Facile Color Tuning, Characterization, and Application of Acid Green 25 and Acid Yellow 25 Co-intercalated Layered Double Hydroxides

Acid Green 25 (AG25) has been cointercalated with Acid Yellow 25 (AY25) into the interlayer of ZnAl layered double hydroxides (LDH) via a coprecipitation method to tune the color of hybrid pigments based on LDHs. The prepared hybrids were analyzed by X-ray diffraction, scaning electron microscopy, Fourier transform infrared microscopy, inductively coupled plasma–emission spectroscopy, thermogravimetry–differential thermal analysis, UV–vis, and CIE 1976 L*a*b* color scales, which show that AG25 and AY25 have been cointercalated into LDH and the color of the prepared LDH can be easily tuned from greenish blue to bluish green and green by adjusting the molar ratio of AY25/AG25. There exists host–guest and guest–guest interactions in the hybrids, and the intercalation into LDH significantly improves the thermal stability of the AY25. The hybrids were used as colorant to prepare green coatings and films, showing their potential application in the fields of paints and plastics

Co<b>-</b>intercalation of Acid Red 337 and a UV Absorbent into Layered Double Hydroxides: Enhancement of Photostability

Organic–inorganic hybrid pigments with enhanced thermo- and photostability have been prepared by co-intercalating C.I. Acid Red 337 (AR337) and a UV absorbent (BP-4) into the interlayer of ZnAl layered double hydroxides through a coprecipitation method. The obtained compounds were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric–differential thermogravimetric–differential thermal analysis, UV–visible spectroscopy, and the International Commission on Illumination (CIE) 1976 L*a*b* color scales. The results show the successful co-intercalation of AR337 and BP-4 into the interlayer region of layered double hydroxides (LDHs) and reveal the presence of host–guest interactions between LDH host layers and guest anions of AR337 and BP-4 and guest–guest interactions between AR337 and BP-4. The intercalation can improve the thermostability of AR337 due to the protection of LDH layers. Moreover, the co-intercalation of AR337 and BP-4 not only markedly enhances the photostability of AR337 but also significantly influences the color of the hybrid pigment

Novel Carbon Paper@Magnesium Silicate Composite Porous Films: Design, Fabrication, and Adsorption Behavior for Heavy Metal Ions in Aqueous Solution

It is of great and increasing interest to explore porous adsorption films to reduce heavy metal ions in aqueous solution. Here, we for the first time fabricated carbon paper@magnesium silicate (CP@MS) composite films for the high-efficiency removal of Zn²⁺ and Cu²⁺ by a solid-phase transformation from hydromagnesite-coated CP (CP@MCH) precursor film in a hydrothermal route and detailedly examined adsorption process for Zn²⁺ and Cu²⁺ as well as the adsorption mechanism. The suitable initial pH range is beyond 4.0 for the adsorption of the CP@MS to remove Zn²⁺ under the investigated conditions, and the adsorption capacity is mainly up to the pore size of the porous film. The composite film exhibits excellent adsorption capacity for both of Zn²⁺ and Cu²⁺ with the corresponding maximum adsorption quantity of 198.0 mg g^–1 for Zn²⁺ and 113.5 mg g^–1 for Cu²⁺, which are advantageous over most of those reported in the literature. Furthermore, the adsorption behavior of the CP@MS film follows the pseudo-second-order kinetic model and the Langmuir adsorption equation for Zn²⁺ with the cation-exchange mechanism. Particularly, the CP@MS film shows promising practical applications for the removal of heavy metal ions in water by an adsorption–filtration system

Facile Synthesis and Acetone Sensing Performance of Hierarchical SnO₂ Hollow Microspheres with Controllable Size and Shell Thickness

A facile method to prepare SnO₂ hollow microspheres has been developed by using SiO₂ microspheres as template and Na₂SnO₃ as tin resource. The obtained SnO₂ hollow microspheres were characterized by X-ray diffraction, scanning electron microscopy, high resolution and transmission electron microscopy, and Brunauer–Emmett–Teller analysis, and their sensing performance was also investigated. It was found that the diameter of SnO₂ hollow microspheres can be easily controlled in the range of 200–700 nm, and the shell thickness can be tuned from 7.65 to 30.33 nm. The sensing tests showed that SnO₂ hollow microspheres not only have high sensing response and excellent selectivity to acetone, but also exhibit low operating temperature and rapid response and recovery due to the small crystal size and thin shell structure of the hollow microspheres, which facilitate the adsorption, diffusion, and reaction of gases on the surface of SnO₂ nanoparticles. Therefore, the SnO₂ hollow microsphere is a promising material for the preparation of high-performance gas sensors

Doping Metal Elements of WO₃ for Enhancement of NO₂‑Sensing Performance at Room Temperature

WO₃ nanoparticles doped with Sb, Cd, and Ce were synthesized by a chemical method to enhance the sensing performance of WO₃ for NO₂ at room temperature. The doping with Sb element can significantly enhance the NO₂-sensing properties of WO₃. Upon exposure to 10 ppm of NO₂, particularly the 2 wt % Sb-doped WO₃ sample exhibits a 6.8-times higher response and an improved selectivity at room temperature compared with those of undoped WO₃. The enhanced NO₂-sensing mechanism of WO₃ by doping is discussed in detail, which is mainly ascribed to the increase of oxygen vacancies in the doped WO₃ samples as confirmed by Raman, photoluminescence, and X-ray photoelectron spectroscopy spectra. In addition, the narrower band gap may also be responsible for the enhancement of response as observed from the corresponding ultraviolet–visible spectra