Showing papers in "Catalysis Communications in 2008"
TL;DR: In this article, it was shown that it is impossible and inappropriate to approximate the Langmuir-Hinshelwood kinetics to zero-order kinetics, and therefore, it is not possible to approximate it to zero order kinetics.
Abstract: The present study reports that it is impossible and inappropriate to approximate the Langmuir–Hinshelwood kinetics to zero order kinetics.
591 citations
TL;DR: In this article, a series of cerium modified MnOx/TiO2 catalysts were prepared by sol-gel method and used for low-temperature selective catalytic reduction (SCR) of NOx with ammonia.
Abstract: A series of cerium modified MnOx/TiO2 catalysts were prepared by sol–gel method and used for low-temperature selective catalytic reduction (SCR) of NOx with ammonia. The experimental results showed that NO conversion could be improved by doping Ce from 39% to 84% at 80 °C with a gas hourly space velocity (GHSV) of 40,000 h−1. This activity improvement may be contributed to the increase of chemisorbed oxygen and acidity after Ce doping. TPR results also verified that the redox property of Ce modified MnOx/TiO2 was enhanced at low-temperature.
538 citations
TL;DR: In this paper, samples of cerium supported on titania with different Ce loadings have been prepared by an impregnation method and tested for the selective catalytic reduction of NO by NH 3 in the presence of excess oxygen.
Abstract: Samples of cerium supported on titania with different Ce loadings have been prepared by an impregnation method and tested for the selective catalytic reduction of NO by NH 3 in the presence of excess oxygen. The catalysts with 5% Ce and above had high activity in the temperature range 275–400 °C at a space velocity of 50,000 h −1 . All the catalysts showed an excellent selectivity to N 2 and high tolerance to SO 2 and H 2 O under our test conditions.
296 citations
TL;DR: In this article, the production of 5-hydroxymethylfurfural (5-HMF) from glucose and fructose catalyzed by TiO2 and ZrO2 under microwave irradiation was studied.
Abstract: Production of 5-hydroxymethylfurfural (5-HMF) from glucose and fructose catalyzed by TiO2 and ZrO2 under microwave irradiation was studied. For the case of TiO2 used in the fructose reaction, 5-HMF yield was 38.1% for a fructose conversion of 83.6% for 5 min reaction time. A 5-HMF yield of 30.5% for a fructose conversion of 65% was obtained for 5 min reaction time in the presence of ZrO2. The ZrO2 was found to promote isomerization of glucose to fructose, in which the selectivity of fructose from glucose became higher than 60% for about 50% glucose conversion for a reaction time of 1 min. Under the conditions (5 ml of 2 wt% fructose solution, 0.05 g of TiO2, 200 °C, and 3 min), fructose conversion and HMF yields by microwave heating (73% and 35%, respectively) were higher than those by sand bath heating (27% and 12%, respectively).
246 citations
TL;DR: A new class of oxyhalide photocatalysts xBiOBr −(1−x)BiOI prepared by a soft chemical method were characterized by X-ray diffraction and UV-Vis diffuse reflectance spectra as discussed by the authors.
Abstract: A new class of oxyhalide photocatalysts xBiOBr–(1−x)BiOI prepared by a soft chemical method were characterized by X-ray diffraction and UV–Vis diffuse reflectance spectra. They are all visible-light-responsive materials with the bandgaps ranging from 1.92 to 2.91 eV. Methyl orange (MO) photocatalytic degradation experiments showed that BiOBr possessed a higher photocatalytic activity than P25 (TiO2) under UV illumination and iodine-modified BiOBr exhibited high photocatlytic activities under visible-light irradiation. The high photocatalytic activity is in close relation with the deep valance band edge position and the internal electric fields between [Bi2O2] slabs and halogen anionic slabs.
241 citations
TL;DR: In this article, the authors showed that the recombination of photogenerated charge carrier between the hybrid orbital of Bi6s and O2p (VB) to the empty W5d orbital is inhibited greatly in composite semiconductors.
