Hybrids of ethylenediamine-modified reduced graphene oxide (RGO) and polythiophene (PTh) were synthesized successfully by in situ chemical polymerization at room temperature for 2 h and loaded on a flexible PET film to construct a smart sensor. The structure and properties of the hybrids have been characterized by XRD, SEM, TG, UV–vis, and FTIR analysis. The NO2-sensing performance of pure PTh- and hybrids-based sensors was examined at room temperature, the results indicate that the hybrid film sensor with 5 wt % RGO not only exhibits high sensitivity to 10 ppm of NO2 gas which is nearly 4 times higher than that of pure PTh and excellent selectivity but also is flexible, low cost, portable, and wearable. The mechanism of sensing performance enhanced by incorporating graphene into PTh also was discussed, which is attributed to large specific surface of the hybrid and synergetic effects between the components in a hybrid.

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.

•SnO2 quantum dots (QDs) have been prepared by a simple precipitation method.•SnO2 nanoparticles with different size have been obtained by annealing the SnO2 QDs.•SnO2 nanoparticles show high sensitivity, fast response (1 s) and recovery (1 s) to ethanol.SnO2 quantum dots (QDs) with diameter of ~2.5 nm has been successfully synthesized by a simple precipitation method without using any capping agent or organic solvent at room temperature, and SnO2 nanoparticles with different diameter were obtained by annealing the as-synthesized SnO2 QDs at different temperature. The SnO2 nanoparticle with small size of 3.7 nm presents high sensing response and ultrafast response (1 s) and recovery (1 s) to ethanol.

•Porous ZnO spherical aggregates have been prepared by a simple method.•The ZnO was composed of nanoparticles and has a specific surface area of 51 m2 g−1.•The ZnO spherical aggregates show excellent photocatalytic performance.Mesoporous ZnO spherical aggregates self-assembled with nanoparticles were prepared in a surfactant-free and template-free route under mild conditions. This ZnO spherical aggregates exhibit excellent photocatalytic degradation performance due to the small nanoparticles, high specific surface area, and porous structures, and also have easy separation and good recycling performance because of the large secondary particle size.ZnO spherical aggregates composed of nanoparticles have been prepared by a simple method. The obtained ZnO spherical aggregates exhibit excellent photocatalytic degradation performance due to the small nanoparticles, high specific surface area, and porous structures, and also have easy separation and good recycling performance because of their large secondary particle size.

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.Keywords: hybrid pigment; intercalation; layered double hydroxides; photostability; thermostability

Acid Blue 129 (AB129) and salicylate have been cointercalated into the interlayer galleries of ZnAl layered double hydroxides (LDHs) through a coprecipitation method to prepare organic–inorganic hybrid pigments with improved photostability. The prepared hybrids were characterized by XRD, FTIR spectroscopy, SEM, TG-DTG-DTA, UV–vis spectroscopy, and CIE 1976 L*a*b* color scales. The results show the successful cointercalation of AB129 and salicylate into the interlayer space of LDHs, forming a new kind of organic–inorganic hybrid pigment, and reveal that intercalation into the interlayer of LDHs can slightly improve the thermal stability of AB129 as a result of the protection offered by LDH layers. The AB129/salicylate molar ratio plays an important part in the color properties of the hybrid pigment. The cointercalation of salicylate can efficiently enhance the photostability of AB129 by absorbing harmful UV rays. Therefore, the cointercalation of AB129 and salicylate into the interlayer of ZnAl LDHs can effectively produce organic–inorganic hybrid pigments with enhanced photostability.