TiO2 Core Shell Research Articles

Development of a high property acetone sensor based on TiO2 core-shell spheres and their sensing mechanism analysis

Development of a high property acetone sensor based on TiO2 core-shell spheres and their sensing mechanism analysis

Synthesis, pharmaceutical properties, and in silico study of ZnO@TiO2 nanocomposite

The use of environmentally friendly production of nanoparticles has recently interest of scientists. The primary goal of this study is to create core–shell nanoparticles zinc oxide @ dioxide titanium (ZnO @ TiO2) for some biomedical application by a two-stage Nd: YAG pulsed laser ablation, the first stage involves laser ablation of a Zinc target to produce ZnO nanoparticles (the core) in colloidal form. Subsequently, in the second stage, TiO2 (the shell) is ablated within the colloidal ZnO Nanoparticles. The transmission electron microscope (TEM) findings approve the synthesis of ZnO @ TiO2, displays an average particle size of 13 nm for ZnO particles, 20 nm of TiO2NPs, and 34 nm of the ZnO@TiO2 NPs. The anti-bacterial efficiency was assessed against the bacterial strains' Bacillus cereus, Proteus mirabilis. Our results discovered inhibition zone of 19 mm and12.50 mm for Bacillus cereus, Proteus mirabilis, correspondingly, when by ZnONPs. Whereas inhibition zone of 20.50 mm and 21.50 mm for Bacillus cereus, Proteus mirabilis, correspondingly, when by TiO2NPs. While with ZnO@TiO2NPs, result was better to 27.50 mm for Bacillus cereus and 24 mm for Proteus mirabilis. The antioxidant efficiency was assessed by DPPH, The results show have strong antioxidant activity for ZnO @ TiO2 core–shell than ZnONPs alone, TiO2NPs alone. Cytotoxicity assay established a significant reduction in cancer cell population pole 72hr. Cytotoxicity of ZnO@TiO2NPs on breast cancer cells was 90.23 %. Computational innovation of TiO2, ZnO and ZnO@TiO2 nanoparticles against breast cancer line gave the highest correlation value and RMSD between ZnO and 6NLV receptors from other nanocomposites.

Selective efficient photocatalytic degradation of antibiotics and direct Z-type migration pathway for hierarchical core-shell TiO2/g-C3N4 composites.

Constructing superior Z-type photocatalytic heterojunction is beneficial to effectively enlarge interface contact, improve the photo-generated carrier separation rate, and retain the high redox ability. In this work, we designed a hierarchical core-shell g-C3N4/TiO2 structure to build Z-type heterojunction via combining simple template method and pyrolysis process. A close-knit Z-type heterojunction was constructed using TiO2 as a thick core and g-C3N4 as an ultra-thin shell. The effects of lamp source, wavelength, tetracycline (TC) concentration, and photocatalyst dose on the degradation performance on TC of g-C3N4/TiO2 were inspected. 0.1TiO2/g-C3N4 photocatalyst had the best degradation rate and highest removal rate within 30min, and its degradation rate was about 49, 23, and 5 times than pure g-C3N4, TiO2, and commercial TiO2/g-C3N4 in respect. Moreover, compared with degradation ability under Xenon lamp, LED irradiation for g-C3N4/TiO2composites showed aremarkable selectivedegradation. The fast and efficient Z-type transfer pathway of 0.1g-C3N4/TiO2 was realized by forming an optimized interface and abundant surface active sites ascribed to the combined action of thick TiO2 core and ultra-thin g-C3N4 shell. In addition, the degradation intermediates were analyzed by LC-MS and suggested pathways of degradation. The work could provide novel design concept to obtain reliable Z-type photocatalysts with hierarchical core-shell structure applied in degradation of antibioticwastewater.