Abstract: Bi2WO6 powders are synthesized through hydrothermal process and Co3O4/Bi2WO6 composites with p–n heterojunction structure are prepared by the impregnation method. Co3O4/Bi2WO6 composites are characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS), UV–Vis absorption spectrum, and photoluminescence spectrum. After Co3O4 is loaded, the ability of visible light absorption of Co3O4/Bi2WO6 composite is enhanced greatly. The PL intensity of Co3O4/Bi2WO6 composite is lower than that of pure Bi2WO6, which clearly indicates that the recombination of photogenerated charge carrier between the hybrid orbital of Bi6s and O2p (VB) to the empty W5d orbital is inhibited greatly in the composite semiconductors. The presence of Co3O4 leads to an increase in photocatalytic activity. The highest efficiency is observed when calcined at 300 °C with 0.2 wt% cobalt content. On the basis of the calculated energy band positions and PL spectra, the mechanism of enhanced photocatalytic activity has been discussed. In addition, the effects of H2O2 concentration and pH value on photocatalytic activity were also presented.
232 citations
TL;DR: In this paper, the photocatalytic activity of synthesized nanowires was evaluated with aqueous methanol solution, and the results indicated that the TiO 2 NWs treated at appropriate post-heat treatment temperature exhibited higher photocatalysttic H 2 evolution than that of starting TiO2 powder (Degussa P-25).
Abstract: TiO 2 nanowires (TiO 2 NWs) were synthesized through the one step hydrothermal process in 10 M NaOH (aq.) at 150 °C for 72 h followed by post-heat-treatment at 300–1000 °C for 2 h. SEM and XRD measurements revealed that as-synthesized TiO 2 NWs were transformed into TiO 2 (B) structure with maintaining 1D morphology at 300–400 °C and further transformed into anatase structure at 500–800 °C. At 900–1000 °C, they partly transformed into rod-shaped rutile structure. The photocatalytic activity of prepared samples was evaluated with photocatalytic H 2 evolution from aqueous methanol solution. The results indicated that the TiO 2 NWs treated at appropriate post-heat-treatment temperature exhibited higher photocatalytic H 2 evolution than that of starting TiO 2 powder (Degussa P-25).
206 citations
TL;DR: In this article, the active site of catalyst for the formation of 1,3-propanediol may be the Pt over WO3 supported on ZrO2.
Abstract: Glycerol hydrogenolysis was catalyzed by Pt/WO3/ZrO2 to give 1,3-propanediol (1,3-PD) in the yields up to 24%. The catalytic activities and the selectivity toward 1,3-PD were remarkably affected by the type of support, loaded noble metal (NM) and the preparation/impregnation procedure. Controlled experiments show that the active site of catalyst for the formation of 1,3-PD may be the Pt over WO3 supported on ZrO2.
201 citations
TL;DR: In this article, a series of polypyrrole-TiO2 nanocomposites with different PPy:TiO 2 ratios were prepared by "in situ"deposition oxidative polymerization of pyrrole hydrochloride using ferric chloride (FeCl3) as oxidant in the presence of ultra fine grade power of anatase TiO2 cooled in an ice bath.
Abstract: A series of polypyrrole–TiO2 (PPy–TiO2) nanocomposites with different PPy:TiO2 ratios were prepared by ‘in situ’deposition oxidative polymerization of pyrrole hydrochloride using ferric chloride (FeCl3) as oxidant in the presence of ultra fine grade power of anatase TiO2 cooled in an ice bath. The samples were characterized by means of TEM, XRD, XPS and UV–vis-diffuse reflectance spectroscope. Their photocatalytic activities were evaluated by photocatalytic degradation of methyl orange aqueous solution under sunlight. PPy–TiO2 nanocomposites show better photocatalytic activity than that of neat TiO2 nanoparticles, which is partly attributed to the sensitizing effect of polypyrrole.
189 citations
TL;DR: The catalytic conversion of glycerol to hydrogen by aqueous-phase reforming (APR) on several platinum based catalysts was studied in this paper, where the application of different pre-treatment conditions resulted in catalysts with metal particle sizes in a range of 1.6-3.2nm.
