Co-doped TiO2 Nanoparticles Research Articles

Green synthesis of undoped and yttrium, bismuth co-doped titanium dioxide nanoparticles using Bryophyllum pinnatum for photocatalytic application

In this research, a non-toxic, inexpensive, and environment-friendly green synthesis route was investigated to synthesize undoped and Y, Bi co-doped TiO2 nanoparticles by using Bryophyllum pinnatum leaf extract. Precursor material titanium isopropoxide (TTIP) was utilized for both undoped and co-doped TiO2 and Yttrium and Bismuth were added to 1, 2, and 3 percent as co-dopants. The obtained undoped and Y, Bi co-doped TiO2 nanoparticles were characterized by various analytical techniques, which include X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and UV–Visible spectroscopy for the evaluation of the structural, morphological, and photocatalytic activity. Anatase phase formation was observed from the XRD analysis for both undoped and Y, Bi co-doped TiO2 nanoparticles. The average particle size for undoped TiO2 nanoparticles was found to be 15.92 nm which raised to 21.70 nm for 3 % co-doping. UV–Vis Spectroscopy analysis revealed a reduction on band gap energy (Eg) for Y, Bi co-doped TiO2 nanoparticles. Methylene blue (MB) photodegradation demonstrates co-doping with Y, Bi significantly increases the photocatalytic activity. Overall, green synthesis using Bryophyllum pinnatum was found to be an economical method to fabricate TiO2 NPs that shows great improvement in photo-degradation characteristics.

Synergistic effects of Co-Mn co-doping on the structural and optical properties of TiO2 nanospheres: Dual functions for DSSC photoanodes and degradation photocatalyst

Synthesizing direct solar irradiance-responsive nanomaterial capable of serving as an efficient photoanode for dye-sensitized solar cells (DSSCs) and active photocatalysts for organic pollutant elimination poses a formidable challenge. This study focused on the synthesis of cobalt and manganese co-doped titanium dioxide (TiO2) nanoparticles via sol-gel technique, enhancing their efficacy in both the DSSCs and methylene blue (MB) dye degradation. X-ray diffraction and Raman analysis confirm the existence of a tetragonal crystal structure with the anatase phase of TiO2, while XPS analysis verifies the successful integration of cobalt and manganese ions into the host lattices. BET analysis has confirmed that Co, Mn co-doped TiO2 exhibits a higher pore volume and specific surface area compared to the undoped TiO2 material. FESEM and HR-TEM reveals spherical shape morphology and EDS mapping confirms the purity of synthesized nanoparticles. Moreover, Co-Mn co-doped TiO2 nanoparticles exhibits a shift in the optical absorption edge towards the visible spectrum in UV-DRS analysis. PL analysis suggests a diminished electron-hole recombination within the doped and co-doped sample. Electrochemical impedance spectroscopy demonstrates improved charge transfer properties. DSSCs employing the co-doped TiO2 exhibit significantly enhanced power conversion efficiency (4.99 %) compared to bare TiO2 (2.03 %), cobalt-doped (2.61 %), and manganese-doped TiO2 (3.97 %). Additionally, it demonstrates exceptional photocatalytic activity, with 87.83 % (Co-Mn co-doped TiO2) degradation efficiency with a lesser time extent for the methylene blue dye degradation. These findings underscore the potential of Co-Mn co-doped TiO2 for addressing dual challenges in renewable energy (DSSC) and environmental remediation (Pollutant removal).