Ultrathin TiO2(B) nanosheets-decorated hollow CoFeP cube as PMS activator for enhanced photocatalytic activity

A novel TiO2(B)/phosphidated CoFe Prussian blue analogs (CoFeP) photocatalyst with core–shell structure was synthesized by hydrothermal method for the activation of peroxymonosulfate (PMS) to degrade TC under solar light. TiO2(B), an ultrathin two-dimensional (2D) layered material, is widely used in photocatalysis. However, the low light absorption efficiency and slow electron mobility limit the application of TiO2(B) in photocatalysis. Here, TiO2(B) was in-situ grown on the surface of phosphidated CoFe Prussian blue analogs (CoFeP). The composites with a core–shell structure can activate peroxymonosulfate (PMS) to degrade tetracycline (TC) under solar light. The optimized TiO2(B)/CoFeP heterojunction achieves a TC degradation rate of 94 % within 5 min, due to that it effectively suppresses the recombination of photogenerated charges and improves light absorption ability. The phosphorization of CoFePBA (CoFe Prussian blue analogs) not only promoted the formation of hollow structures but improved the carrier mobility between TiO2(B) and CoFeP. At the same time, the rapid redox cycle of Fe and Co metal ions promoted the activation of PMS and the rapid degradation of TC. This work provides a new core–shell TiO2(B)/CoFeP heterojunction for sustainable water purification via PMS activation.

Bifunctional linker-assisted assembly of core-shell TiO2 @In2S3 with enhanced photocatalytic activity for reduction of Cr(VI)

Monodispersed anatase TiO2 microspheres were prepared by a modified sol-gel method. In2S3 nanoparticles (NPs) were loaded on the as-prepared TiO2 to form non-core-shell TiO2/In2S3 and core-shell TiO2 @In2S3 composites through a direct deposition method and a linker-assisted assembly strategy, respectively. The catalytic activity of TiO2/In2S3 and TiO2 @In2S3 for HCOONH4-mediated photoreduction of Cr(VI) was comparatively studied. Based on soft and hard acid-base theory and experimental results, the mechanisms for forming the core-shell TiO2 @In2S3 and enhancing photocatalytic activity were elucidated. Results indicate: i) When TiO2 surface is functionalized by dimercaptosuccinic acid (DMSA), a bifunctional linker, In2S3 NPs can be uniformly and tightly attached onto the TiO2 to form core-shell TiO2 @In2S3 composite via the strong binding force between In3+ ions and thiol groups (–SH), whereas In2S3 NPs can't be evenly and firmly anchored to bare TiO2 due to the weaker affinity of In2S3 NPs for TiO2 and thereby non-core-shell TiO2/In2S3 composite is obtained. ii) TiO2 @In2S3 exhibits superior photocatalytic activity to TiO2/In2S3, which can be attributed to more efficient interfacial electron transfer between In2S3 and TiO2 in TiO2 @In2S3 than that in TiO2/In2S3.

Monolithic light concentration by core–shell TiO2 nanostructures templated by monodisperse polymer colloidal monolayers

Nanostructured dielectric overlayers can be used to increase light absorption in nanometer-thin films used for various optoelectronic applications. Here, the self-assembly of a close-packed monolayer of polystyrene nanospheres is used to template a core–shell polystyrene-TiO2 light-concentrating monolithic structure. This is enabled by the growth of TiO2 at temperatures below the polystyrene glass-transition temperature via atomic layer deposition. The result is a monolithic, tailorable nanostructured overlayer fabricated by simple chemical methods. The design of this monolith can be tailored to generate significant absorption increases in thin film light absorbers. Finite-difference, time domain simulations are used to explore the design polystyrene-TiO2 core–shell monoliths that maximize light absorption in a 40 nm GaAs-on-Si substrate as a model for a photoconductive antenna THz emitter. An optimized core–shell monolith structure generated a greater than 60-fold increase of light absorption at a single wavelength in the GaAs layer of the simulated model device.

