Search Results (3,063)

A novel macromolecular photoinitiator (MPI) was synthesized from a copolymer of maleic anhydride and methyl methacrylate and subsequently functionalized with 3-hydroxy-2-methoxy-1,2-diphenylpropan-1-one moieties via a polymer-analogous acylation reaction. The structure and physicochemical properties of the MPI were characterized by IR, UV–Vis, NMR, DSC, and TGA analyses. TiO₂ nanoparticles were successfully functionalized with the MPI, yielding materials with enhanced surface activity and photoinitiating efficiency. The MPI-modified TiO₂ facilitated efficient UV-induced polymerization of methyl methacrylate, as confirmed by DLS and SEM analyses. Compared with unmodified fillers, the resulting composites exhibited improved dispersion, accelerated polymerization rates, and enhanced mechanical properties. This hybrid strategy offers a promising approach for the development of high-performance polymer nanocomposites through the integration of surface-engineered inorganic fillers and photoreactive polymers. Full article

Diesel engines are commonly used in transportation and power generation, but their operation is associated with incomplete combustion and emissions. In this research, four different nanocatalyst additives including Ag, Ag/TiO₂, Ce/TiO₂, and Ag/CeO₂/TiO₂ were studied as diesel fuel additives to improve combustion efficiency and minimize regulated emissions. These nanoparticles were synthesized and characterized by employing X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) techniques. The prepared fuel blends were tested in a single-cylinder diesel engine at additive concentrations of 50, 75, and 100 ppm under varying engine loads. Among the tested formulations, the ternary Ag/CeO₂/TiO₂ blend demonstrated the highest performance. When compared with the baseline diesel fuel, it reduced CO emissions by 32.5%, HC emissions by 27.8%, and NO_x emissions by 29.4%. At the same time, the amount of CO₂ emission has increased by 18.81%, which shows that the combustion is more complete. Also, the same formulation has decreased brake-specific fuel consumption (BSFC) by 18.7% and increased brake thermal efficiency (BTE) by 16.3%. The improved performance is due to the cooperative effect of CeO₂ oxygen buffering, TiO₂ surface-assisted oxidation, and oxidation activity of the silver species. The findings show that the ternary nanocatalyst formulation is an effective approach for optimizing diesel fuel combustion and emissions. Full article

Cu–TiO₂ nanoparticles of a broad range of compositions with 0, 0.002, 0.005, 0.02, 0.05, 0.2, 0.5, 1.0, 2.0, 3.0, 5.0, 7.0 and 10.0 mol% Cu were synthesized via the sol–gel method using copper (II) acetate and titanium tetraisopropoxide (TTIP) precursors at a low hydrolysis ratio of H = 1.25, which favours homogeneous TiO₂ nucleation and Cu dispersion in the host matrix at nanoscale. The precipitated materials were dried at 80 °C and calcined at 450, 500, and 550 °C to form crystalline nanopowders, whose photocatalytic activity was evaluated on the decomposition of a representative pollutant, methylene blue (MB), in aqueous solutions under UVA and sunlight illuminations. The compositions with small Cu content of ~0.05 mol% showed the highest activity. A gain of activity over pure titania of 4 times after calcination at 450 °C, 2.5 times at 500 °C and 20% at 550 °C was measured under UVA illumination. Even higher gain of activity observed under sunlight illumination might be due to an extension of action spectrum to the visible range due to intra-gap defect states produced by Cu²⁺ insertion. The time-resolved microwave conductivity (TRMC) measurements of the photoinduced charges relaxation suggest that both excessive calcination temperature and Cu content decrease the activity due to Cu-defects clustering. Modelling relates the activity to the photoinduced electron-hole pair separation; the optimal Cu content is explained by accessibility of the recombination centre by a conduction band (CB) electron. Accordingly, an increase in calcination temperature resulted in a longer pathlength of CB electron. Full article

