TiO2 Carbon Research Articles

THE EFFECT OF ADDITION NANOPARTICLES ON SHRINKAGE PROPERTY OF ORDINARY PORTLAND CEMENT

Two types of nanomaterial: Tio2 nanoparticles (NPs) and carbon black NPs have used in this research to study their effect on compressive strength, shrinkage and flow table tests Cement mortar. The mixing ratio was 1:2.7:0.485 (cement, sand, water/cement ratio) for compressive strength test and 1:2 (cement, sand) with the water/cement ratio was a variable value for dry shrinkage test. The two nanoparticles’ ratios are (0.25%, 0.75%, 1.25 % and 1.75%) by weight of the Portland cement. The test results show that the highest value of compressive strength was obtained when using Tio2 at 1.25% wt. of cement. But when using carbon black nanoparticles, the greatest value was obtained when adding it with a ratio of 1.75 % wt. of cement. Using two NPs when added to cement mortar has a negative effect on the shrinkage value.

Construction of tunable and high-efficiency microwave absorber enabled by growing flower-like TiO2 on the surface of SiC/C nanofibers

Flower branch-like TiO2@SiC/C composite nanofibers that are lightweight and have high-efficiency microwave absorption (MA) in the 2–18 ​GHz frequency range were fabricated via electrospinning and hydrothermal approaches. Phase analysis results showed the presence of rutile TiO2, β-SiC, and amorphous carbon in the composite nanofibers. Nanowhiskers grew randomly on the surface of the nanofibers along the (101) plane of rutile TiO2 nanocrystalline and formed a flower branch-like structure. The bionic morphology generated a great deal of heterojunctions and porous structures, which enable interfacial polarization, dipole polarization, conductance loss, multirelaxation, and suitable impedance matching through synergistic effects. Therefore, excellent wave-absorbing performance was achieved in the X and Ku bands when the composite nanofibers' filler loading was changed. The minimum reflection loss (RL) value was less than −45.3 ​dB with the thickness of less than 3 ​mm when the composite nanofibers absorber content was 10 ​wt%. Also, the maximum effective absorption bandwidth (EAB) exceeded 5 ​GHz. This study developed a neoteric structure to construct composite fibers loaded with nanowhiskers, and the TiO2@SiC/C nanofibers could be a remarkable candidate for broadband and efficient microwave absorbers. Also, the tunable wave-absorbing performance indicates a wide range of applications is possible under various environmental conditions.

Chitosan-derived nitrogen-doped carbon on Li2ZnTi3O8/TiO2 composite as an anode material for lithium-ion batteries

Although structural stability, non-toxicity, and low cost have attracted industrial attention, Li2ZnTi3O8 (LZTO) is difficult to utilize as an anode material for LIB due to its poor ionic and electronic conductivity. In this research, forming a composite with TiO2 and coating nitrogen-doped carbon on the composite have been carried out to enhance the performance of LZTO. Since the 100 cycles at 200 mA g-1, the nitrogen-doped carbon coated LZTO/TiO2 composite anode material exhibits 80% higher specific discharge capacity than specific discharge capacity of bare LZTO. Furthermore, excellent rate capability and increased specific discharge capacity at high current density are achieved, thus demonstrating the improvements on the electrochemical performance of LZTO stemming from the synergistic effects of composite formation with TiO2 and nitrogen-doped carbon coating.

Foldable high‐strength electrode enabled by nanosheet subunits for advanced sodium‐ion batteries