Applicability of core-shell SiO2 microspheres with a high TiO2 loading as stationary phase for HPLC

BackgroundDue to its high chemical stability, sufficient rigidity and zwitterionic ion exchange properties, TiO2 can be considered as an alternative stationary phase material to SiO2 for high performance liquid chromatography. TiO2 stationary phase is usually prepared by coating TiO2 onto SiO2 support by sol-gel method. However, in the traditional coating method, in order to overcome the rapid hydrolysis rate of tetrabutyl orthotitanate, only a very low concentration of tetrabutyl orthotitanate can be used, resulting in a low loading of TiO2 on the support. ResultsTiO2 core-shell spheres with a good monodispersity were prepared using 0.25 mol L−1 tetrabutyl orthotitanate. The specific surface area, pore volume, pore diameter and TiO2 loading of the TiO2 core-shell spheres were 66 m2 g−1, 0.15 cm3 g−1, 9.8 nm and 57%, respectively. The core-shell spheres were derivatized with n-octadecyltrichlorosilane and then packed into a stainless steel column to test the separation performance for neutral, basic and acidic samples in liquid chromatography. A baseline separation of polyaromatic hydrocarbons was achieved, showing a column efficiency for fluorene of 118075 plates m−1. The prepared stationary phase was also used to separate acidic and basic mixtures, and column efficiencies of 54500 and 25836 plates m−1 were obtained for N,N-dinitroaniline and p-chlorophenol, respectively. The relative standard deviations of the retention times of polyaromatic hydrocarbons for run-to-run, day-to-day and column-to-column repeatability were all below 5.1%. Significance and noveltyThis work demonstrated that TiO2 can be coated in the pores of the shell of SiO2 core-shell spheres with high TiO2 loading using a high concentration of tetrabutyl orthotitanate as the titania source. The experimental results show that the TiO2 coated core-shell spheres can be a good alternative stationary phase for liquid chromatography.

Self-Cleaning and Photodegradable PVDF-g-IL Dye Wastewater Separation Membranes Modified with Dopamine-Coated TiO2 Core-Shell Particles.

In the present work, self-cleaning membranes of ionic liquid-grafted poly(vinylidene fluoride) (PVDF) polydopamine-coated TiO2 were prepared through a nonsolvent-induced phase separation method. PDA facilitates the uniform dispersion of TiO2 nanoparticles in PVDF substrates; meanwhile, TiO2@PDA core-shell particles and the hydrophilic IL improve the hydrophilicity of PVDF membranes and contribute to the increased average pore size and porosity, significantly improving the pure water permeation flux and dye wastewater flux (the water flux increased to 385.9 Lm-2 h-1). In addition, the combined effect of the positively charged IL and the strongly viscous PDA shell layer enhanced the retention and adsorption of dyes so that the retention and adsorption rates of both anionic and cationic dyes were close to 100%. Notably, the hydrophilic PDA allowed more TiO2 to migrate to the membrane surface during the phase transition; on the other hand, dopamine could promote photodegradation. Therefore, the combined two factors for TiO2@PDA were beneficial to the ultraviolet-catalytic (UV-catalytic) degradation of dyes on the surface of the membrane, leading to >80% degradation rates of various dyes. Thus, the high-efficiency and easy-to-operate wastewater treatment technology provides attractive potential for dye removal and resolution of membrane contamination.

Fabrication of ruthenium doped Ag@TiO2 core-shell nanophotocatalyst for the efficient reduction of nitrophenols

In the present study, a novel Ag@Ru/TiO2 core–shell nanophotocatalyst with silver metal cores and ruthenium-doped TiO2 semiconductor shells has been fabricated via an impregnation method and was characterized by XRD, Raman spectroscopy, XPS, UV–vis DRS, STEM, EDX, photoluminescence (PL) spectroscopy, FTIR, and BET analysis. In Ag@Ru/TiO2, the Ag NPs core serves as electron traps to prevent the electron-hole pairs recombination, and Ru doping significantly increases the absorption of visible light of the TiO2. The photocatalytic efficiency of Ag@Ru/TiO2 was assessed by the reduction of 4-nitrophenol (4-NP), 2,4-dinitrophenol (2,4-DNP), and 2,4,6-trinitrophenol (2,4,6-TNP) in presence of visible light. Ag@Ru/TiO2 demonstrated superior photocatalytic performance and attained 100% photocatalytic reduction of 4-NP in 2 min, 2,4-DNP in 3 min, and 2,4,6-TNP in 4 min to their corresponding aminophenols, which was almost 58 and 2.35 times higher than TiO2 and Ag@TiO2. Different experimental parameters including the NaH4 concentration, and the catalyst quantity were also explored. The order of reduction rate constant has been found to be: 4-NP (2.33 min−1) > 2,4-DNP (1.99 min−1) > 2,4,6-TNP (1.4 min−1). Reusability studies revealed the high stability and excellent photocatalytic efficiency of Ag@Ru/TiO2. This novel and highly efficient nanophotocatalyst is a good material for photoreduction of aromatic nitro compounds.

