Search Results (21)

Piezocatalytic therapy (PCT) is a promising strategy for combating implant-associated infections due to its high tissue penetration depth and non-invasive nature. However, its catalytic efficiency remains limited by inefficient electron–hole separation. In this work, an ultrasound-responsive heterojunction (BiOI/Ti₃C₂) was fabricated through in situ growth of bismuth iodide oxide on titanium carbide nanosheets. Subsequently, we integrated BiOI/Ti₃C₂ into poly(e-caprolactone) (PCL) scaffolds using selective laser sintering. The synergistic effect between BiOI and Ti₃C₂ significantly facilitated the redistribution of piezo-induced charges under ultrasound irradiation, effectively suppressing electron–hole recombination. Furthermore, abundant oxygen vacancies in BiOI/Ti₃C₂ provide more active sites for piezocatalytic reactions. Therefore, it enables ultrahigh reactive oxygen species (ROS) yields under ultrasound irradiation, achieving eradication rates of 98.87% for Escherichia coli (E. coli) and 98.51% for Staphylococcus aureus (S. aureus) within 10 minutes while maintaining cytocompatibility for potential tissue integration. This study provides a novel strategy for the utilization of ultrasound-responsive heterojunctions in efficient PCT therapy and bone regeneration. Full article

Owing to high electrical conductivity, layered structure, and abundant surface functional groups, transition metal carbides/nitrides (MXenes) have received enormous interest in the field of gas sensors at room temperature. In this work, we synthesize a heterostructured nanocomposite with indium oxide (In₂O₃) decorated on titanium carbide (Ti₃C₂T_x) nanosheets by electrostatic self-assembly and develop it for high-selectivity NO₂ gas sensing at room temperature. Self-assembly formation of multiple heterojunctions in the In₂O₃/Ti₃C₂T_x composite provide abundant NO₂ gas adsorption sites and high electron transfer activity, which is conducive to improving the gas-sensing response of the In₂O₃/Ti₃C₂T_x gas sensor. Assisted by rich adsorption sites and hetero interface, the as-fabricated In₂O₃/Ti₃C₂T_x gas sensor exhibits the highest response to NO₂ among various interference gases. Meanwhile, a detection limit of 0.3 ppm, and response/recovery time (197.62/93.84 s) is displayed at room temperature. Finally, a NO₂ sensing mechanism of In₂O₃/Ti₃C₂T_x gas sensor is constructed based on PN heterojunction enhancement and molecular adsorption. This work not only expands the gas-sensing application of MXenes, but also demonstrates an avenue for the rational design and construction of NO₂-sensing materials. Full article

The search for effective and reliable methods of photosensitization of oxide-based semiconductor materials is of great significance for their use in photocatalytic reactions of hydrogen production and environmental remediation under natural sunlight. The present study is focused on partial substitution of titanium with manganese in the structure of layered perovskite-like titanate Na₂La₂Ti₃O₁₀, which was employed to yield a series of photocatalytically active materials, Na₂La₂Mn_xTi_3−xO₁₀ (x = 0.002–1.0), as well as their protonated forms H₂La₂Mn_xTi_3−xO₁₀ and nanosheets. It was established that the manganese cations Mn⁴⁺ are embedded in the middle sublayer of oxygen octahedra in the perovskite slabs La₂Mn_xTi_3−xO₁₀²⁻ and that the maximum achievable manganese content x in the products is ≈0.9. The partial cationic substitution in the perovskite sublattice led to a pronounced contraction of the optical band gap from 3.20 to 1.35 eV (depending on x) and, therefore, allowed the corresponding photocatalysts to utilize not only ultraviolet, but also visible and near-infrared light with wavelengths up to ≈920 nm. The materials obtained were tested as photocatalysts of hydrogen evolution from aqueous methanol, and the greatest activity in this reaction was demonstrated by the samples with low manganese contents (x = 0.002–0.01). However, the materials with greater substitution degrees may be of high interest for use in other photocatalytic processes and, especially, in thermophotocatalysis due to their improved ability to absorb the near-infrared part of solar radiation. Full article

