Preparation And Catalytic Performance Of Metalloporphyrins Supported On AgCl-Ag@SiO₂

Metalloporphyrins as biomimetic catalyst can catalyze the oxidation of many hydrocarbons and produce aldehydes, ketones, alcohols and carboxylic. However, The biomimetic catalytic reaction of metalloporphyrin usually need high temperature, high pressure or cocatalyst. Therefore, the selectively catalytic oxidation of metalloporphyrin under mild conditions has always been one of the key studies of the biomimetic catalysis of metalloporphyrin. Ag Cl-Ag which is a new type of plasma visible light catalyst can strongly absorb visible light because of its surfaceplasmon resonance effect. Under visible light irradiation, Ag Cl-Ag can produce a large number of holes and electrons. These holes and electrons can decompose the water to produce ·OH, and degrade organic pollutants into carbon dioxide and water. In this paper, we have combined Ag Cl-Ag with metalporphyrin, induced metalloporphyrin biomimetic catalytic reaction by the free radicals generated by the Ag Cl-Ag plasmon resonance. First of all Ag Cl-Ag@Si O2 nanoparticles were prepared with spherical structure. Then the singlecarboxyl manganese porphyrin was linked on the surface of Ag Cl-Ag@Si O2 nanoparticles through the formation of amide bond. The supported porphyrin catalyst was used to the oxidation reaction of diphenylmethane and its catalytic performances were investigated. The main work was described as following:1. Ag Cl-Ag with different molar ratio of Ag(I)/Ag were synthesized by controlling the ratio of silver carbonate and hydrochloric acid and characterized by means of XRD, SEM, UV-Vis. SEM showed that Ag Cl-Ag particles prepared by microemulsion method were smaller than those of Ag Cl-Ag particles prepared by simple precipitation method, but the Ag Cl-Ag particles prepared by the two methods were all large and the distribution was uneven. The degradation reaction of methyl orange showed that Ag Cl-Ag with Ag(I)/Ag molar ratio of 4 had the best photocatalytic effect. when the Ag(I)/Ag molar ratio increased or decreased, the photocatalytic activity of Ag Cl-Ag will decrease sharply..2. In order to get the small Ag Cl-Ag particles, we used the microemulsion method to wrap the silicon layer in the Ag Cl-Ag surface. Ag Cl-Ag@Si O2 nanoparticles with different silica shell thickness were synthesized by controlling the amount of ethyl silicate and characterized by means of XRD, SEM, UV-Vis. The SEM results showed that Ag Cl-Ag@Si O2 nanoparticles was spherical structure and hadparticles size of 70-80 nm.The degradation reaction of methyl orange showed that silica shell thickness was smaller, its photocatalytic activity was higher.3. Mn CPTPPCl was bonded on the surface of Ag Cl-Ag@Si O2 nanoparticles with the method of solid silanation and characterized by XRD, SEM, UV-Vis, FT-IR. The results showed the structure and paiticle size of the surpported catalyst did not change.In addition, metalloporphyrin was grafted on the surface of Ag Cl-Ag@Si O2 by amide bond. The Immobilized metalloporphyrin was used as catalysts for oxidation of diphenylmethane, The results showed that Ag Cl-Ag can promote the oxidation of diphenylmethane by metalloporphyrin and supported-metalloporphyrin can increase stability and catalytic activity of metalloporphyrin.4. The possibile mechanism of Ag Cl-Ag promoted the catalytic oxidation of diphenylmethane by metalloporphyrin will be preliminarily discussed by the content of peroxide in the reaction process.