In Situ Local Oxidation of SnO Induced by Laser Irradiation: A Stability Study

In this work, semiconductor tin oxide (II) (SnO) nanoparticles and plates were synthesized at room conditions via a hydrolysis procedure. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the high crystallinity of the as-synthesized romarchite SnO nanoparticles with dimensions ranging from 5 to 16 nm. The stability of the initial SnO and the controlled oxidation to SnO2 was studied based on either thermal treatments or controlled laser irradiation using a UV and a red laser in a confocal microscope. Thermal treatments induced the oxidation from SnO to SnO2 without formation of intermediate SnOx, as confirmed by thermodiffraction measurements, while by using UV or red laser irradiation the transition from SnO to SnO2 was controlled, assisted by formation of intermediate Sn3O4, as confirmed by Raman spectroscopy. Photoluminescence and Raman spectroscopy as a function of the laser excitation source, the laser power density, and the irradiation duration were analyzed in order to gain insights in the formation of SnO2 from SnO. Finally, a tailored spatial SnO/SnO2 micropatterning was achieved by controlled laser irradiation with potential applicability in optoelectronics and sensing devices.

Fabrication of a Novel AgBr/Ag2MoO4@InVO4 Composite with Excellent Visible Light Photocatalytic Property for Antibacterial Use

A novel AgBr/Ag2MoO4@InVO4 composite photocatalyst with different heterojunction structures was successfully constructed by compounding InVO4 with Ag2MoO4 and AgBr. According to the degradation, antibacterial and free radical trapping data, the photocatalytic antibacterial and antifouling activities of AgBr/Ag2MoO4@InVO4 composite were evaluated, and the corresponding photocatalytic reaction mechanism was proposed. Adding AgBr/Ag2MoO4@InVO4 composite, the degradation rate of ciprofloxacin (CIP) achieved 95.5% within 120 min. At the same time, the antibacterial rates of Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) achieved 99.99%. The AgBr/Ag2MoO4@InVO4 composite photocatalyst showed promising usage in photocatalytic antibacterial and purification areas.

Structural characterization of SnO nanoparticles synthesized by the hydrothermal and microwave routes

SnO particles were synthesized by an alkali-assisted hydrothermal and microwave methods. The aqueous-based reactions were carried out at pH ~ 8, under inert atmosphere (Ar). The reactions were taken under different times, and a full XRD structural analysis was made to evaluate the conversion from the Sn₆O₄(OH)₄ intermediate to SnO particles. Williamson-Hall analysis showed that the size and strain of the SnO particles were time and route treatment dependent. Microwave heating yielded a single tetragonal SnO phase after 1 h of thermal treatment, and TEM images revealed spherical-shaped SnO nanoparticles with an average size of 9(1) nm. While by the hydrothermal treatment single SnO phase was obtained only after 4 hours, yielding non-uniform and elongated particles with sub-micrometric size. A dissolution-recrystallization process was taken into account as the mechanism for SnO particles formation, in which hydroxylated complexes, Sn₂(OH)₆⁻², then condense to form the oxide. The time-shorting reaction provided by the microwave-assisted synthesis may be attributed to better heat distribution.

Importance of ZnTiO3 Phase in ZnTi-Mixed Metal Oxide Photocatalysts Derived from Layered Double Hydroxide

In this study, ZnTi-mixed metal oxides (ZTM), such as ZnTiO₃, were synthesized from ZnTi layered double hydroxides by varying the molar ratio of Zn/Ti, calcination temperatures, and synthesis methods (hydrothermal or reflux). The surface electronic characteristics of ZTM were investigated by the energy-resolved distribution of electron traps (ERDTs) using reversed double-beam photoacoustic spectroscopy. The ZTM samples obtained by conducting hydrothermal synthesis at 500 °C showed similar ERDT patterns independent of the molar ratio of Zn/Ti, although ZnTiO₃ phase was not observed in the X-ray diffraction pattern, when the Zn/Ti ratio was high. When the ERDT patterns demonstrated a high electron accumulation level near the conduction band bottom in hydrothermal products at 500 °C, a higher photocatalytic phenol degradation efficiency was observed due to the formation of ZnTiO₃ phase. This suggested that the product with the high Zn/Ti molar ratio (Zn/Ti = 6) constituted amorphous ZnTiO_3.The enhanced photocatalytic performance of ZTM could be attributed to the heterojunction of electrons among ZnO, TiO₂, and ZnTiO₃, which enabled electron transfer in the composites, prevented charge recombination, and promoted a wider visible light adsorption by ZnTiO₃ phase irrespective of its crystallinity.

Tunable thickness and band structure of SnO sheets for improved photocatalytic activity

SnO sheets with tunable thickness were prepared via a hydrothermal method by employing PEG as a structure-directing agent and the thickness of SnO exhibited a significant influence on the photocatalytic efficiency.

In situ sulfuration synthesis of flexible PAN-CuS “flowering branch” heterostructures as recyclable catalysts for dye degradation

“Flowering branch”-like PAN-CuS hierarchical heterostructures were in situ synthesized through a facile hydrothermal sulfuration growth process on PAN-based fibers prepared by electrospinning. The PAN fibers can serve as a stable flexible support, while CuS flowers assembled from nanosheets can act as reactive materials, showing high performance in the degradation of dyes. Moreover, these heterostructures can be recovered easily without a decrease in their photocatalytic activity, thus showing favorable recycling capability.

“Flowering branch”-like PAN-CuS hierarchical heterostructures were in situ synthesized through a facile hydrothermal sulfuration growth process on PAN-based fibers prepared by electrospinning.