Adel Ismail - Academia.edu (original) (raw)

Papers by Adel Ismail

Green Chemistry, 2011

Mesostructured Pt/TiO 2 nanocomposites have been synthesized at different Pt (0-2 wt%) and anatas... more Mesostructured Pt/TiO 2 nanocomposites have been synthesized at different Pt (0-2 wt%) and anatase/rutile ratios through simple one-step sol-gel reactions. The as-made mesostructured hybrids were subjected to H 2 gas for 2 h at 450 • C to obtain ordered hexagonal mesoporous Pt/TiO 2 nanocomposites with highly crystalline TiO 2. Subsequently, the samples were calcined at 350 • C in air for 4 h to remove the surfactant. XRD data clearly show that biphasial anatase and rutile mixtures are formed by the addition of the Pt islands. The TEM results indicated that TiO 2 and Pt, are partly in close contact; the lattice fringes exhibit the typical distances, i.e., Pt (111) (2.2 Å) and TiO 2 (101) (3.54 Å). TiO 2 nanoparticles with an average diameter of about 10 nm particles are not agglomerated and quite uniform in size and shape. Also, Pt nanoparticles are well dispersed and exhibit diameters of about 5-12 nm based on the Pt content. Our photocatalysts have been compared with colloidal 0.5 wt% Pt loaded onto commercial photocatalysts either UV-100 Hombikat or Aeroxide TiO 2 P25 by the determination of the initial rate of HCHO formation generated by the photooxidation of CH 3 OH in aqueous suspensions to calculate the corresponding photonic efficiencies. The overall photocatalytic activities of 0.5 wt% Pt/TiO 2 nanocomposites are significantly 3-times higher than that of colloidal 0.5 wt% Pt loaded onto commercial photocatalysts either UV-100 Hombikat or Aeroxide TiO 2 P25. To the best of our knowledge, the measured photonic efficiency x = 15.5% of hexagonal mesostructured Pt/TiO 2 nanocomposites is found to be among the highest x values reported up to now. The superiority of Pt/TiO 2 is attributed to the bicrystalline (anatase/rutile) framework, large surface area, high crystallinity and mesoporous structure of Pt/TiO 2 nanocomposites.

Gold is normally recovered from its ores by cyanidation process, which is a well-known technique ... more Gold is normally recovered from its ores by cyanidation process, which is a well-known technique used worldwide. The merits of cyanide heap leaching technology of gold are well known, but environmental problems arise occasionally due to high toxicity of cyanide. Photocatalytic decomposition of cyanide was achieved using TiO2-SiO2 aerogel, V2O5-SiO2 xerogel or ozone. The cyanide removal efficiencies were increased from 87 to 98.74% and from 85 to 99% by increasing loading wt% from 0.083 to 0.666 and from 0.083 to 0.166 for TiO2-SiO2 aerogel and V2O5-SiO2 xerogel respectively. Also, the rates constant were increased from 0.020 to 0.044min-1 and from 0.022 to 0.045min-1 for TiO2-SiO2 aerogel and V2O5-SiO2 xerogel respectively and the reaction kinetics were found to be first order. On the other hand the optimum conditions of Photocatalytic degradation of cyanide using ozone were found to be 2.5wt% ozone concentration, 1.14m 3 /h airflow as well as 36 Watt (W) UV light power. At these conditions, the cyanide removal efficiency was 99%, the rate constant was found to be 0.0075min-1 and the reaction kinetic was found to be first order.

Catalysts, Jul 27, 2019

Mesoporous TiO 2 nanoparticles were synthesized at different temperatures (400-800 • C). The resu... more Mesoporous TiO 2 nanoparticles were synthesized at different temperatures (400-800 • C). The resulting mesoporous anatase-rutile TiO 2 mixtures between 27 and 82% were found to have different structural properties (morphology, mesoporosity, crystallite phases, and sizes) affected through the calcination process. They were tested for the photocatalytic degradation of the herbicides imazapyr and phenol, compared with the nonporous TiO 2 P-25. The present work is an extension of a previously published study discussing the influence of the rutile content on the photocatalytic performance of the nanocrystals, based on the modified first order kinetic model, where the degradation rate is a function of the specific surface area of the material. The apparent degradation rate using T-800 is 10-fold higher than in the case using TiO 2 P-25. The material with the lowest anatase content (T-800) exhibits the highest photocatalytic activity in terms of initial reaction rate per unit surface area. It is considered that mixed-phase photocatalysts with rutile-anatase exhibit enhanced photoactivity with the increase of the rutile proportion.

International Journal of Electrochemical Science

Mesoporous silicon (PSi) layer was used to create highly sensitive, electrically-based sensor for... more Mesoporous silicon (PSi) layer was used to create highly sensitive, electrically-based sensor for detection of liquid ethanol at room temperature. The PSi nanostructure that is generated in an electrochemical etching of crystalline silicon in HF-based solution was ≈ 4.5 µm thick with an average pore size of 30 nm. The as-fabricated sensor exhibits highly sensitive, reversible response during the real-time measurements of capacitance and conductance. Excellent repeatability of the devise was obtained after six cyclic tests, demonstrating stability of the sensor. Long-term stability for the sensor performance was also observed after four weeks storage. The observed response could be understood in terms of the change in surface charge upon ethanol infiltration into the mesoporous structure.

