Controlled Assembly of Sb₂S₃ Nanoparticles on Silica/Polymer Nanotubes:Insights into the Nature of Hybrid Interfaces

Silica nanotubes can serve as high aspect ratio templates for the deposition of inorganic nanoparticles to form novel hybrids. However, the nature of the interfacial binding is still an unresolved challenge when considered at the atomic level. In this work, novel nanocomposites have been successfully fabricated by the controlled nucleation and assembly of Sb(2)S(3) nanoparticles on the surface of mercaptopropyl-functionalized silica/polymer hybrid nanotubes (HNTs). The Sb(2)S(3) nanoparticles were strongly attached to the HNTs surface by interactions between the pendent thiol groups and inorganic sulfur atoms. Detailed analysis of the geometric and electronic structure using first–principle density functional theory demonstrates charge transfer from the nanoparticles to the underlying HNTs at the Sb(2)S(3)/HNTs interfaces. Formation of a packed array of Sb(2)S(3) nanoparticles on the HNTs results in mixing of the electronic states of the components, and is mediated by the mercaptopropyl bridges between Sb(2)S(3) and the outer layer of the HNTs

Substitutional Doping for Aluminosilicate Mineral and Superior Water Splitting Performance

Abstract 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 AlCl3 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

Inhibitory effects and oxidative damages in Cladophora sp. (Cladophoraceae) exposed to berberine

Cladophora members are present in seawater and freshwater ecosystems worldwide. Their growth poses a serious threat to water environment, fisheries, production and living. In order to explore safe and ecological treatment methods, the inhibitory effects and oxidative damages (48 and 96 h) in Cladophora sp. (Cladophoraceae) exposed to 0–0.30 g L−1 berberine were investigated. Results showed that the LC 50 of berberine to Cladophora was 0.147 g L−1 and 0.063 g L−1 at 48 h and 96 h, respectively. Malondialdehyde and total protein contents first increased and then decreased sharply with increasing exposure concentrations of berberine. The Cladophora cells accelerated protein synthesis when their cell membranes were subjected to oxidative damage. Superoxide dismutase activity was down-regulated slightly after exposure to low berberine concentration (0.05 g L−1) and strongly when the Cladophora cells suffered from great oxidative damage. Total antioxidant capacity (T-AOC) first decreased sharply and then increased with increasing exposure concentrations of berberine. The decrease in T-AOC indicated the enzymatic antioxidants were continuously inhibited with increasing exposure concentrations of berberine. The increase in T-AOC indicated the secretion of non-enzymatic antioxidants was continuously strengthened with increasing exposure concentrations of berberine. Cladophora DNA also underwent oxidative damage due to berberine. Low concentrations of berberine activated its repair mechanisms, but high concentrations could cause irreparable damage. Therefore, these results suggested that berberine could inhibit the growth of Cladophora by oxidative damage, and Cladophora responded physiologically to this stress accordingly

Sepiolite/Fe3O4 composite for effective degradation of diuron

A novel sepiolite-supported Fe3O4 magnetite (SepMag) composite was prepared for diuron degradation. The samples were characterized by X-ray powder diffraction (XRD), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), N2 adsorption-desorption and BET surface area analysis, scanning electron microscope (SEM) as well as transmission electron microscope (TEM). The chemical state of Fe in SepMag composite before and after degradation experiments was characterized by X-ray photoelectron spectroscopy (XPS). The enhanced degradation efficiency for diuron was attributed to the effective generation of hydroxyl radical in ultrasound/SepMag/H2O2 system. The degradation rate of diuron depended upon the composite amount, hydrogen peroxide dosage, initial pH of solution and temperature. The degradation reaction was also optimized by changing the ultrasound intensity and Fe3O4 content in the composites. Moreover, mineralization and degradation pathway were evaluated on the basis of total organic carbon and liquid chromatography mass spectrometry. It was confirmed that with the assistance of ultrasound treatment SepMag composite has potential advantages for the removal of diuron from aqueous solution

