Lu-Ping Zhu

Self-assembled 3D BiOCl hierarchitectures: tunable synthesis and characterization

3D hierarchitectures (HAs) of BiOCl composed of 2D nanosheets, which intercross with each other, have been successfully synthesized by a template-free solvothermal method at 160 °C for 12 h. The morphology and compositional characteristics of the 3D HAs were investigated by various techniques. On the basis of characterization results, the growth of such 3D HAs has been proposed as an Ostwald ripening process followed by self-assembly. The growth and self-assembly of BiOCl nanosheets could be readily tuned with the molar ratio of urea to BiCl3·5H2O, which brought different morphologies and microstructures to the final products. The specific surface area and porosity of the 3D hierarchitectured (HAd) BiOCl also were investigated by using nitrogen adsorption and desorption isotherms. UV–vis spectra reveal that the band gap energies of the 3D HAs can be tuned from 3.05 eV to 3.32 eV. The as-prepared 3D HAd BiOCl showed much higher photocatalytic activity than that of the reported in the literature, which was evaluated by the degradation of Rhodamine-B (RhB) dye under ultraviolet light irradiation.

Synthesis and photocatalytic properties of core–shell structured α-Fe2O3@SnO2 shuttle-like nanocomposites

The core–shell structured α-Fe2O3@SnO2 shuttle-like nanocomposites were synthesized successfully by a simple solvothermal method. The structure and morphology were investigated by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive spectroscopy (EDS). The results reveal that the diameter in the middle part and the length of the heteronanostructures are respectively 110 and 450 nm, and the thickness of the shell composed of 5 nm SnO2 nanoparticles is about 15 nm. The photocatalytic activities of the as-prepared α-Fe2O3@SnO2 core–shell shuttle-like nanocomposites were evaluated by the photocatalytic decolorization of a model pollutant Rhodamine-B (RhB) under ultraviolet light. The as-prepared core–shell shuttle-like nanocomposites showed much higher photocatalytic activity than that of α-Fe2O3 shuttle-like nanorods, SnO2 nanoparticles, and the mixture of α-Fe2O3 nanorods and SnO2 particles, which may be attributed to effective synergy between α-Fe2O3 and SnO2, and the special core–shell structures.

Preparation and photocatalytic properties of SnO 2 coated on nitrogen-doped carbon nanotubes

SnO2 nanoparticles coated on nitrogen-doped carbon nanotubes were prepared successfully via a simple wet-chemical route. The as-obtained SnO2/CNx composites were characterized using X-ray powder diffraction, scanning electron microscopy, and transmission electron microscopy. The photocatalytic activity of as-prepared SnO2/CNx for degradation Rhodamine B under UV light irradiation was investigated. The results show that SnO2/CNx nanocomposites have a higher photocatalytic activity than pure SnO2 and SnO2/CNTs nanocomposites. This enhanced photoresponse indicates that the photoinduced electrons in the SnO2 prefer separately transferring to the CNx, which has a high degree of defects. As a consequence, the radiative recombination of the electron-hole pairs is hampered and the photocatalytic activity is significantly enhanced for the SnO2/CNx photocatalysts.

Enhancement of Photocatalytic Activity on TiO2-Nitrogen-Doped Carbon Nanotubes Nanocomposites

TiO2-nitrogen-doped carbon nanotubes (TiO2-CNx) nanocomposites are successfully synthesized via a facile hydrothermal method. The prepared photocatalysts were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric and differential scanning calorimetry analyses (TGA-DSC). The results show that the TiO2 nanoparticles with a narrow size of 7u2009nm are uniformly deposited on CNx. The photocatalytic activity of the nanocomposite was studied using methyl orange (MO) as a model organic pollutant. The experimental results revealed that the strong linkage between the CNx and TiO2 played a significant role in improving photocatalytic activity. However, the mechanical process for CNx and TiO2 mixtures showed lower activity than neat TiO2. Moreover, TiO2-CNx nanocomposites exhibit much higher photocatalytic activity than that of neat TiO2 and TiO2-CNTs nanocomposites. The improved photodegradation performances are attributed to the suppressed recombination of electrons and holes caused by the effective transfer of photogenerated electrons from TiO2 to CNx.

Facile Fabrication of Platinum Nanoparticles Supported on Nitrogen-doped Carbon Nanotubes and Their Catalytic Activity

A facile impregnation method under mild condition is designed for synthesis of highly dispersed Pt nanoparticles with a narrow size of 4–7 nm on nitrogen-doped carbon nanotubes (CN x ). CN x do not need any pre-surface modification due to the inherent chemical activity. The structure and nature of Pt/CN x were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive spectroscopy spectrum. All the experimental results revealed that the large amount of doped nitrogen atoms in CN x was virtually effective for capturing the Pt(IV) ions. The improved surface nitrogen functionalities and hydrophilicity contributed to the good dispersion and immobilization of Pt nanoparticles on the CN x surface. The Pt/CN x served as active and reusable catalysts in the hydrogenation of allyl alcohol. This could be attributed to high dispersion of Pt nanoparticles and stronger interaction between Pt and the supports, which prevented the Pt nanoparticles from aggregating into less active Pt black and from leaching as well.

Synthesis of nitrogen-doped carbon nanotubes-FePO4 composite from phosphate residue and its application as effective Fenton-like catalyst for dye degradation

Phosphate residue is regarded as a hazardous waste, which could potentially create significant environmental and health problems if it is not properly treated and disposed of. In this study, nitrogen-doped carbon nanotubes-FePO4 (NCNTs-FePO4) composite was successfully synthesized from phosphate residue, and its application as an effective catalyst was explored. Firstly, an effective method was developed to recover FePO4 from phosphate residue, achieving an impressive FePO4 mass recovery rate of 98.14%. Then, the NCNTs-FePO4 catalyst was synthesized from the recovered FePO4 by two main reactions, including surface modification and chemical vapor deposition. Finally, the synthesized NCNTs-FePO4 was applied to photo-degrade 15u202fmg/L Rhodamine B (RhB) in a Fenton-like system. The results showed that 98.9% of RhB could be degraded in 60u202fmin, closely following the pseudo-first-order kinetics model. It was found that even after six consecutive cycles, NCNTs-FePO4 still retained a high catalytic capacity (>50%). Moreover, •OH radicals participating in the RhB degradation process were evidenced using quenching experiments and electron paramagnetic resonance analysis, and a rational mechanism was proposed. It was demonstrated that the materials synthesized from hazardous phosphate residue can be used as an effective catalyst for dye removal.

Self-assembled spherical palladium/HMS nanocomposites and their catalytic application

A novel palladium catalyst immobilised the mesoporous molecular sieve Hexagonal Mesoporous Silica (HMS) was prepared via a self-assembly process. The catalytic activity and recycle ability of the spherical palladium/HMS nanocomposites were examined for the Heck reaction. Palladium nanoparticles incorporated into HMS are characterised by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The morphology of HMS is predominated with spheres, and Pd nanoparticles are randomly distributed throughout the entire silica framework without severe agglomeration. The heterogeneous catalyst is proved to be an active and reusable catalyst in the coupling of ethyl acrylate with aryl halides because of combination, the advantages of stabilising agent and mesoporous silica support.