AbstractPower sources with strong mechanical properties and high‐energy density are highly desirable for the next‐generation flexible electronics. However, the challenge arises from the current electrode structure design, which is unable to bring both satisfactory mechanical and electrochemical properties with high active materials content and mass. Herein, we reported novel flexible, high‐strength, and mechanically stable TiO2‐based film electrodes for advanced sodium‐ion batteries, achieving an ultrahigh strength (up to ≈60 MPa) and commercial‐level areal capacity (4.5 mAh cm−2). Highly‐dispersed TiO2 and interlaced carbon nanotube (CNT) networks are embedded in the sheet‐liked cellulose to form porous, high‐conductive, and high‐active TiO2‐C nanosheets that is basic building subunits of TiO2‐C films, allowing the films with structural robustness and origami‐level flexibility. This strategy reconciles the contradiction between mechanical properties and active material content in flexible electrodes, and the fabricated electrode with a high TiO2 content of >65% can be bent more than 11 000 times without breaking. Meanwhile, good capacity and excellent cycle stability (0.02‰ capacity‐decay rate over 9000 cycles) of TiO2‐C film under a higher active content (75%) has well satisfied the demands of flexible energy storage devices for electrochemical performances. This TiO2‐C subunit assembly methodology demonstrates enormous potential in high‐strength/toughness flexible electrode construction for flexible electronics.image

Synthesis, characterization and photocatalytic activity of a composite based on TiO2 and active carbon prepared from mango pit

In this study, results are presented concerning the development of alternative materials based on titanium dioxide (TiO2) and agro-industrial waste for use in the treatment of effluent contaminated with dyes. The photocatalytic activity of a composite formed by the association of activated carbon, obtained from pit residue of mango, with modified titanium dioxide was evaluated by the degradation of crystal violet dye. From the analysis of X-rays diffratograms, it was observed that the modification introduced in the TiO2, as well as the formation of the composite with activated carbon, lead to wider peaks with lesser intensity, suggesting the formation of small particles. The composite presented the best photocatalytic performance, attributed to the significantly large specific area of this material when compared to pure TiO2, reaching 99% degradation of the organic matter after 60 minutes of reaction time. This is, therefore, a promising material for environmental photocatalysis.

Influence of Far Infrared TiO2 and Multi-Walled Carbon Nanotubes Coatings on the Performance of a Hot Water Heater

This study selects titanium dioxide (TiO2) and multi-walled carbon nanotubes (MWCNTs) as far-infrared materials (FIRMs), and further adds water-based acrylic coatings to prepare far-infrared coatings (FIRCs). FIRCs are uniformly coated on #304 stainless steel sheets to make the test samples, which are then installed between the shell and insulation material of the hot water heater to measure the influences of various FIRCs on the performance of the hot water heater. The research results show no significant difference in the heating rate or heat insulation performance of the hot water heater with or without FIRCs coating. However, the uniformity of the water temperatures of the test samples is significantly improved with FIRCs. Considering that the uniformity of water temperature will inhibit the heating rate and heat insulation performance of the hot water heater, TiO2-FIRC should provide better performance improvement when applied to the hot water heater in this study. The application of TiO2-FIRC to large-scale hot water heaters with a high aspect ratio will effectively improve the quality of hot water supply in the future.

Lightweight, multifunctional MXene/polymer composites with enhanced electromagnetic wave absorption and high-performance thermal conductivity

Polymer composites receive attentions for protecting from electromagnetic (EM) pollution. However, their EM wave (EMW) attenuation mechanism primarily results from reflection rather than absorption. Herein, we prepared poly(vinylidene fluoride)/cobalt (Co)/MXene composite foams that exhibited applicable impedance matching, enhanced EMW absorption and high-performance thermal conduction properties. With CO2-assisted foaming, a uniform foam structure was integrated into the polymer composites, and meanwhile, the introduced MXenes were partially oxidized and transformed into TiO2 and amorphous carbon. The formed TiO2 not only provided extra heterogeneous interfaces and capacitor-like structures in favor of dielectric polarization but also reduced the excessive electrical conductivity of the pristine MXenes to favor impedance matching. Accordingly, the EMW absorbing performance of the composite foam was enhanced with a minimum reflection loss of −45.6 dB at 4 mm when the filler content was only 12 wt% (6 wt% MXene and 6 wt% Co). Additionally, the synergism between the foam structure and TiO2 nanocrystals resulted in improved thermal conductivity, ranging from 1.28 W/(m·K) to 1.36 W/(m·K), which were 2–6 times higher than that in the solid composite films. This study provided new insights into the simultaneously enhanced EMW absorption and dissipating heat ability in polymer composite foams with a low percolation threshold.

