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• The homogeneous double-layer TZS powders with multi-heterojunction structure was prepared by Pechini sol–gel method. • The inner and outer TZS layers form a homogenous junction with excellent compatibility. • The structure of multiple heterojunctions between two layers makes the transfer between electrons and holes more efficient. Traditional heterojunctions are usually constructed with different material systems, resulting in weaker interfacial effects in the catalytic system. In order to solve this problem, we use a simple sol–gel method to construct a homogeneous double-layer TiO 2 -ZrO 2 -SiO 2 photocatalyst with multi-heterojunction (d -TZS), which can effectively improve the photocatalytic property. By investigating the influence of various factors on the photocatalytic performance, the degradation rate of Rh B by d -TZS can reach about 99.6 % within 40 min of photoreaction, and Rh B almost completely degraded within 60 min. This is attributed to three aspects of homogeneity, multiple heterojunctions and oxygen vacancies. Firstly, the inner and outer layers are homogeneous with excellent compatibility, and the outer layer has strong adsorption. Secondly, the multi-heterostructure which forms between the inner-layer multi-heterojunction and the outer layer can separate the photogenerated electrons in each layer to a certain extent. Finally, the oxygen vacancies formed after the bonding of the outer and inner layers can further enhance the mobility of photogenerated carriers. This idea provides new methods for the study of homogenous multiple heterojunctions with high visible light degradation rate. [ABSTRACT FROM AUTHOR]

Synergy is essential to maximize the photocatalytic performance of the catalyst, which makes the preparation of photocatalytic materials with the synergistic effect of adsorption and catalysis become an attractive research direction. Therefore, we have prepared TiO 2 –ZrO 2 –SiO 2 nano-powders by simple Pechini sol-gel method, which can effectively improve the synergistic effect of adsorption and degradation of photocatalytic materials. The results demonstrate that TiO 2 –ZrO 2 –SiO 2 possesses excellent photocatalytic performance and adsorption ability. And it can be deduced that in the TiO 2 –ZrO 2 –SiO 2 system, SiO 2 is as for adsorbent, and TiO 2 and ZrO 2 act synergistically as a photocatalyst. The enhanced photocatalytic ability of TiO 2 –ZrO 2 –SiO 2 is attributed to the acceleration of mass transfer by adsorption process, narrowed bandgap (Eg = 2.9 eV) and effective charge separation rate resulting from the formation of Ti–O–Zr. This work also studied the synergy effect between adsorption and photocatalytic properties in TiO 2 –ZrO 2 –SiO 2 , and synergy factor β is used to evaluate the synergistic effect. Moreover β > 1 in first 30 min of visible light irradiation demonstrates that the remarkable synergistic effect exists in TiO 2 –ZrO 2 –SiO 2 compound system. • TiO 2 –ZrO 2 –SiO 2 photocatalyst with both adsorption and photocatalytic properties was successfully prepared. • β (synergy factor) which explains the adsorption-photocatalytic synergistic effect of TiO 2 –ZrO 2 –SiO 2 system is remarkable. • The adsorption-photocatalytic performance can be regenerated. [ABSTRACT FROM AUTHOR]

ZrB 2 –ZrC–SiC nanopowders with uniform phase distribution were prepared from cost-effective ZrOCl 2 ·8H 2 O by a simple sol-gel method. The synthesis route, ceramization mechanism and morphology evolution of the nanopowders were investigated. ZrB 2 –ZrC–SiC ceramic precursor can be successfully obtained through hydrolysis and condensation reactions between the raw materials. Pyrolysis of the precursor was completed at 650 °C, and it produced ZrO 2 , SiO 2 , B 2 O 3 and amorphous carbon with a yield of 39% at 1300 °C. By heat-treated at 1500 °C for 2 h, highly crystallized ZrB 2 –ZrC–SiC ceramics with narrow size distribution were obtained. With the holding time of 2 h, both the crystal size and the particle size can be refined. Further prolonging the holding time can lead to serious particles coarsening. Studies on the microstructure evolution of the generated carbon during the ceramic conversion demonstrates the negative effect of the ceramic formation on the structure order improvement of the carbon, due to the large amount of defects generated in it by the boro/carbothermal reduction reactions. [ABSTRACT FROM AUTHOR]

• The BTO@TPU films were synthesized via electrospinning route. • The films are stretchable, flexible, waterproof and transparent. • The films can be used in the field of dynamic and multimodal anti-counterfeiting. [Display omitted] Developing novel and practical anti-counterfeiting materials has always been at the forefront of protecting information security. However, achieving the multimodal anti-counterfeiting remains a huge challenge. In this work, we synthesized a series of Bi 2 Ti 4 O 11 :xYb3+, 0.02Er3+ (x = 0.1, 0.2, 0.4) nanoparticles by a sol-gel method and realized the upconverting red, yellow and green luminescence under near infrared (NIR) excitation. To confirm the practicality of the materials, we designed the novel anti-counterfeiting flexible films based on thermoplastic polyurethane (TPU) via electrospinning route. The composite film (BTO@TPU) is transparent, elastic, stretchable, waterproof and environmentally friendly. In addition, no trace of light can be observed under daylight, indicating the films have excellent concealment. Nevertheless, any patterns you desired can be written by a 980 nm laser pointer and the patterns with red, yellow and green luminescence can be "read" by the streamer camera of smart phone. The proof-of-concept experiment provided the novel and flexible BTO@TPU films keen insights in the application of anti-counterfeiting. This work will supply an arena to boost the application of upconverting materials in the field of dynamic and multimodal anti-counterfeiting. [ABSTRACT FROM AUTHOR]