Xiaomeng Lv

Natural leaves-assisted synthesis of nitrogen-doped, carbon-rich nanodots-sensitized, Ag-loaded anatase TiO2 square nanosheets with dominant {001} facets and their enhanced catalytic applications

Extending the UV response of anatase TiO2 photocatalysts into the visible light range can play a pivotal role in promoting the practical applications of these catalysts. Nitrogen and carbon co-doped, silver loaded anatase TiO2 (Ag@NC–TiO2) single-crystal nanosheets dominated by {001} facets were prepared for the first time using leaves as the nitrogen and carbon source by a facile, low cost method. The size of the Ag particles on NC–TiO2 nanosheets can be tuned from 1.5 nm to 15 nm using a photo-reduction strategy. The synthesized Ag@NC–TiO2 nanosheets show higher photocatalytic activity in the photodecomposition of organic pollutants compared to NC–TiO2, TiO2 and P25 under visible light irradiation. The enhanced photocatalytic efficiency was ascribed to a synergistic effect between N, C and Ag. In addition, the formed Ag@NC–TiO2 heteronanosheets are highly dispersible in aqueous solution and are capable of efficient catalysis for the reduction of p-nitrophenol. The present synthesis gives a promising method of forming non-metal co-doped, metal nanoparticles (NPs) loaded anatase TiO2 with dominant {001} facets and for broad applications in catalysis and photocatalysis.

Photodegradation of lambda‐cyhalothrin and cypermethrin in aqueous solution as affected by humic acid and/or copper: Intermediates and degradation pathways

The influence of coexisting humic acids (HA) or Cu²⁺ on the photodegradation of pesticides lambda-cyhalothrin (λ-CHT) and cypermethrin (CPM) in aqueous solution was studied under xenon lamp irradiation. The removal efficiency of pesticides λ-CHT and CPM were enhanced in the presence of either Cu²⁺ or HA but restrained in the presence of both Cu²⁺ and HA. The photodegradation of λ-CHT and CPM followed first-order reaction kinetics. The photodegradation intermediates of λ-CHT and CPM were determined using gas chromatography/mass spectrometry. Possible photodegradation pathways included decarboxylation, ester bond cleavage, dechlorination, and phenyl group removal.

Integrating AgI/AgBr biphasic heterostructures encased by few layer h-BN with enhanced catalytic activity and stability

Using freshly prepared water-soluble KBr crystal as facile, low-cost sacrificial template, AgBr nanocubes were synthesized through one-pot precipitation method, then navy bean shaped AgI/AgBr biphasic heterostructures were synthesized through anion-exchange reaction and encased within few-layer h-BN to obtain final product. The obtained heterostructured AgI/AgBr/h-BN composite without plasmonic noble metal nanoparticles was used as stable and high active photocatalyst for dye degradation under visible light irradiation, comparing both with self-prepared normal AgBr, AgBr cubes, AgI/AgBr navy beans and other related catalysts reported in the literature. The significant boosting of activity was attributed to the formation of AgI/AgBr interface and the coupling of few-layer h-BN, the latter of which not only effectively suppresses the reduction of silver ions but greatly enhance the charge separation. Furthermore, it was suggested that the photogenerated holes and superoxide radical were the main active species according to photoelectron chemical measurements, electron spin resonance spin-trap analysis and radical trapping experiments. Finally, the possible mechanism of enhanced photocatalytic activity and stability was discussed and proposed. The work demonstrates that engineering Ag-based semiconductor coupling with h-BN would profit the design strategy for low-cost, solar-driven photocatalysts.

Anti-fouling graphene oxide based nanocomposites membrane for oil-water emulsion separation

Anti-fouling copper hydroxide nanowires (CHNs)-graphene oxide (GO) nanocomposites membrane was fabricated by a vacuum-assisted filtration self-assembly process. CHNs were covered on the surface and inserted into the interlayers of the GO nanosheets to form the rough surface and nanostructure channels. The membrane with water contact angles (CAs) of 53° and oil CAs of 155° exhibited superior stability, hydrophilicity, underwater superoleophobicity and ultralow oil adhesion, and hence it could separate the oil-water emulsion with a high efficiency of >99%. This membrane showed the combined advantages of high oil rejection rate and ultralow membrane fouling, making it promising for practical oil-water emulsion separation applications.