In this paper, photocatalytic hydrogen production from aqueous methanol solution with metallized ... more In this paper, photocatalytic hydrogen production from aqueous methanol solution with metallized titanium dioxide by platinum and gold is reported. Scherer equation was used to calculate of mean crystallite sizes of bare and metallized TiO 2 via XRD data. The calculated mean crystallite sizes of bare TiO 2 are decreased on metallized it. The AFM images indicate that the shape of bare and metallized TiO 2 is spherical. The particle size was found to be ranging between 9 and 11 crystallite size. The band gap energy for bare TiO 2 , Pt(0.5%)/TiO 2 and Au(0.5%)/TiO 2 were calculated after applying the Kubelka-Munk transformation. The results show that there is a shifting from ultraviolet absorption to visible light absorption (red shift) and as a consequence a narrowing in band gap in was observed. The band gap of bare TiO 2 was reduced from 3.289 eV to 3.263eV for Pt(0.5%)/TiO 2 and to 3.246eV for Au(0.5%)/TiO 2. Photoirradiation of argon purged aqueous methanol solution gave hydrogen in the presence of platinum and gold-loaded nanosized titanium dioxide (Hombikat UV 100). The photocatalytic activity of dehydrogenation of aqueous methanol solution of bear and metallized TiO 2 was in the order Pt(0.5%)/TiO 2 <Au(0.5%)/TiO 2 while no H 2 evolved when using a bare TiO 2. These results depended significantly on the work function values of Pt (5.93 eV) and for Au (5.31 eV).
Highly crystalline anatase TiO2 nanoparticles with high BET surface area have been synthesized by... more Highly crystalline anatase TiO2 nanoparticles with high BET surface area have been synthesized by thermal hydrolysis of titanium(IV) bis(ammoniumlactato) dihydroxide aqueous solutions. The photocatalytic H2 production from aqueous citric acid (CA) solutions over Pt-loaded TiO2 has been investigated under different experimental conditions, that is, different CA concentration, temperature, light intensity, and pH of Pt/TiO2 suspension. For comparison, the photocatalytic dehydrogenation of triethanolamine (TEA) has also been investigated. The highest H2 production rates were obtained at pH 3 and 9 for CA and TEA, respectively. This behavior is readily explained by the adsorption characteristic of the employed reagent on the surface of the charged TiO2. The effect of the photocatalyst loading and the light intensity on the H2 production rate showed the same behavior in the case of CA and TEA evincing that these parameters are catalyst dependent. The apparent activation energies have been determined to be 13.5 ± 1.8 and 14.7 ± 1.6 kJ mol(-1) for CA and TEA, respectively, indicating the existence of an activation energy barrier in a photocatalytic process which can be attributed to the desorption of adsorbed products.
Abstract−Multiwall carbon nanotubes (MWCNTs) have been hydrothermally prepared using polyethylene... more Abstract−Multiwall carbon nanotubes (MWCNTs) have been hydrothermally prepared using polyethylene glycol as the carbon source. Herein, new MWCNTs composites with high adsorption capacity were prepared and applied as efficient adsorbents for adsorption of maxilon blue dye (GRL) from aqueous solution. The morphologies of the MWCNTs were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform-infrared (FT-IR) spectroscopy. The adsorption property of maxilon blue (GRL) from aqueous solution onto MWCNTs was studied as a function of mass dosage, pH of solution, initial dye concentration and temperature. The adsorption of GRL depends on the initial pH of the solution with maximum uptake occurring at about pH 10. The maximum adsorption capacity of prepared MWCNTs was 260.7mg/g. Langmuir, Freundlich and Temkin isotherms were applied to fit the experimental data. The Freundlich equilibrium isotherm fitted well the experimental data indicating the homogeneity of the adsorbent surface sites. Thermodynamics parameters were studied the changes in free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) during adsorption. It is noticeable that the adsorption of GRL dye onto MWCNTs was a spontaneous and endothermic process and indicates that the adsorption is favored at high temperature.