Abstract: The catalytic conversion of glycerol to hydrogen by aqueous-phase reforming (APR) on several platinum based catalysts was studied. Catalysts prepared from a variety of metal precursors, such as platinum ethanolamine, platinum(II)-nitrate, platinum sulfite and tetrammine platinum(II)-nitrate showed similar activities (glycerol conversion 45%) and also identical selectivity (85%) towards hydrogen. The application of different pre-treatment conditions resulted in catalysts with metal particle sizes in a range of 1.6–3.2 nm. In the catalytic reaction selectivity to hydrogen increased with increasing particle size from 78% to 95% while the conversion of glycerol remained nearly constant at 20%. Also, variation of support material from pure γ-alumina to a mixture of γ-, δ- and θ-phases (Puralox®) led to an increase in hydrogen production from 1.2 × 10−3 to 7.6 × 10−3 mol min−1 g cat - 1 . The use of crude glycerol as starting material was successful. However, due to impurities (e.g. NaCl) the rate of hydrogen production (7.6 × 10−3 mol min−1 g cat - 1 ) was lower than observed for pure glycerol (rmax = 3.3 × 10−3 mol min−1 g cat - 1 ) and decreased dramatically (1 × 10−3 mol min−1 g cat - 1 ) after about 4 h time on stream.
170 citations
TL;DR: In this article, fiber-like high-surface-area attapulgite (APT) clay was used as a support of CuO particles, and the textural and structural properties of the prepared CuO/APT catalysts were characterized by X-ray diffraction, scanning and transmission electron microscopy, N2 sorption analysis and Xray photoelectron spectroscopy.
Abstract: Fiber-like high-surface-area attapulgite (APT) clay was used as a support of CuO particles, and the textural and structural properties of the prepared CuO/APT catalysts were characterized by X-ray diffraction, scanning and transmission electron microscopy, N2 sorption analysis and X-ray photoelectron spectroscopy. The catalytic behavior of the prepared CuO/APT catalysts for low-temperature CO oxidation was investigated, indicating interesting catalytic activity that comparable to the previously reported metal oxide supported CuO catalysts. Due to the unique property and the feature of much low cost and easy availability, the use of APT clay renders a great promise to be the catalyst support for the applications in various catalytic reactions including the low-temperature CO oxidation.
Abstract: Flower-shaped CuO nanostructures consist of triangular-shaped leaves, having sharpened tips with the wider bases, have been grown by simple aqueous solution process. Detailed structural observations exhibited the nanocrystalline nature with monoclinic structure for the as-synthesized nanostructures. The photocatalytic activity of the nanostructures was evaluated by examine the degradation of methylene blue. The photocatalytic property of the as-grown structures was probably due to the recycling of Cu1+ ion under light on the CuO interface and large surface area of the flower-like moieties. The XANES studies revealed that properties of as-synthesized products are closer to that of CuO, rather than those of Cu metal and Cu2O.
TL;DR: The three-component one-pot synthesis of 2-amino-5-oxo-dihydropyrano[3,2-c ]chromene derivatives by condensing 4-hydroxycoumarin, aldehydes and alkylnitriles using a catalytic amount of H 6 P 2 W 18 O 62 ǫ 18 H 2 O in aqueous ethanol under heating conditions is reported in this article.
Abstract: The three-component one-pot synthesis of 2-amino-5-oxo-dihydropyrano[3,2- c ]chromene derivatives by condensing 4-hydroxycoumarin, aldehydes and alkylnitriles using a catalytic amount of H 6 P 2 W 18 O 62 · 18H 2 O in aqueous ethanol under heating conditions is reported.
TL;DR: Sulfonated cellulose and starch as new catalysts were prepared and applied for the Fridedlander synthesis of quinolines through a condensation reaction of a 2-aminoarylketone with an activated CH-acid such as cyclic or acyclic β-diketone or cyclic ketone compounds with high yields within several minutes under solvent-free conditions at 100°C as mentioned in this paper.
