High TiO2 Research Articles

An experimental and theoretical validation of dual role of Fe on improving the photocatalytic performance of doped mixed phase titania

The present work proposes a strategic approach of using Fe doping to form a mixed-phase TiO2 direct Z-scheme catalyst at low onset temperature. The doping-induced modifications are explained from the experimental and theoretical viewpoint. Fe-doped Z-scheme-based mixed-phase TiO2 at optimal calcination temperature (TiFe-400) exhibits maximum photon absorption and reduces charge carrier recombination, enhancing photocatalytic and PEC performance. TiFe-400 has the highest rate constant for the degradation of MB (0.084 min−1 under solar irradiation) and showed exceptional photooxidation current (0.8 mA, 1.3 V vs Ag/AgCl). The Z-scheme formation significantly inhibits the recombination of photocarriers, resulting in a directed migration of charge carriers to the high redox potential mixed-phase TiO2. This migration is validated by identifying the primary reactive species participating in the photocatalytic process. This work, demonstrating both experimental and theoretical approaches, may provide valuable insight into designing stable and inexpensive catalysts for dual applications on an industrial scale.

A novel fine-grained TiZrCu alloy tailored for marine environment with high microbial corrosion-resistance

Titanium alloys, usually known as non-corrodible material, are susceptible to microbiologically influenced corrosion (MIC) in marine environment. While titanium-zirconium (TiZr) alloys have been extensively studied in medical applications, the influence of microorganisms, especially marine microorganisms, on their corrosion behavior has not been explored. In this work, a TiZrCu alloy with a combination of excellent mechanical, anti-corrosion, and antibacterial properties was developed by optimizing the Cu content and grain refinement. Its MIC and antibacterial mechanisms against Pseudomonas aeruginosa, a representative marine microorganism, were systematically investigated. 5.5 wt% was determined as the optimal copper content. The fine-grained Ti-15Zr-5.5Cu (TZC-5.5FG) alloy maintained high MIC resistance, exhibiting a corrosion current of 5.7 ± 0.1 nA/cm2 and an antibacterial rate of 91.8 % against P. aeruginosa. The mechanism of improved corrosion resistance was attributed to the denser passive film with high TiO2 content and the lower surface potential difference ΔE. The release of Cu2+ ions, ΔE, and the generation of ROS are three major factors that contribute to the antibacterial performance of TiZrCu alloys. Compared to other available marine metals, TZC-5.5FG alloy exhibited superior comprehensive performance, including excellent mechanical properties and anti-MIC capacity, which make it a promising material for load-bearing applications in marine environment.

Mineralization, geochemical signatures, and provenance of stream sediments on the Jos Plateau, Northcentral Nigeria

This study aimed at determination of mineralization, geochemical signatures and provenance of stream sediments on the Jos Plateau, northcentral Nigeria. Ten (10) stream sediments samples collected were air-dried and subjected to X-Ray Fluorescence analysis. The SiO2 value of 49.79 to 77.03 wt%, Fe2O3 value of 1.30 to 28.84 wt%, Al2O3 value of 5.27 to 18.25 wt%, CaO value of 0.22 to 1.88 wt%, MgO value of 0.12 to 0.92 wt%, K2O value of 0.44 to 2.00 wt% and Na2O value of 0.02 to 0.65 wt%. The low values of CaO (0.22-1.88 wt %) and Na2O (0.02-0.65 wt %) could be associated with the destruction of plagioclase feldspar while low K2O composition (0.44-2.00 wt%) could be associated with the destruction of K-feldspar during weathering. The concentration of MnO (0.06-0.12 wt%) indicates manganite enrichment, the high TiO2 value (0.63-4.25 wt%) shows rutile enrichment while ZrO2 value (0.48-18.48 wt%) indicates zircon mineralization from the underlying lithologies. The high values of pathfinder elements (Y, Zn and Nb) could be attributed to the presence of Older and Younger Granites at the upstream of the study area. Samples 4, 5, 8 and 9 have Thorium (Th) concentrations >15 ppm threshold which point to areas favorable for Th mineralization. Enrichment Factor (EF) ranges from 3.03 to 42.42 indicating moderate, significant, very high enrichment and extremely high enrichment. The Contamination Factor (CF) of 1.27 to 201.03 indicates moderate and very high contamination possibly from geogenic sources. The provenance of stream sediments is associated with felsic and mafic sources

