RESUMEN
A new metal-organic framework (MOF), [Co2(L)2(azpy)]n (compound 1, H2L = 5-(pyridin-4-ylmethoxy)-isophthalic acid, azpy = 4,4'-azopyridine), was synthesized by a solvothermal method and further characterized by elemental analysis, IR spectra, thermogravimetric analysis, single-crystal and powder X-ray diffraction. The X-ray single-crystal diffraction analysis for compound 1 indicated that two cis L22- ligands connected to two cobalt atoms resulted in a macrocycle structure. Through a series of adsorption tests, we found that compound 1 exhibited a high capacity of CO2, and the adsorption capacity could reach 30.04 cm3/g. More interestingly, under 273 K conditions, the adsorption of CO2 was 41.33 cm3/g. In addition, when the Co-MOF was irradiated by a 730 nm laser, rapid temperature increases for compound 1 were observed (temperature variation in 169 s: 26.6 °C), showing an obvious photothermal conversion performance. The photothermal conversion efficiency reached 20.3%, which might be due to the fact that the parallel arrangement of azo units inhibited non-radiative transition and promoted photothermal conversion. The study provides an efficient strategy for designing MOFs for the adsorption of CO2 and with good photothermal conversion performance.
RESUMEN
Forming heterojunctioned composites is an effective way to develop visible-light-driven photocatalysts. A series of BiOBr/NaBiO3 composites were synthesized by surface transformation of NaBiO3 with hydrobromic acid. Commensurate planes of BiOBr and NaBiO3 enabled the formation of a closely bound interface. Composites with <20wt.% BiOBr exhibited excellent photocatalytic activity towards the degradation of chlorophenols under low intensity visible light (λ>400nm). The best photocatalyst was 9% BiOBr/NaBiO3 with a quantum yield of 0.365. No photocorrosion was observed after three cycles. Using radical scavengers and inert atmosphere, holes, superoxide and hydroxyl radicals were found to be involved in the photoactivity of the BiOBr/NaBiO3 composite. Hydroxylated and open-ring diacid molecules were identified as intermediates in the mineralization of 4-chlorophenol.
RESUMEN
Visible-light photocatalysts that degrade organic pollutants in an efficient and recyclable way are highly desirable for water treatment. In this study, UiO-66, a zirconium-based metal-organic framework, was conjugated with AgI to obtain a composite for use as photocatalyst. The AgI/UiO-66 composites with different composition ratios were synthesized by a simple solution method and exhibited remarkable activity for the degradation of rhodamineâ B (RhB) under visible-light irradiation. The scanning electron microscopy and X-ray diffraction results confirmed the outstanding structural stability of the AgI/UiO-66 photocatalysts. The photocatalytic stability of the AgI/UiO-66 composite was further examined by reusing AgI/UiO-66 for long-term dye degradation. The good stability of the AgI/UiO-66 composite can be attributed to the outstanding stability of the UiO-66 framework material, as well as the good interaction between AgI and the UiO-66 framework. The mechanism of the photocatalytic RhB degradation by AgI/UiO-66 was investigated by introducing different scavengers to compete for the possible reactive species involved in the degradation process.
RESUMEN
In the mol-ecule of the title compound, C(23)H(18)BrN(3)O(3), the benzotriazole mean plane makes dihedral angles of 1.26â (1) and 87.39â (1)° with the tolyl and bromophenyl benzene rings, respectively, and the dihedral angle between the benzene rings is 87.27â (1)°. In the crystal structure, mol-ecules are linked into chains along the a axis by C-Hâ¯O inter-molecular hydrogen bonds. The structure is further stabilized by C-Hâ¯π and π-π inter-actions, with a distance of 3.700â (1)â Å between the centroids of the bromophenyl and benzotriazole benzene rings related by symmetry code (x, -1 + y, z).