Polymeric dielectrics have garnered significant interest worldwide due to their excellent comprehensive performance. However, developing polymeric dielectric films with high permittivity (ε_r) and breakdown strength (E_b) and low dielectric loss (tanδ) presents a huge challenge. In this study, amorphous aluminum oxide (Al₂O₃, AO) transition interfaces with nanoscale thickness were constructed between titanium oxide (TiO₂, TO) nanosheets and polyvinylidene fluoride (PVDF) to manufacture composites (PVDF/TO@AO). TO@AO nanosheets showed favorable dispersion in the polymer-based composites. Improved permittivity, suppressed dielectric loss, and enhanced breakdown strength were achieved by introducing AO coating with intermediate permittivity onto TO nanosheets to build a transition interface. The transition interface efficiently depressed the mobility of the charge carrier and electric conduction of the PVDF/TO@AO composites. As a result, the PVDF-based composite with 1 wt% TO@AO showed superior comprehensive performance, including high ε_r of ~12.7, low tanδ of ~0.017, and exceptional E_b of ~357 kV/mm. This strategy supplies a novel paradigm for the application of fabricating dielectric films with excellent comprehensive performance. Full article

Titanium silicon molecular zeolite (TS-1) plays an important role in catalytic reactions due to its unique nanostructure. The straight channel on TS-1 was parallel to the orientation of the short b-axis and directly exposed to the aperture of the 10-member ring with a diameter of 0.54 nm × 0.56 nm. This structure could effectively reduce the diffuse restriction of bulk organic compounds during the oxidative desulfurization process. As a kind of cationic polymer electrolyte, polydimethyldiallyl ammonium chloride (PDDA) contains continuous [C₈H₁₆N⁺Cl⁻] chain segments, in which the Cl⁻ could function as an effective structure-directing agent in the synthesis of nanomaterials. The chain of PDDA could adequately interact with the [0 1 0] plane in the preparation process of zeolite, and then the TS-1 nanosheet with short b-axis thickness (6 nm) could be obtained. The pore structure of the TS-1 nanosheet is controlled by regulating the content of PDDA. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), N₂ physical adsorption analysis, infrared absorption spectrum and ultraviolet–visible spectrum were used to determine the TS-1. The thinner nanosheets exhibit excellent catalytic performance in oxidative desulfurization of dibenzothiophene (DBT), in which the removal rate could remain at 100% after three recycles. Here, the TS-1 nanosheet with short b-axis thickness has a promising future in catalytic reactions. Full article

Drinking water defluoridation has attracted significant attention in the scientific community, from which membrane technology, by exploring thin film nanocomposite (TFN) membranes, has demonstrated a great potential for treating fluoride-contaminated water. This study investigates the development of a TFN membrane by integrating titanium oxide nanosheets (TiO₂ NSs) into the polyamide (PA) layer using interfacial polymerization. The characterization results suggest that successfully incorporating TiO₂ NSs into the PA layer of the TFN membrane led to a surface with a high negative charge, hydrophilic properties, and a smooth surface at the nanoscale. The TFN membrane, containing 80 ppm of TiO₂ NSs, demonstrated a notably high fluoride rejection rate of 98%. The Donnan-steric-pore-model-dielectric-exclusion model was employed to analyze the effect of embedding TiO₂ NSs into the PA layer of TFN on membrane properties, including charge density (X_d), the pore radius (r_p), and pore dielectric constant (ε_p). The results indicated that embedding TiO₂ NSs increased X_d and decreased the εp by less than the TFC membrane without significantly affecting the r_p. The resulting TFN membrane demonstrates promising potential for application in water treatment systems, providing an effective and sustainable solution for fluoride remediation in drinking water. Full article