ACS Omega, 2021

The efficacy of LaNaTaO 3 perovskites decoration RuO 2 at diverse contents for the photocatalytic... more The efficacy of LaNaTaO 3 perovskites decoration RuO 2 at diverse contents for the photocatalytic H 2 generation has been explored in this study. The photocatalytic performance of RuO 2 co-catalyst onto mesoporous LaNaTaO 3 was evaluated for H 2 under UV illumination. 3%RuO 2 /LaNaTaO 3 perovskite photocatalyst revealed the highest photocatalytic H 2 generation performance, indicating that RuO 2 nanoparticles could promote the photocatalytic efficiency of LaNaTaO 3 perovskite significantly. The H 2 evolution rate of 3%RuO 2 /LaNaTaO 3 perovskite is 11.6 and 1.3 times greater than that of bare LaNaTaO 3 perovskite employing either 10% CH 3 OH or pure H 2 O, respectively. Interestingly, the photonic efficiency of 3%RuO 2 /LaNaTaO 3 perovskite was enhanced 10 times than LaNaTaO 3 perovskite in the presence of aqueous CH 3 OH solutions as a hole sacrificial agent. The high separation of charge carriers is interpreted by the efficient hole capture using CH 3 OH, hence leading to greater H 2 generation over RuO 2 /LaNaTaO 3 perovskites. This is attributed to an adjustment position between recombination electron−hole pairs and also the reduction of potential conduction alignment as a result of RuO 2 incorporation. The suggested mechanisms of RuO 2 /LaNaTaO 3 perovskites for H 2 generation employing either CH 3 OH or pure H 2 O were discussed. The photocatalytic performances of the perovskite photocatalyst were elucidated according to the PL intensity and the photocurrent response investigations.

ACS Omega, 2021

Photoreduction of CO 2 is considered a challenge due to the lack of effective photocatalysts with... more Photoreduction of CO 2 is considered a challenge due to the lack of effective photocatalysts with wide-spectrum absorption, active charge separation dynamically, and CO 2 adsorption. Herein, mesoporous Pt/ZnO nanocomposites with different Pt percentages (0.5−2%) have been fabricated using the sol−gel process in the presence of a template for CO 2 photoreduction during visible-light exposure. Pt nanoparticles (NPs) deposited onto mesoporous ZnO with a considerable surface area can effectively promote charge mobility. The mesoporous 1.5% Pt/ZnO nanocomposite exhibits an optimal CH 3 OH yield (668 μmol g −1), which is 18.5-fold larger than that of mesoporous ZnO (36 μmol g −1). The most photoactive material was the 1.5% Pt/ZnO nanocomposite, producing CH 3 OH of 668 μmol g −1 , and the production rate of CH 3 OH over the 1.5% Pt/ZnO nanocomposite (74.11 μmol g −1 h −1) was increased 20 times in comparison with ZnO NPs (3.72 μmol g −1 h −1). The enhancement of CO 2 photoreduction efficiency over Pt/ZnO nanocomposites was attributed to the formation of the heterojunction at the Pt/ZnO interface, promoting a lower resistance to charge transfer and a larger electron transfer to the conduction band. Mesoporous Pt/ZnO nanocomposites offer enhanced accessibility and a larger surface area. Such an unparalleled mesostructure provides a new framework for the construction and design of photoactive materials with high-efficiency photocatalysts.

Materials, 2019

Microcystin-LR (MC-LR), a potent hepatotoxin produced by the cyanobacteria, is of increasing conc... more Microcystin-LR (MC-LR), a potent hepatotoxin produced by the cyanobacteria, is of increasing concern worldwide because of severe and persistent impacts on humans and animals by inhalation and consumption of contaminated waters and food. In this work, MC-LR was removed completely from aqueous solution using visible-light-active C/N-co-modified mesoporous anatase/brookite TiO2 photocatalyst. The co-modified TiO2 nanoparticles were synthesized by a one-pot hydrothermal process, and then calcined at different temperatures (300, 400, and 500 °C). All the obtained TiO2 powders were analyzed by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscope (TEM), specific surface area (SSA) measurements, ultraviolet-visible diffuse reflectance spectra (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and photoluminescence (PL) analysis. It was found that all samples contained mixed-phase TiO2 (anatase and brookite), and the...

Applied Catalysis B: Environmental, 2017

The present investigation focuses on the synthesis of metal oxide nanoparticles (MONPs) via a fac... more The present investigation focuses on the synthesis of metal oxide nanoparticles (MONPs) via a facile hydrothermal route. The material has been characterized by using X-ray diffractometry (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), high resolution transmission electron microscopy (HR-TEM), energy dispersive spectroscopy (EDS), photoluminescence (PL), atomic force microscopy (AFM) and Brunauer-Emmett-Teller (BET) techniques. However, the application of Fe 2 O 3 metal oxide nanoparticles (MONPs) tied with their inimitable chemical and physical nature is thought to emphasize their exploitable medical and biological applications nowadays. Rhodamine-B (RB) was used for photocatalytic degradation studies by using rhombohedral Fe 2 O 3 , afterwards the material was recycled and utilized for toxicity assessments. Undeniably, a meticulous assessment is needed of the factors that influence the biocompatibility and is essential for the safe and sustainable development of the emerging chemically synthesized metal oxide nanoparticle (MONPs). The toxicity assessment of Fe 2 O 3 is necessary to know the bioaccumulation and local or systemic toxicity associated to them. The aim of the present study is to investigate the effects of Fe 2 O 3 and its histological alterations of the heart tissue of albino Wistar rat. The synthesized materials high dose was found to be highly stable and we found more toxicity against the skin melanoma cells (B16-F10), human embryonic kidney (HEK), 293 cells depending on dose. Finally, Escherichia coli, (MTCC 7410) bacterial cell wall damage studies were also conducted to provide a clear determination of rhombohedral nanomaterial behaviour. The fusion of these biocompatibility investigations paves a way for further applications in utilization of these materials in future eco-friendly applications.

