V-doped TiO2 Research Articles

Vanadium-doped TiO<sub>2</sub> Adsorbent-Photocatalyst for Organic Dye Treatment

This study focuses on the synthesis of V-doped TiO2 materials using a modified polyol method to enhance their efficiency. The obtained materials were characterized by various methods such as XRD, EDX, FTIR, SEM, TEM-SAED, Raman, and UV-Vis DRS. The results indicated the crystalline anatase phase of TiO2, with spherical morphology and an average size of 30nm. The UV-DRS measurement demonstrated that doped materials have a lower bandgap than the pristine TiO2. The material possesses dual functionality, with adsorption capability and photocatalytic activity applied to treat organic dye contaminants. Evaluation of MB degradation under UV irradiation revealed an exceptional efficiency of up to 99% within a remarkably short duration of 30 minutes. Furthermore, the catalyst exhibited robust recovery efficiency exceeding 99% after 2 regeneration cycles and retention of approximately 80% after four cycles.

Sol-Gel Multilayered Niobium (Vanadium)-Doped TiO2 for CO Sensing and Photocatalytic Degradation of Methylene Blue.

Multilayered TiO2 films doped either with Niobium or Vanadium (1.2 at. %) were deposited by the sol-gel dip coating method on c-Si and glass substrates. The films on glass substrates were tested for CO sensing and photocatalytic degradation of methylene blue. X-ray diffraction data analysis showed that all the TiO2:Nb(V) films were nanocrystalline in the anatase phase, with a uniform and compact microstructure and a homogeneous superficial structure of small grains with diameters in the range of 13-19 nm. For the electrical characterization, the TiO2:Nb(V) films were incorporated in Metal-Insulator-Semiconductor (MIS) structures. The specific resistivity is of the order of 104 Ωcm and its value decreases with increasing the electrical field, which testifies to the injection of electrons into these layers. From the analysis of the current-voltage curves taken at different temperature- and frequency-dependent capacitance-voltage and conductance-voltage characteristics, the density and parameters of deep levels in these TiO2 films are evaluated and the electron charge transport mechanism is established. It was shown that the current in these TiO2:Nb(V)-Si MIS structures is mainly carried out by inter-trap tunneling via deep levels energetically distributed in the TiO2 bandgap. Testing these sol-gel TiO2:Nb(V) layers for gas sensing and photocatalytic capabilities proved that they could serve such purposes. In particular, the results of the V-doped sol-gel TiO2 film confirm its CO detection capability, which is rarely reported in the literature. For the photodegradation of methylene blue, the Nb-doped TiO2 samples were superior, with nearly double the photocatalytic efficiency of undoped TiO2.

Unveiling the non-innocence of vanadium dopant in TiO2 nanocrystals for advanced energy storage and smart windows

Vanadium doped TiO2 NCs stand out as a promising candidate for energy storage applications due to its high electrical conductivity and redox properties. However, the thermodynamical behavior of the material under working conditions has not been explored and the reasons for its superior performance remain unlocked. This study explores the use of a combination of advanced in situ spectroscopy techniques, including x-ray absorption spectroscopy (XAS), spectro-electrochemistry (SEC), and electrochemical impedance spectroscopy (EIS) to provide unprecedented insights into the intricate electrochemical reaction mechanisms within these nanocrystals. Density functional theory calculations and EIS reveal the active role of substitutional V ions in the TiO2 anatase network as electron donors, enhancing surface charge and carrier density and improving pseudocapacitive properties. Cyclic voltammetry and in situ SEC reveal that V-doped TiO2 NCs exhibit significantly improved charge storage capacities, particularly in the pseudo-capacitance storage mechanism. In situ SEC and XAS analyses indicate that a more effective reduction of Ti4+ ions occurs during the electrochemical process in doped NCs, leading to higher charge capacitance and faster processes. Furthermore, in situ XAS measurements of the V K-edge revealed that the vanadium ions, beyond improving the redox behavior of the host, also actively participate in the reduction process. The significant changes in the V K-edge XANES and extended x-ray absorption fine structure spectra observed under reduction conditions can be ascribed to a change in the structure and oxidation state of the vanadium ions during the electrochemical reaction.

