Background:Metal oxide(MO)nanomaterials and related nanocomposites have been extensively studied for their potential use in water treatment.Because of their controlled morphologies,texture qualities,variable surface c...Background:Metal oxide(MO)nanomaterials and related nanocomposites have been extensively studied for their potential use in water treatment.Because of their controlled morphologies,texture qualities,variable surface chemistry,distinct crystalline nature,high stability,and tunable band edges,MO nanostructured materials are highly selective towards deleting organic contaminants and heavy metal ions via adsorption and semiconductor photocatalysis.Metal-enhanced photocatalysis has recently received increasing interest,mainly due to the ability of the metal to directly or indirectly degrade pollutants.A diverse selection of MOs,with titanium dioxide(Ti O2),zinc oxide(Zn O),iron oxides(IO),and tungsten(W),as well as graphene-MOs nanocomposites with variable structure,crystalline,and morphological properties,offers a powerful platform for the growth of effective catalysts.Methods:The current work discusses novel advancements and potential for the removal of adsorptive and photocatalytic degradation of organic compounds(phenolic,pesticide molecules,dyes,and so on)as well as heavy metal ions using semiconductor materials.A photocatalyst based on a MO-scheme heterostructure can manage the appropriate conduction band(CB)and valence band(VB)locations,securing considerable redox aptitude.This review should be of interest to the broad readership dealing with applied and fundamental aspects of water treatments and material sciences.Various strategies including surface modification,plasmonic enhancement,and metal cocatalysts have been introduced to enhance photocatalytic performance.Significant findings:The current article discussed the significantly utilized synthesis strategies and mechanism of heterojunction photocatalysts using a Z-scheme.Furthermore,adsorption sections guarantee that mercury,chromium,cadmium,arsenic,and lead-based ions are successfully removed from polluted water via the adsorption route.Numerous characteristics,such as concentration,coexisting ions,p H,and kind of chemical have converged to comprehend the 展开更多
We present a study of growth of a novel system of CdTe nanoparticles embedded in sodium/lithium-mixed phosphate glass matrix in a strong quantum confinement regime. The prepared systems are characterized by differenti...We present a study of growth of a novel system of CdTe nanoparticles embedded in sodium/lithium-mixed phosphate glass matrix in a strong quantum confinement regime. The prepared systems are characterized by differential thermal analysis, X-ray diffraction, TEM, optical absorption, infrared and Raman Spectroscopy. We have investigated the effect of glass matrix composition and annealing time on the growing of the CdTe semiconductor nanoparticles. We found that the decrease in Na2O content and addition of ZnO to the glass composition is strongly affecting the nanoparticles formation and capping surface of the nanoparticls. On the other hand, we have calculated the size of nanoparticles by effective mass approximation (EMA) and empirical method based on tight binding approximation and found that the calculation based on tight binding approximation are very plausible than that one calculated by EMA.展开更多
Very small nickel oxide nanoparticles were prepared by a sol-gel procedure using nickel nitrate hexahydrate and ammonium hydroxide as precursors. The particles are in the range of 5 nm-11 rim. The x-ray diffraction （...Very small nickel oxide nanoparticles were prepared by a sol-gel procedure using nickel nitrate hexahydrate and ammonium hydroxide as precursors. The particles are in the range of 5 nm-11 rim. The x-ray diffraction （XRD） crystallography and high resolution transmission electron microscopy （HRTEM） were employed to characterize the samples. They were found to be polycrystalline in nature and fcc （NaCl-type） in structure, with the lattice parameter varying with annealing temperature. HRTEM pictures show that the as-prepared samples are hexagonal in shape. Positron annihilation spectroscopy was used to investigate the Doppler-broadened spectra of the samples. The S and W parameters revealed that the chemical surroundings and momentum distribution of the vacancy clusters vary with crystallite size.展开更多
Colloidal suspensions of semiconductor InP@ZnS nanoparticles were prepared using single-step procedure without precursor injection. Thermal properties of toluene containing InP@ZnS semiconductor with different sizes (...Colloidal suspensions of semiconductor InP@ZnS nanoparticles were prepared using single-step procedure without precursor injection. Thermal properties of toluene containing InP@ZnS semiconductor with different sizes (3.1, 4.2, and 4.6 nm) were measured by mode mismatched dualbeam thermal lens technique. This was done in order to measure the effect of the presence of semiconductor nanoparticles and size on the nanofluids thermal diffusivity. The characteristic time constant of the transient thermal lens was estimated by fitting the experimental data to the theoretical expression for transient thermal lens. The thermal diffusivity of the nanofluids (toluene, containing InP@ZnS semiconductor nanoparticles) it seems to be strongly dependent on the presence of semiconductor nanoparticles and particles size. For the case of nanofluids consisting of InP@ZnS nanoparticles dispersed in toluene, it was observed a decrease in the thermal diffusivity. Such behavior differs from other nanofluids, in the sense that they had shown positive thermal diffusivity enhancement. The minimum diffusivity was achieved for the nanoparticles with lowest size. Plausible explanation for such nanofluids low thermal diffusivity with semiconductor nanoparticles is given. UV-Vis spectroscopy, TEM and high-resolution electron microscopy (HRTEM), and energy dispersive spectroscopy (EDS) techniques were used to characterize the InP@ZnS nanoparticles.展开更多