Abstract: Sulfonated cellulose and starch as new catalysts were prepared and applied for the Fridedlander synthesis of quinolines through a condensation reaction of a 2-aminoarylketone with an activated CH-acid such as cyclic or acyclic β-diketone or cyclic ketone compounds with high yields within several minutes under solvent-free conditions at 100 °C.
TL;DR: In this article, the effect of support and catalyst reduction temperature on the catalytic performance of ruthenium catalysts in the hydrogenolysis of glycerol was studied, which is attributed to two reasons: (1) the growth in Ru particle size caused by heating treatment; (2) the strong metal-support interaction (SMSI), which results in partially covering of Ru metal particles by Ti2O3 species.
Abstract: The effect of support and catalyst reduction temperature on the catalytic performance of ruthenium catalysts in the hydrogenolysis of glycerol was studied. The support material can influence the metal particle size and the reaction routes. The reaction activity decreases with increasing catalyst reduction temperature, which is attributed to two reasons: (1) the growth in Ru particle size caused by heating treatment; (2) the strong metal-support interaction (SMSI), which results in partially covering of Ru metal particles by Ti2O3 species. The covering phenomenon can influence the reaction routes of the hydrogenolysis reaction, and consequently influence the product selectivity.
TL;DR: In this paper, the preparation of 5-hydroymethylfurfural (HMF) by the dehydration of fructose in the presence of the Bronsted acidic ionic liquid, 3-allyl-1-(4-sulfobutyl)imidazolium trifluoromethanesulfonate, as well as its Lewis acid derivative, 3]-al.
Abstract: In this paper, preparations of 5-hydroymethylfurfural (HMF) by the dehydration of fructose in the presence of the Bronsted acidic ionic liquid, 3-allyl-1-(4-sulfobutyl)imidazolium trifluoromethanesulfonate, as well as its Lewis acid derivative, 3-allyl-1-(4-sulfurylchloride butyl)imidazolium trifluoromethanesulfonate, were investigated. It was concluded that the type of acidic ionic liquid used played a significant role in the reaction, and the Lewis acidic ionic liquid acts more effectively than its Bronsted acidic counterpart. By means of UV–visible spectroscopy, the acidities of both kinds of ionic liquids were characterized, together with an effort to correlate the relationship between acidity and activity. Moreover, it was demonstrated that when these acidic ionic liquids were immobilized on silica gel, they can be used as effective and reusable solid catalysts for the dehydration reaction of fructose to HMF, offering much better performances for the title reaction than sulfuric acid and sulfonylchloride modified silica gels in terms of activity and reusability.
TL;DR: In this paper, a 2.5-hydroxymethylfurfural is efficiently oxidized to 2,5-diformylfuran in 63-89% yield using Mn(III)-salen catalysts and sodium hypochlorite, in a pH 11.3 phosphate buffer-CH 2 Cl 2 biphase system at room temperature.
Abstract: 5-Hydroxymethylfurfural is efficiently oxidized to 2,5-diformylfuran in 63–89% yield using Mn(III)–salen catalysts and sodium hypochlorite, in a pH 11.3 phosphate buffer–CH 2 Cl 2 biphase system at room temperature.
TL;DR: A delaminated zeolite with Si/Al = 29, obtained by swelling and ultrasonication of a laminar precursor of Nu-6(2), has been examined as a solid acid catalyst for the liquid phase cyclodehydration of xylose to furfural at 170°C, using a water-toluene biphasic system.
Abstract: A delaminated zeolite with Si/Al = 29, obtained by swelling and ultrasonication of a laminar precursor of Nu-6(2), has been examined as a solid acid catalyst for the liquid phase cyclodehydration of xylose to furfural at 170 °C, using a water–toluene biphasic reactor system. The final material, with a specific surface area about seven times higher than that for proton-exchanged Nu-6(2), gave a reaction rate about two times higher than that for H-Nu-6(2), and could be recycled several times without loss of performance or Al leaching. The furfural yield after 4 h reaction was 47%, compared with 34% in the presence of an H-mordenite sample with Si/Al ∼ 6.
