Effect of platinum doped TiO2 for photoelectrochemical degradation of various dyes / Nurul Qistina Mohammad Azman

In this study, unmodified and Pt doped TiO2 were used as photocatalysts in photoelectrochemical (PEC) and electrochemical (EC) processes. Various dyes ie; rhodamine B, methylene blue, methyl orange and crystal violet were used in this study as model degradation pollutants to determine the effect of Pt on TiO2. From the result, Pt-TiO2 has shown better photocatalytic performance as compared with TiO2 for all dyes. Crystal violet (CV) dye has shown the highest degradation after 30 minutes under PEC process by using Pt-TiO2 sample which was 99.5% removal compared with rhodamine B, methylene blue and methyl orange which ca. 95.2, 98 and 91.8% respectively. CV had also shown the highest k-value under same condition which was ca. 0.212 min-1, where k-value of 0.088, 0.114 and 0.072 min-1 were observed under rhodamine B, methylene blue and methyl orange respectively. PEC process was also proven to be more efficient than EC as light irradiation in PEC process plays a vital role in degradation of dyes. Pt peaks were observed in EDX which indicates the present of Pt element in Pt-TiO2. It was further confirmed by XRD analysis where it shows the peaks representing Pt element at 38.37, 44.03, 64.98 and 78.14°. From the calculation of XRD spectrum, crystalline size of Pt-TiO2 has decreased compared to unmodified TiO2. It indicates that the presence of Pt onto TiO2 plays an important role in enhancing PEC degradation process by decreasing the crystalline size of Pt-TiO2.