A Review on Metal Ions Modified TiO2 for Photocatalytic Degradation of Organic Pollutants

Abstract

TiO2 is a semiconductor material with high chemical stability and low toxicity. It is widely used in the fields of catalysis, sensing, hydrogen production, optics and optoelectronics. However, TiO2 photocatalyst is sensitive to ultraviolet (UV) light; this is why its photocatalytic activity and quantum efficiency are reduced. To enhance the photocatalytic efficiency in the visible light range as well as to increase the number of the active sites on the crystal surface or inhibit the recombination rate of photogenerated electron–hole pairs electrons, various metal ions were used to modify TiO2. This review paper comprehensively summarizes the latest progress on the modification of TiO2 photocatalyst by a variety of metal ions. Lastly, the future prospects of the modification of TiO2 as a photocatalyst are proposed.

Removal of Paracetamol from Aqueous Solutions by Photocatalytic Ozonation over TiO2-MexOy Thin Films

“…This is an important step in delaying the recombination of electrons and holes. In case of (Ti-Ce) system two significant phenomena occur: on CeO 2 oxide surface some oxygen vacancies are formed through interaction with oxygen species from gas/liquid phase and a redox couple Ce 3+ /Ce 4+ (Figure 14D) is formed [91,92]. Furthermore, Ce 3+ is able to generate radicalic species in a similar manner with electrons from the conductive band (Equations ( 21) and ( 22)); a transfer of electrons from CeO 2 also occursconduction band to TiO 2 conduction band since bandgap energy of CeO 2 is situated at more negative values (−0.37 eV) than those of TiO 2 (−0.24 eV) while holes migrate in opposite directions (Equations ( 23) and ( 24)) [92].…”

Recent advances, influencing factors, and future research prospects using photocatalytic process for produced water treatment

“…That ben said Kang et al (2019) reported a poor quantum yield due to the very effective recombination processes acting in the bulk solid and at the solid/electrolyte interface using UV-irradiated semiconductors (Kang et al 2019). Also Jiang et al (2021) reported that obtaining selective oxidation of the target pollutant or pollutants in the presence of other oxidizable organic substrates is relatively complex (Jiang et al 2021) which has become a major set back for photoctalysis systems.…”

Using visible light to activate antiviral and antimicrobial properties of TiO2 nanoparticles in paints and coatings: focus on new developments for frequent-touch surfaces in hospitals

“…Their fast electron-hole recombination, which corresponds to the degradation of the photoelectric energy into heat, meaningfully restricts the photooxidation rate of biomaterials or organic compounds on the surface. 47,48 To overcome this, TiO 2 has been used with metal ions, noble metals, nonmetals, other metal oxides, and polymeric structures like g-C 3 N 4 , [49][50][51][52] to name a few, with improved results.…”