TL;DR: In this article, a series of gold/ironoxide catalysts for catalytic combustion of formaldehyde were prepared by co-precipitation, and the catalysts were stable and remained active in the presence of moisture and are good substitutes for the noble metals (Pt, Pd) catalysts.
Abstract: A series of gold/iron-oxide catalysts for catalytic combustion of formaldehyde were prepared by co-precipitation. The catalyst containing 7.10 wt% of gold exhibited the highest catalytic activity. On this cata:lyst, the catalytic combustion reaction of formaldehyde proceeded at considerable rates at 20 degrees C and complete burn-off of formaldehyde was achieved at 80 degrees C. The catalysts were stable and remained active in the presence of moisture and are good substitutes for the noble metals (Pt, Pd) catalysts. The structure of catalysts, the valence state of gold and the size of gold particles were investigated by X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy techniques. Gold atoms with fractional positive charge (Au delta+) were found to exist in the catalyst and play an important role in the catalytic activity. Interaction between active species and support also provided important contribution to the valence state of gold and the activity for the catalytic combustion of HCHO. (c) 2007 Elsevier B.V. All rights reserved.
TL;DR: Sodium selenate has been found to be an outstanding catalyst for the preparation of tetrahydrobenzo[b]pyran derivatives in aqueous media in very good yields and under entirely green and eco-friendly conditions as mentioned in this paper.
Abstract: Sodium selenate has been found to be an outstanding catalyst for the preparation of tetrahydrobenzo[b]pyran derivatives in aqueous media in very good yields and under entirely green and eco-friendly conditions.
TL;DR: Vanadium and nitrogen co-doped TiO2 nanocrystal (4-5nm) photocatalysts were prepared through direct nitridation of the controlled hydrolysis product of Tetrabutyl titanate in V (IV) ions solution.
Abstract: Vanadium and nitrogen co-doped TiO2 nanocrystal (4–5 nm) photocatalysts were prepared through direct nitridation of the controlled hydrolysis product of Tetrabutyl titanate in V (IV) ions solution. The catalysts were characterized by XRD, BET surface area, XPS, and UV–vis diffuse reflectance spectra. The co-doped TiO2 nanocrystal has a narrower band gap of 2.76 eV than V-doped TiO2 (2.91 eV) and N-doped TiO2 (2.92 eV). The co-doped TiO2 photocatalysts show enhanced photocatalytic activity for the degradation of methylene blue under visible light irradiation (λ > 420 nm) compared with V-doped TiO2 and N-doped TiO2.
TL;DR: Montmorillonite K-10 is an efficient, cost-effective and recyclable catalyst for a one-pot synthesis of quinoxaline derivatives in water at ambient temperature as discussed by the authors.
Abstract: Montmorillonite K-10 is an efficient, cost-effective and recyclable catalyst for a one-pot synthesis of quinoxaline derivatives in water at ambient temperature. This procedure presented is operationally simple, practical and green.
TL;DR: A coprecipitation method has been applied successfully for the preparation of 0.5% palladium supported on MOF-5 as mentioned in this paper, which shows that the palladium is not located inside the micropores but probably bonds to the outer surface of the crystals.
Abstract: A coprecipitation method has been applied successfully for the preparation of 0.5 wt.% palladium supported on MOF-5. The apparent surface area was roughly 900 m 2 /g, the specific micropore volume was 0.3 cm 3 /g, and the powder X-ray diffractograms showed good coincidence with the theoretical pattern of MOF-5. In the hydrogenation of ethyl cinnamate with molecular hydrogen the specific activity of palladium supported on MOF-5 was twice as high as that of a commercial Pd/C catalyst with the same Pd content. It was shown that “true” heterogeneous catalysis takes place, i.e. leached palladium does not contribute to the reaction. In repeated runs the palladium supported on MOF-5 did not show any loss in activity, but a complete loss of micro pore volume was observed. Thus, it can be assumed that the palladium is not located inside the micropores but probably bonds to the outer surface of the crystals.
