Zeolite as an efficient molecular sieve for improvement of catalyst performance in photocatalytic processes

سال انتشار: 1396
نوع سند: مقاله کنفرانسی
زبان: انگلیسی
مشاهده: 301

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شناسه ملی سند علمی:

NZEOLITE04_008

تاریخ نمایه سازی: 11 شهریور 1397

چکیده مقاله:

Zeolites represent an interesting and extreme test case for replication strategies; because the dimensions of their cages and channels are quite similar to those of the organic polymers. Zeolites are hydrated aluminosilicate minerals made from interlinked tetrahedra of alumina (AlO4) and silica (SiO4). In simpler words, they re solids with a relatively open, three-dimensional crystal structure built from the elements aluminum, oxygen, and silicon, with alkali or alkaline- Earth metals (such as sodium, potassium, and magnesium) plus water molecules trapped in the gaps between them. Zeolites are widely used as ion-exchange beds in domestic and commercial water purification, softening, and other applications. In chemistry, zeolites are used to separate molecules (only molecules of certain sizes and shapes can pass through), and as traps for molecules so they can be analyzed. In our recent researches, it can be distinguished that one of the conventional methods for enhancing the activity of a nano semiconductor as a photocatalyst is to use an efficient support material such as metalosilicates (isomorphous substitution of metal ion as Fe, Cr, B , Mn and … for aluminum in zeolite framework), which can increase its effective surface area ; metalosilicate as a support, can offer a very high surface area and also provides an effective and homogenous dispersion of semiconductor particles on the external surface or within the pores of its structure. Moreover, the metalosilicate structure with electron-accepting and donating properties can play an important role in the control of charge transfer processes. Furthermore the strong electrostatic field present in the metalosilicate framework can effectively separate the electrons and holes produced during photo-excitation of nano semiconductor and so resulted in lower recombination of them and higher photodegradation efficiency. According to the results, it can be observed that in the case of supporting nano semiconductors on metalosilicates the efficiency of the photocatalysts increase significantly for semiconductor nano particles as well as the band gap width of the semiconductor change. Thus using metalosilicates leads to an improvement the photocatalytic activity of the prepared semiconductor nanoparticles.

نویسندگان

Masoumeh Khatamian

Department of Inorganic Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz, Iran.