Microscopy and Microanalysis, 2014

Highly ordered mesoporous SBA-15-based silica nanocomposite materials are receiving a great deal ... more Highly ordered mesoporous SBA-15-based silica nanocomposite materials are receiving a great deal of attention due to their interesting structure, which allows hosting nanoparticles for catalytic applications, among many other things. However, to maximize catalytic efficiency, understanding the relationship between their structures and surface chemistries as well as different properties at the subnanometer scale is required. This is essential in order to correlate their structure with their properties and, thereby, develop materials with the best performance. However, such studies are sometimes limited by the lack of reliable characterization techniques, particularly those offering minimal induced damage to the material while allowing detailed analysis of its microstructural features. Therefore, development of such techniques is essential for the overall improvement of catalytic materials.

Arabian Journal of Chemistry, 2014

ZnO doped SnO 2 has been successfully synthesized by the solvothermal method using methanol as or... more ZnO doped SnO 2 has been successfully synthesized by the solvothermal method using methanol as organic solvent. The effect of ZnO/SnO 2 molar ratios on the crystal structure, microstructure, optical and photocatalytic properties has been investigated. The synthesized samples are characterized by X-ray diffraction, transmission electron microscopy, N 2 physical adsorption, FT-IR spectroscopy and UV-Vis spectroscopy. XRD results revealed that all diffraction peaks positions agree well with the reflection of a tetragonal rutile structure of SnO 2 phase without extra peaks at 0.1ZnO:0.9SnO 2 and 0.2ZnO:0.8SnO 2 molar ratios. However, the secondary phase of ZnO at 0.3ZnO:0.7SnO 2 molar ratio was investigated. TEM images revealed that the shape of SnO 2 particles was spherical and the particle sizes of SnO 2 and 0.3ZnO:0.7SnO 2 molar ratio were 6.2 and 16.4 nm, respectively. The newly prepared samples have been tested by the determination of photocatalytic degradation of methylene blue (MB). The results indicated that Zn 2+ doping at 0.3ZnO:0.7 SnO 2 molar ratio showed the highest photocatalytic activity for the MB photodegradation. The heightened photocatalytic activity of ZnO/SnO 2 could be ascribed to the enhanced charge separation derived from the coupling of ZnO with SnO 2 due to the potential energy differences between SnO 2 and ZnO. The recycling tests demonstrated that 0.3ZnO:0.7 SnO 2 photocatalysts were quite stable during that liquid-solid heterogeneous photocatalysis since no decrease in activity in the first four cycles was observed.

The Journal of Physical Chemistry C, 2008

Nanoscale Research Letters, 2014

We successfully developed a single-step detection and removal unit for Bi(III) ions based on dith... more We successfully developed a single-step detection and removal unit for Bi(III) ions based on dithizone (DZ) anchored on mesoporous TiO2 with rapid colorometric response and high selectivity for the first time. [(DZ)3-Bi] complex is easily separated and collected by mesoporous TiO2 as adsorbent and preconcentrator without any color change of the produced complex onto the surface of mesoporous TiO2 (TiO2-[(DZ)3-Bi]) at different Bi(III) concentrations. This is because highly potent mesoporous TiO2 architecture provides proficient channeling or movement of Bi(III) ions for efficient binding of metal ion, and the simultaneous excellent adsorbing nature of mesoporous TiO2 provides an extra plane for the removal of metal ions.

Materials Letters, 2005

ABSTRACT Synthesis of ZnO nanoparticles was carried out by hydrothermal technique in the presence... more ABSTRACT Synthesis of ZnO nanoparticles was carried out by hydrothermal technique in the presence of Hexamethylenetetramine (HMTA) as a surfactant. Statistical design was used to investigate the effect of main parameters (i.e., surfactant concentration, time and temperature) on ZnO particle size and morphology. The results indicated that the formation of ZnO nanoparticles was confirmed, using XRD and SEM, at 100 oC and their crystallinity was improved with temperature rise from 100 to 200 oC. Particle size of ZnO in the range of 55–110 nm is achieved using this technique.

Green Chemistry, 2011

Mesostructured Pt/TiO 2 nanocomposites have been synthesized at different Pt (0-2 wt%) and anatas... more Mesostructured Pt/TiO 2 nanocomposites have been synthesized at different Pt (0-2 wt%) and anatase/rutile ratios through simple one-step sol-gel reactions. The as-made mesostructured hybrids were subjected to H 2 gas for 2 h at 450 • C to obtain ordered hexagonal mesoporous Pt/TiO 2 nanocomposites with highly crystalline TiO 2. Subsequently, the samples were calcined at 350 • C in air for 4 h to remove the surfactant. XRD data clearly show that biphasial anatase and rutile mixtures are formed by the addition of the Pt islands. The TEM results indicated that TiO 2 and Pt, are partly in close contact; the lattice fringes exhibit the typical distances, i.e., Pt (111) (2.2 Å) and TiO 2 (101) (3.54 Å). TiO 2 nanoparticles with an average diameter of about 10 nm particles are not agglomerated and quite uniform in size and shape. Also, Pt nanoparticles are well dispersed and exhibit diameters of about 5-12 nm based on the Pt content. Our photocatalysts have been compared with colloidal 0.5 wt% Pt loaded onto commercial photocatalysts either UV-100 Hombikat or Aeroxide TiO 2 P25 by the determination of the initial rate of HCHO formation generated by the photooxidation of CH 3 OH in aqueous suspensions to calculate the corresponding photonic efficiencies. The overall photocatalytic activities of 0.5 wt% Pt/TiO 2 nanocomposites are significantly 3-times higher than that of colloidal 0.5 wt% Pt loaded onto commercial photocatalysts either UV-100 Hombikat or Aeroxide TiO 2 P25. To the best of our knowledge, the measured photonic efficiency x = 15.5% of hexagonal mesostructured Pt/TiO 2 nanocomposites is found to be among the highest x values reported up to now. The superiority of Pt/TiO 2 is attributed to the bicrystalline (anatase/rutile) framework, large surface area, high crystallinity and mesoporous structure of Pt/TiO 2 nanocomposites.

