Ice-templated synthesis of tungsten oxide nanosheets and their application in arsenite oxidation

Tungsten oxide (WO₃) nanosheets were prepared as catalysts to activate hydrogen peroxide (H₂O₂) in arsenite (As(III)) oxidation. Ice particles were employed as templates to synthesize the WO₃ nanosheets, enabling easy template removal via melting. Transmission electron microscopy and atomic force microscopy revealed that the obtained WO₃ nanosheets were plate-like, with lateral sizes ranging from dozens of nanometers to hundreds of nanometers and thicknesses of <10 nm. Compared to that of the WO₃ nanoparticle/H₂O₂ system, a higher efficiency of As(III) oxidation was observed in the WO₃ nanosheet/H₂O₂ system. Electron spin resonance spectroscopy, radical quenching studies, and As(III) oxidation experiments under anoxic conditions suggested that the hydroperoxyl radical (HO₂^●) acted as the primary oxidant. The WO₃ nanosheets possessed numerous surface hydroxyl groups and electrophilic metal centers, enhancing the production of HO₂^● via H₂O₂ activation. Various anions commonly present in As(III)-contaminated water exhibited little effect on As(III) oxidation in the WO₃ nanosheet/H₂O₂ system. The high oxidation efficiency was maintained by adding H₂O₂ when it was depleted, suggesting that the catalytic activity of the WO₃ nanosheets did not deteriorate after multiple catalytic cycles.

WO3·nH2O Crystals with Controllable Morphology/Phase and Their Optical Absorption Properties

In this work, a one-step hydrothermal route is developed to prepare WO₃·nH₂O crystals with various morphology/phases, for which any surfactants, templates, or structure-directing agents are not used. Five types of WO₃·nH₂O crystals, including o-WO₃·H₂O nanoplates, rectangular m-WO₃ nanosheets, o-WO₃·0.33H₂O microspheres, h-WO₃ nanorods, and bundle-like h-WO₃ hierarchical structures, are successfully obtained by adjusting the amount of H₂SO₄ and reaction temperature. According to the experimental results, the formation mechanism for various WO₃·nH₂O species is proposed. In addition, the optical absorption properties of these WO₃·nH₂O crystals are also investigated by UV-vis absorption spectra.

Oxygen vacancy enriched Cu-WO3 hierarchical structures for the thermal decomposition of ammonium perchlorate

Cu-WO3 hierarchical structures are rapidly prepared and they exhibit excellent catalytic activity in AP decomposition due to their rich oxygen vacancies and Lewis acid sites.

Advances in Template Prepared Nano-Oxides and their Applications: Polluted Water Treatment, Energy, Sensing and Biomedical Drug Delivery

The nano-oxide materials with special structures prepared by template methods have a good dispersion, regular structures and high specific surface areas. Therefore, in some areas, improved properties are observed than conventional bulk oxide materials. For example, in the treatment of dye wastewater, the treatment efficiency of adsorbents and catalytic materials prepared by template method was about 30 % or even higher than that of conventional samples. This review mainly focuses on the progress of inorganic, organic and biological templates in the preparation of micro- and nano- oxide materials with special morphologies, and the roles of the prepared materials as adsorbents and photocatalysts in dye wastewater treatment. The characteristics and advantages of inorganic, organic and biological template are also summarized. In addition, the applications of template method prepared oxides in the field of sensors, drug carrier, energy materials and other fields are briefly discussed with detailed examples.

P-doped WO3 flowers fixed on a TiO2 nanofibrous membrane for enhanced electroreduction of N2

A hierarchically structured electrocatalyst, consisting of P-doped WO₃ flowers fixed on a flexible TiO₂ nanofibrous membrane, presents enhanced NRR performance.

A facile method to synthesize small-sized and superior crystalline Cs0.32WO3 nanoparticles for transparent NIR shielding coatings

Small-sized and superior crystalline Cs_0.32WO₃ nanoparticles used for NIR-shielding were developed by tailoring the molar ratio of Cs/W.