The photocatalytic production of molecular hydrogen (H2) from aqueous solutions of alkyl-alkanola... more The photocatalytic production of molecular hydrogen (H2) from aqueous solutions of alkyl-alkanolamines (triethanolamine (tri-EOA), diethanolamine (di-EOA), ethanolamine (EOA), ethylamine (EA) and ethanol over Pt-loaded commercial (Sachtleben Hombikat UV100) nanoparticle titanium dioxide photocatalysts was studied. These photocatalysts were characterized using X-ray diffraction, Brunauer-Emmett-Teller, field-emission scanning electron microscopy, atomic force microscopy and UV-vis diffuse reflectance spectroscopy techniques. Effect of pH and temperature on photocatalytic hydrogen production of alkyl-alkanolamines was investigated. It was found for all molecules under study that the amount of hydrogen produced at a constant illumination time is a function of pH and temperature. At all temperatures investigated the rate of hydrogen production at pH 9 followed the order tri-EOAethanolamine > di-EOA ≈ EOA > ethanol > EA. From the values of the photocatalytic rate constants at va...
In order to enhance the efficiency of water splitting by the TiO2 nanoprticles, Pt-modified TiO2 ... more In order to enhance the efficiency of water splitting by the TiO2 nanoprticles, Pt-modified TiO2 nanoparticles were prepared by the photodeposition method. TiO2 were synthesized by solvent free-hydrothermal reaction using TALH as the precursor. TiO2 nanoparticles exhibiting large surface area were synthesized by a hydrothermal treatment of a water soluble titanium(IV) bis(ammoniumlactato) dihydroxide (TALH) complex in presence of ammonium hydroxide[1]. The obtained powders were characterized by X-ray diffraction, scanning electron microscopy, diffuse reflectance spectroscopy, and nitrogen adsorption. The photocatalytic performances of the catalysts were measured by hydrogen generation from a mixture of water and citric acid (CA), water and triethanolamine (TEOA) under as pH-solution dependent LED/UVA light irradiation. The effects of reaction parameters, such as amount of Pt/TiO2, initial concentration of sacrificial agents (CA or TEOA), solution temperature, light intensity and the...
(8aS)-9-(6-(1-hydroxy-15-phenyl)hex-5-yn-1-yl)-8a-methyl-1,2,6b,7,8,8a,9,14,14a,14b-decahydronap... more (8aS)-9-(6-(1-hydroxy-15-phenyl)hex-5-yn-1-yl)-8a-methyl-1,2,6b,7,8,8a,9,14,14a,14b-decahydronaphto [2´,1´:4,5]indeno[1,2-b]indol-4-ol (7)
In this paper, photocatalytic hydrogen production from aqueous methanol solution with metallized ... more In this paper, photocatalytic hydrogen production from aqueous methanol solution with metallized titanium dioxide by platinum and gold is reported. Scherer equation was used to calculate of mean crystallite sizes of bare and metallized TiO 2 via XRD data. The calculated mean crystallite sizes of bare TiO 2 are decreased on metallized it. The AFM images indicate that the shape of bare and metallized TiO 2 is spherical. The particle size was found to be ranging between 9 and 11 crystallite size. The band gap energy for bare TiO 2 , Pt(0.5%)/TiO 2 and Au(0.5%)/TiO 2 were calculated after applying the Kubelka-Munk transformation. The results show that there is a shifting from ultraviolet absorption to visible light absorption (red shift) and as a consequence a narrowing in band gap in was observed. The band gap of bare TiO 2 was reduced from 3.289 eV to 3.263eV for Pt(0.5%)/TiO 2 and to 3.246eV for Au(0.5%)/TiO 2. Photoirradiation of argon purged aqueous methanol solution gave hydrogen in the presence of platinum and gold-loaded nanosized titanium dioxide (Hombikat UV 100). The photocatalytic activity of dehydrogenation of aqueous methanol solution of bear and metallized TiO 2 was in the order Pt(0.5%)/TiO 2 <Au(0.5%)/TiO 2 while no H 2 evolved when using a bare TiO 2. These results depended significantly on the work function values of Pt (5.93 eV) and for Au (5.31 eV).
Highly crystalline anatase TiO2 nanoparticles with high BET surface area have been synthesized by... more Highly crystalline anatase TiO2 nanoparticles with high BET surface area have been synthesized by thermal hydrolysis of titanium(IV) bis(ammoniumlactato) dihydroxide aqueous solutions. The photocatalytic H2 production from aqueous citric acid (CA) solutions over Pt-loaded TiO2 has been investigated under different experimental conditions, that is, different CA concentration, temperature, light intensity, and pH of Pt/TiO2 suspension. For comparison, the photocatalytic dehydrogenation of triethanolamine (TEA) has also been investigated. The highest H2 production rates were obtained at pH 3 and 9 for CA and TEA, respectively. This behavior is readily explained by the adsorption characteristic of the employed reagent on the surface of the charged TiO2. The effect of the photocatalyst loading and the light intensity on the H2 production rate showed the same behavior in the case of CA and TEA evincing that these parameters are catalyst dependent. The apparent activation energies have been determined to be 13.5 ± 1.8 and 14.7 ± 1.6 kJ mol(-1) for CA and TEA, respectively, indicating the existence of an activation energy barrier in a photocatalytic process which can be attributed to the desorption of adsorbed products.