Multi‐shelled Hollow Nanospheres of SnO2/Sn@TiO2@C Composite as High‐performance Anode for Lithium‐Ion Batteries

AbstractTo overcome two main drawbacks of SnO2 as anode material in lithium‐ion batteries, low conductivity and poor cycling stability, SnO2/Sn@TiO2@C composite is prepared via one‐pot hydrothermal reaction to synthesize SnO2/C precursor‐assembled hollow nanospheres and then coated with TiO2 and resorcinol‐formaldehyde resin. After calcination, multi‐shelled hollow nanospheres of SnO2/Sn@TiO2@C are formed. When used as anode material in lithium‐ion batteries, the as‐prepared composite exhibits high discharge capacity of 1565 mAh g−1 at 0.5 A g−1. After 300 cycles at 1 A g−1, the discharge capacity still reaches 961 mAh g−1 with capacity fading rate of just 0.11 % per cycle. The average discharge capacity reaches 395 mAh g−1 even at 5 A g−1. The superior lithium storage performance mainly benefits from the unique multi‐shelled hollow nanosphere structure. The coating TiO2 and amorphous carbon increase structural and cycling stabilities of SnO2/Sn hollow nanospheres. The outermost carbon shell further enhances electronic conductivity of the composite. The hollow nanosphere structure also endows SnO2/Sn nanoparticles with high electrochemical activity. This work proposes a feasible synthesis and structure design strategy for the development of advanced SnO2‐based composite materials.

A General Strategy to Fabricate Flexible Oxide Ceramic Nanofibers with Gradient Bending‐Resilience Properties

AbstractInorganic materials assembled with rigid elements such as crystals or graphitized carbon generally show brittleness and hardness. However, it is found that both TiO2 ceramic crystal nanofibers (NFs) and carbon NFs show superior flexibility, in which the former are surprisingly knottable and the latter exhibit excellent bending‐resilience property. The different flexure mechanisms are revealed by fabricating composite NFs of these two constituents and find that the carbon NFs can be recovered to the original states after releasing the external force, while the bending‐resilience is weakened and the softness of the composite NFs is enhanced upon increasing the TiO2 content. The graphitized carbon can store mechanical deformation energy that enables the NFs with bending‐resilience, while both the homogeneous interfaces between TiO2 crystals and the heterogeneous interfaces between TiO2 and carbon can alleviate stress concentration, which reduce the flexural modulus of the composite NFs. By filling different contents of elastic carbon into TiO2 NFs, a series of flexible NFs that exhibit gradient bending‐resilience properties are fabricated. This study provides a deeper understanding of the mechanical properties of inorganic materials.

OPTICAL, STRUCTURAL, THERMAL AND MORPHOLOGICAL CHARACTERIZATION OF 4, 4’- DIAMINODIPHENYL SULPHONE/TITANIUM DIOXIDE/MULTIWALLED CARBON NANOTUBE NANOCOMPOSITES

Polymeric nanocomposites based on electroactive conductive polymers with nanoparticle fillers have won considerable attention in recent years due to its highly desirable multifunctional characteristics. In the present study, 4, 4’- diaminodiphenyl sulphone has been polymerized and composites were prepared by adding TiO2 and multiwalled carbon nanotube to the polymer by magnetic stirring. These nanocomposites have been characterized using analytical techniques such as UV-Vis, FT-IR, XRD, FE-SEM, EDS and TGA/ DTA analysis. The incorporation of multiwalled carbon nanotube and titanium dioxide in poly 4, 4’-diaminodiphenyl sulphone has been endorsed by FT-IR analysis. It showed that the peak at 453, 431 cm- 1 confirms the stretching vibration of the Ti-O bond of TiO2 and the absorption peaks at 2925 and 2283 cm-1 are imputed to symmetrical telescopic vibrations of the methylene group (-CH2-) of carbon nanotubes. This confirms the incorporation of TiO2 and multi-walled carbon nanotubes into the polymer matrix in the prepared nanocomposites. The XRD pattern showed formation in the nanoscale range (5.94 nm). SEM analysis showed that the variation in polymer morphology depended mainly on titanium dioxide and multi-walled carbon nanotubes.