Crystal Research and Technology, 2006

Alumina sources can influence different aspects of ZSM‐5 crystallization and it leads to change i... more Alumina sources can influence different aspects of ZSM‐5 crystallization and it leads to change in the properties of the final product. The crystallinity of nanosized ZSM‐5 zeolite from precursors mixtures containing different alumina sources, e.g. sodium aluminate, aluminum sulphate, aluminum hydroxide and alumina has been studied. The produced samples were investigated using XRD, SEM, FT‐ IR and BET surface area. The product obtained by sodium aluminate and aluminum sulphate was ZSM‐5 phase. Whereas, the product obtained by aluminum hydroxide and alumina was the albit phase. As‐synthesized ZSM‐5 was prepared by sodium aluminate, as alumina source was the highest crystallinity. It was found that the average crystallite size increased in the following order; alumina

Chemistry – A European Journal, 2007

Appropriate design of nanosensors for optically selective, sensitive sensing systems is needed fo... more Appropriate design of nanosensors for optically selective, sensitive sensing systems is needed for naked‐eye detection of pollutants for environmental cleanup of toxic heavy‐metal ions. Mesostructured materials with two‐ or three‐dimensional (2D or 3D) geometries and large particle morphologies show promise as probe carriers, and can therefore be used to reproducibly fabricate uniformly packed nanosensors. This is the first report on the effects of significant key properties of the mesostructured carriers, such as morphology, geometry, and pore shape, on the functionality of optical nanosensor designs. Such mesostructured sensors with superior physical characteristics can be used as components in sensing systems with excellent stability and sensitivity, and with rapid detection response. The nanosensor design can enhance the selectivity even at low concentrations of the pollutant target ions (nanomolar level). Among the nanosensors developed here, the large pore‐surface grains of hi...

Journal of Materials Chemistry, 2011

Titanium dioxide is a very important semiconductor with a high potential for applications in phot... more Titanium dioxide is a very important semiconductor with a high potential for applications in photocatalysis, solar cells, photochromism, sensoring, and various other areas of nanotechnology. Increasing attention has recently been focused on the simultaneous achievement of high bulk crystallinity and the formation of ordered mesoporous TiO 2 frameworks with high thermal stability. Mesoporous TiO 2 has continued to be highly active in photocatalytic applications because it is beneficial for promoting the diffusion of reactants and products, as well as for enhancing the photocatalytic activity by facilitating access to the reactive sites on the surface of photocatalyst. This steady progress has demonstrated that mesoporous TiO 2 nanoparticles are playing and will continue to play an important role in the protection of the environment and in the search for renewable and clean energy technologies. This review focuses on the preparation and characterisation of mesoporous titania, noble metals nanoparticles, transition metal ions, non-metal/doped mesoporous titania networks. The photocatalytic activity of mesoporous titania materials upon visible and UV illumination will be reviewed, summarized and discussed, in particular, concerning the influence of preparation and solid-state properties of the materials. Reaction mechanisms that are being discussed to explain these effects will be presented and critically evaluated.

Scientific Reports, 2019

Nd1−xSrxMnO3 nanocomposites perovskites were synthesized using sol gel method at different Sr con... more Nd1−xSrxMnO3 nanocomposites perovskites were synthesized using sol gel method at different Sr content x = 0.3, 0.5, 0.7, and 0.9. The photocatalytic performance of the Nd1−xSrxMnO3 nanocomposites for photodegradation of Acridine orange dye (AO) was evaluated over visible light illumination. The single phase of orthorhombic pbnm was formed for x = 0.3 and 0.5; however monoclinic and orthorhombic were observed at x = 0.7 and 0.9. The Energy gap of the Nd1−xSrxMnO3 nanocomposites were estimated for all concentrations to be in the range of 3 ± 0.05 eV. The photocatalytic efficiency of Nd0.3Sr0.7MnO3 nanocomposite was 95% of the initial AO dye concentration within 3 h illumination time. The linear increase of the photodegradation rate was found in our samples as a result of the increase of Sr contents from 0.3 to 0.7wt %. Interestingly, the Nd0.3Sr0.7MnO3 content has the highest degradation rate of AO which is two times faster than undoped NdMnO3. This superior behavior in photocatalytic...

Research on Chemical Intermediates, 2019

Zinc oxide-doped tin dioxide (ZnO-SnO 2) nanomaterials were prepared by a sol-gel method with and... more Zinc oxide-doped tin dioxide (ZnO-SnO 2) nanomaterials were prepared by a sol-gel method with and without different amounts (0.5, 1.0 and 2.0 g) of polyethylene glycol (PEG). The prepared nanocomposites were characterized for structural, surface and optical properties. The effect of a PEG on the prepared ZnO-SnO 2 nanocomposites was investigated. The photocatalytic activities of the synthesized nanocomposites were evaluated by methylene blue dye degradation under UV illumination. The ZnO-SnO 2 nanocomposites prepared with 2.0 g of PEG showed the highest degradation efficiency of 87.30%, suggesting that adding PEG enhances the photocatalytic performance of ZnO-SnO 2 nanocomposites due to increased inhibition of e − /h + pair recombination and efficient generation of superoxide radical anions and hydroxyl radicals.