Abstract−Multiwall carbon nanotubes (MWCNTs) have been hydrothermally prepared using polyethylene... more Abstract−Multiwall carbon nanotubes (MWCNTs) have been hydrothermally prepared using polyethylene glycol as the carbon source. Herein, new MWCNTs composites with high adsorption capacity were prepared and applied as efficient adsorbents for adsorption of maxilon blue dye (GRL) from aqueous solution. The morphologies of the MWCNTs were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform-infrared (FT-IR) spectroscopy. The adsorption property of maxilon blue (GRL) from aqueous solution onto MWCNTs was studied as a function of mass dosage, pH of solution, initial dye concentration and temperature. The adsorption of GRL depends on the initial pH of the solution with maximum uptake occurring at about pH 10. The maximum adsorption capacity of prepared MWCNTs was 260.7mg/g. Langmuir, Freundlich and Temkin isotherms were applied to fit the experimental data. The Freundlich equilibrium isotherm fitted well the experimental data indicating the homogeneity of the adsorbent surface sites. Thermodynamics parameters were studied the changes in free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) during adsorption. It is noticeable that the adsorption of GRL dye onto MWCNTs was a spontaneous and endothermic process and indicates that the adsorption is favored at high temperature.
The photocatalytic production of molecular hydrogen (H2) from aqueous solutions of alkyl-alkanola... more The photocatalytic production of molecular hydrogen (H2) from aqueous solutions of alkyl-alkanolamines (triethanolamine (tri-EOA), diethanolamine (di-EOA), ethanolamine (EOA), ethylamine (EA) and ethanol over Pt-loaded commercial (Sachtleben Hombikat UV100) nanoparticle titanium dioxide photocatalysts was studied. These photocatalysts were characterized using X-ray diffraction, Brunauer-Emmett-Teller, field-emission scanning electron microscopy, atomic force microscopy and UV-vis diffuse reflectance spectroscopy techniques. Effect of pH and temperature on photocatalytic hydrogen production of alkyl-alkanolamines was investigated. It was found for all molecules under study that the amount of hydrogen produced at a constant illumination time is a function of pH and temperature. At all temperatures investigated the rate of hydrogen production at pH 9 followed the order tri-EOAethanolamine > di-EOA ≈ EOA > ethanol > EA. From the values of the photocatalytic rate constants at va...
In order to enhance the efficiency of water splitting by the TiO2 nanoprticles, Pt-modified TiO2 ... more In order to enhance the efficiency of water splitting by the TiO2 nanoprticles, Pt-modified TiO2 nanoparticles were prepared by the photodeposition method. TiO2 were synthesized by solvent free-hydrothermal reaction using TALH as the precursor. TiO2 nanoparticles exhibiting large surface area were synthesized by a hydrothermal treatment of a water soluble titanium(IV) bis(ammoniumlactato) dihydroxide (TALH) complex in presence of ammonium hydroxide[1]. The obtained powders were characterized by X-ray diffraction, scanning electron microscopy, diffuse reflectance spectroscopy, and nitrogen adsorption. The photocatalytic performances of the catalysts were measured by hydrogen generation from a mixture of water and citric acid (CA), water and triethanolamine (TEOA) under as pH-solution dependent LED/UVA light irradiation. The effects of reaction parameters, such as amount of Pt/TiO2, initial concentration of sacrificial agents (CA or TEOA), solution temperature, light intensity and the...
(8aS)-9-(6-(1-hydroxy-15-phenyl)hex-5-yn-1-yl)-8a-methyl-1,2,6b,7,8,8a,9,14,14a,14b-decahydronap... more (8aS)-9-(6-(1-hydroxy-15-phenyl)hex-5-yn-1-yl)-8a-methyl-1,2,6b,7,8,8a,9,14,14a,14b-decahydronaphto [2´,1´:4,5]indeno[1,2-b]indol-4-ol (7)
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