High-strength TiO2/TPU composite fiber based textiles for organic pollutant removal

Effective integration of nanostructured photocatalysts into polymer matrices is crucial for the broad practical application of fiber-based photocatalytic composite textiles. Herein, highly durable TiO2/TPU composite fibers with high TiO2 content (>30 wt. %) were prepared through wet spinning using 1D electrospun TiO2 nanofibers (TNFs). Due to the fiber reinforcement principle, the TNF/TPU composite fibers exhibited superior mechanical properties compared with pure TPU fibers. Furthermore, the TNF/TPU composite fibers with a ratio of 1:2 process impressive degradation efficiency for rhodamine B (RhB). The orientation of 1D TNFs and stronger interface between TNF and TPU matrices not only enable the excellent load sharing and transfer effects following fiber pullout and crack bridging mechanisms, but also improve photogenerated charge transfer efficiency, resulting in high strength and high photocatalytic activity. In addition, enhanced TNF exposure on the fiber is due to the hollow and porous structures of composite fibers, which is advantageous for photocatalytic degradation. Notably, when the RhB concentration exceeded 15 ppm, the TNF/TPU composite fibers exhibited higher degradation efficiency than the TNF powder. Therefore, TNF/TPU composite fiber–based textiles with high photocatalytic activity and strength are promising for overcoming the separation and recovery issues of nanostructured catalysts in practical wastewater treatment applications.

Late Paleozoic–Early Mesozoic subduction history of Mudanjiang Ocean: New insights from greenschist in the Heilongjiang Complex, NE China

This paper presents zircon U-Pb ages, whole-rock major and trace element data, and Sr-Nd-Hf isotopic compositions for the greenschists from the Heilongjiang Complex in NE China. Based on the geochronological and geochemical characteristics, the greenschists from the Heilongjiang Complex can be categorized into three series: Early Permian tholeiitic series (275 ± 1 Ma and 273 ± 1 Ma), Middle Permian alkaline series (261 ± 1 Ma), and Early Jurassic alkaline series (179 ± 1 Ma). The Early Permian tholeiitic greenschist samples are characterized by remarkable negative Nb and Ta anomalies, and they exhibit relatively low whole-rock (87Sr/86Sr)i values (0.703896–0.704252), along with positive εNd(t) values (+7.66 to +8.65) and positive εHf(t) values (+0.92 to +11.51), implying that their protoliths originated from the partial melting of a depleted mantle wedge that has been metasomatized by subducted slab fluids. The Middle Permian alkaline greenschist samples have high Nb (17.3–19.0 ppm), TiO2 (1.40–1.64 wt%), and P2O5 (0.60–0.68 wt%) concentrations, and they are enriched in large ion lithophile elements and light rare earth elements, and depleted in high field strength elements and heavy rare earth elements, with high whole-rock (87Sr/86Sr)i values (0.709434–0.709949), negative εNd(t) values (−4.73 to −4.72) and varied εHf(t) values (−10.11 to +4.86), which compositionally align with those of Nb-enriched basalts. Based on the geochronological and geochemical characteristics, we propose that the protolith generation of Middle Permian alkaline greenschists was associated with the partial melting of a mantle wedge that had been metasomatized by subduction slab-derived melts. The Early Jurassic alkaline greenschist samples display OIB affinities, characterized by whole-rock (87Sr/86Sr)i values ranging from 0.705161 to 0.705926, εNd(t) values between +6.16 and +6.19, and εHf(t) values from +3.44 to +9.32, indicating the formation of the protolith for the Early Jurassic alkaline greenschist was related to the upwelling of the asthenosphere resulting from slab break-off. By integrating regional geological data, we can trace the subduction evolution of the Mudanjiang Ocean back to the Early Permian, and the slab break-off during the Early Jurassic likely corresponded to the early stage of the closure of the Mudanjiang Ocean.

