RESUMO
Taking cetyltrimethylammonium bromide (CTAB) as the template and using TiO2 as the substrate, coral-globular-like composite Ag/TiO2-SnO2 (CTAB) was successfully synthesized by the sol-gel combined with a temperature-programmed treatment method. X-ray diffraction, scanning electron microscopy (SEM), UV-vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, SEM combined with X-ray energy dispersive spectroscopy, and N2 adsorption-desorption tests were employed to characterize samples' crystalline phase, chemical composition, morphology and surface physicochemical properties. Results showed that composites not only had TiO2 anatase structure, but also had some generated SnTiO4, and the silver species was metallic Ag0. Ag/TiO2-SnO2 (CTAB) possessed a coral-globular-like structure with nanosheets in large quantities. The photocatalytic activity of Ag/TiO2-SnO2 (CTAB) had studied by degrading organic dyes under multi-modes, mainly using rhodamine B as the model molecule. Results showed that the coral-globular-like Ag/TiO2-SnO2 (CTAB) was higher photocatalytic activity than that of commercial TiO2, Ag/TiO2-SnO2, TiO2-SnO2 (CTAB), and TiO2-SnO2 under ultraviolet light irradiation. Moreover, Ag/TiO2-SnO2 (CTAB) composite can significantly affect the photocatalytic degradation under multi-modes including UV light, visible light, simulated solar light and microwave-assisted irradiation. Meanwhile, the photocatalytic activity of Ag/TiO2-SnO2 (CTAB) was maintained even after three cycles, indicating that the catalyst had good usability.
Assuntos
Processos Fotoquímicos , Rodaminas/química , Prata/química , Compostos de Estanho/química , Adsorção , Animais , Catálise , Luz , Microscopia Eletrônica de Varredura , Estrutura Molecular , Espectroscopia Fotoeletrônica , Espectrometria por Raios X , Propriedades de Superfície , Titânio , Raios Ultravioleta , Difração de Raios XRESUMO
A sample grating distributed feedback quantum cascade laser array aim at broad tunability and enhanced side mode suppression ratios is presented. Utilizing a sample grating dependence on emission wavelength and epitaxial side down bonding technique, the array of laser ridges exhibited three separated single mode emissions centered at 4.760, 4.721, and 4.711 µm respectively, in continuous wave at room temperature. Side mode suppression ratios of >35 dB and continuous wave output powers of >10 mW per laser ridge were obtained.