Journal of the Taiwan Institute of Chemical Engineers, 2017

Green Chemistry, 2011

Mesostructured Pt/TiO 2 nanocomposites have been synthesized at different Pt (0-2 wt%) and anatas... more Mesostructured Pt/TiO 2 nanocomposites have been synthesized at different Pt (0-2 wt%) and anatase/rutile ratios through simple one-step sol-gel reactions. The as-made mesostructured hybrids were subjected to H 2 gas for 2 h at 450 • C to obtain ordered hexagonal mesoporous Pt/TiO 2 nanocomposites with highly crystalline TiO 2. Subsequently, the samples were calcined at 350 • C in air for 4 h to remove the surfactant. XRD data clearly show that biphasial anatase and rutile mixtures are formed by the addition of the Pt islands. The TEM results indicated that TiO 2 and Pt, are partly in close contact; the lattice fringes exhibit the typical distances, i.e., Pt (111) (2.2 Å) and TiO 2 (101) (3.54 Å). TiO 2 nanoparticles with an average diameter of about 10 nm particles are not agglomerated and quite uniform in size and shape. Also, Pt nanoparticles are well dispersed and exhibit diameters of about 5-12 nm based on the Pt content. Our photocatalysts have been compared with colloidal 0.5 wt% Pt loaded onto commercial photocatalysts either UV-100 Hombikat or Aeroxide TiO 2 P25 by the determination of the initial rate of HCHO formation generated by the photooxidation of CH 3 OH in aqueous suspensions to calculate the corresponding photonic efficiencies. The overall photocatalytic activities of 0.5 wt% Pt/TiO 2 nanocomposites are significantly 3-times higher than that of colloidal 0.5 wt% Pt loaded onto commercial photocatalysts either UV-100 Hombikat or Aeroxide TiO 2 P25. To the best of our knowledge, the measured photonic efficiency x = 15.5% of hexagonal mesostructured Pt/TiO 2 nanocomposites is found to be among the highest x values reported up to now. The superiority of Pt/TiO 2 is attributed to the bicrystalline (anatase/rutile) framework, large surface area, high crystallinity and mesoporous structure of Pt/TiO 2 nanocomposites.

Gold is normally recovered from its ores by cyanidation process, which is a well-known technique ... more Gold is normally recovered from its ores by cyanidation process, which is a well-known technique used worldwide. The merits of cyanide heap leaching technology of gold are well known, but environmental problems arise occasionally due to high toxicity of cyanide. Photocatalytic decomposition of cyanide was achieved using TiO2-SiO2 aerogel, V2O5-SiO2 xerogel or ozone. The cyanide removal efficiencies were increased from 87 to 98.74% and from 85 to 99% by increasing loading wt% from 0.083 to 0.666 and from 0.083 to 0.166 for TiO2-SiO2 aerogel and V2O5-SiO2 xerogel respectively. Also, the rates constant were increased from 0.020 to 0.044min-1 and from 0.022 to 0.045min-1 for TiO2-SiO2 aerogel and V2O5-SiO2 xerogel respectively and the reaction kinetics were found to be first order. On the other hand the optimum conditions of Photocatalytic degradation of cyanide using ozone were found to be 2.5wt% ozone concentration, 1.14m 3 /h airflow as well as 36 Watt (W) UV light power. At these conditions, the cyanide removal efficiency was 99%, the rate constant was found to be 0.0075min-1 and the reaction kinetic was found to be first order.

Catalysts, Jul 27, 2019

Mesoporous TiO 2 nanoparticles were synthesized at different temperatures (400-800 • C). The resu... more Mesoporous TiO 2 nanoparticles were synthesized at different temperatures (400-800 • C). The resulting mesoporous anatase-rutile TiO 2 mixtures between 27 and 82% were found to have different structural properties (morphology, mesoporosity, crystallite phases, and sizes) affected through the calcination process. They were tested for the photocatalytic degradation of the herbicides imazapyr and phenol, compared with the nonporous TiO 2 P-25. The present work is an extension of a previously published study discussing the influence of the rutile content on the photocatalytic performance of the nanocrystals, based on the modified first order kinetic model, where the degradation rate is a function of the specific surface area of the material. The apparent degradation rate using T-800 is 10-fold higher than in the case using TiO 2 P-25. The material with the lowest anatase content (T-800) exhibits the highest photocatalytic activity in terms of initial reaction rate per unit surface area. It is considered that mixed-phase photocatalysts with rutile-anatase exhibit enhanced photoactivity with the increase of the rutile proportion.

International Journal of Electrochemical Science

Mesoporous silicon (PSi) layer was used to create highly sensitive, electrically-based sensor for... more Mesoporous silicon (PSi) layer was used to create highly sensitive, electrically-based sensor for detection of liquid ethanol at room temperature. The PSi nanostructure that is generated in an electrochemical etching of crystalline silicon in HF-based solution was ≈ 4.5 µm thick with an average pore size of 30 nm. The as-fabricated sensor exhibits highly sensitive, reversible response during the real-time measurements of capacitance and conductance. Excellent repeatability of the devise was obtained after six cyclic tests, demonstrating stability of the sensor. Long-term stability for the sensor performance was also observed after four weeks storage. The observed response could be understood in terms of the change in surface charge upon ethanol infiltration into the mesoporous structure.

