Nanosize gold deposited on TiO2, by homogeneous deposition-precipitation (HDP) using urea as the ... more Nanosize gold deposited on TiO2, by homogeneous deposition-precipitation (HDP) using urea as the precipitation agent is an active/selective and reusable catalyst for the epoxidation of styrene (at 82 °C) by anhydrous t-butyl hydroperoxide (TBHP). The activity and epoxide selectivity of the Au/TiO2 catalyst in the epoxidation is increased with increasing the Au loading on the TiO2 support. The Au/TiO2 catalyst prepared by the deposition precipitation using sodium hydroxide as the precipitation agent (DP method) has much lower gold loading and also lower Au dispersion and consequently possesses lower epoxidation activity as compared to that prepared by the HDP method. The styrene oxide selectivity is not influenced very significantly by the catalyst preparation method or by the Au loading (except at the very low Au loading). In the Au/TiO2 catalysts prepared by both the methods, Au is found to exist in both the metallic (Au0) and cationic (Au3+) forms.
ABSTRACT The influence of promoters (Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Tm) on the catalytic ... more ABSTRACT The influence of promoters (Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Tm) on the catalytic performance of sol-gel prepared Ni/g-Al2O3 catalysts in CO2 reforming of methane was investigated. The catalysts investigated were characterised using the following techniques: synchrotron X-Ray diffraction, X-ray Photoemission Spectroscopy, a Temperature Programmed Reduction technique and N2 adsorption desorption isotherms. It was found that there was almost a linear relationship between catalyst activity and the extent to which nickel was reduced in the catalysts tested.
Langmuir : the ACS journal of surfaces and colloids, Jan 8, 2016
This work investigates the structure-activity properties of CuOx-decorated CeO2 nanocubes with a ... more This work investigates the structure-activity properties of CuOx-decorated CeO2 nanocubes with a meticulous scrutiny on the role of the CuOx/CeO2 nanointerface in the catalytic oxidation of diesel soot, a critical environmental problem all over the world. For this, a systematic characterization of the materials has been undertaken using transmission electron microscopy (TEM), transmission electron microscopy-energy-dispersive X-ray spectroscopy (TEM-EDS), high-angle annular dark-field-scanning transmission electron microscopy (HAADF-STEM), scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS), X-ray diffraction (XRD), Raman, N2 adsorption-desorption, and X-ray photoelectron spectroscopy (XPS) techniques. The TEM images show the formation of nanosized CeO2 cubes (∼25 nm) and CuOx nanoparticles (∼8.5 nm). The TEM-EDS elemental mapping images reveal the uniform decoration of CuOx nanoparticles on CeO2 nanocubes. The XPS and Raman studies show that the ...
... Tania R. van den Anckera, Suresh K. Bhargava*b, Fabian Mohrb, Stavroula Papadopoulosc, Colin... more ... Tania R. van den Anckera, Suresh K. Bhargava*b, Fabian Mohrb, Stavroula Papadopoulosc, Colin L. Rastond, Brian W. Skeltone ... 6, H. Schmidbaur, A. Grohmann and ME Olmos, in Gold, Progress in Chemistry, Biochemistry and Technology, ed. H. Schmidbaur, John Wiley & ...
ABSTRACT We present a facile and low temperature approach for the fabrication of flexible organic... more ABSTRACT We present a facile and low temperature approach for the fabrication of flexible organic electronic devices by growing high aspect ratio nanorod arrays of potassium 7,7,8,8-tetracyanoquinodimethane (KTCNQ), a crystalline organic semiconductor with charge transfer capabilities, on cotton threads interwoven within the three-dimensional (3-D) matrix of a cotton textile. We demonstrate the capability of this material in developing opto-electronic switches and gas sensors. The ability to grow KTCNQ nanorod arrays in a radial symmetry directly on textile as a versatile 3-D microtemplate can be extended to the synthesis of a variety of metal-organic charge transfer complexes onto different flexible substrates that can find applications in electronics, catalysis and sensing.
