Dispersion Of TiO2 Nanoparticles Research Articles

Investigative study on the AC and DC breakdown voltage of nanofluid from Jatropha–Neem oil mixture for use in oil-filled power equipment

This paper investigated the feasibility of developing alternative insulating nanofluid from a mixture of Jatropha and Neem oils into which compositions of 0.2 to 1.0 wt% of titanium oxide nanoparticles were dispersed. FTIR, SEM–EDX and XRD analyses of titanium oxide nanoparticles were carried out. The DC and AC breakdown voltages were measured and analysed using Weibull statistical tool. In the Weibull statistical analysis, it was observed that the characteristic breakdown field strength of PJO is higher relative to PNO and has slight differences compared to the PJNO sample. With the dispersion of TiO2 nanoparticles, the characteristic breakdown strength improved as compared with the base oil. Furthermore, the developed Jatropha–Neem mixture nanofluid recorded characteristic breakdown field strength that is much higher compared to that of the mineral oil sample. The mixture of Jatropha and Neem oil nanofluid sample possessed the highest characteristic breakdown strength among prepared nanofluids which indicates that the characteristic breakdown strength of the oil samples has been improved considerably with the dispersion of TiO2 nanoparticles. The results have shown the viability of Jatropha–Neem nanofluid as insulating oil for use in oil-filled power equipment.

Alginate/TiO2@LDH microspheres: A promising bioactive scaffold with cytocompatibility and antibacterial activity

In this study, a hybrid of TiO2@LDH was applied to fabricate a bone scaffold to take the advantages of both nanostructures. In addition to the role of LDH in the biomineralization process, it was used to provide a suitable bed for the better dispersion of TiO2 nanoparticles and prevent them from aggregations. The main limitation in the usage of these nanoceramics in the preparation of bone scaffolds is their powder state, which prevents their fixation in the desired place. So, alginate (Alg) was selected as the matrix to embed this nanohybrid and support its stability and fixation. Bioactivity of the prepared Alg/TiO2@LDH scaffolds was assessed by incubation in the simulated body fluid at 37 °C for 28 days. Field emission scanning electron microscopy as well as energy dispersive X-ray were used to prove the biomineralization on the scaffolds. MTT test showed that the scaffold containing 6 wt% of the TiO2@LDH do not have any toxicity effects on the MG-63 cell line. Also, this scaffold presented outstanding antibacterial ability against Staphylococcus aureus, which is known as an important infecting agent in the bone scaffolds. The proposed Alg/TiO2@LDH scaffold in this study could be a proper candidate to be used in bone tissue engineering.

A comparative study on the photodegradation efficiency of TiO<SUB align="right">2-CS hybrid beads under wet and dry conditions

The direct ex-situ technique successfully produced chitosan (CS) support TiO2 hybrid beads under wet and dry circumstances. The addition of CS to TiO2 photocatalysis improves adsorption, dispersion, and stability. The active surface, crystallinity, and morphology of the hybrid beads were determined, confirming the samples' homogenous granular morphology and homogeneous dispersion of TiO2 nanoparticles in the CS matrix. The more vital interaction between TiO2 and CS molecules was responsible for the lower IR peak intensities of the OH and NH2 groups of wet hybrid beads. Raman spectroscopy and field emission scanning electron microscopy revealed that the crystallinity and phase of TiO2 in both wet and dry samples are almost indistinguishable. With the optimal catalyst loading of 6 g, the photodegradation study revealed that wet hybrid beads reported adsorption of 95% for MB, while dry hybrid beads reported 75% for MO. Therefore, to enhance interactions between TiO2 and CS, TiO2-CS wet hybrid beads have superior stability, surface functioning, and adsorption capabilities, as determined by characterisation results.

Nonthermal plasma catalysis enhances simultaneous removal of toluene and ozone over TiO2@ZIF-8