Green synthesis of N, B co-doped TiO2 nanoparticles with enhanced photocatalytic and antioxidant activities

BackgroundReactive dyes are widely used in the fabric production, and because they are poisonous, and hazardous, their release into the environment today indicates a rise in pollution in the environment. Biosynthetic approach that is also environmentally benign has gained an abundance of recognition for its eco-friendly products, biocompatibility, and long-term economic viability. MethodsIn the present investigation, TiO2 (T) and N, B co-doped-TiO2 (NB-T) nanoparticles (NPs) were prepared biologically using mangrove aqueous extract by the sol-gel method to compare their photocatalytic degradation activity of an aqueous solution of reactive red 250 dye (RR250) under visible light irradiation at different times. The antioxidant activities of T and NB-T NPs samples were evaluated. The synthesized samples were characterized using different techniques. Main findingsThe findings showed that photocatalytic degradation activity of NB-T NPs reaches 100 % after 60 min of the degradation process, where it reaches maximum (38.1 %) for T NPs at the highest catalyst dose. The results showed that NB-T NPs have a conformal surface structure and stronger photocatalytic properties than Pure T. Measurements of Chemical Oxygen Demand (COD) were made, and a significant reduction in values was seen, showing the technique's high potential for removing RR250 dye from aqueous solutions. The NB-T sample showed the maximum activity, as indicated by the estimated IC50 value (34.98 μg/mL). Both T and NB-T NPs showed significant DPPH free radical scavenging activity.

Strontium and manganese co-doped TiO2 nanoparticles for the enhanced photocatalytic degradation of methylene blue dye

Strontium and manganese co-doped TiO2 nanoparticles for the enhanced photocatalytic degradation of methylene blue dye

Exploring annealing-triggered phase transformation, photoluminescence quenching, and synergistic effects of Co-doped TiO2 nanoparticles

This study investigates the influence of defects on the electronic, optical, and magnetic properties of tetragonal titanium dioxide (TiO2) and its cobalt-doped variant, Ti0.95Co0.05O2. The research findings of diffraction studies confirms the formation of phases such as anatase, rutile, and their combination within TiO2 nano-structures following annealing. The Debye-Scherrer's rings observed in the selected area electron diffraction patterns and transmission electron microscopy images showed an aggregate of randomly oriented nano-structures. Additionally, elemental analysis confirms the presence of Ti and O as primary constituents. The detailed analysis using microscopy and spectroscopy study identified a high-spin D2h state in Co2+, indicative of lattice defects across the TiO2 nano-structures. A blue shifting in the photoluminescence band gap emission peaks suggested the presence of oxygen vacancy defects in the doped nano-structures. Notably, the increased surface defects and reduced catalyst size promote rapid migration of electron-hole pairs to reaction sites i.e.; on the surface, thereby reducing recombination rates. Ultimately, the study concludes that anatase TiO2, due to its exceptional catalytic performance, is more favourable for applications in photo-catalysis and spintronics than its rutile or mixed-phase counterparts.

Enhanced Energy Storage in PVDF-Based Nanocomposite Capacitors through (00l)-Oriented BaTiO3 Single-Crystal Platelets.

Flexible nanocomposite dielectrics with inorganic nanofillers exhibit great potential for energy storage devices in advanced microelectronics applications. However, high loading of inorganic nanofillers in the matrix results in an inhomogeneous electric field distribution, thereby hindering the improvement of the energy storage density (Ue) of the dielectrics. Herein, we proposed a strategy that utilized (00l)-oriented barium titanate (BT) single-crystal platelets to fabricate trilayered nanocomposite dielectrics for energy storage applications. The trilayered nanocomposites consisted of two high-permittivity layers of (Ta2O5, Al2O3) codoped TiO2 nanoparticles (Ta-Al@TiO2 nps) dispersed in a poly(vinylidene fluoride) (PVDF) matrix to facilitate large electric displacement and a middle layer of (00l)-oriented BT single-crystal platelets to provide high breakdown strength. Hence, the trilayered PVDF/Ta-Al@TiO2 nps/BT single-crystal platelet nanocomposite film attains an outstanding Ue of 16.9 J cm-3 at 370 kV mm-1, which is ∼625% higher than that of the single-layer PVDF/Ta-Al@TiO2 nps film. Finite element simulation further clarified that the successive inner layer of highly (00l)-oriented BT single-crystal platelets could effectively restrain the propagation of electrical treeing in trilayered nanocomposites. This research offers an effective approach for developing flexible dielectric capacitors with an excellent energy storage performance.

