Abstract
Doping inorganic acid ions represents a promising pathway to improving the photocatalytic activity of TiO(2), and oxygen vacancy has been regarded as the determinant factor for photocatalytic activity. A series of samples doped with Cl(-), NO(3)(-), and SO(4)(2-) was prepared via a simple sol-gel method. Two different oxygen vacancies in the crystal layer of NO(3)(-)/TiO(2) and Cl(-)/TiO(2) were found, and those are [Ti(3+)]-V(0)-[Ti(3+)] and [Ti(3+)]-Cl, respectively. The photocurrent of NO(3)(-)/TiO(2) with [Ti(3+)]-V(0)-[Ti(3+)] is significantly greater than that of Cl(-)/TiO(2) with [Ti(3+)]-Cl. The least oxygen vacancy is in the gel layer of SO(4)(2-)/TiO(2), and the negligible photocurrent is due to difficulty in forming a stable sol. Furthermore, the process conditions for the application of TiO(2) were investigated in this work. The optimal process parameters are to adjust the solution to pH = 3 during sol-gel preparation, to adopt 550 °C as the calcination temperature, and to use an alkaline electrolyte, while the rest of the preparation conditions remain unchanged. This work reveals a new avenue for designing efficient photocatalysts for air pollutant degradation.