Antibacterial Food Packaging Nanomaterial Based on Atomic Layer Deposition for Long-Term Food Storage.

The aim of the present work is to use the latest achievements of nanotechnology (atomic layer deposition, ALD) in the field of food packaging to prevent biofilm formation by food-associated bacteria. Some potential applications of nanotechnology in the food packaging industry are studied in the manuscript, in the field of antibacterial materials for food packaging. The ALD technique was used to synthesize vanadium (V)-doped TiO2 thin nanofilm on commercially available polypropylene (PP) food container to enhance an antibacterial activity for potential use in food packaging, to reduce spoilage, thereby, prolonging the food shelf- life. To better understand the ability and effectiveness of the antimicrobial packaging material of V-doped TiO2, to prevent the biofilm formation by dairy-associated pathogenic bacteria, the coated and uncoated PP containers with a fresh raw cow's milk were tested. We have illustrated the effectiveness of ALD Al2O3 + TiVOx nanocoating against populations of milk-borne pathogenic bacteria.

Boosting Photocatalytic Activity Using Vanadium Doped Titanium Oxide with Reduced Graphene Oxide (RGO)/Semiconductor Nanocomposites

Textile waste materials are increasing day by day with the depletion of water. This increasing concentration of ions, functional groups, and ammonia present in the water as a byproduct from the industries produce toxicity. This affects the human and aquatic life. The sustainability of the materials to rule out this toxicity can be done by Reduced Graphene Oxide synthesized by modified Hummer’s method. The composite of V-doped TiO2 and RGOwas synthesized by hydrothermal method and V-doped TiO2/RGOand perfluorocarbon synthesized by sonication. Methylene blue was used as an indicator to improve the pH of the wastewater under sunlight. The product was characterized by the powder X-ray Diffraction method. It has confirmed the synthesis of the product. The ultraviolet/visible spectroscopy was employed to study the absorbance decreases with time which is the confirmation of degradation of methylene blue with time and it was clearly observed that photocatalytic activity of the product for the degradation of methylene blue which is an organic dye and hazardous to the environment. The findings obtained can be utilize for the industrial waste-water treatment with metallic ions.

Electronic properties and photodegradation ability of V–TiO2 for aniline

Photocatalytic technology has broad prospects in the degradation of organic pollutants due to its green, energy-saving and high-efficiency characteristics. In this study, TiO2 and V–TiO2 were prepared by hydrothermal method, and the catalysts were tested by experimental and theoretical calculations under a 400 W metal halide lamp degradation efficiency for aniline (30 mg/L). The synthetic photocatalysts were characterized by XRD, HRTEM, FT-IR, XPS, UV–Vis DRS, PL, EIS, and photocurrent, the results showed that the edges of the V-doped TiO2 absorption band were redshifted, the band gap value were reduced, the photocatalytic activity were improved, and the PL showed e−/h+ had the lowest composite rate for 1.5 mol%V–TiO2 and broadens the optical response range. 1.5 mol% V was the optimal value for photodegrading aniline, and moderate V modification can significantly inhibit the complexation of e−/h+ pairs. Finally, stability measurements performed over 5 cycles show that 1.5 mol%V–TiO2 has excellent stability. The calculation results show that the optical band gap of V–TiO2 were significantly reduced, the photocatalytic performance of V–TiO2 were greatly enhanced.

