Functional Nanomaterials Made By Porphyrin

Owing to the unique optical, electrical, and magnetic properties as well as the intriguing intramolecularÏ€-Ï€interactions, porphyrins, as novel functional materials, have potential application in materials science, such as in molecular electronics, molecular information storage, and nonlinear optics. With the goal of obtaining nanomaterials with special functions by utilizing the unique electronic structures and optoelectronic properties of porphyrins and their derivatives, we have focused our attention on the study of porphyrins and synthesized several nanomaterials with porphyrins. The major research work is as follows:1. The degradation of dyes using TiO₂ photocatalyst sensitized with meso-tetra (4-carboxyphenyl) porphyrin (H2TPPC) or meso-tetra (4-nitrophenyl) porphyrin (TNO₂PP).Research on TiO₂ photocatalysis has attracted considerable attention recently. TiO₂ is the most commonly utilized photocatalyst because some of its forms have reasonable photoactivity. Besides, it has many advantages such as being nontoxic, insoluble and comparatively inexpensive. However, the light absorption region of anatase-typed TiO₂ particles does not fit with the solar spectrum because the solar energy above 3.0 eV only makes up less than 5% of whole sunlight. Therefore, the development of low-band gap photoactive materials, that is, the so-called visible light photocatalysts, is strongly urged for solving environmental and energy problems. Dye sensitization is considered to be an efficient method to modify the photoresponse properties of TiO₂ particles. In this study, we have investigated an application of TiO₂ photocatalyst sensitized with porphyrin to degrade dyes under visible light irradiation. The results from the photocatalytic experiment are as follows:: (1) The photocatalysis efficiency of H2TPPC-TiO₂ to degrade ACBK is found to be better than that of TNO₂PP-TiO₂.(2) H2TPPC adsorbed on the surface of TiO₂ with carboxyl as the coordinating group is better than TNO₂PP(是这个意思吗?). The adsorption mechanism of TNO₂PP on the TiO₂ surface can be attributed to the weak chemisorption. (3) In the photocatalytic degradation of ACBK by H2TPPC-TiO₂, the reaction rate was related to the wavelength of light source in addition to lamp power. The degradation rate was increased with power-strengthening. (4) The reaction exactly followed the first-order kinetic law.2. The self-assembly of tin (IV) porphyrin nanoparticles.In recent years, self-assembly has been increasingly employed to design and prepare functional materials. Self-assembly of functional organic molecules into well defined nanostructures through various noncovalent interactions such asÏ€-Ï€interaction, van der Waals, and hydrogen bonding has proved important for the development of advanced functional molecular materials as well as nanoscale electronic and optoelectronic devices. We synthesized discrete free-standing porphyrin nanparticles using a reprecipitation method, which is an approach widely used in the synthesis of organic nanoparticles. The self-assembly of tin (IV) porphyring was investigated thoroughly by changing the volume of aqueous solution for the first time, and it was found that the morphology of the porphyrin nanoparticles changed dramatically in this process. Further detailed analyses of their aggregation modes were conducted by spectroscopic methods such as ultraviolet-visible (UV-vis) absorption and X-ray diffraction (XRD). It was found that Sn(OH)2TBrPP and Sn(OH)2TClPP assembled into a J-aggregate, assembled into an H-aggregate, Sn(OH)2TMOPP assembled into a J-aggregate, whereas Sn(OH)2TPP has both types of interactions in the nanoparticles.