Studies on Synthesis, Characterization, and Photocatalytic Activity of TiO2 and Cr-Doped TiO2 for the Degradation of p-Chlorophenol

Md Kamrul Hossain; Md Mufazzal Hossain; Shamim Akhtar

doi:10.1021/acsomega.2c05107

Studies on Synthesis, Characterization, and Photocatalytic Activity of TiO₂ and Cr-Doped TiO₂ for the Degradation of p-Chlorophenol

ACS Omega. 2023 Jan 3;8(2):1979-1988. doi: 10.1021/acsomega.2c05107. eCollection 2023 Jan 17.

Authors

Md Kamrul Hossain¹, Md Mufazzal Hossain², Shamim Akhtar¹

Affiliations

¹ Department of Chemistry, University of Chittagong, Chittagong4331, Bangladesh.
² Department of Chemistry, University of Dhaka, Dhaka1000, Bangladesh.

Abstract

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.