The anticorrosion behavior and mechanism of Ti3C2 nanosheets for titania pigmented epoxy coatings

Utilization of Ti3C2 nanosheets for enhancing anticorrosion of epoxy resin coatings has been reported. But the epoxy coatings in real world are mainly pigmented coatings. Unfortunately, the anticorrosion behavior of Ti3C2 nanosheets for the pigmented epoxy coatings is rarely concerned. In this work, both 0.5 wt% unmodified Ti3C2 nanosheets (U-Ti3C2) or 0.5 wt% (3-glycidyloxypropyl)trimethoxysilane-modified Ti3C2 nanosheets (G-Ti3C2) were introduced into solvent-based titania pigmented epoxy coatings. Corrosion resistance of coatings was evaluated by electrochemical impedance spectroscopy and salt spray tests. A titania concentration effect was interestingly exhibited for the anticorrosion behavior Ti3C2-containing pigmented coatings. Enhanced anticorrosion was only demonstrated when TiO2 content was not above 10 wt% for U-Ti3C2 or 5 wt% for G-Ti3C2. Moreover, the pigmented coatings with U-Ti3C2 have better corrosion resistance than those with G-Ti3C2, being contrary to the phenomenon observed in pure epoxy resin coatings. The different anticorrosion behavior of Ti3C2 nanosheets for epoxy coatings with various TiO2 contents was mainly attributed to the different dispersion states of TiO2 pigments, that is, improved dispersion at low TiO2 content and deteriorated dispersion at high TiO2 content, after addition of Ti3C2 nanosheets.

Geochemistry and conditions of formation of Mesoarchean banded iron formations (BIF-1) from the Kostomuksha Greenstone belt, Karelian Craton

Three variably old groups of banded iron formation (BIF) are known in the Kostomuksha Greenstone belt (KGB) of the Karelian Craton. This paper deals with the earliest of them, Mesoarchean (2.87–2.81 Ga) – BIF-1. BIF-1 occurs among the komatiite-basalt unit of the KGB. BIF-1 consists mainly of quartz and magnetite, with varying amounts of amphibole, biotite, and garnet; they contain 48.3-58.6 SiO2 and 21.34–33.82 wt. %, Fe2O3T, suggesting that the rocks are BIF. BIF-1 of the KGB, as well as most Archean BIFs, contain high Fe2O3T, concentration, display a contrasting positive Eu anomaly, lost of Ce anomaly, the depletion of LREE relative to HREE. However, they stand out among other BIFs with high Al2O3, TiO2, MgO, K2O, Cr, Ni, Zr, Ba, Cu and Zn concentrations. BIF-1 was formed in a marine basin in an anoxic atmosphere due to hydrothermal fluids, the proportion of which varies from 20 to 80 %, and a terrigenous component derived mainly from basalts, komatiites, and dacites in host rocks. Mesoarchean BIF-1 of the KGB s was formed in a small rift within an oceanic volcanic plateau, the formation of which is associated with the influence of a mantle plume on the oceanic lithosphere.

Titania-Cored Janus Multipods as UV-Protective Pickering Emulsifiers for Sunscreens.

Pickering emulsifiers have gained significant interest as alternatives for conventional surfactants in various applications that includes pharmaceutics, food, homecare products, and cosmetics. However, their function is primarily focused on enhancing emulsion stability of which still remains to be resolved. Herein, Janus multipods are presented that simultaneously shield UV while offering high emulsion stability. These particles are prepared by growing multiple silicon dioxide (SiO2) nanopods using sol-gel method on a spherical titanium dioxide (TiO2) core with a thin SiO2 shell. The incorporation of high refractive index TiO2 in the core is shown to effectively shield UV while the SiO2 shell suppresses the photocatalytic activity. Moreover, by utilizing wax colloidosomes as templates, these multipod nanoparticles are further modified to exhibit Janus characteristics. This leads to strong adsorption of the Janus multipods at the oil/water emulsion interface where the multipod feature additionally reinforces the interfacial stabilization by interdigitation and interlocking of the Janus multipods to suppress detachment of the highly dense particles from the interface. As these Janus multipods offer effective UV protection as well as excellent emulsion stability, it is envisioned that they have great potential in advanced cosmetic formulations which require both enhanced sunscreen performance and better feeling in skincare products.

