Congcong Chi

Waste cotton-derived carbon materials were synthesized using various chemical activators, and their performance as solid acid catalyst supports was studied. The pore surface structures of the carbon materials were quantitatively characterized by surface fractal dimension, and the relationship between pore surface structure and the density of catalyst was also investigated. The pore sizes were grouped into four ranges, including fractal dimensions D1 (0.32 nm to 2.0 nm) and D2 (2.0 nm to 50 nm), as revealed by N2 adsorption and Frenkel-Halsey-Hill fractal theory. In addition, D3 (50 nm to1000 nm) and D4 (1000 nm to 200,000 nm) were revealed by mercury intrusion porosimetry and the Friesen-Mikula fractal theory. The surface fractal dimension D was found to be proportional to the density of SO3H groups from sulfonation at the same carbonization temperature. A larger D value corresponded to the exposure of more active sites, which was more favorable for improving the density of SO3H gro...

Using sodium metavanadate and calcium acetate as raw materials, citric acid and Polyvinylpyrrolidone (PVP) as morphological control agents, the flowerlike calcium vanadate microspheres were prepared by ethylene glycol (EG)-water binary solvent thermal method. The effects of solvent ratio, reaction temperature and time on the morphology were investigated, and the growth mechanism of the flowerlike calcium vanadate microspheres was elucidated. The microspheres had the most complete morphology at the EG/H2O ratio of 4∶3. More obvious and better growth of flower clusters was shown for longer reaction time. With the increase of temperature, the crystallinity of the product gradually increased.

The lanthanide complexes [Yb(fac)(HO), Yb(tta)(HO), Nd(tta)(HO)] functionalized nanofibrillated cellulose (Ln-NFC) nanopapers with near-infrared (NIR) luminescence and high transparency are rapidly fabricated after solvent exchange using a simple suction filtration film-making method. The effects of NFC and lanthanide complexes content on their photophysical properties of Ln-NFC nanopapers and their mechanism of UV filters are fully investigated. With increasing lanthanide complexes content in the Ln-NFC nanopaper, their transmittances are gradually decreased while their NIR luminescences are obviously increased. Yb-fac NFC nanopaper has high UVB block rate at 298 nm, whereas the high UVA block ratio of Ln-tta NFC nanopaper is observed at 345 nm. Ln-NFC nanopapers show a much higher photostability without decomposition under UV irradiation at 365 nm over 5 h. The emission spectra of the Ln-NFC nanopaper process the NIR luminescence of the corresponding lanthanide ions through the efficient triplet-triplet energy transfer process. Ln-NFC nanopapers can bring a brilliant future for UV filters, labeling fields and marking soft materials application.

A flexible and stretchable conductor was achieved by embedding fractal-structured silver particles in a PDMS substrate, which can stretch up to 100% and bend and twist up to 180°, and which possesses good mechanical and electronic stability.

Alkaline pre-extraction and hydrothermal hydrolysis were carried out with eucalyptus chips. Two methods were used to determine and calculate the extraction yield of five-carbon sugars. One is an indirect method, based on the difference of pentosan content between the chips before and after pre-extraction. The other method is to directly measure the content of five-carbon sugars in the extracting solution.