Effect of modifying TiO2 powdert with SiO2 and ZrO2 nanoparticles on its composition, structure, optical properties, and on the alteration of these parameters under solar spectrum quanta

Visible Light-Promoted Enhanced Photocatalytic Hydrogen Generation by the CeF3:Ho3+-Incorporated TiO2 Nanosystem

“…Metal oxide semiconductors, such as TiO 2 , SrTiO 3 , and NaTaO 3 , have unparalleled stability and activity for photocatalytic water splitting into hydrogen and oxygen. − Unfortunately, these semiconductors can effectively absorb only 5% of solar energy because to their naturally wide band gaps. As a result, non-metals or anions (N, S, C, F, Br, and I) and metal ions (such as Mo 6+ , V 4+ , Co 3+ , Cu + , Ag + , Sn 2+ , Pb 2+ , Bi 3+ , Cr 3+ , Rh 3+ , and Ni 2+ ) have been typically incorporated into the matrix of these oxide semiconductors to tailor the electronic structure by building new energy bands or localizing impurity levels between the band gap. − The doping technique, however, most often weakened the redox capacity of the photogenerated charge carriers and harmed the semiconductors’ effective band edges, making it impossible to only extract H 2 or O 2 from H 2 O when exposed to visible light. , To maintain the original properties of these semiconductors while obtaining broad-spectrum receptiveness, the usage of rare earth-based up-conversion (UC) nanomaterials has become essential. − Rare earth up-conversion materials can transform low-energy photons into high-energy emission photons when exposed to radiation. Typically, an up-conversion material consists of a host material that has been doped with optically active activators and sensitizer ions. − The use of suitable dopant host pairs is required for controlling the energy transfer up-converting phenomenon .…”