The growth of nanocrystals (NCs) from metal oxide-based substrates with exposed high-energy facets is of particular importance for many important applications, such as solar cells as photoanodes due to the high reactivity of these facets. The hydrothermal method remains a current trend for the synthesis of metal oxide nanostructures in general and titanium dioxide (TiO₂) in particular since the calcination of the resulting powder after the completion of the hydrothermal method no longer requires a high temperature. This work aims to use a rapid hydrothermal method to synthesize numerous TiO₂-NCs, namely, TiO₂ nanosheets (TiO₂-NSs), TiO₂ nanorods (TiO₂-NRs), and nanoparticles (TiO₂-NPs). In these ideas, a simple non-aqueous one-pot solvothermal method was employed to prepare TiO₂-NSs using tetrabutyl titanate Ti(OBu)₄ as a precursor and hydrofluoric acid (HF) as a morphology control agent. Ti(OBu)₄ alone was subjected to alcoholysis in ethanol, yielding only pure nanoparticles (TiO₂-NPs). Subsequently, in this work, the hazardous chemical HF was replaced by sodium fluoride (NaF) as a means of controlling morphology to produce TiO₂-NRs. The latter method was required for the growth of high purity brookite TiO₂ NRs structure, the most difficult TiO₂ polymorph to synthesize. The fabricated components are then morphologically evaluated using equipment, such as transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), electron diffraction (SAED), and X-ray diffraction (XRD). In the results, the TEM image of the developed NCs shows the presence of TiO₂-NSs with an average side length of about 20–30 nm and a thickness of 5–7 nm. In addition, the image TEM shows TiO₂-NRs with diameters between 10 and 20 nm and lengths between 80 and 100 nm, together with crystals of smaller size. The phase of the crystals is good, confirmed by XRD. The anatase structure, typical of TiO₂-NS and TiO₂-NPs, and the high-purity brookite-TiO₂-NRs structure, were evident in the produced nanocrystals, according to XRD. SAED patterns confirm that the synthesis of high quality single crystalline TiO₂-NSs and TiO₂-NRs with the exposed {001} facets are the exposed facets, which have the upper and lower dominant facets, high reactivity, high surface energy, and high surface area. TiO₂-NSs and TiO₂-NRs could be grown, corresponding to about 80% and 85% of the {001} outer surface area in the nanocrystal, respectively. Full article

Carbon dioxide (CO₂) photoreduction to high-value products is a technique for dealing with CO₂ emissions. The method involves the molecular transformation of CO₂ to hydrocarbon and alcohol-type chemicals, such as methane and methanol, relying on a photocatalyst, such as titanium dioxide (TiO₂). In this research, TiO₂ nanosheets (TNS) were synthesized using a hydrothermal technique in the presence of a hydrofluoric acid (HF) soft template. The nanosheets were further composited with graphene oxide and doped with copper oxide in the hydrothermal process to create the copper−TiO₂ nanosheets/graphene oxide (CTNSG). The CTNSG exhibited outstanding photoactivity in converting CO₂ gas to methane and acetone. The production rate for methane and acetone was 12.09 and 0.75 µmol h⁻¹ g_cat⁻¹ at 100% relative humidity, providing a total carbon consumption of 71.70 µmol g_cat⁻¹. The photoactivity of CTNSG was attributed to the heterostructure interior of the two two−dimensional nanostructures, the copper−TiO₂ nanosheets and graphene oxide. The nanosheets−graphene oxide interfaces served as the n−p heterojunctions in holding active radicals for subsequent reactions. The heterostructure also directed the charge transfer, which promoted electron−hole separation in the photocatalyst. Full article

Synthesis of nanomaterials with specific morphology is an essential aspect for the optimisation of its properties and applications. The application of nanomaterials is being discussed in a wide range of areas, one of which is directly relevant to the environment through photocatalysis. To produce an effective photocatalyst for environmental applications, morphology plays an important role as it affects the surface area, interfaces, crystal facets and active sites, which ultimately affects efficiency. The method of synthesis and synthesis temperature can be the basic considerations for the evaluation of a particular nanomaterial. In this study, we have considered the aspects of morphology with a basic understanding and analyzed them in terms of nanomaterial efficacy in photocatalysis. Different morphologies of specific nanomaterials such as titanium dioxide, zinc oxide, silver phosphate, cadmium sulphide and zinc titanate have been discussed to come to reasonable conclusions. Morphologies such as nanorods, nanoflower, nanospindles, nanosheets, nanospheres and nanoparticles were compared within and outside the domain of given nanomaterials. The different synthesis strategies adopted for a specific morphology have been compared with the photocatalytic performance. It has been observed that nanomaterials with similar band gaps show different performances, which can be linked with the reaction conditions and their nanomorphology as well. Materials with similar morphological structures show different photocatalytic performances. TiO₂ nanorods appear to have the best features of efficient photocatalyst, while the nanoflowers show very low efficiency. For CdS, the nanoflower is the best morphology for photocatalysis. It appears that high surface area is the key apart from the morphology, which controls the efficiency. The overall understanding by analyzing all the available information has enumerated a path to select an effective photocatalyst amongst the several nanomaterials available. Such an analysis and comparison is unique and has provided a handle to select the effective morphology of nanomaterials for photocatalytic applications. Full article

