Preparation of Fe3+-Ag/TiO2 Nano-particles and Its Photocatalytic Degradation to Formaldehyde

摘要

1.Introduction Formaldehyde is the main volatility polluting gas caused by modem fitment. Traditionally, reagents (such as carbamide, melamine) used in the degradation to formaldehyde are inclined to generate pollution circulation. Titania is a very versatile material with attractive applications in environment protecting, in paintings, in the production of electrochemistry electrodes, capacitors, solar cells, catalysis and photo catalysis[1]. Comparing to normal photo catalysts, its excellent photo-chemical stability, low cost and non-toxicity can be cited. However, its wide band-gap energy (ca. 3.0 eV for futile and 3.2 eV for anatase) means that only 5% of solar spectrum is used. Moreover, TiO2 presents a relatively high electron-hole recombination rate which is detrimental to its photo activity. In this sense, doping with metals or metal ions could make a double effect. Firstly, it could reduce the band gap energy, thus shifting the absorption band to the visible region. Secondly, metals could provoke a decrease in electron-hole recombination rate, acting as electron traps.