Synthesis of lanthanide-doped TiO₂nanoparticles and their photocatalytic activity under visible light

Abstract

Four different lanthanide (Ce, Dy, Lu, and Sm) doped TiO2 mesoporous materials were synthesised using the sol–gel method with titanium (IV) isopropoxide as the precursor. All of the synthesized materials were characterised using different analytical techniques, BET, PXRD, TEM, SEM-EDX, Raman, FTIR, photoluminescence, and UV-DRS spectroscopy. Photocatalytic activity and efficacy of the materials in the degradation of caffeine in aqueous solutions was investigated under visible light illumination. Although all materials showed good photocatalytic activity, Ce-doped TiO2 exhibited relatively better activity than the other three catalysts. High photoactivity of the catalysts was attributed to the presence of lanthanides and their ability to generate ions that scavenge electrons under visible light, thereby enhancing photodegradation of caffeine. All materials proved to be good and were recyclable without loss of catalytic activity up to three runs. An intermediate [N-1,3,6-trimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-yl)formamide] (TDTF) and two products (6-amino-1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropymidin-5-ly)-(methyl)-carbamic acid (ATCA) and N-methyl-N-(methylcarbomoyl)-2-oxoacetamide (MMO) were identified by the LC–MS spectra.

Effect of Doping TiO2 NPs with Lanthanides (La, Ce and Eu) on the Adsorption and Photodegradation of Cyanide—A Comparative Study

“…The FTIR spectra shown in Figure 2 b–d allowed to demonstrate that, due to doping, the broad band of the TiO 2 semiconductor, shown in the region of 540–900 cm −1 in Figure 2 a, changes drastically. According to the literature, this change can be attributed to the presence of Ln-–O stretching modes of vibrations [ 24 ]. Unresolved bands suggest the existence of uniform stresses in the lattice, which is generally associated with defects in the material structure.…”

“…In order to decrease recombination of the pairs (e − /h + ) and shift the absorption wavelength to the wanted visible region (>λ = 400 nm), several specific surface modifications on TiO 2 have been suggested, including doping with different elements, including lanthanides [ 19 , 20 , 21 , 22 , 23 ]. In fact, lanthanide metal ions (Ln 3+ ) have been employed as TiO 2 dopants in numerous investigations since they can considerably modify the physicochemical properties of this photocatalyst [ 24 ]. Doping of TiO 2 with lanthanide elements can occur through two mechanisms.…”

Experimental and computational study of metal oxide nanoparticles for the photocatalytic degradation of organic pollutants: a review

“…In eqn (11), molecular O 2 reacts with the electrons (e − ) in the CB and resulted in O 2 c − . Then, O 2 c − reacts with water molecules to produce cOH radical species, as shown in eqn (12). On the other hand, as shown in eqn (13), the h + can react with H 2 O on the surface of photocatalyst to produce cOH radical species.…”

“…His research interest is dealing with the various optoelectrical properties of inorganic semiconductors. materials, 12 meaning that for overcoming environmental pollution, the degradation of harmful and toxic contaminant organic compounds using semiconducting photocatalysts is of great signicance. 13 A semiconducting photocatalyst is a material that is used as a catalyst in photocatalytic processes.…”

Physical and photocatalytic properties of Nd codoped (Ag, Cu)TiO2 thin films

“…Alternatively, the improvement of TiO 2 photocatalytic properties by lanthanide ions (rare earth) has been also reported. Since the 4f electron configuration exhibits absorption in the visible light region, several studies reported the effect of some rare-earth ions like Er 3+ , Sm 3+ , Pr 3+ and Nd 3+ [23][24][25][26], resulting in a redshift of its edge absorption. More recently, N. Nithya et al showed that Nd-doped TiO 2 enhanced the degradation of methylene blue (MB) and Congo red (CR) than pure TiO 2 nanoparticles [27].…”