Pickering emulsion-based TiO2@PPy janus microspheres for efficient photocatalytic degradation of 5-methylbenzotriazole

The importance of photocatalysts is indisputable in scientific research. Improving the efficiency of photocatalysis depends on appropriate catalyst structure design and synthesis strategies that enhance the separation and migration efficiency of photogenerated charge carriers. In this study, we used a Pickering emulsion-based template masking method to prepare Janus-like core-shell TiO2 @PPy under in-situ UV irradiation. Compared to non-Janus-like core-shell catalysts, Janus-like catalysts showed 1.5–10 times higher efficiency for the degradation of 5-MBT. The two catalysts were analyzed using time-resolved photoluminescence(TRPL), and the fitting analysis of the results indicated that the Janus-like catalyst exhibited a higher proportion of long-lived charge carriers. This indicates that the Janus structure has a decisive effect on the charge separation of photocatalyst particles. The electron transfer mechanism of the Janus composite catalyst was further determined by EPR and band structure analysis. This work demonstrates a simple and scalable preparation strategy to enhance the efficiency of photocatalysts.

Enhanced lubrication by core-shell TiO2 nanoparticles modified with PEG-400

PurposeThe purpose of this paper is to enhance the characteristics of TiO2 nanoparticles (NPs). Because these NPs stick together easily and are difficult to distribute evenly, they cannot be used extensively in lubricating oils. Altering TiO2 was recommended as an alternate way for making NPs simpler to disperse.Design/methodology/approachThrough dielectric barrier discharge plasma (DBDP)-assisted ball mill diagnostics and modeling of molecular dynamics, TiO2@PEG-400 NPs were produced using the DBDP-assisted ball mill. The NPs’ microstructure was examined using FESEM, TEM, XRD, FT-IR and TG-DSC. Using the CFT-1 reciprocating friction tester, the tribological properties of TiO2@PEG-400 NPs as base oil additives were studied. EDS and XPS were used to examine the surface wear of the friction pair.FindingsTribological properties of the modified NPs are vastly superior to those of the original NPs, and the lipophilicity value of TiO2 NPs was improved by 200%. It was determined through tribological testing that TiO2@PEG-400’s exceptional performance might be attributable to a chemical reaction film made up of TiO2, Fe2O3, iron oxide and other organic chemicals.Originality/valueThis work describes an approach for preventing the aggregation of TiO2 NPs by coating their surface with PEG-400. In addition, the prepared NPs can enhance the tribological performance of lubricating oil. This low-cost, high-performance lubricant additive has tremendous promise for usage in marine engines to minimize operating costs while preserving navigational safety.

Surface properties and de-polluting performance of a photocatalytic coating incorporating novel core@shell nanospheres for cementitious substrate

The surface of long-term exposed building materials usually shows serious deterioration under continuous environmental erosion, which can greatly shorten the service life of building structures. The application prospect of multifunctional photocatalytic materials in civil engineering is promising but the engineering application is still limited due to the inherent defects of traditional photocatalytic materials. In this paper, the ordinary Portland cement (OPC) and alkali activated slag (AAS) mortar samples were prepared with a photocatalytic coating incorporating novel core@shell nanospheres which feature with TiO2 core and CoAl-layered double hydroxide shell (TiO2@CoAl-LDH). The surface roughness, microhardness, contact angle and capillary water absorption of coated and uncoated mortars were analyzed and characterized to explore the effect of photocatalytic coating on surface properties. The photocatalytic activity and photo-induced hydrophilicity of the coated mortar were investigated by degrading methylene blue and contact angle tests. A simulated rainwater washing test was designed to evaluate the long-term stability of photocatalytic coatings on mortar substrate. The results show that compared with unwashed coated mortar, the coated mortar after rainwater washing can still maintain a higher photocatalytic activity, whereby the surface hydrophilicity was increased with the decrease of the surface roughness and capillary water absorption. As a newly developed protective coating material, TiO2@CoAl-LDH is expected to confer multifunctional properties to the cementitious materials.