We developed a novel conductometric device with nanostructured gold (Au) sensitive layer which sh... more We developed a novel conductometric device with nanostructured gold (Au) sensitive layer which showed high-performance for elemental mercury (Hg(0)) vapor detection under simulated conditions that resemble harsh industrial environments. That is, the Hg(0) vapor sensing performance of the developed sensor was investigated under different operating temperatures (30-130 °C) and working conditions (i.e., humid) as well as in the presence of various interfering gas species, including ammonia (NH3), hydrogen sulfide (H2S), nitric oxide (NO), carbon mono-oxide (CO), carbon dioxide (CO2), sulfur dioxide (SO2), hydrogen (H2), methane (CH4), and volatile organic compounds (VOCs) such as ethylmercaptan (EM), acetaldehyde (MeCHO) and methyl ethyl ketone (MEK) among others. The results indicate that the introduction of Au nanostructures (referred to as nanospikes) on the sensor's surface enhanced the sensitivity toward Hg(0) vapor by up-to 450%. The newly developed sensor exhibited a limit of detection (LoD) (∼35 μg/m(3)), repeatability (∼94%), desorption efficiency (100%) and selectivity (∼93%) when exposed to different concentrations of Hg(0) vapor (0.5 to 9.1 mg/m(3)) and interfering gas species at a chosen operating temperature of 105 °C. Furthermore, the sensor was also found to show 91% average selectivity when exposed toward harsher industrial gases such as NO, CO, CO2, and SO2 along with same concentrations of Hg(0) vapor in similar operating conditions. In fact, this is the first time a conductometric sensor is shown to have high selectivity toward Hg(0) vapor even in the presence of H2S. Overall results indicate that the developed sensor has immense potential to be used as accurate online Hg(0) vapor monitoring technology within industrial processes.
An efficient and simple approach has been developed for the regio-selective synthesis of iodo-sub... more An efficient and simple approach has been developed for the regio-selective synthesis of iodo-substituted dihydrofurans from amine substituted alkynols. The resulting iodo-substituted dihydrofurans have been further diversified by C-C couplings and C-N coupling reactions to afford a diverse range of substituted dihydrofuran derivatives.
Novel cobalt (Co), copper (Cu) and zinc (Zn) exchanged chabazite related SAPO-18 solid acid catal... more Novel cobalt (Co), copper (Cu) and zinc (Zn) exchanged chabazite related SAPO-18 solid acid catalysts were prepared and characterised using techniques such as BET (nitrogen sorption), FTIR, ICP-OES, XPS and XRD. A detailed in situ FTIR investigation undertaken ...
Nanosize gold deposited on TiO2, by homogeneous deposition-precipitation (HDP) using urea as the ... more Nanosize gold deposited on TiO2, by homogeneous deposition-precipitation (HDP) using urea as the precipitation agent is an active/selective and reusable catalyst for the epoxidation of styrene (at 82 °C) by anhydrous t-butyl hydroperoxide (TBHP). The activity and epoxide selectivity of the Au/TiO2 catalyst in the epoxidation is increased with increasing the Au loading on the TiO2 support. The Au/TiO2 catalyst prepared by the deposition precipitation using sodium hydroxide as the precipitation agent (DP method) has much lower gold loading and also lower Au dispersion and consequently possesses lower epoxidation activity as compared to that prepared by the HDP method. The styrene oxide selectivity is not influenced very significantly by the catalyst preparation method or by the Au loading (except at the very low Au loading). In the Au/TiO2 catalysts prepared by both the methods, Au is found to exist in both the metallic (Au0) and cationic (Au3+) forms.
ABSTRACT The influence of promoters (Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Tm) on the catalytic ... more ABSTRACT The influence of promoters (Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Tm) on the catalytic performance of sol-gel prepared Ni/g-Al2O3 catalysts in CO2 reforming of methane was investigated. The catalysts investigated were characterised using the following techniques: synchrotron X-Ray diffraction, X-ray Photoemission Spectroscopy, a Temperature Programmed Reduction technique and N2 adsorption desorption isotherms. It was found that there was almost a linear relationship between catalyst activity and the extent to which nickel was reduced in the catalysts tested.
Langmuir : the ACS journal of surfaces and colloids, Jan 8, 2016
This work investigates the structure-activity properties of CuOx-decorated CeO2 nanocubes with a ... more This work investigates the structure-activity properties of CuOx-decorated CeO2 nanocubes with a meticulous scrutiny on the role of the CuOx/CeO2 nanointerface in the catalytic oxidation of diesel soot, a critical environmental problem all over the world. For this, a systematic characterization of the materials has been undertaken using transmission electron microscopy (TEM), transmission electron microscopy-energy-dispersive X-ray spectroscopy (TEM-EDS), high-angle annular dark-field-scanning transmission electron microscopy (HAADF-STEM), scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS), X-ray diffraction (XRD), Raman, N2 adsorption-desorption, and X-ray photoelectron spectroscopy (XPS) techniques. The TEM images show the formation of nanosized CeO2 cubes (∼25 nm) and CuOx nanoparticles (∼8.5 nm). The TEM-EDS elemental mapping images reveal the uniform decoration of CuOx nanoparticles on CeO2 nanocubes. The XPS and Raman studies show that the ...