Structural and Spectroscopic properties of Eu3+ doped SiO2–TiO2 nanoparticles for photonic applications

The Eu3+-doped TiO2 nanoparticles in sol gel silicate glasses of composition (80-x)SiO2 + 20TiO2 + 0.5xEu2O3, (SiTiEu) where x = 0.0 0.5, 1.5, 2.5 and 3.5 mol%, have been prepared by sol-gel technique. The glass samples were investigated by thermos-gravimetric analysis (TGA/DTA), ATR-FTIR, XRD, SEM, TEM, EDX, optical absorption and photoluminescence emission spectroscopy at room temperature (RT). The absorption wavelength of TiO2 doped sol-gel silicate glass were red shifted due to a reduction in band gap energy with increasing annealing temperatures. According to the TEM images, all of the particles were spherical and had an average diameter is around 10 nm. The visible spectra of the Eu3+ doped TiO2 nanoparticles in sol-gel silicate glasses displayed characteristic PL emission 5D0→7FJ (J = 0, 1, 2, 3, 4, 5) transitions of Eu3+ ions at 370 nm excitation. The anatase TiO2:1.5Eu3+ nanocomposite showed high photoluminescence emission at 370 nm excitation, which was attributed to the f-f transitions of Eu3+. The hypersensitive 5D0→7F2 transition was responsible for the major red emission. From the recorded spectra, radiative parameters and Judd-Ofelt (JO) intensity parameters were computed. The Eu3+ co-doped TiO2 nanoparticles in sol-gel silicate glasses displayed emissions mostly in the red regions realized from a CIE chromaticity diagram. The results suggested that materials may be used as an optical material of technological importance such as display devices and also for optical amplifier.

Improved photocatalytic performance of Sn/Cl co-doped TiO2 nanoparticles via a novel volatilization solid solution method

Sn/Cl co-doped TiO2 nanoparticles were synthesized via a novel volatile solid solution method. The effect of SnCl2·2H2O concentration (0–35.4 mol.%) and calcination temperature on thermal effect, crystal structure, morphology, composition, light absorption and photocatalytic performance of TiO2 nanoparticles was investigated by TG-DSC, XRD, SEM, EDS, TEM, HRTEM, SAED, UV–Vis, PL, photocurrent test, EIS and XPS. Results indicate that Sn and Cl are co-doped into TiO2 crystal lattice forming a mixed anatase-rutile TiO2 phase without SnO2 phase when SnCl2·2H2O concentration is below 17.7 mol.%, and excess SnCl2·2H2O caused the rutile SnO2 generation and simultaneous rutile TiO2 disappearance. The degradation efficiency of methyl orange reaches 98.7 % using 17.7 mol.% SnCl2·2H2O modified TiO2 calcined at 380 °C after 2 h of 15 W UV light irradiation, which is 19.72 % and increases by two times compared with that of pure TiO2 (8.98 %) after 2 h of 15 W visible light irradiation, both showing the maximum photocatalytic performance possibly due to the simultaneous increased active surface sites, enhanced light absorption and improved separation efficiency of photogenerated electron-hole pairs resulted from small particle size, reduced energy band gap and formation of mixed anatase-rutile TiO2 phases. Reactive species scavenging experiments revealed that O.-2 and h+ play a dominant role in photodegradation process.