Core-shell Bi-containing spheres and TiO2 nanoparticles co-loaded on kaolinite as an efficient photocatalyst for methyl orange degradation

Improving the efficiency/cost ratio is the key to the practical application of photocatalysts. Using cheap minerals as carriers is an effective means to improve the efficiency/cost ratio of photocatalysts. Here, kaolinite was used to co-load TiO2 nanoparticles and Bi containing core-shell spheres forming the composites with excellent photocatalytic performance. The rate constant per unit mass of TiO2 in the optimal sample reached 18 times that of TiO2. Kaolinite plays important roles in promoting photocatalytic activity by improving the dispersion of TiO2 and the adsorption of O2 molecules and MO anions, besides the type-II energy band alignment of TiO2 and BixOy.

Core–shell defective TiO2 nanoparticles by femtosecond laser irradiation with enhanced photocatalytic performance

Herein, the authors present a new defect formation mechanism related to the laser wavelength. Short pulse width lasers only modify the surface layer, resulting in core-shell defective TiO2. Unlike long pulse lasers, the bulk of particles remains unchanged.

Enhanced selective photocatalytic oxidation of a bio-derived platform chemical with vacancy-induced core-shell anatase TiO2 nanoparticles

2,5-Furandicarboxylic acid (FDCA), a biodegradable alternative to fossil fuels, can be obtained via the catalytic oxidation of 2,5-hydroxymethlyfurfural (HMF), which is sourced from biomass. Anatase TiO2 nanoparticles (NPs) with oxygen vacancies (Vo) effectively promote the oxidation process under ultraviolet/visible-light illumination. The conversion process is accelerated by introducing anatase TiO2 NPs with a Vo-densified shell and stoichiometric core, which is achieved by a simple base treatment after synthesis. The defective shell acts as an electron-rich catalytic platform to facilitate HMF oxidation. Base-treated NPs measuring less than 20 nm yield ∼40% conversion to FDCA via HMF oxidation at room temperature in water. The photocatalytic activity is achieved at a 580% higher rate than with the corresponding untreated TiO2. Spectroscopic characterizations clearly visualize the densified layer of Vo enclosing the surface of the high-performance TiO2 NPs. Our results provide new insights into the optimal defect engineering of oxide-based catalysts for efficient biomass conversions.

Heterojunction nanochannel arrays based on SiC Core–TiO2 shell for efficiently enhanced photoelectrochemical water splitting

Heterojunction nanochannel arrays based on SiC Core–TiO2 shell for efficiently enhanced photoelectrochemical water splitting

Improved Photoelectric Performance with Self-Powered Characteristics through TiO2 Surface Passivation in an α-Ga2O3 Nanorod Array Deep Ultraviolet Photodetector

Recently, α-Ga2O3 nanorod array (NRA)-based deep ultraviolet (DUV) photodetectors have attracted more and more attention in the optoelectronic field due to their wide band gap, highly effective detection area, and simple preparation method. Unfortunately, the large number of defects in the α-Ga2O3 NRAs hinder the transportation of charge carriers, resulting in a low on–off ratio, low responsivity, and low detectivity. Wide band gap materials such as TiO2 and Al2O3 are often used as surface passivation layers to passive the defects in semiconductors, which is an effective way to improve the performance of photodetectors. Herein, an α-Ga2O3–TiO2 core–shell NRA-based photovoltaic-type DUV photodetector with an optimized graphene upper electrode has been successfully fabricated. Thanks to the passivation effect and type-II staggered band alignment of α-Ga2O3 and TiO2, the photogenerated carriers can be separated and transported efficiently. The α-Ga2O3–TiO2 core–shell NRA photodetector exhibits a large photocurrent of ∼110.88 nA, a responsivity (R) of 0.176 mA/W, a photoresponse speed of 0.72/0.14 s, and an Idark/Iphoto current ratio of 616 under 254 nm light at 0 V. In addition, the effect of humidity on the α-Ga2O3–TiO2 NRA device has been studied, and a proposed model of the mechanism has been built. Our research suggests a possible technique for developing high-performance α-Ga2O3 NRA-based photodetectors, which has the potential to further their applications.