TiO2 and ZnO Nanoparticles Immobilized on Magnetic Sulfonated Melamine‐Formaldehyde: Structure Identification and Performance as Recyclable Catalysts for the Biginelli Reaction

AbstractSulfonated melamine‐formaldehyde (SMF) containing high dispersed TiO2 and ZnO nanoparticles were fabricated into magnetic nanocomposites by two different method material incorporation protocols, including calcination and wet impregnation. Their catalytic performance was investigated toward Biginelli reaction. For the preparation of the first catalyst series, a two‐step protocol was used. Initially, Fe3O4 nanoparticles were coated with SMF (Fe3O4/SMF). Subsequently, they were decorated consecutively with TiO2 (Fe3O4/SMF/TiO2) and ZnO (Fe3O4/SMF/ZnO). The second set of catalysts was prepared using a two‐step process. Fe3O4 nanoparticles were first used to modify SMF (SMF/Fe3O4). Following the initial step, the surface of SMF/Fe3O4 was decorated with both TiO2 (SMF/Fe3O4/TiO2) and ZnO (SMF/Fe3O4/ZnO). To understand the characteristics of the synthesized nanocomposites, a variety of characterization techniques were employed. New catalysts enabled the rapid synthesis (30–45 min) of a range of biologically active 3,4‐dihydropyrimidinones based on the Biginelli reaction with high yields (70–95 % isolated).

Formic Acid Dehydration Using Mechanochemically Prepared TiO2‐Graphite Composites

AbstractCommercial high surface area graphite (HSAG300) and commercial TiO2 were used to produce composite materials through a simple mechanochemical method involving milling and ultrasonic treatments. The acid and basic sites exposed on the surfaces of these materials were characterized by temperature‐programmed desorption (TPD) of ammonia and carbon dioxide. The catalytic materials were tested in the dehydration reaction of formic acid to produce hydrogen‐free CO. While HSAG300 is practically inactive under reaction conditions (continuous gas flow at temperatures in the range of 100–250 °C), all samples containing TiO2 are active, exhibiting high selectivity to CO without significant deactivation at moderate reaction temperatures. It is demonstrated that the presence of graphite in the catalysts enhances the specific catalytic activity of TiO2. Assuming that the dehydration reaction is catalyzed by acid sites on the TiO2 surfaces, a comparative evaluation of the surface sites reveals that the graphite‐TiO2 interactions not only change the density of surface sites but also modify the strength of the acid centers of TiO2. In summary, the interaction of HSAG300 with TiO2 modulates the surface properties of the prepared composite catalysts, decreasing the total number of basic surface sites and increasing the strength of acidic sites compared to bare TiO2.

Blooming microflowers: Shaping TiO2 nanostructures via anodization in metal chloride-based electrolytes

TiO2 microflowers, consisting of nanotubes, were generated via potentiostatic anodization in fluoride-free electrolytes infused with metal chlorides. Anodizing titanium foil at 15 V for 10 min in electrolytes containing 0.1 M of FeCl3·6H2O, CrCl3·6H2O, FeCl2·4H2O, and CuCl2·2H2O yielded nanotubes with outer diameters of approximately 30 nm, 45 nm, 50 nm, and 60 nm, respectively. The introduction of metal chloride to the electrolyte significantly altered the anodization kinetics, facilitating the growth of TiO2 microflowers. These structures consist of nanotube bundles that are of few microns in length with tunable diameters, achieved rapidly within the anodization timeframe. Microflowers formed in FeCl3·6H2O electrolyte feature high aspect ratio TiO2 nanotube bundles with smaller diameters and higher nucleation density, whereas those developed in CrCl3·6H2O, FeCl2·4H2O, and CuCl2·2H2O electrolytes exhibit less preferable morphology.