Correction: A sustainable nanobioremediation approach for Tunisian landfill leachate using Ag/Fe co-doped TiO2 nanoparticles combined with Saccharomyces cerevisiae

Correction: A sustainable nanobioremediation approach for Tunisian landfill leachate using Ag/Fe co-doped TiO2 nanoparticles combined with Saccharomyces cerevisiae

Influences of phase structure and hydrogenation on the optical and dielectric properties of (La/Ni) merge codoped TiO2 nanoparticles

Influences of phase structure and hydrogenation on the optical and dielectric properties of (La/Ni) merge codoped TiO2 nanoparticles

Enhanced charge separation by incomplete calcination modified co-doped TiO2 nanoparticle for isothiazolinone photocatalytic degradation

Enhanced charge separation by incomplete calcination modified co-doped TiO2 nanoparticle for isothiazolinone photocatalytic degradation

Defect engineered N-S codoped TiO2 nanoparticles for photocatalytic and optical limiting applications: Experimental and DFT insights

N-S codoped TiO2 nanoparticles (NPs) were synthesized using a sol–gel cum hydrothermal approach, with ammonium sulfate as the nitrogen and sulfur source compound. The calcination temperature was varied from 500 to 700 °C. The pristine samples exhibited a mixed phase of anatase and brookite, while the doped samples exhibited only the anatase phase, as confirmed by X-ray diffraction (XRD) analysis. Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of N-H vibrations and S-O bidentate complexation with Ti4+ ions. Electron paramagnetic resonance (EPR) revealed the presence of Ti3+ signals, confirming the creation of oxygen defects in the doped samples. The absorption and emission properties of the samples were investigated using ultraviolet–visible (UV–Vis) and photoluminescence (PL) spectroscopy. Vibrating sample magnetometry (VSM) analysis confirms the room-temperature ferromagnetic behavior of the N-S doped TiO2, which was attributed to the presence of oxygen vacancies, as evidenced by the EPR and PL results. The N-S doped TiO2 samples demonstrated superior photocatalytic degradation of Rhodamine B (RhB), Methylene Blue (MB), and Congo Red (CR) dyes under visible light illumination compared to the pristine TiO2. This enhanced performance was attributed to the presence of N and S dopants in TiO2, which create new energy levels within the band structure of TiO2, allowing for efficient absorption of visible light and subsequent generation of reactive species for dye degradation. N-S doping modifies the electronic structure of TiO2, enhancing two-photon absorption (TPA). This increased TPA efficiency suggests promising applications in optical devices, such as laser protection systems and optical limiters. Density Functional Theory (DFT) investigation also confirms that the presence of oxygen vacancies generates energy states below the conduction band. This, in turn, benefits the absorption of more visible light during photocatalytic activities and leads to a notable nonlinear absorption in optical limiting. Overall, the N-S doping strategy significantly improves the photocatalytic and optical limiting performance of TiO2 NPs, making them promising candidates for a wide range of applications.

Photocatalytic degradation of Orange-II by surfactant assisted Mn/Mg co-doped TiO2 nanoparticles under visible light irradiation

In this research, the photocatalytic effect was studied for sol-gel synthesized Mn/Mg co-doped metal oxide (TiO2) nanoparticles (NPs), which are encapsulated with anionic Gemini surfactant. The physicochemical properties of Mn/Mg co-doped TiO2 were investigated using a variety of characterization techniques, FT-IR, UV Vis-DRS, XRD, SEM, EDX, TEM, BET and PL. Characterization results reveal that Mn/Mg dopants stabilize TiO2 in the form of anatase phase and reduce the bandgap energy. Presence of strong chemical bonding and functional groups at the interface of dopant and TiO2 NPs was confirmed with FT-IR. The photocatalytic activity of these catalysts was assessed by the degradation of Orange II (AO7) using visible light irradiation. Of the variable nanomaterials MMT5-GS2 showed remarkable results. The photoluminescence studies revealed that OH radicals are the reactive species and responsible for oxidative photocatalytic degradation of Orange II.

