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The low surface area, high recombination rate of photogenerated charge carriers, narrow visible range activity, and difficulty in the separation from cleaned solutions limit the wide application of g-C3N4 as a photocatalyst. Herein, we have succeeded in developing a one-pot strategy to overcome the above-mentioned difficulties of g-C3N4. The broadening of the visible-light response range and inducing magnetic nature to g-C3N4 was succeeded by preparing a nanocomposite with Fe2O3 via a facile solvothermal method. The preparation method additionally imparted layer exfoliation of g-C3N4 as evident from the XRD patterns and TEM images. The strong interaction between the components is revealed from the XPS analysis. The broadened visible-light absorbance of Fe2O3/g-C3N4 with a Z-scheme photocatalytic degradation mechanism is well evident from the UV—Vis DRS analysis and PL measurement of the composite with terephthalic acid. The active species of photocatalysis were further investigated using scavenging studies in methylene blue degradation that revealed hydroxyl radicals and holes as the major contributors to the activity of Fe2O3/g-C3N4. [ABSTRACT FROM AUTHOR]

A completely green method is reported here for the preparation of ethyl cellulose submicrospherical capsules wrapped with graphene. Graphene preparation is done by the sonication-assisted graphite exfoliation with the use of ethyl cellulose in an ethanol medium. Edge functionalization of graphene with ethyl cellulose under solvothermal treatment, as suggested from the XRD patterns, can be the driving force for the graphene wrapping of ethyl cellulose capsules that are formed during the addition of excess water to the stable graphene dispersion. Material morphology and structure are analyzed using various characterization techniques, and the novel nanocomposite is effectively used in Cr (VI) removal from aqueous solution, where maximum adsorption is observed in acidic pH indicating the dominance of electrostatic adsorption. The equilibrium data fitted more to Langmuir isotherm than the Freundlich isotherm. [ABSTRACT FROM AUTHOR]

Highly porous ceria nanoflakes are prepared by a facile citric acid assisted sol–gel method. A Mn incorporated solid solution of CeO2 was also efficiently developed without disturbing the nanoflake morphology of pure CeO2. The formation of fluorite CeO2 with crystallite size ranging from 5–8 nm is evidently revealed from XRD analysis. The introduction of Mn to CeO2 resulted in the formation of smaller crystallites of CeO2 with reduced particle size and lattice parameters. SEM images displayed the flake like nature of CeO2 and Mn/CeO2 with meso and macro pores. TEM images confirm the pore size reduction of CeO2 with Mn doping which is already indicated from BET-BJH-surface area and pore-volume analysis. The presence of a large amount of oxygen vacancies in CeO2 upon Mn introduction is indicated from the drastic reduction in the peak intensities in the Raman spectrum. XPS results revealed that Ce exists in its +4 oxidation state whereas Mn exists in its +3 oxidation state, both of which are favorable for oxidation reactions. The catalytic performance of the prepared nanoflakes is investigated in the simultaneous oxidation of CO and C3H8. Mn incorporated CeO2 showed 100% oxidation of CO from 300 °C onwards and 84% hydrocarbon oxidation is observed even at a high gas flow rate of 500 ml/min at 400 °C over 0.5 g of the catalyst. [ABSTRACT FROM AUTHOR]

Catalysts with efficient dispersion, high activity, and minimum leaching of active component are evergreen areas of interest in the field of catalysis. Incorporation of active component on high surface area materials helps to attain uniform dispersion, increased activity and stability for the catalyst system. Mesoporous materials like SBA-15 are widely used as catalyst support because of its high surface area, thermal and hydrothermal stability, uniform hexagonal mesopores, etc. Here we have synthesized copper oxide modified SBA-15 catalysts with various weight percentages of copper metal and its activity towards the dehydrogenation of cyclohexanol was studied. The reaction was monitored on a continuous flow fixed bed gas phase reactor. Various parameters for the reaction were optimized. SBA-15 with less than 10% Cu content was observed to be the most effective catalyst. The catalysts were found to be competent for the reaction with efficient dispersion of the active component and minimum deactivation. [ABSTRACT FROM AUTHOR]

Herein, we report a facile and novel strategy for the synthesis of 3-dimensional holey graphene nanoarchitecture, which is appropriately functionalized with nitrogen and sulfur via hydrothermal-assisted chemical etching of graphene oxide using ammonium persulfate. The chemical functionalization of the material was proved from XPS and FTIR spectral analyses. Sulfur exists as sulfonic acid group, whereas nitrogen got doped into the graphene network as revealed from the XPS analysis. The 3-dimensional morphology as well as porous nature of the developed material was confirmed from SEM and TEM images, respectively. Raman spectral analysis indicated the defective nature of the holey graphene as expected. Both N doping and sulfonation could enhance the utility of holey graphene as a carbocatalyst when compared to graphene oxide or reduced graphene oxide. The prepared material showed high catalytic efficiency towards the selective oxidation of ethylbenzene to acetophenone. [ABSTRACT FROM AUTHOR]