V-doped TiO2 nanobelt array for high-efficiency electrocatalytic nitrite reduction to ammonia

Electrocatalytic nitrite (NO2−) reduction to ammonia (NH3) has been an attractive topic, which not only removes NO2− pollutants existing in surface water and underground water but also synthesizes value-added NH3. Nevertheless, the inactive kinetics for direct six-electron NO2−-to-NH3 conversion makes it challenging to explore efficient electrocatalysts for the NO2− reduction reaction (NO2RR). Herein, we report a V-doped TiO2 nanobelt array on a titanium plate (V–TiO2/TP) as a highly efficient NO2RR electrocatalyst. The experimental results and theoretical calculations clarify that V doping can enhance the intrinsic electrical conductivity and effectively optimize the free energy of the TiO2 (101) crystal plane in the potential determining step, resulting in a positive effect on electrochemical NO2RR to NH3. The designed V–TiO2/TP exhibits an outstanding electrochemical NO2RR property with a high NH3 yield of 540.8 μmol h−1 cm−2 at −0.7 V and an excellent Faradaic efficiency of 93.2% at −0.6 V versus reversible hydrogen electrode, superior to TiO2/TP.

Enhanced electrochemical properties of Zn and V-doped TiO2 nanoparticles synthesized via non-aqueous sol–gel route for supercapacitor application

Enhanced electrochemical properties of Zn and V-doped TiO2 nanoparticles synthesized via non-aqueous sol–gel route for supercapacitor application

ALD coated polypropylene hernia meshes for prevention of mesh-related post-surgery complications: an experimental study in animals

In this work, thermal atomic layer deposition (ALD) was used to synthesize vanadium (V)-doped TiO2 thin nanofilm on polypropylene (PP) hernia meshes. Multiple layers of (Al2O3 + TiVO x ) nano-films were coated on the PP hernia mesh surface to provide a layer with a total thickness of 38 nm to improve its antibacterial properties, thereby, prevent mesh-related post-surgery complications. Highly conformal V-doped TiO2 nanofilm were deposited on PP mesh at a temperature of 85 °C. Rats and rabbits have been used to evaluate the tissue reaction on coated PP hernia meshes and biomechanical testing of the healed tissue. Five rabbits and ten rats have been implanted with ALD coated and uncoated (control) PP meshes into the back of rats and abdominal wall of rabbits. Histology of the mesh-adjacent tissues and electron microscopy of the explanted mesh surface were performed to characterize host tissue response to the implanted PP meshes. The effect of V-doped TiO2 coating on a living organism and fibroblast functions and bacterial activities were studied. The present results indicated that ALD coating improves adhesion properties and exhibited enhanced antibacterial activity compared to uncoated PP mesh. It was shown that V-doped TiO2 coatings were highly effective in inhibiting S. aureus and E. coli adhesion and exhibited excellent antibacterial activity. We found that V-doping of TiO2, unlike bare TiO2, allows generated and further procured strong redox reactions which effectively kills bacteria under visible light. We have reported comparative analysis of the use of undoped (bare) TiO2 and V-doped TiO2 as a coating for PP meshes and their action in biological environment and preventing biofilms formation compared with uncoated PP meshes. The PP meshes coated with V-doped TiO2 showed significantly lower shrinkage rates compared with an identical PP mesh without a coating. We have shown that ALD coatings provide non-adhesive and functional (antibacterial) properties.

All-solid-state Z-scheme heterostructures of 1T/2H-MoS2 nanosheets coupled V-doped hierarchical TiO2 spheres for enhanced photocatalytic activity

Highly efficient all-solid-state Z-scheme semiconductors are of great significance to the photocatalytic performance. Herein, we design and construct edge-rich bicrystalline 1T/2H-MoS2 nanosheet cocatalyst modified V-doped hierarchical TiO2 microspheres for the photocatalytic removal of oxytetracycline hydrochloride. In this catalyst system, the conductive 1T phase of MoS2 accelerates the charge transfer kinetics and works as an electron mediator in a Z-scheme, while 2H phase of MoS2 and V-TiO2 is the photosensitizer and reactant adsorbed sites, respectively. The optimized VTM-5% heterojunction possesses superior degradation efficiency than that of bare components, which is ascribed to the enhanced light-harvesting capacity, populated exposed active sites, rapid photogenerated charge transfer, and excellent affinity to reactant molecules. Moreover, a built-in electric field forms via an intensive electronic interaction of positively charged V-TiO2 and negatively charged 1T/2H-MoS2, as confirmed by density functional theory calculation. This study provides new insights into the rational design of noble metal-free cocatalyst-based Z-scheme photocatalysts toward environmental remediation.

