Monodisperse TiO<sub>2</sub> Spheres with High Charge Density and Their Self‐Assembly

Xia, Hongbo; Wu, Shao-Yi; Su, Xin; Zhang, Shufen

doi:10.1002/asia.201601347

Cited by 20 publications

(16 citation statements)

References 45 publications

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“…1B). Previous studies also suggest that thiol group attaches via the deprotonated S atom to metal based nanoparticles (Green, 2010;Li et al, 2016;Gaceur et al, 2012) or through the carboxyl end (Xia et al, 2016). The striking feature of strong H bonding due to eOH and v(NH) stretching was observed in the region of 3276 cm −1 in the QD-GLY spectrum.…”

Section: Characterization Of the Cds-qdsmentioning

confidence: 74%

Surface coating determines the response of soybean plants to cadmium sulfide quantum dots

Majumdar

Villani

et al. 2019

NanoImpact

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Quantum dots (QDs) are used in an array of applications from electronic devices to medicine, leading to environmental release and accumulation in landfills and agricultural soils. However, their effects on plants have been least studied among other engineered nanomaterials. In the current study, soybean seedlings were exposed to 50-200 mg/L cadmium sulfide quantum dots (CdS-QDs) to elucidate their bioaccumulation and biological response in comparison to Cd 2+ ions and bulk-CdS. To understand the role of surface coatings on QD stability, uptake, translocation, subcellular localization and cellular response, bare CdS-QDs were capped with ligands varying in polarity and surface charge. Four common ligands, including trioctylphosphine oxide, polyvinylpyrrolidone, mercaptoacetic acid, and glycine were used to synthesize QD-TOPO, QD-PVP, QD-MAA, and QD-GLY, respectively. In aqueous suspension, QD-MAA particles were most stable, maintaining their size at 332 nm with least Cd 2+ dissolution (9%) after 14 d, whereas QD-TOPO formed large aggregates of size 3861 nm with 27% Cd 2+ dissolution. Upon exposure to 100 mg/L bare and coated CdS-QDs in vermiculite for 14 d, soybean roots accumulated Cd, ranging from 568 (QD-MAA) to 1010 (QD-PVP) μg/g tissue dry weight (DW); statistically equivalent to bulk-CdS treatment (639 μg/g DW). In the roots, Cd from CdCl 2 , bulk-CdS, QD-MAA and QD-GLY accumulated primarily in the cell wall (~40-55%) followed by organelles (28-40%), suggesting apoplastic pathway; whereas in QD-TOPO, dissolved Cd 2+ ions accumulated mainly in the membranes. The exception was QD-PVP, which sequestered Cd mainly in the organelles (49%) in roots, potentially via symplastic pathway and translocated to shoots, resulting in reduced leaf biomass. Results suggested that peroxidases play the predominant role in quenching the oxidative stress caused by CdS-QD exposure. At the highest CdS-QD treatment (200 mg/L), root lignification allowed the plants to restrict Cd accumulation, except in QD-PVP, where lignification was reduced by 21% leading to higher Cd content in shoots. Increased amino acid content in the leaves was noted as a stress tolerance mechanism by the plants exposed to 200 mg/L QD treatments. This study highlights the significant influence that surface coating exerts on QDs fate and effects in a planted system.

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Section: Characterization Of the Cds-qdsmentioning

confidence: 74%

Surface coating determines the response of soybean plants to cadmium sulfide quantum dots

Majumdar

Villani

et al. 2019

NanoImpact

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“…The TiO 2 nanospheres were prepared by using our previously reported method . In brief, TBT (0.1 mL) and thioglycolic acid (0.006 mL) were added to ethanol (14 mL).…”

Section: Methodsmentioning

confidence: 99%

“…The TiO 2 nanospheres were prepared by using our previously reported method. [13] In brief, TBT (0.1 mL) and thioglycolic acid (0.006 mL) were added to ethanol (14 mL). This mixture was kept under magnetic stirring for some time at RT,t hen water (1.5 mL) was quickly added to the solution.…”

Section: Preparation Of Tio 2 Spheresmentioning

confidence: 99%

“…Herein, we have developed a facile ion adsorption–heating method, which involves an ion adsorption process combined with a heating process, to prepare hollow PbS‐TiO 2 hybrid nanoparticles with well‐defined structures. Based on our previous report, the TiO 2 spheres prepared with thioglycolic acid as the ligand are aggregates of nanoparticles, and each nanoparticle is covered with thioglycolic acid ligands. It was reported that thiol (SH) groups have a strong ability to adsorb metal ions .…”

Section: Introductionmentioning

confidence: 99%

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Controlled Synthesis of Hollow PbS‐TiO₂ Hybrid Structures through an Ion Adsorption–Heating Process and their Photocatalytic Activity