ACS Omega, 2021

The efficacy of LaNaTaO 3 perovskites decoration RuO 2 at diverse contents for the photocatalytic... more The efficacy of LaNaTaO 3 perovskites decoration RuO 2 at diverse contents for the photocatalytic H 2 generation has been explored in this study. The photocatalytic performance of RuO 2 co-catalyst onto mesoporous LaNaTaO 3 was evaluated for H 2 under UV illumination. 3%RuO 2 /LaNaTaO 3 perovskite photocatalyst revealed the highest photocatalytic H 2 generation performance, indicating that RuO 2 nanoparticles could promote the photocatalytic efficiency of LaNaTaO 3 perovskite significantly. The H 2 evolution rate of 3%RuO 2 /LaNaTaO 3 perovskite is 11.6 and 1.3 times greater than that of bare LaNaTaO 3 perovskite employing either 10% CH 3 OH or pure H 2 O, respectively. Interestingly, the photonic efficiency of 3%RuO 2 /LaNaTaO 3 perovskite was enhanced 10 times than LaNaTaO 3 perovskite in the presence of aqueous CH 3 OH solutions as a hole sacrificial agent. The high separation of charge carriers is interpreted by the efficient hole capture using CH 3 OH, hence leading to greater H 2 generation over RuO 2 /LaNaTaO 3 perovskites. This is attributed to an adjustment position between recombination electron−hole pairs and also the reduction of potential conduction alignment as a result of RuO 2 incorporation. The suggested mechanisms of RuO 2 /LaNaTaO 3 perovskites for H 2 generation employing either CH 3 OH or pure H 2 O were discussed. The photocatalytic performances of the perovskite photocatalyst were elucidated according to the PL intensity and the photocurrent response investigations.

ACS Omega, 2021

Photoreduction of CO 2 is considered a challenge due to the lack of effective photocatalysts with... more Photoreduction of CO 2 is considered a challenge due to the lack of effective photocatalysts with wide-spectrum absorption, active charge separation dynamically, and CO 2 adsorption. Herein, mesoporous Pt/ZnO nanocomposites with different Pt percentages (0.5−2%) have been fabricated using the sol−gel process in the presence of a template for CO 2 photoreduction during visible-light exposure. Pt nanoparticles (NPs) deposited onto mesoporous ZnO with a considerable surface area can effectively promote charge mobility. The mesoporous 1.5% Pt/ZnO nanocomposite exhibits an optimal CH 3 OH yield (668 μmol g −1), which is 18.5-fold larger than that of mesoporous ZnO (36 μmol g −1). The most photoactive material was the 1.5% Pt/ZnO nanocomposite, producing CH 3 OH of 668 μmol g −1 , and the production rate of CH 3 OH over the 1.5% Pt/ZnO nanocomposite (74.11 μmol g −1 h −1) was increased 20 times in comparison with ZnO NPs (3.72 μmol g −1 h −1). The enhancement of CO 2 photoreduction efficiency over Pt/ZnO nanocomposites was attributed to the formation of the heterojunction at the Pt/ZnO interface, promoting a lower resistance to charge transfer and a larger electron transfer to the conduction band. Mesoporous Pt/ZnO nanocomposites offer enhanced accessibility and a larger surface area. Such an unparalleled mesostructure provides a new framework for the construction and design of photoactive materials with high-efficiency photocatalysts.

Materials, 2019

Microcystin-LR (MC-LR), a potent hepatotoxin produced by the cyanobacteria, is of increasing conc... more Microcystin-LR (MC-LR), a potent hepatotoxin produced by the cyanobacteria, is of increasing concern worldwide because of severe and persistent impacts on humans and animals by inhalation and consumption of contaminated waters and food. In this work, MC-LR was removed completely from aqueous solution using visible-light-active C/N-co-modified mesoporous anatase/brookite TiO2 photocatalyst. The co-modified TiO2 nanoparticles were synthesized by a one-pot hydrothermal process, and then calcined at different temperatures (300, 400, and 500 °C). All the obtained TiO2 powders were analyzed by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscope (TEM), specific surface area (SSA) measurements, ultraviolet-visible diffuse reflectance spectra (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, and photoluminescence (PL) analysis. It was found that all samples contained mixed-phase TiO2 (anatase and brookite), and the...

Applied Catalysis B: Environmental, 2017

The present investigation focuses on the synthesis of metal oxide nanoparticles (MONPs) via a fac... more The present investigation focuses on the synthesis of metal oxide nanoparticles (MONPs) via a facile hydrothermal route. The material has been characterized by using X-ray diffractometry (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), high resolution transmission electron microscopy (HR-TEM), energy dispersive spectroscopy (EDS), photoluminescence (PL), atomic force microscopy (AFM) and Brunauer-Emmett-Teller (BET) techniques. However, the application of Fe 2 O 3 metal oxide nanoparticles (MONPs) tied with their inimitable chemical and physical nature is thought to emphasize their exploitable medical and biological applications nowadays. Rhodamine-B (RB) was used for photocatalytic degradation studies by using rhombohedral Fe 2 O 3 , afterwards the material was recycled and utilized for toxicity assessments. Undeniably, a meticulous assessment is needed of the factors that influence the biocompatibility and is essential for the safe and sustainable development of the emerging chemically synthesized metal oxide nanoparticle (MONPs). The toxicity assessment of Fe 2 O 3 is necessary to know the bioaccumulation and local or systemic toxicity associated to them. The aim of the present study is to investigate the effects of Fe 2 O 3 and its histological alterations of the heart tissue of albino Wistar rat. The synthesized materials high dose was found to be highly stable and we found more toxicity against the skin melanoma cells (B16-F10), human embryonic kidney (HEK), 293 cells depending on dose. Finally, Escherichia coli, (MTCC 7410) bacterial cell wall damage studies were also conducted to provide a clear determination of rhombohedral nanomaterial behaviour. The fusion of these biocompatibility investigations paves a way for further applications in utilization of these materials in future eco-friendly applications.