Ultrasmall TiO2 nanoparticles (average diameter of 6.6 nm) were encapsulated inside zeolitic imidazolate framework-8 (ZIF-8) via a self-assembly method, and the synthesized TiO2@ZIF-8 catalyst was applied for the removal of toluene using nonthermal plasma (NTP). Physicochemical characterization was performed to investigate the structure and morphology of TiO2@ZIF-8. The results revealed the high dispersion of TiO2 nanoparticles in ZIF-8 and the formation of a Z-type heterojunction between TiO2 and ZIF-8, which efficiently utilized the UV light generated during plasma discharge to produce •OH and •O2‾. Upon treating toluene exhaust gas of 100 mg·(m3) −1 at 92.5% relative humidity, the toluene conversion efficiency was significantly improved to 91.17% with a COX selectivity of 76.45% by TiO2@ZIF-8 in NTP-catalysis at a specific energy density (SED) of 507 J L−1, which was improved by 45.96% and 52.27%, respectively. This was mainly due to the good hydrophobicity of ZIF-8, which helped maintain efficient catalytic performance under high humidity. The maximum ozone decomposition efficiency of 99.22% was achieved for the accelerated charge transfer efficiency and nearly formed NTP discharge behavior in the porous structures of the catalyst. In the 36-h stability test, high efficiency of toluene conversion, COX selectivity, and ozone decomposition were maintained with no significant decay observed. Discharge characteristic analysis and electron paramagnetic resonance (EPR) characterization revealed the mechanism of toluene degradation in which electrons, ·OH, ·O2 ⁻, and O3 participated in toluene degradation. The possible pathways of toluene degradation were proposed based on the intermediates detected by chromatography–mass spectrometry. This work provides a new approach for anchoring and dispersing nanoparticles by ZIF-8 to avoid the reunion of nanoparticles and a new direction for synthesizing high-performance catalysts for volatile organic compound (VOC) degradation in NTP-catalysis.

Significantly enhanced antifouling and separation capabilities of PVDF membrane by synergy of semi-interpenetrating polymer and TiO2 gel nanoparticles

PVDF membrane has strong hydrophobicity and low anti-pollution performance, greatly limiting its practical application. These drawbacks have been successfully overcome by designing and then preparing a membrane with a semi-interpenetrating polymer (semi-IPN) of PVDF/poly(acrylic acid) (PAA) as the membrane matrix, TiO2 nanoparticles as functional components and F127 as pore-forming agent. The semi-IPN was prepared by copolymerizing acrylic acid with N,N methyl acrylamide in the presence of PVDF, and the TiO2 gel nanoparticles were in situ formed in the membrane-forming process. The properties of the composite membrane were significantly affected by the semi-IPN, F127 and TiO2. By adjusting the membrane structure with the semi-IPN, F127 and TiO2 nanoparticles, we prepared a composite membrane with a water contact angle of 40°, a BSA rejection ratio of 87.5% and a water flux of 802.5 L/m2/h/bar. After a simple UV irradiation, the water flux of this composite membrane rose to 1030 L/m2/h/bar, without any rejection decline. The membrane contaminated by humic acid could recover the water flux up to above 95.3% of its original value by a single UV irradiation, showing a very good antifouling performance. In addition, the composite membrane also exhibited a very strong pollution resistance and separation performance for bovine serum albumin and oil-water emulsion. All in all, based on the synergy of the semi-IPN and the evenly dispersed TiO2 nanoparticles, the prepared composite membrane exhibited excellent comprehensive properties and demonstrated a great potential for various separation applications.

Structural analysis of sol-gel derived TiO2 nanoparticles: a critical impact of TiO2 nanoparticles on thermo-mechanical mechanism of glass fiber polymer composites

The incorporation of inorganic nanoparticles with thermosetting epoxy polymer is an emerging field of research over the past few years. It is well analyzed that epoxy matrix is brittle in nature that shows rapid crack initiation and rapid propagation without increasing applied stress value. Therefore, researchers are showing their interest in nanoparticles embedded epoxy composites to improve their fracture resistance (brittleness and toughness). In this investigation, the dispersion of TiO2 nanoparticles at different weight fractions (0-2 %) with glass fiber reinforced epoxy composites is performed to enhance structural and thermo-mechanical properties. The TiO2 nanoparticles are prepared by sol-gel method and structural analysis of TiO2 nanoparticles shows greater interfacial bond with epoxy matrix and glass fibers due to fine dispersion of nanoparticles. From obtained results, a significant enhancement in their tensile strength (38.56 %), flexural strength (30.52 %), inter-laminar shear stress (25.22 %), impact strength (327.10 %), micro-hardness (48.53 %) and fracture energy (40.19 %) with a minimal detrimental effect on toughness was revealed for GFRP-T1.0 compare to GFRP-T0.0 composite laminates. The stiffness and rigidity also improved up to 52.72 % and 34.13 % respectively for GFRP-T1.5 compare to GFRP-T0.0 composite laminates. The effects of nanoparticles contents and clustering size on thermal stability and glass transition temperature of developed composites are observed by thermo-gravimetric analysis. The surface morphology of TiO2 nanoparticles is characterized by transmission electron microscope (TEM) while the dispersion of nanoparticles and failure of developed composites were analyzed by scanning electron microscopy (SEM).

