Preparation of TiO2/graphene/nano silver compound photocatalyst and degradation of formaldehyde thereby

Abstract

The invention discloses a compound photocatalyst formed by co-modifying TiO2 by silver and graphene. The compound photocatalyst is prepared from the following steps: (1) dispersing graphene oxide in water to obtain a graphene oxide dispersion solution; (2) dissolving AgNO3 in water to obtain an AgNO3 solution; (3) mixing the graphene oxide dispersion solution, the AgNO3 solution, TiO2 powder and sodium citrate and uniformly dispersing the mixture; (4) transferring the mixture obtained in the step (3) to a hydrothermal kettle, and raising the temperature for a hydrothermal reaction; and (5) after the reaction, cooling the mixture to room temperature and washing and drying the same. The preparation method of the compound photocatalyst is simple and feasible and economic in raw material, doesnot generate toxic and harmful substances, can degrade formaldehyde in air under irradiation of visible light, and can be used repeatedly.

Description

technical field [0001] The invention relates to a kind of silver and graphene co-modified TiO 2 The formed composite photocatalyst and the preparation method of the composite photocatalyst. The composite photocatalyst of the invention can be used in the field of photocatalytic purification of pollutants in the air and photodegradation of organic pollutants, especially formaldehyde in the environment. Background technique [0002] Due to TiO 2 It can oxidize most organic pollutants on its surface into CO under relatively mild conditions 2 and H 2 O, no secondary pollution and the reaction process is easy to control, so TiO 2 As a photocatalyst, it plays a very important role in the purification of indoor air. But TiO 2 There are also several defects as follows: (1) TiO 2 Photogenerated electron e - and hole h + It is easy to compound, resulting in the reduction or even disappearance of its photocatalytic activity; (2) TiO 2 The forbidden band width Eg is very large,...

AI Technical Summary

Problems solved by technology

But TiO 2 There are also several defects as follows: (1) TiO 2 Photogenerated electron e - and hole h + It is easy to compound, resulting in the reduction or even disappearance of its photocatalytic activity; (2) TiO 2 The band gap Eg is very large, which is 3.2eV, so it can only absorb and utilize about 4% of the ultraviolet part of sunlight, but cannot effectively use the visible part of sunlight, resulting in low photocatalytic efficiency

For example, Chinese patent application 20111043450.5 does not provide strong evidence that silver ions are reduced to nano-silver, and there is no measurement of the size of silver particles. Even the applicant himself has abandoned the patent application; Chinese patent 201410198481.1 discloses The process cannot obtain silver nanoparticles with a larger particle size. The silver particles disclosed in this patent are only 3nm, which is limited to the treatment of organic pollutants in waste liquid, and this patented process will produce a large amount of alkali waste liquid; Chinese patent 201210380928.8 Among the disclosed catalyst materials, silver exists in the form of silver ions (silver phosphate), which is different from the structure of simple silver nanoparticles.

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