Number Of Peripheral Groups Research Articles

Solvothermal preparation of copper(II) porphyrin-sensitized mesoporous TiO2 composites: enhanced photocatalytic activity and stability in degradation of 4-nitrophenol

Four new copper(II) porphyrins CuPp(1, 2, 3, 4) with a different number of peripheral ester groups were synthesized and used to sensitize the mesoporous TiO2 under solvothermal condition, and accordingly, four mesoporous CuPp(1, 2, 3, 4)/TiO2 composites were obtained. These composites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, BET nitrogen adsorption–desorption isotherms (BET), UV–vis diffuse reflectance spectroscopy (UV–vis-DRS), and Fourier-transform infrared spectroscopy (FT-IR). The results showed the crystal structure and morphology of mesoporous TiO2 were not affected by the porphyrin existence on its surface. The photocatalysis properties of mesoporous TiO2 and CuPp(1, 2, 3, 4)/TiO2 have been evaluated by conducting the photocatalytic degradation of 4-nitrophenol (4-NP) under visible-light irradiation, and the result showed their higher photocatalytic activities and the order is: CuPp(4)/TiO2 > CuPp(3)/TiO2 > CuPp(2)/TiO2 > CuPp(1)/TiO2 ≫ TiO2. The probable reasons are their large surface area and different number of peripheral groups in CuPp, which separate electron–hole pairs efficiently. The repetition test of CuPp(1, 2, 3, 4)/TiO2 composites demonstrated that they still maintained superior photocatalytic activity over six recycles.

Studies on coal macerals; [Part] 4, Chlorination of exinite and fusinite

Products of chlorination suggest 9that in exinite a greater proportion of disordered structure is present, and the number of condensed aromatic rings is not more than two; sulfur is more firmly bound; the number of peripheral groups is greater. Fusinites have more condensed structures, the number of hydroaromatic structures is negligible, and the number of condensed rings present is more than two.9