Bis(4-hydroxyphenyl)methanone (BHPM), a common ultraviolet stabilizer and filter (USF), is extensively added in sunscreens; however, BHPM is proven as an endocrine disruptor, posing a serious threat to aquatic ecology, and BHPM should be then removed. As sulfate radical (SO₄^•−) could be useful for eliminating emerging contaminants, oxone appears as a favorable source reagent of SO₄^•− for degrading BHPM. Even though cobalt is a useful catalyst for activating oxone to generate SO₄^•−, it would be even more promising to utilize ambient-visible-light irradiation to enhance oxone activation using cobaltic catalysts. Therefore, in contrast to the conventional cobalt oxide, cobalt titanium oxide (CTO) was investigated for chemical and photocatalytic activation of oxone to eliminate BHPM from water. Especially, a special morphology of nanosheet-assembled configuration of CTO was designed to maximize active surfaces and sites of CTO. Thus, CTO outperforms Co₃O₄ and TiO₂ in degrading BHPM via oxone activation. Furthermore, the substituent of Ti enabled CTO to enhance absorption of visible light and possessed a much smaller E_g. These photocatalytic properties intensified CTO’s activity for oxone activation. CTO possessed a significantly smaller E_a of degradation of USFs than other catalytic systems. Mechanistic insight for degrading BHPM by CTO + oxone was explicated for identifying contribution of reactive oxygen species to BHPM degradation. The BHPM degradation pathway was also investigated and unveiled in details via the DFT calculation. These results validated that CTO is a superior cobaltic alternative for activating oxone to eliminate BHPM. Full article

Hexavalent chromium is very carcinogenic, and it is, therefore, important to remove it from wastewater prior to disposal. This study reports the photoreduction of Cr(VI) under simulated sunlight using graphene-derived TiO₂ nanowire (TNW) composites. Electrophoretic deposition (EPD) of graphene oxide (GO) and reduced graphene oxide (rGO) was carried out on rutile phase TNWs. The TNWs were fabricated by thermal oxidation of titanium foil in the presence of 1M potassium hydroxide mist at 750 °C. The TNWs uniformly covered the surface of the titanium foil. EPD of GO or rGO was done as a function of time to produce deposits of different thicknesses. The photocatalytic performances of the GO/TNWs or rGO/TNWs were tested to reduce Cr(VI) under visible light. The performance of rGO/TNWs in reducing Cr(VI) was better than GO/TNWs. A 10-second-deposited rGO on TNW samples can reduce 10 mg/L Cr(VI) within 30 min under visible light, likely as a result of the high electron transfer from rGO to TNWs accelerating the Cr(VI) reduction. Full article

Nanoparticles (NPs) have high multifunctional potential to simultaneously enhance implant osseointegration and prevent infections caused by antibiotic-resistant bacteria. Here, we present the first report on using plasma electrolytic oxidation (PEO) to incorporate different combinations of reduced graphene oxide (rGO) and silver (Ag) NPs on additively manufactured geometrically ordered volume-porous titanium implants. The rGO nanosheets were mainly embedded parallel with the PEO surfaces. However, the formation of ‘nano-knife’ structures (particles embedded perpendicularly to the implant surfaces) was also found around the pores of the PEO layers. Enhanced in vitro antibacterial activity against methicillin-resistant Staphylococcus aureus was observed for the rGO+Ag-containing surfaces compared to the PEO surfaces prepared only with AgNPs. This was caused by a significant improvement in the generation of reactive oxygen species, higher levels of Ag⁺ release, and the presence of rGO ‘nano-knife’ structures. In addition, the implants developed in this study stimulated the metabolic activity and osteogenic differentiation of MC3T3-E1 preosteoblast cells compared to the PEO surfaces without nanoparticles. Therefore, the PEO titanium surfaces incorporating controlled levels of rGO+Ag nanoparticles have high clinical potential as multifunctional surfaces for 3D-printed orthopaedic implants. Full article

