Preparation And Photocatalytic Performance Of F-TiO₂ Photocatalyst

Abstract

The environmental problems in today's society are becoming increasingly serious. It is imminent to seek an economic and efficient environmental governance method. Titanium dioxide has become one of the most suitable semiconductor for environmental purification due to its characteristic, such as excellent photocatalysis, stability, low cost and non-toxic, etc. Nevertheless, TiO2 is limited by several undesirable characteristics, such as its wide band gap (3.2 eV) that can only be excited by ultraviolet light, which occupies only 7 % of the entire solar spectrum. In addition, TiO2 exhibits rapid recombination of photo-induced electrons and holes (e−/h+), which significantly decreases quantum efficiency. This thesis focused on increasing the photocatalytic activity of TiO2 under simulated sunlight irradiation. F-TiO2 composite was synthesized via a simple sol-gel method by using NaF as the fluorine source followed by heat treatment at aerobic or anaerobic calcination, and their photocatalytic ability has been evaluated. The research results are as followed: F-modification can generate more oxygen vacancies because of the replacement of surface -OH groups by the F species, which can inhibit the recombination of photoelectrons with holes by the captured photoelectrons, promote the generation of Ti3+ and narrow the band gap 2.75 eV, thereby enhancing the quantum efficiency of photocatalysis.