Synthesis Of Series Porphyrin Compounds And Their Photocatalytic Properties

Porphyrins are a special class of macrocyclic compounds, with the particular structure and the unique properties, porphyrins have received more and more attention from many investigators in various fields, such as analytical chemistry, photophysics, biomimetic chemistry, electrochemistry, photochemistry. studied in many research areas as for their unique structures and properties. Meanwhile, TiO₂ was given high attention and popularity in photocatalysis research area, since TiO₂ electrode successfully utilized to decompose water into hydrogen. As a kind of organic- inorganic composite photosensitive catalytic material, porphyrins-TiO₂ brings more and more hope to people as it develops. Particularly, in the aspect of dealing with polluted water. It is verified that porphyrins-TiO₂ can efficiently degrade the organic molecules in aqueous solutions and thus purify water utilizing the solar energy. However, the research on porphyrin-TiO₂ in photocatalytic degradation is still not complete and systematic, for example, the effects of porphyrin structures, radicals and metal ion of metalloporphyrins on photocatalytic efficiency still remain unknown.Hence, we synthesized series porphyrin compounds and impregnated them onto the TiO₂ surface to produce a porphyrin-TiO₂ photocatalyst, to investigate the influence of porphyrin structures on photocatalytic efficiency by photo-degradation of Rhodamine B under visible light. Using by"Adler"method synthesized tetraphenylporphyrin and meso-(4-chlorophenyl) porphrin and their corresponding Cu(II),Zn(II),Ni(II),Mn(II),Pd(II) metalloporphyrins, sum to ten. All the compounds were characterized by 1H-NMR, IR and UV-vis etc. The metalloporphyrin-TiO₂ photocatalyst were also prepared and the photocatalytic efficiency of porphyrin-TiO₂ was tested by degradation of Rhodamine B in aqueous solution under visible light, as to find out that the coordination of metal is the key factor on photocatalysis. Moreover, tetraphenylporphyrins and meso-(4-chlorophenyl) porphrins having different photocatalytic efficiency, because of bring Cl- ions. photocatalytic efficiency order of two series porphyrin compounds is MT(p-Cl)PP-TiO₂ï¹¥MTPP-TiO₂, and metalloporphyrin orders of each series: ZnTPP-TiO₂ï¹¥CuTPP-TiO₂ï¹¥MnTPP-TiO₂ï¹¥NiTPP-TiO₂ï¹¥PdTPP-TiO₂.