Halloysite nanotubes (HNTs) showed natural nanotubular structures with similar chemical composition to kaolin. This paper reviewed the exciting applications of HNTs due to their abundantly deposit, ...nanoscale lumens, high length-to-diameter ratios, and relatively low surface hydroxyl group density. HNTs have been used as ideal templates for conveniently immobilizing nanoparticles, which could enable the construction of designed nano-architectures that are extremely attractive as supports for heterogeneous catalysts and for use in the fuel cells and related technologies that exploited the inherent ‘smallness’ and hollow characteristics of the nanoparticles. The recent developments in this area by exploring the various techniques with which HNTs could be functionalized with metal nanoparticles, and the diverse applications of the resulting materials overviewed in detail. The corresponding interfacial characteristics of the nanocomposites were emphasized.
Display omitted
•Halloysite nanotubes (HNTs) have notubular structures with low surface group density.•The wide applications of HNTs-metal composites were in detail summarized.•The techniques for functionalizing HNTs with metal nanoparticles were reviewed.•The interfacial characteristics between metal nanoparticles and HNTs were analyzed.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The in situ synthesis of mesoporous nanotubes from natural minerals remains a great challenge. Herein, we report the successful synthesis of mesoporous silica nanotubes （MNTs） with a varying ...inner-shell thickness and a preserved clay outer shell from natural-halloysite nanotubes （HNTs）. After the enlargement of the lumen diameter of the tubular aluminosilicate clay by acid leaching, uniform mesopores were introduced by a modified pseudomorphic transformation approach, while the clay outer shell was well-preserved. Using density functional theory calculations, the atomic structure evolution and the energetics during A1 leaching and Si-OH condensation were studied in detail. After the leaching of A1 ions from the HNTs, local structural changes from Al（Oh） to A1（V） at a medium leaching level and to AI（Td） at a high leaching level were confirmed. The calculated hydroxylation energy of two kinds of silica components in the acid-leached HNTs （the distorted two-dimensional silica source in the inner shell and the intact aluminosilicate structure in the outer shell） was 0.5 eV lower or 1.0 eV higher than that of bulk silica, which clarifies the different behavior of the silica components in the hydrothermal process. The successful synthesis of reactive MNTs from HNTs introduces a new strategy for the synthesis of mesoporous nanocontainers with a special morphology using natural minerals. In particular, MNT samples with numerous reactive AI（V） species and a specific surface area up to 583 m^2/g （increased by a factor of 10） are promising drugloading nanocontainers and nanoreactors.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract
Death from acute hemorrhage is a major problem in military conflicts, traffic accidents, and surgical procedures, et al. Achieving rapid effective hemostasis for pre-hospital care is ...essential to save lives in massive bleeding. An ideal hemostasis material should have those features such as safe, efficient, convenient, economical, which remains challenging and most of them cannot be achieved at the same time. In this work, we report a rapid effective nanoclay-based hemostatic membranes with nanoclay particles incorporate into polyvinylpyrrolidone (PVP) electrospun fibers. The nanoclay electrospun membrane (NEM) with 60 wt% kaolinite (KEM1.5) shows better and faster hemostatic performance in vitro and in vivo with good biocompatibility compared with most other NEMs and clay-based hemostats, benefiting from its enriched hemostatic functional sites, robust fluffy framework, and hydrophilic surface. The robust hemostatic bandages based on nanoclay electrospun membrane is an effective candidate hemostat in practical application.
Emerging hierarchical MoS2/pillared-montmorillonite （MoS2/PMMT） hybrid nanosheets were successfully prepared through facile in-situ hydrothermal synthesis of MoS2 within the interlayer of ...cetyltrimethylammonium bromide PMMT, and their catalytic performance was evaluated by the reduction reaction of 4-nitrophenol （4-NP） using NaBH4 as a reductant. Microstructure and morphology characterization indicated that MoS2/PMMT exhibited hybrid-stacked layered structures with an interlayer spacing of 1.29 nm, and the MoS2 nanosheets were intercalated within the montmorillonite （MMT） layers, with most of the edges exposed to the outside. The catalytic activity and stability of MoS2/PMMT were both enhanced by the MMT. With the MoS2/PMMT as the catalyst, the apparent reaction rate constant of the 4-NP reduction was 0.723 min-1 and was maintained at -0.679 min-1 after five reaction cycles. The structural evolution of MoSdPMMT and the possible catalysis mechanism for the reduction reaction of 4-NP were investigated. The as-prepared MOSR/PMMT hybrid nanosheets are promising candidates for catalytic application in the water-treatment and biomedical fields. The strategy developed in this study can provide insights for designing hybrid nanosheets with diverse heterogeneous two-dimensional （2D） nanomaterials.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
A helical TiO2 nanotube (TNT) array modified with cuprous oxide (Cu2O) electrode was fabricated and used for nonenzymatic glucose detection. The structure and morphology of Cu2O/TNT were ...characterized by X-ray diffraction and transmission electron microscopy. The electrocatalytic performance of Cu2O/TNT electrode for glucose oxidation was investigated by cyclic voltammetry and chronoamperometry. At an applied potential of +0.65V versus SCE, a linear range was obtained within the concentration range of 3.0–9.0mM with a detection limit of 62μM (signal/noise=3). The response time was approximately 3s after adding 0.10mM glucose. Formate and gluconic acid were identified as the main products of the glucose oxidation using 1H NMR spectrometry. A possible mechanism for continuous glucose oxidation was also proposed.