TL;DR: In this article, a liquid-phase synthesis of biodiesel by transesterification of sunflower oil with methanol is carried out by using zirconia-supported isopoly and heteropoly tungstates (HPAs) as catalysts.
Abstract: The liquid-phase synthesis of biodiesel by transesterification of sunflower oil with methanol is carried out by using zirconia-supported isopoly and heteropoly tungstates (HPAs) as catalysts. The isopoly and heteropoly tungstate catalysts were prepared by suspending zirconium oxyhydroxide in water/methanol solution of ammonium metatungstate/silicotungstic acid, phosphotungstic acid (WO3/HPA loading, 15%) followed by drying and calcination at 750 °C. The catalysts were characterized by XRD, Raman spectroscopy, IR spectroscopy, NH3-TPD and FTIR pyridine adsorption spectroscopy. XRD results indicate that the presence of isopoly and heteropoly tungstates stabilizes ZrO2 in tetragonal phase. Raman and IR spectra of the catalysts show that tungstate species exist as zirconia-anchored octahedral mono-oxotungstate. The acidity measurements by NH3-TPD and FTIR pyridine adsorption spectroscopy show that zirconia-supported phosphotungstate has the highest total acidity and zirconia-supported isopoly tungstate has the highest Bronsted acidity. The zirconia-supported isopoly tungstate shows superior catalytic performance compared to zirconia-supported heteropoly tungstate catalysts. Under the reaction conditions of 200 °C and methanol/oil molar ratio 15, 15% WO3/ZrO2 calcined at 750 °C gave 97% conversion of oil. This catalyst also efficiently catalyzes methanolysis of other vegetable oils like mustard oil and sesame oil. The deactivated catalyst could be regenerated by calcination without appreciable loss in activity.
TL;DR: In this paper, metal doped TiO 2 catalyst sensitized with Ru II (2,2′-bipyridyl-4,4′-dicarboxylate) 2 -(NCS) 2 (N3 dye) is employed to photoreduce CO 2 with H 2 O under concentrated natural sunlight to fuels in an optical fiber photoreactor.
Abstract: Metal doped TiO 2 catalyst sensitized with Ru II (2,2′-bipyridyl-4,4′-dicarboxylate) 2 -(NCS) 2 (N3 dye) is employed to photoreduce CO 2 with H 2 O under concentrated natural sunlight to fuels in an optical-fiber photoreactor. Production rate of methane of 0.617 μmol/g-cat h is measured on N3-dye-Cu(0.5 wt%)-Fe(0.5 wt%)/TiO 2 coated on optical fiber in April 12, 2007 in Taipei, Taiwan with the average concentrated solar light intensity of 20 mW/cm 2 . Full absorption of visible light of N3-dye along with efficient charge transfer in N3 dye–TiO 2 system give rise to the superior photoreduction of the resulting dye adsorbed catalyst.
TL;DR: Bronsted acidic ionic liquid, 1-methylimidazolium triflouroacetate ([Hmim]TFA) catalyzed synthesis of 1,8-dioxo-octahydroxanthenes and 1-8-decahydroacridines in excellent yields and short period of times at 80°C.
Abstract: Bronsted acidic ionic liquid, 1-methylimidazolium triflouroacetate ([Hmim]TFA) catalyzed synthesis of 1,8-dioxo-octahydroxanthenes and 1,8-dioxo-decahydroacridines in excellent yields and short period of times at 80 °C. Anions effects of the ionic liquid on the reaction rate have been investigated. The ionic liquid was easily separated from the reaction mixture by water extraction and was recycled four times without any loss in activity.
TL;DR: In this paper, the effect of sulfate content and calcination temperature on the structure, acidity and catalytic activity of tin oxide was investigated, and the catalytic performance was evaluated on the esterification of acetic acid with amyl alcohol in the vapor phase between 150 and 250°C.