For most particle-based applications, formulation in the liquid phase is a decisive step, and thus, particle interactions and stability in liquid media are of major importance. The concept of Hansen solubility paramet...For most particle-based applications, formulation in the liquid phase is a decisive step, and thus, particle interactions and stability in liquid media are of major importance. The concept of Hansen solubility parameters (HSP) was initially invented to describe the interactions of (polymer) molecules and their solubility in different liquids and is increasingly being used in particle technology to describe dispersibility. Because dispersions are not thermodynamically stable, the term Hansen dispersibility parameters (HDP) is used instead of HSP (SiiE, Sobisch, Peukert, Lerche,& Segets, 2018). Herein, we extend a previously developed standardized and non-subjective method for determination of Hansen parameters based on analytical centrifugation to the important class of quantum materials. As a technically relevant model system, zinc oxide quantum dots (QDs) were used to transfer our methodology to nanoparticles (NPs) with sizes below lOnm. The results obtained using the standard procedure starting from a dried powder were compared with those obtained through redispersion from the wet sediment produced during the typical washing procedure of QDs, and drying was observed to play an important role. In conclusion, our study reveals the high potential of HDP for quantifying the interfacial properties of NPs as well as their link to dispersibility.展开更多
Aminocaproic acid (ACA) mixed methanolic lead acetate-thiourea (PbAc-TU) complex as precursor for fabrication of lead sulphide (PbS) nanoparticles (NPs) has been explained. The size, structure and morphology of as-pre...Aminocaproic acid (ACA) mixed methanolic lead acetate-thiourea (PbAc-TU) complex as precursor for fabrication of lead sulphide (PbS) nanoparticles (NPs) has been explained. The size, structure and morphology of as-prepared ACA-capped PbS NPs were systematically characterized by scanning electron microscopy (SEM), Transmission electron mi-croscopy (TEM), X-ray diffraction (XRD), Uv-vis spectroscopy and Brunauer-Emmett-Teller (BET) techniques. The obtained results show that the synthesized PbS NPs are nanocrystalline, size quantized and their agglomeration shows a mesoporous network of 8.7 nm in pore size. The binding nature of ACA molecules on PbS surface was studied by thermo gravimetric analysis (TGA), Fourier transform infrared (FTIR) and X-ray photoelectron (XPS) techniques. Results indicate that ACA acts as a soft template that restricts the growth of PbS NPs through its binding to Pb surface via nitrogen lone pair.展开更多
文摘Background:Metal oxide(MO)nanomaterials and related nanocomposites have been extensively studied for their potential use in water treatment.Because of their controlled morphologies,texture qualities,variable surface chemistry,distinct crystalline nature,high stability,and tunable band edges,MO nanostructured materials are highly selective towards deleting organic contaminants and heavy metal ions via adsorption and semiconductor photocatalysis.Metal-enhanced photocatalysis has recently received increasing interest,mainly due to the ability of the metal to directly or indirectly degrade pollutants.A diverse selection of MOs,with titanium dioxide(Ti O2),zinc oxide(Zn O),iron oxides(IO),and tungsten(W),as well as graphene-MOs nanocomposites with variable structure,crystalline,and morphological properties,offers a powerful platform for the growth of effective catalysts.Methods:The current work discusses novel advancements and potential for the removal of adsorptive and photocatalytic degradation of organic compounds(phenolic,pesticide molecules,dyes,and so on)as well as heavy metal ions using semiconductor materials.A photocatalyst based on a MO-scheme heterostructure can manage the appropriate conduction band(CB)and valence band(VB)locations,securing considerable redox aptitude.This review should be of interest to the broad readership dealing with applied and fundamental aspects of water treatments and material sciences.Various strategies including surface modification,plasmonic enhancement,and metal cocatalysts have been introduced to enhance photocatalytic performance.Significant findings:The current article discussed the significantly utilized synthesis strategies and mechanism of heterojunction photocatalysts using a Z-scheme.Furthermore,adsorption sections guarantee that mercury,chromium,cadmium,arsenic,and lead-based ions are successfully removed from polluted water via the adsorption route.Numerous characteristics,such as concentration,coexisting ions,p H,and kind of chemical have converged to comprehend the
文摘We present a study of growth of a novel system of CdTe nanoparticles embedded in sodium/lithium-mixed phosphate glass matrix in a strong quantum confinement regime. The prepared systems are characterized by differential thermal analysis, X-ray diffraction, TEM, optical absorption, infrared and Raman Spectroscopy. We have investigated the effect of glass matrix composition and annealing time on the growing of the CdTe semiconductor nanoparticles. We found that the decrease in Na2O content and addition of ZnO to the glass composition is strongly affecting the nanoparticles formation and capping surface of the nanoparticls. On the other hand, we have calculated the size of nanoparticles by effective mass approximation (EMA) and empirical method based on tight binding approximation and found that the calculation based on tight binding approximation are very plausible than that one calculated by EMA.