Insight into the activity of TiO2@nitrogen-doped hollow carbon spheres supported on g-C3N4 for robust photocatalytic performance

Designing an advance nanostructure semiconductor is an efficient strategy to promote the charge separation and thus improve the photocatalytic activity. Herein, a relatively high recombination rate of electron-hole pairs and low specific surface area of g-C3N4 (GCN) were subjected to the surface deposition of the core shell nanoparticles composed of nitrogen doped hollow carbon spheres (N-HCSs) as the supporting scaffold and TiO2 nanoparticles as the photoactive layer. The ternary composites with different TiO2@N-HCS content were prepared through a simplified nanocasting method followed by the two consecutive hydrothermal process. The effects of nitrogen doping in carbon framework, and nanoparticles amount were evaluated on the photocatalytic ability through the photodegradation of tetracycline (TC) molecules under the visible light irradiation. At the optimum content of core shell nanoparticles (7 wt%), the solar-driven TC photocatalytic degradation for ternary composite was approximately 85%, which was much better (about three times) than that of the pure GCN. More interestingly, the experimental results revealed that doping of nitrogen atoms has a positive role on the charge separation and the resulting photocatalytic efficiency. The employed hollow carbon spheres here play three important roles: (1) providing a substrate to uniformly dispersion of TiO2 nanoparticles without any aggregation; (2) reducing the combination of charge carriers and improving the separation of photoinduced carriers; (3) formation of larger surface area and more active sites on the photocatalyst surface. Furthermore, the underlying photocatalytic degradation mechanism was introduced by the controlled experiments using photoluminescent and radical scavenger tests.

Printable dielectric elastomers of high electromechanical properties based on SEBS ink incorporated with polyphenols modified dielectric particles

In this work, a recently developed 3D additive processing technology termed electrohydrodynamic (EHD) printing was employed to fabricate dielectric elastomer (DE) films by using styrene-ethylene-butylene-styrene (SEBS) inks with the addition of high dielectric titanium dioxide (TiO2) nanoparticles. In order to improve the dispersibility of TiO2 in the SEBS matrix, extracted walnut polyphenols were utilized for surface modification of TiO2 nanoparticles labelled wp-TiO2. The effect of the applied voltage on the ink jet morphology of the obtained SEBS based inks during EHD printing was analyzed. The prepared films had precision patterned shapes and their morphology was studied. It revealed that the dispersibility of TiO2 nanoparticles in the SEBS matrix and their compatibility were greatly improved using this procedure. Furthermore, the printed DE films were found to have excellent mechanical, dielectric and electromechanical properties. For the range of DEs fabricated, the SEBS/10%wp-TiO2 composite exhibited the maximum actuated area strain of 21.5% at an electric field of about 34.0 V/μm without degradation of other properties.

Controllable fabrication of photocatalytic TiO2 brookite thin film by 3D-printing approach for dyes decomposition

An immobilized photocatalytic system is being considered as an advantage for wastewater treatment. The stability and durability of photocatalytic materials in film form strongly depend on both supported materials and immobilization techniques. In this work, the composite of a styrene-acrylate (DC668) polymeric binder and the TiO2 brookite spherical nanoparticles (NPs) was immobilized on the surface of the glass substrate by direct-ink-writing technique using a 3D printer. Physicochemical and photocatalytic properties were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy, respectively. Rose bengal (RB) was used as the target pollutant to investigate the photocatalytic behavior of the obtained TiO2/DC668 composite thin film which was evaluated by UV–VIS absorption spectra. We found that an amount of less than 10% of the industrial DC668 emulsion has significantly improved the dispersion of TiO2 NPs in the polymeric matrix as well as the adhesion of 3D-printed TiO2 thin film to the glass surface. After UV-A light exposure for 300 min, the decomposition rate of RB over TiO2 film was 0.029 min−1 corresponding to the nearly complete decolourization. The reuse tests show that the thin-film photocatalyst was remarkably stable. Its high activity can be maintained after four uses with the RB dyes photodegradation efficiency of 92%. The photo-catalyzing capacity of the thin films with immobilized TiO2 NPs was slightly lower than that of only bare TiO2 NPs, but the thin film can be efficiently reused for more cycles without any further separation. Thereby, the 3D-printed TiO2 brookite thin-film photocatalysts provide the potential for application in large-scale wastewater treatment.

Environmentally Friendly UV-Protective Polyacrylate/TiO2 Nanocoatings.

