In Situ Formation of Micropore-Rich Titanium Dioxide from Metal-Organic Framework Templates

Efficient Adsorption-Assisted Photocatalysis Degradation of Congo Red through Loading ZIF-8 on KI-Doped TiO2

Zeolitic imidazolate framework-8 (ZIF-8) was evenly loaded on the surface of TiO₂ doped with KI, using a solvent synthesis method, in order to produce a ZIF-8@TiO₂ (KI) adsorption photocatalyst with good adsorption and photocatalytic properties. The samples were characterized by XRD, SEM, EDX, XPS, BET and UV-Vis. The photocatalytic efficiency of the material was obtained by photocatalytic tests. The results indicate that the doping with I inhibited the grain growth and reduced the crystallite size of TiO₂, reduced the band gap width and improved the utilization rate for light. TiO₂ (KI) was a single crystal of anatase titanium dioxide. The combination of ZIF-8 and TiO₂ (KI) improved the specific surface area and increased the reaction site. The ZIF-8@TiO₂ (KI) for Congo red was investigated to validate its photocatalytic performance. The optimal concentration of Congo red solution was 30 mg/L, and the amount of catalyst was proportional to the degradation efficiency. The degradation efficiency of ZIF-8@TiO₂ (5%KI) was 76.42%, after being recycled four times.

Self-assembly of TiO2/ZIF-8 nanocomposites for varied photocatalytic CO2 reduction with H2O vapor induced by different synthetic methods

Photoreduction of carbon dioxide (CO2) provides an effective perspective for solving the energy crisis and environmental problems. Herein, two types of composite photocatalysts (TiO2/ZIF-8) based on ZIF-8 and TiO2 have been designed and synthesized with the help of the grinding method and the solid-synthesis method. Both composite photocatalysts are employed for the photocatalytic reduction of CO2. In composite photocatalysts prepared by the grinding method, ZIF-8 particles are distributed on the surface of TiO2, and provide extra available spaces for storing CO2, which is beneficial for improving their photoreduction performances. As a result, an enhanced CO formation rate of 21.74 μmol g-1 h-1 with a high selectivity of 99% is obtained for this family of composite photocatalysts via the solid-gas mode without photosensitizers and sacrificial agents. For comparison, the other family of composite photocatalysts synthesized via the solid-synthesis method possesses structures similar to ZIF-8, where TiO2 is encapsulated inside the framework of ZIF-8. This structural feature obstructs the contact between the active sites of TiO2 and CO2, and leads to lower activities. The best CO formation rate of this family is only 10.67 μmol g-1 h-1 with 90% selectivity. Both the structural features of the two families of photocatalysts are described to explain their differences in photoreduction performances. The experimental finding reveals that different synthetic approaches indeed result in diversified structures and varied photocatalytic performances. This work affords a new scalable and efficient approach for the rational design of efficient photocatalysts in the area of artificial photosynthesis.

Review of craniofacial regeneration in China

AIM

Tissue engineering has been recognised as one of the most effective means to form a new viable tissue for medical purpose. Tissue engineering involves a combination of scaffolds, cells, suitable biochemical and physicochemical factors, and engineering and materials methods. This review covered some biomedicine, such as biomaterials, bioactive factors, and stem cells, and manufacturing technologies used in tissue engineering in the oral maxillofacial region, especially in China.

MATERIALS AND METHODS

Data for this review were identified by searches of Web of Science and PubMed, and references from relevant articles using the search terms "biomaterials", "oral tissue regeneration", "bioactive factors" and "stem cells". Only articles published in English between 2013 and 2018 were included.

CONCLUSION

The combination of stem cells, bioactive factors and 3D scaffolds could be of far-reaching significance for the future therapies in tissue repair or tissue regeneration. Furthermore, the review also mentions issues that need to be solved in the application of these biomedicines.