Synthesizing and Optimizing Rutile TiO2 Nanoparticles for Magnetically Guided Drug Delivery.

IntroductionTitanium dioxide nanoparticles (TiO2 NPs) have shown tremendous potential in targeted drug-delivery applications. Among various mechanisms, magnetically guided transport of drugs is one such technique for the said purpose. TiO2 NPs being diamagnetic or sometimes exhibiting very weak ferromagnetism can be modified by treating them with suitable magnetic materials.MethodsRutile TiO2 NPs were synthesized and doped with Iron Supplement FericipXT and rare-earth metals like cerium, erbium and neodymium via sol–gel technique. FericipXT-coated rutile TiO2 NPs were synthesized in three different core-shell ratios (1:3, 1:1 and 3:1). The resulting samples were characterized via X-ray Diffraction (XRD), Vibrating Sample Magnetometer (VSM) and High-Resolution Transmission Electron Microscopy (HR-TEM).ResultsXRD of FericipXT-doped TiO2 NPs showed a rutile phase for 1% and 3% doping; however, only a small fraction of the maghemite phase was obtained for 5% doping. The XRD plots of Ce-doped, Er-doped and Nd-doped TiO2 NPs showed a variety of phases of TiO2 NPs (such as anatase/rutile/mixed) along with the oxide phases of the corresponding rare-earth metal. The presence of various iron titanium oxides and iron oxides was found in core-shell NPs. HR-TEM images confirmed the formation of 1:3, 1:1 and 3:1 core-shell TiO2 NPs. VSM studies showed that the resulting NPs depicted magnetism in the form of superparamagnetism, ferromagnetism and even paramagnetism.DiscussionThe doping to 3% does not affect the original phase of the resulting TiO2 NPs as depicted from the XRD; however, a doping of 5% and more resulted in extra phases corresponding to the dopant added. FericipXT was loaded over TiO2 NPs in amorphous form. Among all the samples synthesized, FericipXT-coated TiO2 NPs demonstrated the best magnetic ability. It was deduced that coating with a magnetic material drastically improves the magnetic character of the host NPs.

Enhanced Photoelectrocatalytic Activity of TiO2 Nanowire Arrays via Copolymerized G-C3N4 Hybridization

Photoelectrocatalytic (PEC) oxidation is an advanced technology that combines photocatalytic oxidation (PC) and electrolytic oxidation (EC). PEC activity can be greatly enhanced by the PC and EC synergy effect. In this work, novel copolymerized g-C3N4 (denoted as CNx)/TiO2 core-shell nanowire arrays were prepared by chemical vapor deposition. CNx were deposited on the surface of TiO2 nanowire arrays using organic monomer 4,5-dicyanidazole and dicyandiamide as copolymerization precursor. TiO2 nanowire arrays provide a direct and fast electron transfer path, while CNx is a visible light responsive material. After CNx deposition, the light response range of TiO2 is broadened to 600 nm. The deposition of CNx shell effectively improves the PC efficiency and PEC efficiency of TiO2. Under visible light irradiation and 1 V bias potential, the rate constant k of PEC degradation of CNx/TiO2 core-shell nanowire arrays is 0.0069 min−1, which is 72% higher than that of pure TiO2 nanowires. The built-in electric field formed in the interface between TiO2 core and CNx shell would effectively promote photogenerated charge separation and PEC activity.

Development of a Core-Shell Heterojunction TiO2 /SrTiO3 Electrolyte with Improved Ionic Conductivity.

The front cover artwork is provided by Prof. Faze Wang's group at the Southeast University. The built-in electric field created by the semiconductor heterostructure confines the proton transport on the surface layer of the nanocomposite core-shell heterostructure imparting faster ion transport and lower activation energy. Read the full text of the Research Article at 10.1002/cphc.202200170.