Acrylic resin is widely used in the fabrication of complete dentures, interacting significantly with the intraoral environment. However, complete dentures face challenges such as stability issues and biofilm accumulation. Glaze application is a common method to reduce surface porosity and microbial adhesion, but it also decreases surface wettability, potentially impairing salivary film formation essential for peripheral sealing. This study aimed to incorporate titanium dioxide and zinc oxide nanoparticles into the glaze applied to thermally activated acrylic resin (TAAR) via spray coating to enhance surface wettability and antifungal activity. Four groups were tested: G (TAAR + commercial glaze − control); AlG (TAAR + commercial glaze + aluminum oxide − roughness control); TiG (TAAR + commercial glaze + titanium dioxide); and ZnG (TAAR + commercial glaze + zinc oxide). Evaluations included flexural strength, color and translucency, surface analysis and antibiofilm activity against Candida albicans. Data were analyzed using one-way ANOVA. No statistically significant differences in mechanical strength (MPa) were observed (G: 108.54 ± 8.36; AlG: 113.60 ± 11.95; ZnG: 111.98 ± 9.27; TiG: 113.66 ± 10.41). Surface roughness significantly increased, and contact angle decreased, indicating improved wettability. Regardless of the antifungal activity no improvement was detected (G: 6.71 ± 0.10; AlG: 6.82 ± 0.08; ZnG: 6.72 ± 0.20; TiG: 6.66 ± 0.18). In conclusion, the incorporation of nanoparticles into the glaze improves the wettability of acrylic resin surfaces, potentially enhancing peripheral sealing and denture retention, which is beneficial for patients with reduced alveolar ridge height. Full article

This study presents the rational design of a visible-light-responsive TiO₂/polyaniline (PANI) nanofiber heterostructure via in situ oxidative polymerization to overcome the limited visible-light absorption and rapid charge recombination of TiO₂. Comprehensive characterization using XRD, FT-IR, XPS, SEM, UV–Vis DRS, and EIS confirmed the successful integration of TiO₂ nanoparticles within a conductive polyaniline nanofiber network, enabling efficient interfacial charge transfer. The optimized TiO₂/PANI-30 composite exhibited outstanding photocatalytic performance, achieving ~99% degradation of Basic Fuchsin dye within 40 min under visible light, significantly outperforming pristine TiO₂. The enhanced activity is attributed to improved visible-light absorption, reduced bandgap energy, and suppressed electron–hole recombination, supported by optical and electrochemical analyses. Kinetic studies indicated pseudo-first-order behavior, with TiO₂/PANI-30 showing the highest rate constant. Radical trapping experiments identified superoxide and hydroxyl radicals as the main active species, with •OH playing a dominant role. A direct Z-scheme charge transfer mechanism was suggested, preserving strong redox potentials and promoting reactive oxygen species generation. Additionally, the photocatalyst demonstrated excellent stability and reusability. These findings highlight the suggested potential of TiO₂/PANI systems as efficient and sustainable photocatalysts for wastewater treatment. Full article