Microscopy and Microanalysis, 2014

Highly ordered mesoporous SBA-15-based silica nanocomposite materials are receiving a great deal ... more Highly ordered mesoporous SBA-15-based silica nanocomposite materials are receiving a great deal of attention due to their interesting structure, which allows hosting nanoparticles for catalytic applications, among many other things. However, to maximize catalytic efficiency, understanding the relationship between their structures and surface chemistries as well as different properties at the subnanometer scale is required. This is essential in order to correlate their structure with their properties and, thereby, develop materials with the best performance. However, such studies are sometimes limited by the lack of reliable characterization techniques, particularly those offering minimal induced damage to the material while allowing detailed analysis of its microstructural features. Therefore, development of such techniques is essential for the overall improvement of catalytic materials.

Arabian Journal of Chemistry, 2014

ZnO doped SnO 2 has been successfully synthesized by the solvothermal method using methanol as or... more ZnO doped SnO 2 has been successfully synthesized by the solvothermal method using methanol as organic solvent. The effect of ZnO/SnO 2 molar ratios on the crystal structure, microstructure, optical and photocatalytic properties has been investigated. The synthesized samples are characterized by X-ray diffraction, transmission electron microscopy, N 2 physical adsorption, FT-IR spectroscopy and UV-Vis spectroscopy. XRD results revealed that all diffraction peaks positions agree well with the reflection of a tetragonal rutile structure of SnO 2 phase without extra peaks at 0.1ZnO:0.9SnO 2 and 0.2ZnO:0.8SnO 2 molar ratios. However, the secondary phase of ZnO at 0.3ZnO:0.7SnO 2 molar ratio was investigated. TEM images revealed that the shape of SnO 2 particles was spherical and the particle sizes of SnO 2 and 0.3ZnO:0.7SnO 2 molar ratio were 6.2 and 16.4 nm, respectively. The newly prepared samples have been tested by the determination of photocatalytic degradation of methylene blue (MB). The results indicated that Zn 2+ doping at 0.3ZnO:0.7 SnO 2 molar ratio showed the highest photocatalytic activity for the MB photodegradation. The heightened photocatalytic activity of ZnO/SnO 2 could be ascribed to the enhanced charge separation derived from the coupling of ZnO with SnO 2 due to the potential energy differences between SnO 2 and ZnO. The recycling tests demonstrated that 0.3ZnO:0.7 SnO 2 photocatalysts were quite stable during that liquid-solid heterogeneous photocatalysis since no decrease in activity in the first four cycles was observed.

The Journal of Physical Chemistry C, 2008

Nanoscale Research Letters, 2014

We successfully developed a single-step detection and removal unit for Bi(III) ions based on dith... more We successfully developed a single-step detection and removal unit for Bi(III) ions based on dithizone (DZ) anchored on mesoporous TiO2 with rapid colorometric response and high selectivity for the first time. [(DZ)3-Bi] complex is easily separated and collected by mesoporous TiO2 as adsorbent and preconcentrator without any color change of the produced complex onto the surface of mesoporous TiO2 (TiO2-[(DZ)3-Bi]) at different Bi(III) concentrations. This is because highly potent mesoporous TiO2 architecture provides proficient channeling or movement of Bi(III) ions for efficient binding of metal ion, and the simultaneous excellent adsorbing nature of mesoporous TiO2 provides an extra plane for the removal of metal ions.

Materials Letters, 2005

ABSTRACT Synthesis of ZnO nanoparticles was carried out by hydrothermal technique in the presence... more ABSTRACT Synthesis of ZnO nanoparticles was carried out by hydrothermal technique in the presence of Hexamethylenetetramine (HMTA) as a surfactant. Statistical design was used to investigate the effect of main parameters (i.e., surfactant concentration, time and temperature) on ZnO particle size and morphology. The results indicated that the formation of ZnO nanoparticles was confirmed, using XRD and SEM, at 100 oC and their crystallinity was improved with temperature rise from 100 to 200 oC. Particle size of ZnO in the range of 55–110 nm is achieved using this technique.

Green Chemistry, 2011

Mesostructured Pt/TiO 2 nanocomposites have been synthesized at different Pt (0-2 wt%) and anatas... more Mesostructured Pt/TiO 2 nanocomposites have been synthesized at different Pt (0-2 wt%) and anatase/rutile ratios through simple one-step sol-gel reactions. The as-made mesostructured hybrids were subjected to H 2 gas for 2 h at 450 • C to obtain ordered hexagonal mesoporous Pt/TiO 2 nanocomposites with highly crystalline TiO 2. Subsequently, the samples were calcined at 350 • C in air for 4 h to remove the surfactant. XRD data clearly show that biphasial anatase and rutile mixtures are formed by the addition of the Pt islands. The TEM results indicated that TiO 2 and Pt, are partly in close contact; the lattice fringes exhibit the typical distances, i.e., Pt (111) (2.2 Å) and TiO 2 (101) (3.54 Å). TiO 2 nanoparticles with an average diameter of about 10 nm particles are not agglomerated and quite uniform in size and shape. Also, Pt nanoparticles are well dispersed and exhibit diameters of about 5-12 nm based on the Pt content. Our photocatalysts have been compared with colloidal 0.5 wt% Pt loaded onto commercial photocatalysts either UV-100 Hombikat or Aeroxide TiO 2 P25 by the determination of the initial rate of HCHO formation generated by the photooxidation of CH 3 OH in aqueous suspensions to calculate the corresponding photonic efficiencies. The overall photocatalytic activities of 0.5 wt% Pt/TiO 2 nanocomposites are significantly 3-times higher than that of colloidal 0.5 wt% Pt loaded onto commercial photocatalysts either UV-100 Hombikat or Aeroxide TiO 2 P25. To the best of our knowledge, the measured photonic efficiency x = 15.5% of hexagonal mesostructured Pt/TiO 2 nanocomposites is found to be among the highest x values reported up to now. The superiority of Pt/TiO 2 is attributed to the bicrystalline (anatase/rutile) framework, large surface area, high crystallinity and mesoporous structure of Pt/TiO 2 nanocomposites.