Xia

Zhang

2017

Chemistry An Asian Journal

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Hollow hybrid nanostructures have received significant attention because of their unique structural features. This study reports a facile ion adsorption-heating method to fabricate hollow PbS-TiO hybrid particles. In this method, the TiO spheres used as a substrate material to grow PbS are aggregates of many small amorphous TiO particles, and each small particle is covered with thioglycolic acid ligands through Ti -carboxyl coordination. When Pb ions are added to a colloidal solution of these TiO spheres, these ions are adsorbed by sulfhydryl (-SH) groups to form metal thiolates, and the C-S bond is dissociated by heating to release S . The S ions react with Pb ions to form PbS without additive sulfur sources. Additionally, the amorphous TiO spheres are transformed into the anatase phase during the heating process. As a result, the crystallization of TiO spheres along with the formation of PbS is simultaneously carried out by heating. During the heating process, owing to the Kirkendall effect of S diffusion and the Ostwald ripening effect of the crystallization of amorphous TiO spheres, PbS-TiO hollow hybrid structures can be obtained. The XRD and XPS characterizations proved the formation of anatase TiO and PbS. The TEM characterization confirmed the formation of hollow structures in the PbS-TiO hybrid sample. The photocatalytic activity of the hollow PbS-TiO hybrid spheres have been investigated for the degradation of Cr under visible light. The results show that hollow PbS-TiO hybrid spheres exhibited the highest photocatalytic activity, in which almost all the Cr was degraded after 140 min.

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“…Colloidal crystals can be self‐assembled from a colloidal suspension by evaporation of the liquid solvent or by gravity sedimentation in a variety of approaches, such as spin coating, vertical deposition, electrophoresis, centrifugation, freezing, physical confinement, or convective self‐assembly to name a few of them.…”

Section: Introductionmentioning

confidence: 99%

Effects of processing parameters on 3D structural ordering and optical properties of inverse opal photonic crystals produced by atomic layer deposition

Campos

Furlan

García

et al. 2019

Int J Ceramic Engine & Sci

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Vertical convective self‐assembly has been extensively used for the preparation of direct photonic crystals, which can be later infiltrated with a more stable material, such as oxide ceramics, by atomic layer deposition. However, the relationship between the self‐assembly parameters of the direct photonic crystals and the optical properties of the inverse opal photonic crystals remains elusive. In this work, the effect of different experimental parameters on the 3D structure and the density of defects of polystyrene direct photonic crystals produced by vertical convective self‐assembly was assessed. Self‐assembly was investigated using deionized water as media with polymer particles’ concentrations up to 2 mg/mL; temperatures of 40, 50, and 80°C; and relative humidity of 45%, 70%, and 90%. The 3D structure of the resultant direct photonic materials was characterized by the combination of scanning electron microscopy and image analysis, and their optical properties were assessed by reflectance measurements. These results were correlated with the performance of oxide‐based inverse opal photonic crystals produced by the controlled infiltration of the former direct photonic crystals by atomic layer deposition (ALD). It was found that the thickness increased with the concentration of polystyrene particles, while the photonic structure ordering is dependent on the synergy between humidity and temperature. Results also showed higher defects population with increasing evaporation temperature and decreasing relative humidity.

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Monodisperse TiO₂ Spheres with High Charge Density and Their Self‐Assembly

Cited by 20 publications

References 45 publications

Surface coating determines the response of soybean plants to cadmium sulfide quantum dots

Surface coating determines the response of soybean plants to cadmium sulfide quantum dots

Controlled Synthesis of Hollow PbS‐TiO₂ Hybrid Structures through an Ion Adsorption–Heating Process and their Photocatalytic Activity

Effects of processing parameters on 3D structural ordering and optical properties of inverse opal photonic crystals produced by atomic layer deposition

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Monodisperse TiO2 Spheres with High Charge Density and Their Self‐Assembly

Cited by 20 publications

References 45 publications

Surface coating determines the response of soybean plants to cadmium sulfide quantum dots

Surface coating determines the response of soybean plants to cadmium sulfide quantum dots

Controlled Synthesis of Hollow PbS‐TiO2 Hybrid Structures through an Ion Adsorption–Heating Process and their Photocatalytic Activity

Effects of processing parameters on 3D structural ordering and optical properties of inverse opal photonic crystals produced by atomic layer deposition

Contact Info

Product

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About

Monodisperse TiO₂ Spheres with High Charge Density and Their Self‐Assembly

Controlled Synthesis of Hollow PbS‐TiO₂ Hybrid Structures through an Ion Adsorption–Heating Process and their Photocatalytic Activity