Why five decades of massive research on heterogeneous photocatalysis, especially on TiO2, has not yet driven to water disinfection and detoxification applications? Critical review of drawbacks and challenges

Visible Light Absorption Is Not Always Related to N-Doped TiO2 and High Photocatalytic Activity in Materials Synthesized by the Sol–Gel Method Using Urea and Ammonia as Precursors

“…Thus, the photoinduced holes and electrons remain in the semiconductor with the less oxidative VB (in this case, the g-C 3 N 4 VB with a redox potential of +1.4 V vs NHE at pH 7.0). The less reductive CB (in this case, the TiO 2 with a redox potential of −0.33 V vs NHE at pH 7.0) and several authors support g-C 3 N 4 /TiO 2 type II heterojunctions imply composite materials with low photocatalytic activity. ,− In addition, the presence of oxygen vacancies in this heterojunction may negatively affect the photocatalytic activity of the composite material since these would serve as recombination centers (Scheme ).…”

“…TiO 2 is a metal oxide semiconductor offering suitable properties such as high photochemical stability and abundance. It has successfully been explored in different photocatalytic reactions to destroy organic pollutants and inactivate bacteria in water and air interfaces, synthesis of organic molecules, CO 2 reduction to solar fuels production, H 2 production, and solar photovoltaic cells. − However, TiO 2 has a wide band gap (3.2 eV for anatase and 3.0 eV for rutile), limiting its photocatalytic solar- and visible light-induced applications.…”

Structure, Synthesis, and Catalytic Performance of Emerging MXene-Based Catalysts

“…In the field of photocatalytic hydrogen precipitation, TiO 2 has carried out a large number of reported studies due to its abundance, low price, effectiveness, and suitable CB and VB edge energy levels [ 78 , 79 , 80 , 81 ]. However, the existence of traditional TiO 2 has the disadvantages of low light utilization and fast photogenerated carrier complexation hindering its further industrial large-scale application [ 82 , 83 ]. The electronic properties of MXenes are related to end groups and transition metal elements.…”

Alternative and Classical Processes for Disinfection of Water Polluted by Fungi: A Systematic Review

“…Moreover, kinetically, there is a competition between the recombination processes (10 −12 s) and interfacial charge transfer (10 −10 -10 −7 s), which causes limitations in the production of ROS in TiO 2 -photocatalysis to eliminate pollutants. Although attempts have been made to improve the production of ROS (e.g., heterojunctions), the degradation rates towards biological and chemical targets concerning individual photocatalysts maintain the kinetics in the range of hours [182], in addition to the need to remove the catalyst from water after the treatment. All these aspects represent a strong drawback for practical applications of the TiO 2 -photocatalysis and competition with other AOPs for fungi inactivation in aqueous matrices.…”