Rutile-phase TiO2@carbon core-shell nanowires and their photoactivation in visible light region

Titanium dioxide (TiO2) has been acknowledged as one of the efficient photocatalysts in the UV region. To extend the photo-absorption region toward visible lights, the TiO2 nanowires enclosed with carbon shells (TiO2@carbon core-shell nanowires) were synthesized by a chemical vapor deposition technique at various temperatures from 650 to 950 °C. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) analyses revealed that TiO2 cores and carbon shells are rutile and graphitic structures, respectively. From Raman spectra, the peak intensity of the Eg mode was observed to be redshifted with elevated growth temperatures due to the increase in oxygen vacancies in the TiO2@carbon core-shell nanowires. From X-ray photoelectron spectroscopy (XPS) results, the oxygen vacancies were strongly related to the Ti3+ ions. The UV–visible spectroscopic studies show a possible decrease in photocatalytic energy from 3.1 to 2.7 eV for the TiO2@carbon core-shell nanowires, indicating that the light absorption was enhanced in the visible-light region. The optical absorbance results confirmed the presence of the mid-gap states due to the oxygen vacancies, which are responsible for the visible-light absorption. The photocatalytic activity of the TiO2@carbon core-shell nanowires studied by methylene blue (MB) dye degradation is effective under visible lights.

Mechanism and Kinetics of Oxidation Reaction of Aqueous Ti3C2Tx Suspensions at Different pHs and Temperatures.

Understanding the oxidation reaction of aqueous Ti3C2Tx MXene suspensions is very important for fostering fundamental academic studies as well as widespread industrial applications. Herein, we investigated the mechanism and kinetics of the oxidation reaction of aqueous Ti3C2Tx suspensions at various pH and temperature conditions. Through comprehensive analysis, the mechanism of the chemical oxidative degradation of aqueous Ti3C2Tx colloids was established. Chemical oxidation produces solid products such as TiO2 and amorphous carbon as well as various gaseous species including CH4, CO, CO2, and HF. Additionally, our comprehensive kinetic study proposes that aqueous Ti3C2Tx dispersions are degraded via an acid-catalyzed oxidation reaction, where, under acidic conditions, the protonation of the hydroxyl terminal groups on the Ti3C2Tx flakes induces electron localization on titanium atoms and accelerates their oxidation reaction. In contrast, under basic conditions, the electrostatically alkali-metalized hydroxyl intermediates forming a bulky solvent cage results in less electron localization on titanium atoms, and thus retards their oxidative degradation.

A two-step hydrothermal synthesis of TiO2/C/FeS2 composite as high performance anode for lithium ion batteries

TiO2/C/FeS2 composite as high performance anode material for lithium ion batteries (LIBs) is prepared via a two-step hydrothermal strategy. The high specific surface area of TiO2/C/FeS2 enlarge the contact area between electrode and electrolyte. Moreover, external TiO2 nanoparticles and carbon rods effectively mitigate the volume expansion of FeS2. TiO2/C/FeS2 composite exhibits a high specific capacity of 1057.5 mAh g−1 at 0.2 A g−1, and superior long-term cycling performance. Additionally, TiO2/C/FeS2 electrode shows pseudocapacitive behavior during cycles, which is contributed to lithium storage. This work reveals the potential application of TiO2/C/FeS2 composite as high performance anode material.

CoO hierarchical mesoporous nanospheres@TiO2@C for high-performance lithium-ion storage

The hierarchical mesoporous structure is an ideal active material structure for lithium-ion batteries and other energy storage devices. In this work, we report a universal chelation-carbonization-oxidation path to synthesize CoO nanocrystalline-assembled hierarchical mesoporous nanospheres with Co-glycerate inorganic-organic hybrid spheres as the precursor, followed by the coating of TiO2 and amorphous carbon. The electrochemical measurements demonstrate, as an anode of lithium-ion batteries, as-prepared CoO@TiO2@C exhibits high reversible capacity, stable cycling performance and good rate capability. It can deliver discharge capacity of 1136 mAh g−1 after 200 cycles at current density of 0.5 A g−1 and average discharge capacity of 493 mAh g−1 even at high current density of 5 A g−1. The excellent lithium storage performance benefits from the multiple structural advantages. The nanocrystalline-assembled hierarchical mesoporous nanosphere endows CoO with high electrochemical activity. The robust TiO2 and amorphous carbon shells improve structure stability and electronic conductivity of CoO hierarchical mesoporous nanospheres.