Crystal Research and Technology, 2006

Alumina sources can influence different aspects of ZSM‐5 crystallization and it leads to change i... more Alumina sources can influence different aspects of ZSM‐5 crystallization and it leads to change in the properties of the final product. The crystallinity of nanosized ZSM‐5 zeolite from precursors mixtures containing different alumina sources, e.g. sodium aluminate, aluminum sulphate, aluminum hydroxide and alumina has been studied. The produced samples were investigated using XRD, SEM, FT‐ IR and BET surface area. The product obtained by sodium aluminate and aluminum sulphate was ZSM‐5 phase. Whereas, the product obtained by aluminum hydroxide and alumina was the albit phase. As‐synthesized ZSM‐5 was prepared by sodium aluminate, as alumina source was the highest crystallinity. It was found that the average crystallite size increased in the following order; alumina

Chemistry – A European Journal, 2007

Appropriate design of nanosensors for optically selective, sensitive sensing systems is needed fo... more Appropriate design of nanosensors for optically selective, sensitive sensing systems is needed for naked‐eye detection of pollutants for environmental cleanup of toxic heavy‐metal ions. Mesostructured materials with two‐ or three‐dimensional (2D or 3D) geometries and large particle morphologies show promise as probe carriers, and can therefore be used to reproducibly fabricate uniformly packed nanosensors. This is the first report on the effects of significant key properties of the mesostructured carriers, such as morphology, geometry, and pore shape, on the functionality of optical nanosensor designs. Such mesostructured sensors with superior physical characteristics can be used as components in sensing systems with excellent stability and sensitivity, and with rapid detection response. The nanosensor design can enhance the selectivity even at low concentrations of the pollutant target ions (nanomolar level). Among the nanosensors developed here, the large pore‐surface grains of hi...

Journal of Materials Chemistry, 2011

Titanium dioxide is a very important semiconductor with a high potential for applications in phot... more Titanium dioxide is a very important semiconductor with a high potential for applications in photocatalysis, solar cells, photochromism, sensoring, and various other areas of nanotechnology. Increasing attention has recently been focused on the simultaneous achievement of high bulk crystallinity and the formation of ordered mesoporous TiO 2 frameworks with high thermal stability. Mesoporous TiO 2 has continued to be highly active in photocatalytic applications because it is beneficial for promoting the diffusion of reactants and products, as well as for enhancing the photocatalytic activity by facilitating access to the reactive sites on the surface of photocatalyst. This steady progress has demonstrated that mesoporous TiO 2 nanoparticles are playing and will continue to play an important role in the protection of the environment and in the search for renewable and clean energy technologies. This review focuses on the preparation and characterisation of mesoporous titania, noble metals nanoparticles, transition metal ions, non-metal/doped mesoporous titania networks. The photocatalytic activity of mesoporous titania materials upon visible and UV illumination will be reviewed, summarized and discussed, in particular, concerning the influence of preparation and solid-state properties of the materials. Reaction mechanisms that are being discussed to explain these effects will be presented and critically evaluated.

Scientific Reports, 2019

Nd1−xSrxMnO3 nanocomposites perovskites were synthesized using sol gel method at different Sr con... more Nd1−xSrxMnO3 nanocomposites perovskites were synthesized using sol gel method at different Sr content x = 0.3, 0.5, 0.7, and 0.9. The photocatalytic performance of the Nd1−xSrxMnO3 nanocomposites for photodegradation of Acridine orange dye (AO) was evaluated over visible light illumination. The single phase of orthorhombic pbnm was formed for x = 0.3 and 0.5; however monoclinic and orthorhombic were observed at x = 0.7 and 0.9. The Energy gap of the Nd1−xSrxMnO3 nanocomposites were estimated for all concentrations to be in the range of 3 ± 0.05 eV. The photocatalytic efficiency of Nd0.3Sr0.7MnO3 nanocomposite was 95% of the initial AO dye concentration within 3 h illumination time. The linear increase of the photodegradation rate was found in our samples as a result of the increase of Sr contents from 0.3 to 0.7wt %. Interestingly, the Nd0.3Sr0.7MnO3 content has the highest degradation rate of AO which is two times faster than undoped NdMnO3. This superior behavior in photocatalytic...

Research on Chemical Intermediates, 2019

Zinc oxide-doped tin dioxide (ZnO-SnO 2) nanomaterials were prepared by a sol-gel method with and... more Zinc oxide-doped tin dioxide (ZnO-SnO 2) nanomaterials were prepared by a sol-gel method with and without different amounts (0.5, 1.0 and 2.0 g) of polyethylene glycol (PEG). The prepared nanocomposites were characterized for structural, surface and optical properties. The effect of a PEG on the prepared ZnO-SnO 2 nanocomposites was investigated. The photocatalytic activities of the synthesized nanocomposites were evaluated by methylene blue dye degradation under UV illumination. The ZnO-SnO 2 nanocomposites prepared with 2.0 g of PEG showed the highest degradation efficiency of 87.30%, suggesting that adding PEG enhances the photocatalytic performance of ZnO-SnO 2 nanocomposites due to increased inhibition of e − /h + pair recombination and efficient generation of superoxide radical anions and hydroxyl radicals.

Journal of the Taiwan Institute of Chemical Engineers, 2017