A moderate-Ti lunar mare soil simulant: IGG-01

Lunar soil simulants play a crucial role in scientific research, payload tests and in-situ resource utilization (ISRU) experiments. However, the currently available lunar soil simulants are either low in TiO2 content (≤3 wt%) or high in TiO2 content (≥6.7 wt%), despite orbital observations indicating lunar soils with moderate TiO2 content being widely distributed on the lunar surface. In December 2020, China's Chang'e−5 (CE-5) mission successfully returned a new mare soil sample characterized by high FeO content (22.5 wt%) and moderate TiO2 content (5.5 wt%), providing an opportunity to develop moderate-TiO2 lunar soil simulants. This study presents a newly developed simulant of the CE-5 lunar soil named IGG-01, which closely replicates the major physical and chemical properties of the CE-5 lunar soil. The median particle size of IGG-01 is 68.69 ± 4.44 μm, and its estimated specific surface area is 0.34 m2/g. It contains 17.6 wt% FeO and 4.8 wt% TiO2. It consists of pyroxene (49.3 wt%), plagioclase (40.9 wt%), ilmenite (6.1 wt%), and olivine (3.7 wt%), with specific gravity and bulk density are 3.33 g/cm³ and 1.86 g/cm³, respectively. The friction angle is 41.8°, and the cohesion is 19.2 kPa. It exhibits strong and weak reflectance absorption features in the 1 and 2 μm band centers. The physical properties of IGG-01 are also comparable to those of Apollo samples and typical lunar mare soil simulants. The unique chemical composition of IGG-01 makes it suitable for various scientific and engineering experiments, including but not limited to the study of dusty plasma migration, water formation via solar wind injection, oxygen preparation via hydrogen reduction, and tests involving the movement of rovers and excavation equipment.

Plagioclase Megacrysts in Mesoproterozoic Amphibolites from the New Jersey Highlands, USA: Indicators of Mixed-Source Magma and Fractionation Interruption in Anorthosite-Dominated Terrains

Rare amphibolite in the New Jersey Highlands containing plagioclase megacrysts ≤13 cm long forms bodies 0.5 to 2 m thick that preserve a penetrative metamorphic fabric and have sharp, conformable contacts against Mesoproterozoic country rocks. The megacrystic amphibolites were emplaced as thin dikes along extensional faults between 1160 and 1130 Ma. Amphibolites contain weakly zoned, subhedral andesine megacrysts (An29–44) in a matrix of plagioclase (An18–38), magnesio-hastingsite, biotite, diopside, Fe-Ti oxides, and apatite. The whole-rock major oxide composition of the megacrystic amphibolite matrix has high TiO2 (2.07 wt.% ± 2.0%), Al2O3 (17.03 wt.% ± 0.87%), and Fe2O3t (12.84 wt.% ± 3.2%) that represents an Al-Fe-rich mafic magma type that is characteristic of anorthosite associations globally. The whole-rock, rare earth element (REE) composition of the megacrystic amphibolite matrix is characterized by enrichments in light rare earth elements (LREEs) (La/YbN = 1.73–10.69) relative to middle (MREEs) and heavy (HREEs) rare earth elements (Gd/YbN = 1.30–1.85), and most samples have small positive Eu anomalies (Eu/Eu* = 0.95–1.25). The megacrystic amphibolite matrix is also enriched in large ion lithophile elements (LILEs) and depleted in high field strength elements (HFSEs) (e.g., Ba/Nb = 24–22). Megacrystic amphibolites formed through partial melting of subduction-modified lithospheric mantle that fractionated olivine and plagioclase, producing a high-Al-Fe mafic magma. Plagioclase megacrysts formed through extraction of a plagioclase-rich crystal-liquid mush from anorthosite that mixed with mafic magma and collected in the upper part of the mid-crustal magma (depth of ~20 km based on Al-in-hornblende geobarometry) chamber through flotation. Periodic tapping of this mixed source by extensional fractures led to emplacement of the amphibolites as dikes and may have interrupted the extensive fractionation and plagioclase separation necessary to form voluminous anorthosite intrusions.

