Structural and optical properties of Fe@C doped TiO2 thin films prepared by sol–gel method

A Review of Synthesis Methods, Modifications, and Mechanisms of ZnO/TiO2-Based Photocatalysts for Photodegradation of Contaminants

“…Some elements like N, C, S, B, P, I, and F as dopants are used to narrow the band gap energy and extend the recombination time of electrons and holes to improve the photocatalytic efficiency . Nitrogen, due to its similarity with oxygen in terms of ionic radius and 2p energy level, is commonly used as a modifying agent and replaces with oxygen in the photocatalytic lattice. − On the other hand, doping with carbon materials is an effective approach to change the optical properties of the photocatalysts and improve photocatalytic activity due to the electron transfer potential, light absorption, and physicochemical durability of carbons as dopants . Sulfur, the same as oxygen, is a VIA group element that has comparable physicochemical properties, but the ionic radius and electronegativity values of sulfur are different.…”

“…Doping with magnetic compounds like Fe 2 O 3 , metals, and other metal oxides increases the agglomeration affinity of the nanocomposite and oxidation when exposed to the air. These adverse effects result from reinforcement of the surface energy, which decreases the specific surface area and makes the ultimate goal pointless . These modification strategies, under most conditions, have synergic effects toward improving photocatalytic performance.…”

“… 194 − 196 On the other hand, doping with carbon materials is an effective approach to change the optical properties of the photocatalysts and improve photocatalytic activity due to the electron transfer potential, light absorption, and physicochemical durability of carbons as dopants. 197 Sulfur, the same as oxygen, is a VIA group element that has comparable physicochemical properties, but the ionic radius and electronegativity values of sulfur are different. When oxygen is replaced with sulfur in the ZnO structure and S-doped ZnO fabrication, the photocatalytic activity improves due to the creation of sulfur defects in the photocatalytic lattice.…”

“…These adverse effects result from reinforcement of the surface energy, which decreases the specific surface area and makes the ultimate goal pointless. 197 These modification strategies, under most conditions, have synergic effects toward improving photocatalytic performance. Therefore, additional modification in order to conquer some drawbacks of introducing new dopants demands consideration.…”