Metal-organic framework derived vanadium-doped TiO2@carbon nanotablets for high-performance sodium storage

Titanium dioxide (TiO2) as a potential anode material for sodium-ion batteries (SIBs) suffers from the intrinsic poor electronic conductivity and sluggish ionic diffusivity, thus usually leading to the inferior electrochemical performance. Herein, we demonstrate a facile strategy to enhance the sodium storage performance of TiO2via vanadium (V) doping, using the pre-synthesized V-doped Ti-based metal–organic framework (MOF, MIL-125) as the precursor, which can be converted into the V-doped TiO2 with simultaneous carbon hybridization and controlled V-doping amount (denote as VxTiO2@C, where × represents the V/Ti molar ratio (RV/Ti)). V-doping not only affects the morphology of the MIL-125 changing from thick to thin nanotablets, but also greatly enhances the electrochemical performance of the VxTiO2@C. When used as an anode for SIBs, the V0.1TiO2@C exhibits a much higher reversible capacity of 211 mAh/g than that for the undoped TiO2@C (only 156 mAh/g) after 150 cycles at 100 mA/g. Even after high-rate long-term cycling, the V0.1TiO2@C can still display a capacity of 180 mAh/g with a high capacity retention of 137% at 1000 mA/g after 4500 cycles. Structural/electrochemical measurements reveal that V-doping induces the formation of oxygen vacancies as well as Ti3+ species, which efficiently improve the electric conductivity and the ion diffusivity of the electrode. Meanwhile, the thinner V0.1TiO2@C nanotablets with porous structure and carbon hybridization could facilitate the ion/electron transfer with shortened diffusion pathways.

Humidity Sensing Performance of V: TiO2 3D Nanostructure-based Humidity Sensor

Titanium dioxide (TiO2) three-dimensional (3D) nanostructure has been prepared and doped with vanadium (V) using a solution immersion method. The resultant material exhibited improved performance in the role of the sensing element in resistive-type humidity sensor. The improvement is attributed to the arrangement of the nanorod structure which appears to be more closely packed in the V-doped TiO2 when compared to the undoped TiO2. Another possible reason is due to the increased of defect sites, namely oxygen vacancies of the V-doped sample which enhance the dissociation of the adsorbed water molecules.

V-doped TiO2 photocatalysts and their application to pollutant degradation.

V-doped TiO2 materials (0.01, 0.05, 0.10, and 1.00 nominal atomic %) were synthesized by the sol-gel method and characterized by X-ray diffraction, Raman spectroscopy, UV-visible diffuse reflectance spectroscopy, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, and H2-temperature programmed reduction. Two vanadium precursors (vanadyl acetylacetonate and ammonium metavanadate) and three calcination temperatures (400, 500, and 600°C, with and without air circulation) were assayed. The efficiency of the materials as photocatalysts was studied by the degradation of phenol with UV and visible lamps. The photocatalyst prepared from vanadium acetylacetonate, with a vanadium content of 0.01 nominal atomic %, calcination at 400°C without air circulation (0.01VTi-400), showed the best performance, reaching 100% and 30% degradation of phenol (50μM) by irradiation with UV lamps (3h) and visible lamps (5h), respectively. To evaluate the efficiency of this catalyst in the degradation of other structurally related compounds, two substituted phenols were selected: 4-chlorophenol and 4-nitrophenol. The 0.01VTi-400 photocatalyst showed to be applicable to the degradation of phenolic compounds when the substituent was an activating group or a weakly deactivating group (for electrophilic reactions). Additionally, the selectivity of 0.01VTi-400 for phenol degradation in the presence of Aldrich humic acid was tested: phenol degradation reached 68% (3h, UV lamps). The performance of 0.01VTi-400 indicated that it is a promising material for further applications.