Abstract: The effect of sulfate content and calcination temperature on the structure, acidity and catalytic activity of tin oxide was investigated. Sulfated tin oxide samples were characterized by thermal analysis (DTA and TGA), powder X-ray diffraction (XRD) and N 2 adsorption at −196 °C. The surface acidity was measured by Potentiometric titration, DSC-TGA and FT-IR techniques. The catalytic performance was evaluated on the esterification of acetic acid with amyl alcohol in the vapor phase between 150 and 250 °C. XRD measurements show that the sulfating of SnO 2 tends to hinder the crystallization of SnO 2 and inhibits crystal growth. It was found that the surface acidity increases with the increase of thermal treatment up to 550 °C, while the further increase of calcination temperature beyond 750 °C leads to a decrease of acid sites and acid sites strength. The addition of sulfate to SnO 2 brings about an increase of the specific surface area, whereas the calcination temperature exhibits a reverse trend. The formation of amyl acetate increases with increase of surface acidities. Lewis and Bronsted acid sites appears to be needed for catalytic activity in amyl acetate formation, both are maximum when the sulfate content and calcination temperature are 30 wt.% and 550 °C, respectively.
TL;DR: A series of TiO 2 /ACF samples were prepared by sol-gel-adsorption method and were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and nitrogen adsorption.
Abstract: A series of TiO 2 /ACF samples were prepared by sol–gel-adsorption method and were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and nitrogen adsorption. SEM showed that calcined temperature had an important influence on final structure morphologies of TiO 2 films. XRD analysis implied that all samples presented anatase structure, carbon surfaces located under TiO 2 film could influence the crystalline degree of TiO 2 . Nitrogen adsorption measurement indicated that some pores located in activated carbon fiber (ACF) were covered by TiO 2 film. Photocatalytic degradations of methyl orange solution and acid fuchsine solution showed that dye compounds could be removed rapidly from water by TiO 2 /ACF samples because of dual functions: absorption of ACF and photocatalytic degradation of TiO 2 film, and there was a matched relation between pore diameter of immobilized sample and molecular size of dye compound.
TL;DR: Fe 3 O 4 -poly(3,4-ethylene-dioxythiophene) core-shell nanoparticles as heterogeneous Fenton catalysts were synthesized by acid etching-mediated chemical oxidation polymerization.
Abstract: Fe 3 O 4 –poly(3,4-ethylene-dioxythiophene) (PEDOT) core-shell nanoparticles as heterogeneous Fenton catalysts were synthesized by acid etching-mediated chemical oxidation polymerization. Compared with pristine Fe 3 O 4 nanoparticles or commercialized iron oxide nanopowder, Fe 3 O 4 –PEDOT core-shell nanoparticles demonstrated outstanding catalytic performance for the degradation of Reactive Black 5 (RB5) and Orange II. In the case of the degradation of RB5, Fe 3 O 4 –PEDOT core-shell nanoparticles had an approximately 2.5 times higher catalytic activity than commercialized Fe 3 O 4 nanopowder. In addition, the ultrathin PEDOT shell can suppress leaching of iron cation through coordination formation, facilitating the catalytic reaction in the confined region of the nanoparticle surface.
TL;DR: In this paper, Ru/Al2O3, Ru/C and Ru/ZrO2 were applied to the hydrogenolysis of glycerol to propanediol, and the effect of Re as an additive on the catalytic performance of Ru catalysts was examined.
Abstract: Ru/Al2O3, Ru/C and Ru/ZrO2 catalysts were applied to the hydrogenolysis of glycerol to propanediol, and the effect of Re as an additive on the catalytic performance of Ru catalysts was examined. The catalyst systems were characterized by N2 adsorption/desorption, XRD, TEM-EDX and XPS. The hydrogenolysis of glycerol was carried out under the conditions of 120–180 °C, 4–10 MPa hydrogen pressure and 4–8 h, and the conversion of glycerol varied from 18.7% to 29.7% over Ru/Al2O3, Ru/C and Ru/ZrO2 catalysts. The reaction results indicate that Re possesses high promoting effect on the catalytic performance of Ru catalysts in glycerol hydrogenolysis.