Novel synthesis of Cl/N Co-doped TiO2 nanoparticles for enhanced photocatalytic activity

The N/Cl co-doped TiO2 nanostructures were studied as photocatalyst for rhodamine B (RhB), Methylene Blue (MB), and Methyl Orange (MO) degradation. A Commercial TiO2 (P25) grade was also compared to our materials. The N/Cl co-doped TiO2 at different Ti4+ precursors were synthesized by the co-precipitation method. The structural, surface morphology, and surface area were analyzed by XRD, SEM, TEM, and BET. Optical properties of samples were investigated by UV-visible spectroscopy showing that the N/Cl co-doped TiO2 has smaller bandgap than the P25. Overall, the improved N/Cl co-doped TiO2 samples showed better performance than the P25 for RhB, MB and MO degradations.

One-pot hydrothermal preparation of Ni and I co-doped brookite-anatase TiO2 nanoparticles with remarkably enhanced photoreduction activity of CO2 to CH4

Ni and I co-doped TiO2 nanoparticles with mixed anatase-brookite phase (Ni/I-TiO2) were synthesized by the hydrothermal-calcination method for photocatalytic CO2 reduction with H2O vapor. The I and Ni co-doping, anatase-brookite phase junction, as well as the presence of Ti(III) and Ni(III) endowed the catalyst with promoted visible light absorption, increased reduction ability of photogenerated electrons, facilitated charge separation and migration along with modulated CO2 adsorption mode and capacity, ultimately resulting in boosted photocatalytic activity and product selectivity as compared with those of pure TiO2. The CO, CH4 and O2 yields of the optimized Ni/I-TiO2 reached 3.49, 158.25 and 246.30 μmol/gcat after 15 h of light illumination, which decreased slightly after 9 cycles, and the product selectivity was above 98 % for photocatalytic reduction of CO2 to CH4 with Ni and I co-doping. The in-situ FTIR results with the observation of CH3O and CH3 intermediates confirmed CH4 formation, and the possible mechanism of photocatalytic CO2 reduction over Ni/I-TiO2 was elucidated. This work provides new insights to pursue efficient catalysts for the selective photocatalytic CO2 reduction to CH4.

Augmentation of photocatalytic degradation of methylene blue dye using lanthanum and iodine Co-doped TiO2 nanoparticles, their regeneration and reuse; and preliminary phytotoxicity studies for potential use of treated water

The photocatalytic degradation of methylene blue (MB) dye using Lanthanum (La) and Iodine (I) co-doped TiO2 (Ti1−x-yLaxIyO2, where x = 0.00 – 0.05, y = 0.00 – 0.005) nanoparticles prepared through the solution combustion method has been investigated in the current study. The photocatalysts' characterization was done using various techniques, including FTIR for identifying functional groups, XRD for determining crystallinity and crystallite size, DRS for estimating the band gap, and XPS for identifying elements and their oxidation states. The co-doping of La and I in TiO2 causes narrowing the band gap and suppresses the recombination of e–/h+ pairs, which surges its photocatalytic activity. The La and I co-doped TiO2 nanoparticles exhibited a photodegradation efficiency of 98% for MB within 40 min, significantly outperforming undoped TiO2 and commercial TiO2 photocatalyst Aeroxide P-25. Moreover, regeneration experiments demonstrated excellent reusability of the nanoparticles. To find potential use of photocatalytically treated water in irrigation, the phytotoxicity study was done with "Vigna radiata" germination. The evaluation of phytotoxicity demonstrates that the treated water may be used for irrigation purposes.

Structure phase-induced photodegradation properties of cobalt-sulfur co-doped TiO2 nanoparticles synthesized by hydrothermal route

The authors report a scheme for enhancing the photodegradation properties of TiO2 nanoparticles (TiO2 NPs) by controlling their structural phases through cations doping (cobalt and Sulfur). Cobalt-sulfur co-doped TiO2 nanoparticles were synthesized via a hydrothermal process, with sulfur content varying at levels of 0.69, 1.37, and 2.06 atomic percent (at. %), while maintaining a constant cobalt content of 0.2 at. %. Our finding shows that the methyl blue dye loaded with pure TiO2 degraded marginally in 120 min (⁓ 10.5%) while in the presence of an optimally doped sample (Co: 0.2 at. %, S 2.06 at. %), it degraded almost 93% for the same duration. The study explores the underlying physical mechanisms that contribute to the varying levels of photoactivity, and these mechanisms are found to be influenced by the valency of the doping agents. The findings of this study demonstrate that precise control over the formation of the anatase phase through doping enables the production of a remarkably efficient TiO2-based photocatalyst. Our results indicate great prospects in enhancing TiO2-based photocatalyst development chemically, a suitable approach for large-scale nanoparticle production for industrial applications.