The modern world is confronting critical environmental and biomedical challenges, underscoring the urgent need for the development of multifunctional materials—an inherently interdisciplinary field, bridging materials science and engineering, environmental science and biomedicine. Titanium dioxide (TiO₂) is widely recognized for its photocatalytic and antiviral properties, enabling the degradation of pollutants and mitigation of viral contamination under solar irradiation. Nevertheless, it exhibits certain limitations, such as wide band gap and high recombination rate of photogenerated electron–hole pairs. To address these limitations, TiO₂ prepared by a co-precipitation method was modified with N-Doped Carbon Dots (N-CDs) via a hydrothermal treatment, which extend light absorption into the visible region and enhance charge separation. Further functionalization with silver nanoparticles (Ag NPs)—well known for their antimicrobial properties—via a simple thermal process under ambient conditions, introduced additional reactive oxygen species generation, creating a synergistic effect. The as-prepared TiO₂, TiO₂/N-CDs and TiO₂/N-CDs/Ag samples were characterized via several techniques, such as XRD, micro-Raman, FT-IR, TEM and UV-Vis. In addition, their photocatalytic and antiviral activity against methylene blue (MB) and nitrogen oxide (NO_x) pollutants, as well as SARS-CoV-2, was evaluated. Based on the results of liquid-phase photocatalysis, TiO₂, TiO₂/N-CDs and TiO₂/N-CDs/Ag presented a degradation efficiency of 78%, 85% and 95%, respectively, whereas different trends were observed under gaseous-phase conditions. The TiO₂/N-CDs/Ag hybrid material demonstrated superior antiviral activity against SARS-CoV-2 (IC₅₀: 1.24 ± 0.34 g/L), compared to both TiO₂ (IC₅₀: 1.78 ± 0.30 g/L) and TiO₂/N-CDs (IC₅₀: >2.5 g/L), highlighting its potential as an effective multifunctional material. Finally, TiO₂/N-CDs/Ag was incorporated onto a paper substrate, demonstrating antiviral activity, showing promising scalability for application across a wide range of future substrates. To the best of our knowledge, this is the first study presenting TiO₂/N-CDs/Ag with dual photocatalytic and antiviral activity. Full article

Despite exhibiting exceptional structural stability, spinel lithium titanate (Li₄Ti₅O₁₂, LTO) suffers from inherent limitations in both electronic conductivity and ionic diffusion kinetics, limiting its high-rate application. In this study, pringle-shaped Li₄Ti₅O₁₂/carbon (LTO/C) composite was synthesized using low-cost sucrose as the organic carbon source, using a facile hydrothermal-calcination method. Each pringle-shaped nanosheet was composed of Li₄Ti₅O₁₂ nanoparticles that are 15 nm in size, which can shorten lithium-ion diffusion distances as well as better the contact between electrolyte and active materials. Meanwhile, the uniform carbon cladding improves the material’s electronic conductivity. Owing to the synergistic effects between the mesoporous LTO nanosheets and carbon coating, LTO/C-6.31 wt% presented remarkable rate capability and cycling stability, delivering 145.5 mAh g⁻¹ at 20 C over 1000 cycles with 93.93% capacity retention. This work demonstrates an effective synthesis route to developing high-rate capability and long-cycle-life anode materials for LIBs. Full article

Nanocomposites consisting of titanium carbonitride nanoparticles (TiCN) and epoxy resin were fabricated and studied as the filler content was varied. Nanocomposites’ structural investigation was conducted via X-ray Diffraction technique (XRD), while their morphology was examined by employing Scanning Electron Microscopy (SEM). Viscoelastic mechanical properties were assessed by Dynamic Mechanical Thermal Analysis (DMTA). Results revealed the reinforcing ability of TiCN nanoparticles. The dielectric characterization of the nanocomposites was carried out using Broadband Dielectric Spectroscopy (BDS) over a wide frequency and temperature range. Dielectric spectroscopy revealed two relaxation processes related to the polymer matrix: the α-relaxation, associated with the glass-to-rubber transition, and the β-relaxation, associated with the rearrangement of side polar groups. In addition, in the low-frequency–high-temperature region, interfacial polarization (IP) was observed. IP is related to the presence of nanoparticles and to the accumulation of unbound charges at the system’s interface and includes contributions from a dipolar process and charge migration (conductivity). Alternating current conductivity generally increases with filler content, though it is also affected by frequency and temperature. Conductivity could influence Electrode Polarization (EP), which often masks the dipolar process of IP. A simple method for removing the EP effect is formulated and tested. Full article