Surface phonon activation for broadband high emissivity via textured structure on TiO2 coating

In the pursuit of developing broadband high emissivity coatings for metallic radiation thermal protection, conventional approaches often involve complex photonic structures or the incorporation of transition metals and rare earth additives, which pose significant technological challenges and environmental concerns. Here, we present a straightforward and eco-friendly surface structuring strategy for creating a high emissivity TiO2 coating on titanium, eliminating the need for environmentally hazardous additives. By controlling surface micropore diameter to ∼6 um through soft-sparking discharge, we successfully engineered a textured surface that effectively mitigates the intrinsic emissivity dip of planar TiO2 at wavelengths with weak polarization extinction (3–8 µm) and strong polarization resonance (>12 µm). Finite-difference time-domain (FDTD) simulations highlighted the crucial role of micropores in confining the incident electric field, maximizing the absorption potential of surface phonon polaritons. This improvement yields an impressive emissivity of 0.83 across the thermal infrared spectrum. The coating also demonstrated robust resistance to oxidation and retained its high emissivity at elevated temperatures, presenting a promising solution for sustainability in spacecraft and electronic applications.

Spectroscopic Characterization of Ti Sites in MWW Zeolite in Presence of Hydrogen Peroxide

AbstractTi‐MWW zeolite is a promising catalyst for partial oxidation reactions. In the present work, a Ti‐MWW sample with high TiO2 loading was synthesized. It was revealed that the Ti insertion in the purely siliceous MWW framework mainly occurs during the post treatment washing with HNO3, when the double structure directing agent synthetic method is used. By exploiting carbon monoxide, acetonitrile, pyridine and ammonia as probe molecules in infrared spectroscopy and diffuse reflectance ultraviolet spectroscopy, the acidic behavior of the Ti sites and the interaction of the Ti sites with hydrogen peroxide (H2O2) were revealed. The Ti Lewis acid sites showed stronger acidity than the one observed in Titanium Silicalite‐1 (TS‐1), with MFI framework. This is coherent with previously reported results, suggesting that a significative fraction of the Ti sites in Ti‐MWW are TiOH(SiO)3 instead of Ti(OSi)4. The Ti‐peroxo and ‐hydroperoxo complexes formed upon H2O2 were shown to be more labile than in TS‐1 and they were shown to be completely reversible upon calcination.

Geochronology and Petrogenesis of Late Carboniferous to Early Permian Basalts in the Central Lhasa Subterrane, Southern Tibet: Implications for the Evolution of the Sumdo Paleo‐Tethys Ocean

AbstractBasalts from the Late Carboniferous to Early Permian are extensively developed in the central Lhasa subterrane, southern Tibet. Studying the petrogenesis of these rocks may have implications for the late Paleozoic arc magmatism along the central Lhasa subterrane uncovering more of the evolution of the Sumdo Paleo‐Tethys Ocean and its dynamic mechanism. Basalt samples from the Luobadui Formation in the Leqingla area, NW of Linzhou City in the central Lhasa subterrane, southern Tibet exhibit arc‐like geochemical signatures in a subduction‐zone tectonic setting characterized by high Al2O3 and low TiO2 contents, fractionated REE patterns with low Nb/La ratios and high LREE concentrations, and negative HFSE anomalies. Based on their higher Th/Ce, Nb/Zr, and lower Ba/Th, Pb/Nd ratios, slightly negative to positive εNd(t) values, and the relatively high Sr‐Pb isotopic compositions, these samples were probably derived from partial melting of a depleted mantle source of garnet + spinel lherzolite, metasomatized by subducted sediments around 297 Ma. Modeling of the trace elements indicates that these basalts experienced fractional crystallization of olivine, clinopyroxene and minor plagioclase during magma ascent and eruption. It is proposed that these Late Carboniferous–Early Permian basalts are associated with the northward subduction of the Sumdo Paleo‐Tethys Ocean seafloor along the southern margin of the central Lhasa subterrane.

High Specific Surface Area TiO2 Aerogels Incorporated in situ with Co/Mn Oxides as Stable Electrochemical Capacitor Electrodes