C@TiO2 core-shell adsorbents for efficient rhodamine B adsorption from aqueous solution

Abstract In the present work, C@TiO2 core-shell adsorbents were successfully prepared and the adsorption capacities for rhodamine B (RB) were investigated at different conditions. The adsorbents were prepared by first in-situ hydrolysis and deposition of TBOT on the surface of ZIF-8 nanoparticles to obtain ZIF-8@titania gel, and then carbonization. XRD, SEM, TEM, and N2 adsorption-desorption techniques were employed to characterize the adsorbents. The results showed that the adsorbents were comprised of TiO2 shell and carbon core. Large surface area and hierarchical pores, which were different from ZIF-8 derived porous carbon, were generated due to the less contraction of carbon during carbonization when robust TiO2 shell covered on the surface. The highest adsorption capacity for RB was 298 mg/g on C@TiO2. Apart from the hierarchical pores and large surface area, the low surface charge of C@TiO2 core-shell adsorbents was also observed, which also contributed to the high adsorption capacity for cationic dyes. The reuse experiments showed that the adsorbents maintained the high adsorption capacity after 5 cycles. The high stability is crucial for practical application.

Silanization integrating TiO2 nanorods-carbon fiber for improving mechanical and wear-resisting behaviors of phenolic composite

A covalently bonded 3-aminopropyltriethoxysilane (APS)-TiO2 nanorods-woven carbon fiber (WCF) was designed though the in-situ hydrothermal growth followed by the chemical grafting. The silanization for TiO2 nanorods-WCF improved both the mechanical interlocking and chemical interaction among TiO2 nanorods, carbon fiber and phenolic, as well as the interfacial bonding between TiO2 nanorod and carbon fiber, thus formed an effective transition interface. The designed WCF offered a 157.1% increase of tensile strength compared to the desized-WCF. Moreover, the optimized interfacial binding and Si-based transfer film on worn surface leaded to the increased frictional coefficient and a 63.0% decrease of wear rate for composite under sliding frication. The APS-TiO2 nanorods-woven carbon fiber was proven to be an advanced reinforcement for wear-resistance phenolic composite.

TiO2 and TiO2-Carbon Hybrid Photocatalysts for Diuron Removal from Water

TiO2 and TiO2-activated carbon (AC) photocatalysts have been prepared (by sol-gel synthesis), characterized, and tested in the removal of diuron from water under simulated solar light. The preparation variables of the two series of catalysts are: (i) heat-treatment temperature of bare TiO2 (350, 400, 450 and 500 °C) and (ii) activated carbon content (0.5, 1, 5, and 10 wt.%) in TiO2-AC samples heat-treated at 350 °C. The activated carbon was previously prepared by hydrothermal carbonization of saccharose and has spherical shape. The heat-treatment temperature does not determine the efficiency of TiO2 for diuron photocatalytic degradation, but clearly influences the diuron adsorption capacity. The capacity of TiO2-AC samples for diuron removal increases with the carbon content and it is the result of combined diuron adsorption and photodegradation. Thus, the sample with highest carbon content (10 wt.% nominal) leads to the highest diuron removal. The TiO2-AC photocatalysts have proved to be capable of degrading diuron previously adsorbed in dark conditions, which allows their regeneration.