Display omitted
•Helical Cu2O/TiO2 nanotubes array electrode for nonenzymatic glucose detection has been fabricated.•A proposed electrochemical sensor has highly selective, sensitive, stable and fast determination of glucose.•Formate and gluconic acid were identified as the main product of the glucose oxidation reaction using 1H NMR spectrometry.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Natural two-dimensional （2D） kaolinite nanoclay has been incorporated into an emerging drug delivery system. The basal spacing of the kaolinite nanoclay was expanded from 0.72 to 4.16 nm through the ...intercalation of various organic guest species of different chain lengths, which can increase the efficiency in drug delivery and reduce the toxicity of doxorubicin （DOX）. Original kaolinite （Kaolin） and the Kaolin intercalation compounds exhibited a high level of biocompatibility and very low toxicity towards cells of pancreatic cancer, gastric cancer, prostate cancer, breast cancer, colorectal cancer, esophageal cancer, and differentiated thyroid cancer. However, lung cancer and hepatocellular cancer cells need more strict compositional, structural, and morphological modulations for drug delivery carriers. DOX-Kaolin and the DOX-Kaolin intercalation compounds showed dramatically faster drug release in moderately acidic solution than in neutral condition, and exhibited enhanced therapeutic effects against ten model cancer cell cultures in a dose-dependent manner. The use of 2D nanoclay materials for a novel drug delivery system could feasibly pave a way towards high-performance nanotherapeutics, with superior antitumor efficacy and significantly reduced side effects.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The construction and application of a new type of composite material are achieved more and more attention. However, expected Sb2Se3/attapulgite composites aim to use the low price, and high ...adsorption of attapulgite in assembling Sb2Se3 is quite difficult to be acquired by a facile and benign environmental hydrothermal method. In this manuscript, we developed a new way for preparation of an emerging composite by means of Sb2O3 as a media linking Sb2Se3 and attapulgite together, and finally won an emerging composite Sb2Se3/Sb2O3@attapulgite, which presented an excellent catalytic properties for catalytic hydrogenation of p-nitrophenol. It was noted that the Sb2Se3/Sb2O3@attapulgite composites exhibited a high conversion rate for the hydrogenation of p-nitrophenol that was up to 90.7% within 15 min, which was far more than the 61.5% of Sb2Se3 sample. The excellent catalytic performance was attributed to the highly dispersion Sb2Se3 microbelts and Sb2Se3@Sb2O3@attapulgite rods, which would improve the adsorption of the reactant species and facility electronic transfer process of the catalytic hydrogenation of p-nitrophenol.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A novel visible-light-driven photocatalyst of Ag/AgGaO2 metal semiconductor heterostructures (MSH) has been prepared by a combined sol-gel and ion exchange method. XRD, DRS, SEM, PL and XPS were ...employed to characterize the as-synthesized samples. The Ag/AgGaO2 MSH exhibited a remarkably high photocatalytic activity for the degradation of methyl blue (MB) under visible light irradiation. The degradation rate of Ag/AgGaO2 MSH reached to 95% in decomposing MB for 180 min, which is 31.2% higher compared to that of pure AgGaO2 photocatalyst. The improved photocatalytic performance of Ag/AgGaO2 MSH could be ascribed to the synergistic effect, which is the enhanced visible-light absorption and efficient electron-hole separation. This suggests that Ag/AgGaO2 MSH would have a potential application in the fields of dye wastewater purification.
Display omitted
•A novel visible-light-driven Ag/AgGaO2 photocatalyst was successfully prepared.•Photocatalyst exhibited obvious absorption in the visible region.•Photocatalytic performance was remarkably improved.•Enhanced activity was caused from the synergistic effect of metal semiconductor heterostructures.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Substitutional doping is a strategy in which atomic impurities are optionally added to a host material to promote its properties, while the geometric and electronic structure evolution of natural ...nanoclay mineral upon substitutional metal doping is still ambiguous. This paper first designed an efficient lanthanum (La) doping strategy for nanotubular clay (halloysite nanotube, HNT) through the dynamic equilibrium of a substitutional atom in the presence of saturated AlCl
3
solution, and systematic characterization of the samples was performed. Further density functional theory (DFT) calculations were carried out to reveal the geometric and electronic structure evolution upon metal doping, as well as to verify the atom-level effect of the La doping. The CdS loading and its corresponding water splitting performance could demonstrate the effect of La doping. CdS nanoparticles (11 wt.%) were uniformly deposited on the surface of La-doped halloysite nanotube (La-HNT) with the average size of 5 nm, and the notable photocatalytic hydrogen evolution rate of CdS/La-HNT reached up to 47.5 μmol/h. The results could provide a new strategy for metal ion doping and constructive insight into the substitutional doping mechanism.
Engineered nanoparticle–support interaction is an effective strategy for tuning the structures and performance of engineered nanoparticles. Here, we show that tuning the dehydroxylation of kaolinite ...nanoclay as the support could induce zinc oxide–kaolinite interactions. We used free energy theory, electron microscopy, and X-ray photoemission spectroscopy to identify interaction strengths between metal oxides and the underlying nanoclay induced by dehydroxylation. Desirable exposure of nanoparticle sites and the geometrical and crystal structure were obtained by tuning the interface interactions between ZnO nanoparticles and nanoclay. The surface free energy of zinc oxide–nanoclay results in different interfacial interactions, and the properties of the surface free energy electron-donating (γ−) and electron-accepting (γ+) parameters have significant effects on the electron acceptor. This could, in turn, promote stronger interactions between zinc oxide and the kaolinite surface, which produce more active (0001) Zn-polar surfaces with promoting zinc oxide nanoparticles growing along the direction. Reactive oxygen species, leached zinc ions, and electron transfer can modulate the antibacterial activities of the samples as a function of interface free energy. This further demonstrates the interfacial interactions induced by dehydroxylation. This work has new application potential in biomedicine and materials science.
Full text
Available for:
CEKLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
PDF