Titanium (Ti) and its nanoparticles are widely used in 3D printing due to a high corrosion resistance, biocompatibility, and lightweight potential. However, the atomic-scale mechanism of sintering densification and phase transition remains unclear, which limits the performance regulation of additively manufactured Ti components. In this work, molecular dynamics simulations were performed to study the sintering and phase-transition behavior of multi-sized Ti nanoparticles under 3D printing conditions. The melting point of 2 nm Ti nanoparticles decreases to about 1000 K, while that of 12 nm particles approaches the bulk value of 1941 K. Two distinct stages were observed during surface-energy-induced phase transition: initial lattice reconstruction at 800–1100 K, followed by complete melting above 1500 K. Smaller nanoparticles exhibited stronger pre-melting and faster atomic diffusion, which effectively filled interparticle pores and reduced the porosity. Increasing particle contact points shortens atomic diffusion paths, accelerates densification, and alleviates stress concentration. This study reveals the size-dependent sintering mechanism of Ti nanoparticles at the atomic level, providing theoretical guidance for the process optimization, microstructure control, and performance improvement of aerospace and biomedical titanium components fabricated by additive manufacturing. Full article

Cyclic pollutants such as dyes, antibiotics, phenols and VOCs in water and atmosphere feature stable structures and are difficult to mineralize, which constitutes the core problem in current environmental governance. Semiconductor photocatalysis provides a green strategy for the advanced treatment of such pollutants. Electrospun black TiO₂/Ag-loaded SiO₂ nanofiber membranes have become a research hotspot owing to their multi-component synergistic advantages. This paper systematically reviews the preparation processes and structure regulation methods of electrospun SiO₂ nanofiber membranes; expounds the loading strategies of black TiO₂ and Ag nanoparticles, the interface regulation mechanisms and the synergistic photocatalytic mechanism of the ternary composite system; summarizes the application progress in the degradation of cyclic pollutants in water and atmospheric VOCs; and emphatically analyzes the performance characteristics and key issues in the ring-opening degradation of cyclic pollutants. Studies show that the high specific surface area and porous structure of SiO₂ nanofiber membranes offer excellent support for catalytic reactions. In addition, black TiO₂ achieves a full-spectrum response through defect engineering; the SPR effect and Schottky barrier of Ag significantly improve carrier separation efficiency; and the synergistic effect of the three components enhances the adsorption–catalytic degradation capacity. Current challenges remain in ring-opening efficiency and stability, requiring multi-method breakthroughs to overcome bottlenecks, clarify mechanisms and promote engineering applications. This paper provides theoretical references for the development of high-performance fiber-based photocatalytic materials and lays a foundation for the practical application of electrospun inorganic nanofiber membranes in the field of environmental catalysis. Full article

Because the environmental pollution arising from microplastics and carbon emissions continues to intensify, biodegradable alginate fibers have become green candidates to relieve the environmental crisis. However, the facile fabrication of alginate fibers with excellent mechanical strength and specific functionalities remains challenging. This study incorporates titanium dioxide (TiO₂) nanoparticles into pre-crosslinked sodium alginate (SA) spinning solutions to fabricate multifunctional alginate composite fibers by a one-step wet-spinning strategy. Due to the pre-crosslinking of calcium ions (Ca²⁺), the spinning solution shows favorable rheological performance for wet spinning, ensuring the continuous fabrication of the fibers. By optimizing the TiO₂ content, SA/TiO₂ composite fibers exhibit oriented and uniform morphology, as well as enhanced mechanical performance (breaking stress of 400 MPa and Young’s modulus of 17.2 GPa). The incorporation of TiO₂ also endows the fibers with excellent formaldehyde degradation and quick self-extinguished capacity, expanding their applications in formaldehyde-removal and flame-retardant textiles. Full article