Descriptor-Guided Design and Experimental Synthesis of Metal-Doped TiO2 for Propane Dehydrogenation

Recently, coordinated unsaturated TiO₂ due to the oxygen vacancy has been found to have good application prospects in propane dehydrogenation (PDH) reactions. The oxygen vacancy can be effectively adjusted by metal doping into TiO₂. In the present paper, density functional theory calculations were conducted to study the PDH reaction of TiO₂ doped with transition metals in the fourth period with the aim to screen for an effective doping metal. A good linear relationship was found between the calculated turnover frequency and co-adsorption energy of H and Propyl species, justifying such co-adsorption energy as a useful descriptor for screening PDH catalysts. Compared with pure-phase TiO₂, V-doped TiO₂ exhibits a lower propane C–H bond breaking energy barrier (0.93 eV) and a higher TOF (5.67 × 10–³ s–¹) value. According to the calculation results, the V-doped TiO₂ catalyst was successfully synthesized. The experimental results show that the r(C₃H₆) rises with V doping.

Enhanced Sensitivity of Humidity Sensor Prepared using Vertically Aligned V-doped TiO2 Nanorods Array

This article reports on the performance of vanadium-doped TiO2 nanorod arrays (TNA)-based humidity sensor. The sensing material was prepared using a facile solution immersion method. Humidity sensor was fabricated using the prepared thin films and was tested using humidity chamber and a current measuring circuit, built with microcontroller. Improvement to the sensitivity was observed for the V-doped TNA sensor with sensitivity value of 15.0 compared to 9.9 for the undoped TNA sensor. The increased performance is attributed to the enlargement of nanorods diameter, improvement of crystallinity and the increase in oxygen vacancy defect sites of the V-doped sample.

V-TiO2 nanospindles with regulating tumor microenvironment performance for enhanced sonodynamic cancer therapy

Sonodynamic therapy, with advantages in large tissue penetration depth and great controllability, is a promising type of non-invasive cancer treatment method. Developing sonosensitizers with high reactive oxygen species (ROS) quantum yield and the ability to regulate tumor microenvironment to achieve enhanced performances in sonodynamic therapy would thus be rather attractive. Herein, vanadium (V) doped TiO2 (V-TiO2) nanospindles with glutathione-depleting properties are fabricated for enhanced sonodynamic cancer therapy. Due to doping of the V element, the bandgap of V-TiO2 nanospindles is reduced, increasing the efficiency of ultrasound-triggered ROS production compared to that of pure TiO2 nanoparticles. More interestingly, the doping of V also makes V-TiO2 nanospindles an effective Fenton-like agent, which can catalyze the generation of highly toxic hydroxyl radicals (•OH) from endogenous H2O2 in the tumor, thus enabling cancer-killing through chemodynamic therapy. In addition, the V doping also endows V-TiO2 nanospindles with the function of glutathione depletion, further amplifying the oxidative stress generated by chemodynamic-sonodynamic therapy. In vitro cell experiments and in vivo animal experiments demonstrate that V-TiO2 nanospindles can effectively kill cancer by the combined chemodynamic-sonodynamic therapy, significantly improving the tumor treatment outcomes. Importantly, V-TiO2 with the ultrasmall spindle morphology can be quickly excreted from the body, without causing any long-term toxicity. This work illustrates that doping TiO2 with other special elements is a meaningful strategy to fabricate nanostructures with interesting functions useful in biomedicine.