Visible light assisted photocatalytic degradation of mixture of reactive ternary dye solution by Zn–Fe co-doped TiO2 nanoparticles

The current study deals with the synthesis of novel Zn, and Fe co-doped TiO2 photocatalyst by the sol-gel method at room temperature. The prepared photocatalysts are characterized by several standard analytical tools. X-ray diffraction (XRD) and Raman analysis verifies the tetragonal anatase phase of TiO2 in all synthesized nanoparticles. The morphology and chemical composition of ZFT_2.5 were confirmed using the Field-Emission Scanning Electron Microscope (FE-SEM) and energy dispersive X-ray (EDAX) analysis respectively. X-ray photoelectron spectroscopy (XPS) measurements verify the binding energies of a host and dopant material. The High resolution transmission electron microscopy (HR-TEM) reveals the presence of spherical nanoparticles in ZFT_2.5 photocatalyst with a diameter ranging from 8 to 20 nm. The absorption spectra of the prepared nanoparticles exhibit strong absorption in visible light. The synergistic effect created by Zn and Fe blocked the light induced charge carriers and delayed the recombination probability. The photocatalyst ZFT_2.5 was tested for photocatalytic degradation against the mixture of the three cationic dyes [rhodamine B (RhB), malachite green (MG), and methylene blue (MB)] under exposure of visible light. Total organic carbon (TOC) study was performed to evaluate the organic character of the photodegradate dye solution.

Photoelectrochemical reduction of 3-nitroacetophenone using C–N co-doped TiO2 nanoparticles as a photoanode

Photoelectrochemical reduction of 3-nitroacetophenone using C–N co-doped TiO2 nanoparticles as a photoanode

Enhanced photocatalytic activity in RhB dye degradation by Mn and B co-doped mixed phase TiO2 photocatalyst under visible light irradiation

Here, we report synthesis of undoped, manganese (Mn) doped, boron (B) doped and Mn-B co-doped TiO2 nanoparticles (NPs) by a cost-effective sol-gel method. The structural properties, phase, micro-morphology and particle size of the synthesized nanoparticles have been characterized by X-ray diffraction, Raman spectroscopy, Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS) techniques. These studies revealed that undoped and mono (Mn/B) doped TiO2 NPs exhibit only anatase phase, whereas (Mn and B) co-doped TiO2 NPs exhibit anatase and rutile mixed phase structure. Furthermore, co-doping reduces the particle size, agglomeration in aqueous medium and the sample possesses crystal defects. UV–Visible diffusive reflectance spectroscopy (DRS) revealed that the co-doped sample demonstrates extended optical response in the visible wavelength range of the solar spectrum and is red shifted when compared to undoped and mono doped TiO2 NPs. The obtained optical band gap (2.11 eV) and the Urbach energy (1.12 eV) for the Mn and B co-doped TiO2 NPs suggest the formation of mid-gap energy states, which might make this NPs a suitable candidate for photocatalysis in the visible light spectrum. We investigated the photocatalytic degradation of rhodamine B (RhB) dye by the synthesized NPs under visible light irradiation. Our studies revealed that co-doped TiO2 photocatalyst can degrade 99% of RhB dye within 90 min of visible light irradiation and can retain 95% degradation efficiency up to the third consecutive cycles. Finally, we provide a plausible explanation for such enhanced visible light assisted photocatalytic performance.