TiO2 and Cr–TiO2 nanoparticles
(NPs)
have been synthesized by the sol–gel method using titanium
isopropoxide as the precursor of Titania. The prepared samples were
analyzed by employing scanning electron microscopy, energy-dispersive
X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy,
and Fourier transform infrared analyses. Under UV irradiation, the
photocatalytic activities of TiO2 and Cr–TiO2 were observed by estimating the % degradation of p-chlorophenol (PCP) as a sample pollutant. The extent of
degradation was investigated, varying the catalyst dosage, initial
PCP concentration, irradiation time, and solution pH. The experimental
results show that efficiency of catalysts initially increases but
decreases later on, whereas the % degradation of PCP is the highest
at its lowest initial concentration. For TiO2 and Cr–TiO2 NPs at their optimal catalyst dosage of 2.0 g/L, acidic pH,
and with UV irradiation for 90 min, the observed % degradation of
PCP is 50.23 ± 3.12 and 66.51 ± 2.14%, respectively. Thus,
the prepared Cr–TiO2 NPs have enhanced the degradation
efficiency of PCP with an irradiation time which is four time less
than those reported earlier. From the kinetics analysis, the degradation
reaction of PCP is found to follow a pseudo-first-order model and
the rate constants are 0.0075 and 0.0122 min–1 for
pure TiO2 and Cr–TiO2 NPs, respectively.
The present study has further revealed that owing to the lower rate
of electron–hole pair recombination, the photocatalytic activity
of Cr–TiO2 NPs becomes higher than that of TiO2. Therefore, as viable photocatalytic agents, Cr–TiO2 NPs are suggested to be used also for efficient degradation
of other organic pollutants.