First-principles study on electronic, magnetic properties and optical absorption of vanadium doped rutile TiO2

The electronic, magnetic properties and optical absorption of vanadium (V) doped rutile TiO2 have been studied by the generalized gradient approximation GGA and GGA+U (Hubbard coefficient) approach respectively. On the one hand, we consider the influence of vanadium with different doping concentration on the electronic structure. On the other hand, we study double V atoms doped TiO2, mainly study four V-doped TiO2 configurations, and find the magnetic ground states are ferromagnetic state. For the TiO2@V-V1, TiO2@V-V3 and TiO2@V-V4 configurations without O ion as bridge between V-V atoms, there will have a metastable state of antiferromagnetic configurations, while, for the TiO2@V-V2 configurations with an O ion as bridge between V-V atoms, due to the existence of superexchange between V-O-V, there will only exist the ground state of ferromagnetic state and there are no other metastable configurations. Furthermore, the optical properties of V-doped TiO2 are calculated. The results show that the V-doped TiO2 has strong infrared light absorption and visible light absorption.

Expression of Concern: Synthesis and characterization of V-doped TiO2 nanoparticles through polyol method with enhanced photocatalytic activities

Expression of Concern: Synthesis and characterization of V-doped TiO2 nanoparticles through polyol method with enhanced photocatalytic activities

Vanadium and Nitrogen Co-Doped Titanium Dioxide (TiO2) with Enhanced Photocatalytic Performance: Potential in Wastewater Treatment

The vanadium (V) and nitrogen (N) dopants on TiO₂ demonstrated superior photocatalytic performance for the degradation of methylene blue (MB) dye under visible light. The vanadium, V, N-co-doped TiO₂ was synthesized by a modified sol-gel method. It revealed that V and N codoping had a significant effect on the band gap (Eg) of TiO₂, where the pristine TiO₂ possessed a wide band gap (3.18 eV) compared to V-doped TiO₂ (2.89 eV) and N-doped TiO₂ (2.87 eV) while the V, N-co-doped TiO₂ depicted the narrowest band gap (2.65 eV). The greatly increased specific surface area for the V, N-co-doped TiO₂ (103.87 m²/g) as compared to P25 TiO₂ (51.68 m²/g) also contributed to the major improvement in the MB dye degradation efficiency (0.055 min-1). The V, N-co-doped TiO₂ exhibit rapid photocatalytic activity for the degradation of MB with almost 99% of degradation in 120 minutes.

Ultrafast optical spectroscopy of semiconducting and plasmonic nanostructures and their hybrids

The knowledge of the carrier dynamics in nanostructures is of fundamental importance for the development of (opto)electronic devices. This is true for semiconducting nanostructures as well as for plasmonic nanoparticles (NPs). Indeed, improvement of photocatalytic efficiencies by combining semiconductor and plasmonic nanostructures is one of the reasons why their ultrafast dynamics are intensively studied. In this work, we will review our activity on ultrafast spectroscopy in nanostructures carried out in the recently established EuroFEL Support Laboratory. We have investigated the dynamical plasmonic responses of metal NPs both in solution and in 2D and 3D arrays on surfaces, with particular attention being paid to the effects of the NP shape and to the conversion of absorbed light into heat on a nano-localized scale. We will summarize the results obtained on the carrier dynamics in nanostructured perovskites with emphasis on the hot-carrier dynamics and in semiconductor nanosystems such as ZnSe and Si nanowires, with particular attention to the band-gap bleaching dynamics. Subsequently, the study of semiconductor-metal NP hybrids, such as CeO2-Ag NPs, ZnSe-Ag NPs and ZnSe-Au NPs, allows the discussion of interaction mechanisms such as charge carrier transfer and Förster interaction. Finally, we assess an alternative method for the sensitization of wide band gap semiconductors to visible light by discussing the relationship between the carrier dynamics of TiO2 NPs and V-doped TiO2 NPs and their catalytic properties.