Shock Tube Measurements and Kinetic Investigation on the Ignition Delay Times of Methane/Dimethyl Ether Mixtures

In this work, the ignition delay times of stoichiometric methane/dimethyl ether (DME) were measured behind the reflected shock waves over a wide range of conditions: temperatures between 1134 and 2105 K, pressures of 1, 5, and 10 bar, a DME blending ratio from 0 to 100% (M100 to M0), and an argon concentration of 95%. The present shock tube facility was validated by comparing the measured ignition delay times of DME with literature values and was used for measurement of the subsequent methane/DME ignition delay times. The ignition delay times of all mixtures exhibit a negative pressure dependence. For a given temperature, the ignition delay time of methane/DME decreases remarkably with the presence of only 1% DME. As the DME blending ratio increases, the ignition delay times are correspondingly decreased; however, the ignition promotion effect of DME is decreased. The calculated ignition delay times of methane/DME mixtures using two recently developed kinetic mechanisms are compared with those of measurements. The NUI C4 mechanism yields good prediction for the ignition delay time of methane. With an increase of the DME blending ratio, the performance of this model becomes moderated. Zhao’s DME model yields good prediction for all of the mixtures studied in this work; thus, it was selected for analyzing the ignition kinetics of methane/DME fuel blends, through which the nonlinear effect of DME addition in promoting ignition is interpreted

Interfacial Chemical Bond Modulation of Co₃(PO₄)₂‑MoO_3–<i>x</i> Heterostructures for Alkaline Water/Seawater Splitting

The development of a high current density with high energy conversion efficiency electrocatalyst is vital for large-scale industrial application of alkaline water splitting, particularly seawater splitting. Herein, we design a self-supporting Co3(PO4)2-MoO3–x/CoMoO4/NF superaerophobic electrode with a three-dimensional structure for high-performance hydrogen evolution reaction (HER) by a reasonable devise of possible “Co-O-Mo hybridization” on the interface. The “Co-O-Mo hybridization” interfaces induce charge transfer and generation of fresh oxygen vacancy active sites. Consequently, the unique heterostructures greatly facilitate the dissociation process of H2O molecules and enable efficient hydrogen spillover, leading to excellent HER performance with ultralow overpotentials (76 and 130 mV at 100 and 500 mA cm–2) and long-term durability of 100 h in an alkaline electrolyte. Theoretical calculations reveal that the Co3(PO4)2-MoO3–x/CoMoO4/NF promotes the adsorption/dissociation process of H2O molecules to play a crucial role in improving the stability and activity of HER. Our results exhibit that the HER activity of non-noble metal electrocatalysts can be greatly enhanced by rational interfacial chemical bonding to modulate the heterostructures

Interfacial Chemical Bond Modulation of Co₃(PO₄)₂‑MoO_3–<i>x</i> Heterostructures for Alkaline Water/Seawater Splitting

The development of a high current density with high energy conversion efficiency electrocatalyst is vital for large-scale industrial application of alkaline water splitting, particularly seawater splitting. Herein, we design a self-supporting Co3(PO4)2-MoO3–x/CoMoO4/NF superaerophobic electrode with a three-dimensional structure for high-performance hydrogen evolution reaction (HER) by a reasonable devise of possible “Co-O-Mo hybridization” on the interface. The “Co-O-Mo hybridization” interfaces induce charge transfer and generation of fresh oxygen vacancy active sites. Consequently, the unique heterostructures greatly facilitate the dissociation process of H2O molecules and enable efficient hydrogen spillover, leading to excellent HER performance with ultralow overpotentials (76 and 130 mV at 100 and 500 mA cm–2) and long-term durability of 100 h in an alkaline electrolyte. Theoretical calculations reveal that the Co3(PO4)2-MoO3–x/CoMoO4/NF promotes the adsorption/dissociation process of H2O molecules to play a crucial role in improving the stability and activity of HER. Our results exhibit that the HER activity of non-noble metal electrocatalysts can be greatly enhanced by rational interfacial chemical bonding to modulate the heterostructures