This study investigates the impact of TiO₂ incorporation (0, 2, 4, 6, 8 wt.%) on the structural, optical, electrical, mechanical, and antibacterial properties of electrospun PVA/PVP nanofibers. FESEM observations revealed continuous, randomly oriented nanofibrous films with an average diameter in the 77–96 nm range, depending on TiO₂ content. FTIR and XRD analyses confirmed successful nanoparticle integration, showing effective interfacial interactions and the presence of crystalline TiO₂ phases within the semi-crystalline PVA/PVP matrix. Optical studies demonstrated a progressive decrease in the indirect band gap with increasing TiO₂ loading, decreasing from 3.75 to 3.54 eV according to the Tauc method and from 3.70 to 3.43 eV according to the ASF method, accompanied by an increase in Urbach energy from 0.43 to 0.64 eV, indicating enhanced structural disorder and tail state formation. The optical dispersion parameters obtained from the Wemple−DiDomenico model were consistent with these trends. Electrical characterization showed enhanced DC conductivity with increasing TiO₂ content and a marked reduction in thermal activation energy from 2.54 eV for the neat blend to 0.98 eV at higher TiO₂ loading, confirming facilitated charge transport in nanocomposite system. Mechanical characterization indicated that TiO₂ reinforcement improved both stiffness and strength, with the 6 wt.% sample achieving an optimal strength–ductility synergy (8.9 MPa and 121.5% elongation). Additionally, TiO₂ loading significantly boosted antibacterial performance, particularly against Escherichia coli and Staphylococcus aureus at 8 wt.%. These multifunctional properties position PVA/PVP:TiO₂ nanofibers as highly promising candidates for flexible biomedical coatings, optoelectronic devices, and advanced functional surfaces. Full article

The long-term exposure of asphalt pavement to ultraviolet radiation causes significant performance degradation and reduces its service life. To enhance the UV resistance of asphalt, nanocomposite modifiers have been incorporated through mechanical blending. However, their effectiveness has been largely limited by poor component uniformity. To address this issue, UV-resistant antioxidant nano-TiO₂ was employed to modify the UV-shielding of layered porous carbon (PC), resulting in the synthesis of nano-TiO₂ intercalated PC (TiO₂/PC). The PC nanosheet was modified by TiO₂ nanoparticles via in situ growth, significantly improving the dispersion homogeneity of TiO₂. Comprehensive characterization (SEM/EDS/FT-IR/XPS) confirmed the successful synthesis of TiO₂/PC with well-defined interfacial bonding. Compared to control samples (PC, TiO₂, and TiO₂ + PC), the asphalt modified by TiO₂/PC-2 composite demonstrated superior UV aging resistance, lower physical aging indices and reduced rheological aging parameters. Moreover, TiO₂/PC modifier prominently suppressed the formation of oxidative groups (C=O/S=O), improved the colloidal stability, and delayed the sol–gel transition of the modified asphalt. The synergistic UV shielding mechanism was attributed to the enhanced UV absorption of TiO₂, multi-reflection and scattering within the PC matrix, and the radical scavenging capabilities of both components. These results provide new design insights for developing anti-UV aging modifiers for asphalt pavements. Full article

Wire arc additive manufacturing (WAAM) demands aluminum feedstock with tightly controlled diameter and high surface integrity. Adding hard TiC nanoparticles is a viable route to enhance the mechanical response of Al wires, yet the associated increase in contact severity can accelerate the wear of wire processing tools, particularly cemented carbide dies. This study elucidates the unidirectional sliding interaction between a TiC reinforced Al WAAM wire, and a WC/Co die material containing 5 wt% Co, using a modified scratch testing configuration under dry and lubricated conditions. Two dominant mechanisms are identified: (i) aluminum adhesion on the die surface and (ii) third body abrasion arising from WC particle pull out, promoted by preferential degradation of the cobalt binder. The presence of TiC nanoparticles reduces both the extent of Al transfer and the intensity of third body abrasion, an effect that is further amplified by lubrication. Consistently, lubrication also diminishes surface defects on the wire after sliding. The results provide a mechanistic basis to balance wire strengthening with tool life and highlight practical levers—nanoparticle reinforcement and lubrication strategies—for mitigating die damage while preserving WAAM wire surface quality. Full article