Synthesis of Fe-Doped TiO2 for Photocatalytic Processes under UV-Visible Light: Effect of Preparation Methods on Crystal Size—A Systematic Review Study

ABSTRACT Objective is to investigate effect of preparation methods on crystal size at synthesis of Fe-doped TiO2 as a systematic review study. All references (455) were found by manual duplication and finally n = 136 records remained. After reading their titles, abstracts and full-texts, 58 relevant full-text articles were included based on the considered exclusion criteria. Finally, 21 relevant full-text articles, which consisted of crystal size data, were selected to conduct this systematic review study. The relevant publications were from 2005 to 2019. In 14 studies (66.67%), Fe-doped TiO2 was prepared by sol-gel method. In many of the studies related to sol-gel method, crystal sizes range from 5 to 25 nm. Among the applied methods for preparation of Fe-doped TiO2, ultrasonic and microwave methods on crystal sizes 58 nm and 170.24 nm were the highest volume. In general, even though the studies used the same procedures, they reported different results. It is concluded that in these studies, in addition to preparation methods, other parameters could be effected on the crystal sizes, such as type of Ti procurers. However, that should be investigated in future studies as a systematic review.