In this paper, porous zinc oxide (ZnO) nanosheets were successfully prepared by a simple low-temperature hydrothermal method. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) tests showed that the synthesized product was ZnO with porous sheet structure. The diameter of porous nanosheets was about 100 nm and the thickness was about 8 nm. As a photocatalyst, the degradation efficiencies of porous ZnO nanosheets for methyl orange (MO), methylene blue (MB) and Rhodamine B (RhB) were 97.5%, 99% and 96.8%, respectively. In addition, the degradation efficiency of ZnO for mixed dyes (Mo, MB and RhB) was satisfactory, reaching 97.7%. The photocatalytic stability of MB was further tested and remained at 99% after 20 cycles. In the experiment, ZnO/FTO (fluorine-doped tin oxide) composites were prepared by using ZnO as the conductive layer. Titanium dioxide (TiO₂) was deposited on the surface of ZnO/FTO by electrodeposition, so as to obtain a TiO₂/ZnO/FTO composite. By studying the electrochromic properties of this composite, it was found that the TiO₂/ZnO/FTO composite shows a large light modulation range (55% at 1000 nm) and excellent cycle stability (96.6% at 200 cycles). The main reason for the excellent electrochromic properties may be the synergistic effect between the porous structure and the polymetallic oxides. This study is helpful to improve the photocatalytic efficiency and cycling stability of metal oxides, improve the transmittance of thin films and provide a new strategy for the preparation of ZnO composite materials with excellent photocatalytic and electrochromic properties. Full article

The purpose of this present study is to prepare a stable mineral-oil (MO)-based nanofluid (NF) for usage as a coolant in a transformer. Nanoparticles (NPs) such as hexagonal boron nitride (h-BN) and titanium oxide (TiO₂) have superior thermal and electrical characteristics. Their dispersion into MO is likely to elevate the electrothermal properties of NFs. Therefore, different batches of NFs are prepared by uniformly dispersing the insulating h-BN and semiconducting TiO₂ NP of different concentrations in MO. Bulk h-BN NP of size 1μm is exfoliated into 2D nanosheets of size 150–200 nm, subsequently enhancing the surface area of exfoliated h-BN (Eh-BN). However, from the zeta-potential analysis, NP concentration of 0.01 and 0.1 wt.% are chosen for further study. The thermal conductivity and ACBDV studies of the prepared NF are performed to investigate the cooling and insulation characteristics. The charging-dynamics study verifies the enhancement in ACBDV of the Eh-BN NF. Weibull statistical analysis is carried out to obtain the maximum probability of ACBDV failure, and it is observed that 0.01 wt.% based NF has superior cooling and insulation properties than MO and remaining batches of NFs. Full article

Interface engineering is usually considered to be an efficient strategy to promote the separation and migration of photoexcited electron-hole pairs and improve photocatalytic performance. Herein, reduced graphene oxide/mesoporous titanium dioxide nanotube heterojunction assemblies (rGO/TiO₂) are fabricated via a facile hydrothermal method. The rGO is anchored on the surface of TiO₂ nanosheet assembled nanotubes in a tightly manner due to the laminated effect, in which the formed heterojunction interface becomes efficient charge transfer channels to boost the photocatalytic performance. The resultant rGO/TiO₂ heterojunction assemblies extend the photoresponse to the visible light region and exhibit an excellent photocatalytic hydrogen production rate of 932.9 μmol h⁻¹ g⁻¹ under simulated sunlight (AM 1.5G), which is much higher than that of pristine TiO₂ nanotubes (768.4 μmol h⁻¹ g⁻¹). The enhancement can be ascribed to the formation of a heterojunction assembly, establishing effective charge transfer channels and favoring spatial charge separation, the introduced rGO acting as an electron acceptor and the two-dimensional mesoporous nanosheets structure supplying a large surface area and adequate surface active sites. This heterojunction assembly will have potential applications in energy fields. Full article