nd January 2016; Revised: 1st February 2016; Accepted: 17th February 2016How to Cite: Shahirah, M.N.N., Ayodele, B.V., Gimbun, J., Cheng, C.K. (2016). Samarium Promoted Ni/Al2O3 Catalysts for Syngas Production from Glycerol Pyrolysis. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (2): 238-244 (doi:10.9767/bcrec.11.2.555.238-244)Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.2.555.238-244

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