Nanocomposite aerogels comprised of TiO2 and metal (Co and Mn) oxides are synthesized via an in situ sol–gel method in this study, and their structural, compositional and electrochemical properties are evaluated for possible applications as electrodes in energy storage devices. The inclusion of metallic oxides into TiO2 aerogels hinder the formation of titania crystalline phases, preserved particle sizes close to their original dimensions and yielded higher specific surface areas compared to pure TiO2 aerogels after heat treatment. High specific surface areas in aerogels positively affect the electrochemical properties, allowing a high electrochemical activity of the electrodes, in addition to intensifying the transport of ions and solvents through the mesoporous network of this material. Evaluation of the electrochemical properties of the aerogel‐based nanocomposites involves galvanostatic charge–discharge, cyclic voltammetry, and impedance spectroscopy. The nanocomposites exhibit enhanced electrochemical properties and stable performance within the range suitable for supercapacitor applications, as indicated by the Ragone chart. Notably, aerogels with higher incorporation of cobalt and manganese oxides in TiO2 aerogels exhibit significantly elevated specific surface areas, reaching 562 and 555 m2 g−1, respectively. These values are notably high for nanocomposites, underscoring the potential of these electroactive materials for electrochemical capacitors.

Carrier gradient core-double shell structure with heterojunction transition layer for significantly enhancing dielectric properties

In this work, to prohibit the undesirable large dielectric loss and electric-field distortion of the conductive fillers/polymer with a high dielectric constant, TiO2 (TO) and Al2O3 (AO) shells were successively coated on the surface of amorphous carbon (C) to prepare the C@TO@AO core-double shell nanoparticles. This novel design of gradually varying the multilayer hierarchical interface achieved the gradient reduction of carrier concentration from the C core to the TO and AO layers. And the introduction of the multilayer hierarchical interface was advantageous to the enhancement of interface polarization. Moreover, the excellent integrated dielectric properties could be effectively achieved by adjusting the layer thickness and crystal structure of the TO layer. It was worth noting that the TO transition layer with anatase and rutile heterojunctions (HTO) had a significant enhancement in the dielectric constant of the composites induced by the strength of interfacial polarization and built-in electric field inside the HTO layer. Furthermore, the simulated electric field distribution inside the composites was further investigated to reveal the mechanism of enhanced dielectric properties. This work exerts important guiding significance for the reasonable structure design and the elaborate regulation of the shell micro-structures to improve the dielectric properties of composites.

Characteristics of Nanoparticles in Late Pliocene Paleo-Mountain Fire Relics in Jinsuo Basin, Yunnan Province and Their Implications for Paleoclimate Evolution

Wildfires significantly affect climate and environmental changes, closely tied to extreme weather responses. Vegetation combustion emits greenhouse gases (CO2, CH4, CO), warming the climate. Climate shifts, in turn, impact vegetation growth, altering combustible material types and quantities, thus affecting wildfire intensity, duration, and frequency. Wildfires profoundly affect ecosystems, influenced by factors like atmospheric oxygen and climate. Their combustion gases impact climate and vegetation growth. Recent advancements in studying ancient wildfires include analyzing nanoparticles as key indicators. This study discovered six types of nanoparticles in ancient wildfire remains, with sizes ranging from 50 nm to 500 nm and diverse compositions including elements such as C, O, Mg, Al, Ti, Fe, S, Ca, and P. These findings indicate that wildfires generate a variety of nanoparticles, offering new insights into ancient fire events. Elemental analysis revealed low magnesium but high calcium and aluminum levels, suggesting a warm, humid paleoclimate during these fires. The presence of high Ti-O ratios and carbon-rich nanoparticles points to ground fires with incomplete combustion. This research underscores the significance of nanoparticles in understanding the history and characteristics of ancient wildfires.

TiO2/ZnO-based composite thin films coated on FTO surface by screen printing method: increasing dye-sensitized solar cell performance

This study examined the impact of hydrothermally synthesized TiO2:ZnO composite-based nanopowders on the efficiency of dye-sensitized solar cells (DSSCs). Pure TiO2, 3TiO2:1ZnO, 1TiO2:1ZnO, 1TiO2:3ZnO, and pure ZnO thin films were coated on the conductive glass surface by the screen printing method. XRD and SEM were used to examine the thin film’s surface photographs and crystal structure, respectively. XRD analyses confirmed the formation of targeted crystal phases in the structure. It was understood from SEM studies that the TiO2:ZnO composite structure was formed successfully. I-V characterization results showed that the cell combined with the composite 3TiO2:1ZnO electrode had the highest power conversion efficiency (9.9%). In addition, it was determined from EIS analysis that interfacial charge transfer occurred more efficiently in cells with high TiO2 ratio.