Lithium silicate is one of the suitable heterogeneous catalysts for biodiesel production. The possibilities of large number of combinations of different reaction parameters make the optimization of biodiesel production process over various heterogeneous catalysts highly tedious, necessitating the development of alternate strategies for parameter optimization. Here, Box-Behnken design (BBD) coupled with response surface methodology (RSM) is employed to optimize the process parameters required for the production of biodiesel from waste cooking oil using lithium silicate as catalyst. Simple method of impregnation was performed for the material preparation and the catalyst was analyzed using different techniques. It was found that the activity is directly proportional to the basicity data obtained from temperature programmed desorption (TPD) of CO over various catalyst systems. The material exhibits macroporous morphology and the major crystalline phase of the most active catalyst was found to be LiSiO. The effects of different reaction parameters were studied and a biodiesel yield of 100% was obtained under the predicted optimum reaction conditions of methanol : oil molar ratio 15 : 1, catalyst amount 7 wt%, reaction temperature 55 °C and reaction time 2.5 h. The validation experiments showed a correlation coefficient of 0.95 between the predicted and experimental yield of biodiesel, which indicates the high significance of the model. The fuel properties of biodiesel obtained under the optimum conditions met the specifications as mentioned in ASTM D6751 and EN 14214 standards. Catalyst heterogeneity and low reaction temperature are the major attractions of the present biodiesel preparation strategy. [ABSTRACT FROM AUTHOR]

The photocatalytic activity of carbon and nitrogen co-doped sol gel TiO is tested using methyleneblue degradation and it is found that the activity drops sharply with increase in calcination temperature. The system calcined at 300 °C was found to be the most efficient in dye degradation and can be considered as a good candidate for the future photocatalytic applications. This highly active anion doped TiO is found to show amorphous nature. Elemental analysis reveals the co existence of C and N dopants, which may be responsible for the high efficiency of the catalyst. Visible absorbance is evident from the UV-VIS Diffuse Reflectance Spectra. The N adsorption desorption studies show the H1 hysteresis loops and a well defined mesoporous nature is observed for the catalytic systems prepared in the presence of urea. XPS analysis indicates the presence of Ti-C and Ti-N bonds which are responsible for the visible light activity of the photocatalysts. [ABSTRACT FROM AUTHOR]

The present work describes the immobilization of α-amylase over well ordered mesoporous molecular sieve SBA-15 with different pore diameters synthesized by post synthesis treatment (PST) hydrothermally after reaction at 40°C. The materials were characterized by N2 adsorption–desorption studies, small angle X-ray diffraction, scanning electron microscopy and high resolution transmission electron microscopy. Since α-amylase obtained from Bacillus subtilis has dimensions of 35 × 40 × 70 Å it is expected that the protein have access to the pore of SBA-15 (PST-120°C) with diameter 74 Å. The pore dimension is appropriate to prevent considerable leaching. The rate of adsorption of the enzyme on silica of various pore sizes revealed the influence of morphology, pore diameter, pore volume and pH. [ABSTRACT FROM AUTHOR]

The enzyme α-amylase was immobilized on montmorillonite K-10 via adsorption and covalent bonding. These two modes of attachment play a vital role in the leaching of enzyme. Covalent bonding retains most of the enzyme even at high loadings. The significance of temperature has also been established. Higher temperatures lead to severe leaching in case of adsorbed enzyme. Covalent linkage, being of higher strength, does not yield to enzyme leaching even at high temperatures. [ABSTRACT FROM AUTHOR]

Sol-gel method was used for the preparation of titania. A series of sulfated titania catalysts with different sulfate loadings were prepared and characterized by X-ray diffraction, FTIR, UV-VIS DRS, TGA, BET surface area and pore volume. The acidity of these systems was determined by TPD of ammonia. Sulfate ion impregnation decreases the crystallite size and stabilizes the anatase phase of TiO. Surface area was found to increase with the sulfate loading. FTIR results show strong bidentate bridge of sulfate species. The catalytic performance of TiO/SO for liquid phase benzylation of toluene was studied. It was found that the conversion increases with sulfate loading. [ABSTRACT FROM AUTHOR]

The liquid-phase Friedel-Crafts acylation of benzene using benzoyl chloride as benzoylating agent was carried out over a CuMnFeO(x = 0, 0.2, 0.4, 0.6, 0.8 and 1) type system. The catalytic activity has been correlated with surface acidity. [ABSTRACT FROM AUTHOR]

Vanadia impregnated iron-pillared montmorillonites with different weight percentages of vanadia have been prepared. Subsequent characterization by XRD, FT-IR, surface area and pore volume measurements was carried out. Acidity was determined by three independent techniques namely thermogravimetric desorption of 2,6-dimethylpyridine, spectrophotometric monitoring of adsorption of perylene and temperature-programmed desorption of ammonia. Conversion of cumene in the vapor phase has been performed as a test reaction of acidity. Aniline methylation was carried out to check the catalytic efficiency of the solids. [ABSTRACT FROM AUTHOR]

This paper discusses the benzylation of toluene with benzyl alcohol over iron promoted sulfated zirconia systems and the influence of the various reaction parameters on the catalytic activity and selectivity. Along with the benzylated product, benzyl ether, formed by the self-condensation of benzyl alcohol, was also obtained as a major side product. [ABSTRACT FROM AUTHOR]

Supported vanadia systems synthesized by the excess solvent technique were characterized by different analytical methods. The selective oxidation activity of the system was examined towards the decomposition of ethanol. [ABSTRACT FROM AUTHOR]

Kinetic parameters such as the activation energy (E) and Arrhenius frequency factor (A) for the N-methylation of aniline using methanol over Zn-Co ferrites have been calculated. The E value is found to be lower than the existing best alkylating systems such as γ-alumina and magnesium oxide. [ABSTRACT FROM AUTHOR]