文摘Very small nickel oxide nanoparticles were prepared by a sol-gel procedure using nickel nitrate hexahydrate and ammonium hydroxide as precursors. The particles are in the range of 5 nm-11 rim. The x-ray diffraction （XRD） crystallography and high resolution transmission electron microscopy （HRTEM） were employed to characterize the samples. They were found to be polycrystalline in nature and fcc （NaCl-type） in structure, with the lattice parameter varying with annealing temperature. HRTEM pictures show that the as-prepared samples are hexagonal in shape. Positron annihilation spectroscopy was used to investigate the Doppler-broadened spectra of the samples. The S and W parameters revealed that the chemical surroundings and momentum distribution of the vacancy clusters vary with crystallite size.
文摘Colloidal suspensions of semiconductor InP@ZnS nanoparticles were prepared using single-step procedure without precursor injection. Thermal properties of toluene containing InP@ZnS semiconductor with different sizes (3.1, 4.2, and 4.6 nm) were measured by mode mismatched dualbeam thermal lens technique. This was done in order to measure the effect of the presence of semiconductor nanoparticles and size on the nanofluids thermal diffusivity. The characteristic time constant of the transient thermal lens was estimated by fitting the experimental data to the theoretical expression for transient thermal lens. The thermal diffusivity of the nanofluids (toluene, containing InP@ZnS semiconductor nanoparticles) it seems to be strongly dependent on the presence of semiconductor nanoparticles and particles size. For the case of nanofluids consisting of InP@ZnS nanoparticles dispersed in toluene, it was observed a decrease in the thermal diffusivity. Such behavior differs from other nanofluids, in the sense that they had shown positive thermal diffusivity enhancement. The minimum diffusivity was achieved for the nanoparticles with lowest size. Plausible explanation for such nanofluids low thermal diffusivity with semiconductor nanoparticles is given. UV-Vis spectroscopy, TEM and high-resolution electron microscopy (HRTEM), and energy dispersive spectroscopy (EDS) techniques were used to characterize the InP@ZnS nanoparticles.
文摘For most particle-based applications, formulation in the liquid phase is a decisive step, and thus, particle interactions and stability in liquid media are of major importance. The concept of Hansen solubility parameters (HSP) was initially invented to describe the interactions of (polymer) molecules and their solubility in different liquids and is increasingly being used in particle technology to describe dispersibility. Because dispersions are not thermodynamically stable, the term Hansen dispersibility parameters (HDP) is used instead of HSP (SiiE, Sobisch, Peukert, Lerche,& Segets, 2018). Herein, we extend a previously developed standardized and non-subjective method for determination of Hansen parameters based on analytical centrifugation to the important class of quantum materials. As a technically relevant model system, zinc oxide quantum dots (QDs) were used to transfer our methodology to nanoparticles (NPs) with sizes below lOnm. The results obtained using the standard procedure starting from a dried powder were compared with those obtained through redispersion from the wet sediment produced during the typical washing procedure of QDs, and drying was observed to play an important role. In conclusion, our study reveals the high potential of HDP for quantifying the interfacial properties of NPs as well as their link to dispersibility.
基金the Natural Sciences and Engineering Research Council of Canada(NSERC)for financial support of this work.
文摘Aminocaproic acid (ACA) mixed methanolic lead acetate-thiourea (PbAc-TU) complex as precursor for fabrication of lead sulphide (PbS) nanoparticles (NPs) has been explained. The size, structure and morphology of as-prepared ACA-capped PbS NPs were systematically characterized by scanning electron microscopy (SEM), Transmission electron mi-croscopy (TEM), X-ray diffraction (XRD), Uv-vis spectroscopy and Brunauer-Emmett-Teller (BET) techniques. The obtained results show that the synthesized PbS NPs are nanocrystalline, size quantized and their agglomeration shows a mesoporous network of 8.7 nm in pore size. The binding nature of ACA molecules on PbS surface was studied by thermo gravimetric analysis (TGA), Fourier transform infrared (FTIR) and X-ray photoelectron (XPS) techniques. Results indicate that ACA acts as a soft template that restricts the growth of PbS NPs through its binding to Pb surface via nitrogen lone pair.