Catalytic Performance of TiO2–Carbon Mesoporous-Derived from Fish Bones in Styrene Oxidation with Aqueous Hydrogen Peroxide as an Oxidant

The catalytic performance of titania-supported carbon mesoporous-derived from fish bones (TiO2/CFB) has been investigated in styrene oxidation with aqueous H2O2. The preparation steps of (TiO2/CFB) catalyst involved the carbonization of fish bones powder at 500 °C for 2 h. followed by impregnation of titania using titanium(IV) isopropoxide (500 µmol) precursor, and calcined at 350 °C for 3 h. The physical properties of the adsorbents were characterized using Fourier transform infrared, X-ray diffraction (XRD), Scanning electron microscopy with energy dispersive X-ray (SEM-EDX), and nitrogen adsorption-desorption studies. The catalytic test was carried out using styrene oxidation with H2O2 as an oxidant at room temperature for 24 h. Its catalytic activity was compared with Fe2O3/CFB, CuO/CFB, TiO2, and CFB catalysts. It is demonstrated that the catalytic activity of TiO2/CFB catalyst has the highest compared to Fe2O3/CFB, CuO/CFB, TiO2, and CFB catalysts in the oxidation of styrene with styrene conversion ~23% and benzaldehyde selectivity ~90%. Kinetics of TiO2/CFB catalyzed oxidation of styrene has been investigated and mechanism for oxidation of styrene has been proposed. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Toxicogenomic Profiling of 28 Nanomaterials in Mouse Airways.

Toxicogenomics opens novel opportunities for hazard assessment by utilizing computational methods to map molecular events and biological processes. In this study, the transcriptomic and immunopathological changes associated with airway exposure to a total of 28 engineered nanomaterials (ENM) are investigated. The ENM are selected to have different core (Ag, Au, TiO2, CuO, nanodiamond, and multiwalled carbon nanotubes) and surface chemistries (COOH, NH2, or polyethylene glycosylation (PEG)). Additionally, ENM with variations in either size (Au) or shape (TiO2) are included. Mice are exposed to 10 µg of ENM by oropharyngeal aspiration for 4 consecutive days, followed by extensive histological/cytological analyses and transcriptomic characterization of lung tissue. The results demonstrate that transcriptomic alterations are correlated with the inflammatory cell infiltrate in the lungs. Surface modification has varying effects on the airways with amination rendering the strongest inflammatory response, while PEGylation suppresses toxicity. However, toxicological responses are also dependent on ENM core chemistry. In addition to ENM‐specific transcriptional changes, a subset of 50 shared differentially expressed genes is also highlighted that cluster these ENM according to their toxicity. This study provides the largest in vivo data set currently available and as such provides valuable information to be utilized in developing predictive models for ENM toxicity.

Isotropic Hedgehog-Shaped-TiO2/Functional-Multiwall-Carbon-Nanotube Micromotors with Phototactic Motility in Fuel-Free Environments.

Directional motion in response to specific signals is critically important for micro/nanomotors in precise cargo transport, obstacle avoidance, collective control, and complex maneuvers. In this work, a kind of isotropic light-driven micromotor that is made of hedgehog-shaped TiO2 and functional multiwall carbon nanotubes (Hs-TiO2@FCNTs) has been developed. The FCNTs are closely entangled with Hs-TiO2 and form a close-knit matrix on the surface of Hs-TiO2, which facilitates the transfer of electrons from Hs-TiO2 to FCNTs. Due to the high redox potential of Hs-TiO2, excellent electron-hole separation efficiency by the addition of FCNTs, and isotropic morphology of the micromotor, these Hs-TiO2@FCNT micromotors show phototactic and fuel-free propulsion under unidirectional irradiation of UV light. It is the first time to demonstrate isotropic micromotors that are propelled by self-electrophoresis. The isotropy of Hs-TiO2@FCNT micromotors makes them immune to the rotational Brownian diffusion and local flows, exhibiting superior directionality. The motion direction of our micromotors can be precisely tuned by light and a velocity of 8.9 μm/s is achieved under 160 mW/cm2 UV light illumination. Photodegradation of methylene blue and active transportation of polystyrene beads are demonstrated for a proof-of-concept application of our micromotors. The isotropic design of the Hs-TiO2@FCNT micromotors with enhanced photocatalytic properties unfolds a new paradigm for addressing the limitations of directionality control and chemical fuels in the current asymmetric light-driven micromotors.