... Tania R. van den Anckera, Suresh K. Bhargava*b, Fabian Mohrb, Stavroula Papadopoulosc, Colin... more ... Tania R. van den Anckera, Suresh K. Bhargava*b, Fabian Mohrb, Stavroula Papadopoulosc, Colin L. Rastond, Brian W. Skeltone ... 6, H. Schmidbaur, A. Grohmann and ME Olmos, in Gold, Progress in Chemistry, Biochemistry and Technology, ed. H. Schmidbaur, John Wiley & ...
ABSTRACT We present a facile and low temperature approach for the fabrication of flexible organic... more ABSTRACT We present a facile and low temperature approach for the fabrication of flexible organic electronic devices by growing high aspect ratio nanorod arrays of potassium 7,7,8,8-tetracyanoquinodimethane (KTCNQ), a crystalline organic semiconductor with charge transfer capabilities, on cotton threads interwoven within the three-dimensional (3-D) matrix of a cotton textile. We demonstrate the capability of this material in developing opto-electronic switches and gas sensors. The ability to grow KTCNQ nanorod arrays in a radial symmetry directly on textile as a versatile 3-D microtemplate can be extended to the synthesis of a variety of metal-organic charge transfer complexes onto different flexible substrates that can find applications in electronics, catalysis and sensing.
We developed a novel conductometric device with nanostructured gold (Au) sensitive layer which sh... more We developed a novel conductometric device with nanostructured gold (Au) sensitive layer which showed high-performance for elemental mercury (Hg(0)) vapor detection under simulated conditions that resemble harsh industrial environments. That is, the Hg(0) vapor sensing performance of the developed sensor was investigated under different operating temperatures (30-130 °C) and working conditions (i.e., humid) as well as in the presence of various interfering gas species, including ammonia (NH3), hydrogen sulfide (H2S), nitric oxide (NO), carbon mono-oxide (CO), carbon dioxide (CO2), sulfur dioxide (SO2), hydrogen (H2), methane (CH4), and volatile organic compounds (VOCs) such as ethylmercaptan (EM), acetaldehyde (MeCHO) and methyl ethyl ketone (MEK) among others. The results indicate that the introduction of Au nanostructures (referred to as nanospikes) on the sensor's surface enhanced the sensitivity toward Hg(0) vapor by up-to 450%. The newly developed sensor exhibited a limit of detection (LoD) (∼35 μg/m(3)), repeatability (∼94%), desorption efficiency (100%) and selectivity (∼93%) when exposed to different concentrations of Hg(0) vapor (0.5 to 9.1 mg/m(3)) and interfering gas species at a chosen operating temperature of 105 °C. Furthermore, the sensor was also found to show 91% average selectivity when exposed toward harsher industrial gases such as NO, CO, CO2, and SO2 along with same concentrations of Hg(0) vapor in similar operating conditions. In fact, this is the first time a conductometric sensor is shown to have high selectivity toward Hg(0) vapor even in the presence of H2S. Overall results indicate that the developed sensor has immense potential to be used as accurate online Hg(0) vapor monitoring technology within industrial processes.
An efficient and simple approach has been developed for the regio-selective synthesis of iodo-sub... more An efficient and simple approach has been developed for the regio-selective synthesis of iodo-substituted dihydrofurans from amine substituted alkynols. The resulting iodo-substituted dihydrofurans have been further diversified by C-C couplings and C-N coupling reactions to afford a diverse range of substituted dihydrofuran derivatives.
Novel cobalt (Co), copper (Cu) and zinc (Zn) exchanged chabazite related SAPO-18 solid acid catal... more Novel cobalt (Co), copper (Cu) and zinc (Zn) exchanged chabazite related SAPO-18 solid acid catalysts were prepared and characterised using techniques such as BET (nitrogen sorption), FTIR, ICP-OES, XPS and XRD. A detailed in situ FTIR investigation undertaken ...
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