Structure and photocatalytic activity of Ti1−X MX O2 (M = Zr, Co and Mo) synthesized by pulverized solid state technique

Abstract

AbstractA set of transition metal doped nanosized TiO2 particles with anatase structure were synthesized by the pulverization method and their ability to photocatalytically degrade the dye Alizarin Red S was investigated. Characterization of the Zr-, Co- and Mo-doped photocatalysts was conducted with the aid of XRD, SEM, EDX, TEM, BET and spectral analysis. X-ray diffraction patterns did not reflect the appearance of any peaks due to dopants, however dopants were observed in SEM-EDX analysis. Particle sizes were in the range of 25 nm as per TEM and XRD analysis. Upon doping, a prominent decrease in surface area was observed. The percentage composition of each of the dopants was confirmed by EDX analysis. Doped samples depicted many mid-bands in the Kubelka Munk plots due to d-d transition of dopants. Experiments were conducted to compare the photocatalytic activity under identical UV and solar light exposure. Zr-doped TiO2 at the molecular scale exhibited better photocatalytic activity in degradation of Alizarin, with a lower band-gap energy that can respond to visible light. However, Co- and Mo-doped TiO2 appeared to suppress the photoactivity. A rise in the number of mid-bands causing effective separation or recombination of charge carriers strongly influences the rate of the degradation process.