The development of coatings that maintain the attractive natural appearance of wood while providing ultraviolet (UV) protection is extremely important for the widespread use of wood products. In this study, the influence of different types (powder form and aqueous dispersions) of TiO2 in an amount of 1.0 wt% by monomer weight on the properties of environmentally friendly polyacrylate (PA)/TiO2 emulsions prepared by ex situ and in situ polymerization, as well as on the UV-protective properties of the coating films, was investigated. The results showed that the addition of TiO2 significantly affected the particle size distribution of PA and the viscosity of PA varied according to the preparation method. Compared with the ex situ preparation method, in situ polymerization provides better dispersibility of TiO2 nanoparticles in PA coating film, as well as a better UV protection effect and greater transparency of the coating films. Better morphology and transparency of nanocoating films were achieved by adding TiO2 nanofillers in aqueous dispersion as compared to the addition of TiO2 in powder form. An increase in the glass transition temperature during UV exposure associated with cross-linking in the polymer was less pronounced in the in situ-prepared coating films, confirming better UV protection, while the photocatalytic effect of TiO2 was more pronounced in the ex situ-prepared coating films. The results indicate that the method of preparation has a significant influence on the properties of the coating films.

An assessment of the TiO2 nanoparticle concentration in the C. inophyllum biodiesel blend on the engine characteristics of a DI diesel engine

In the present study, C. inophyllum biodiesel blend (CIB20) was prepared and mixed with the titanium dioxide (TiO2) nanoparticle in different concentrations. The properties of fuel samples (diesel, CIB20, CIB20TNP20, CIB20TNP40, CIB20TNP60 and CIB20TNP80) were measured as per the standards of ASTM. Various tests were conducted on the diesel engine by using test fuels to analyse the effect of nanoparticle concentration on the engine characteristics. The BTE for CIB20TNP80 fuel was increased by 11% and BSFC curtailed by 16% compared with CIB20 fuel. The CO, HC, and smoke emissions were reduced by 30%, 21% and 17.6% for the CIB20TNP80 fuel, respectively compared to the CIB20 fuel, at the outset the NOx emissions were marginally increased with the addition of nanoparticles. It is concluded that the dispersion of TiO2 nanoparticles into biodiesel blend improves the fuel properties and engine performance with compromise results of exhaust emissions.

High-performance antibacterial film via synergistic effect between uniformly dispersed TiO2 nanoparticles and multifunctional quaternary ammonium cationic ligand

Due to the extraordinary photocatalytic effect, TiO2 nanoparticles (TiO2 NPs) have been widely applied in antibacterial fields. However, the agglomeration problem and dependence on light of TiO2 NPs seriously limit their antibacterial activity and practical applications. This study proposed an ingenious, facile and effective strategy for the preparation of polyacrylate/TiO2 nanocomposite antibacterial films by emulsion polymerization. In this work, a quaternary ammonium cationic ligand Vinylbenzyldimethyldodecylammonium chloride (VDAC) was successfully synthesized, which acted as a trinity of cationic ligand, organic antibacterial agent and polymerizable emulsifier to improve the dispersion of TiO2 NPs by electrostatic interaction and play the synergistic antibacterial effect with TiO2 NPs. The results demonstrated that TiO2 NPs were truly uniformly dispersed in the matrix and the particles sizes were reduced to around 5 nm. Moreover, the systematic investigations of antibacterial performance indicated that the prepared nanocomposite films displayed excellent antibacterial and antibiofouling abilities through the synergistic antibacterial effect of TiO2 NPs and VDAC. The films could maintain close to 100 % antibacterial rate and completely inhibit bacterial adhesion and biofilm formation in 7 days, exhibiting long-term and stable antibacterial performance. The nanocomposite films in this work exhibit a great potential to be applied to antibacterial coatings and other fields requiring high antibacterial properties.

Microwave-assisted hydrothermal synthesis of sulfonated TiO2-GO core–shell solid spheres as heterogeneous esterification mesoporous catalyst for biodiesel production

In accordance with the need for green production, the aim of current research is to synthesize a highly recyclable mesoporous SO3H-GO@TiO2 catalyst possessing both Brönsted and Lewis acid sites for one-pot catalyzing the esterification of inexpensive acidic feedstocks namely palm fatty acid distillate (PFAD), containing free fatty acids (FFAs, >85 wt%) and a considerable amount of water (3 wt%). The mesoporous sulfonated GO@TiO2 catalyst was synthesized using a two-step hydrothermal microwave-assisted method featured by uniform dispersion of TiO2 nanoparticles inside the mesopore framework of GO and post-sulfonation treatment. The effect of different GO:Ti ratios (1:0.1, 1:0.3, 1:0.5, and 1:1) on textural properties were examined and therefore, the ratio of 1:1 was selected as the optimum ratio for further experiments. The mesoporous SO3H-GO@TiO2 catalyst was characterized using Raman spectroscopy, Brunauer–Emmett–Teller (BET), X-Ray diffraction (XRD), temperature-programmed desorption (TPD), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray (EDX), and the results revealed that the as-developed catalyst possessed desirable textural properties as well as strong acidity with a combination of both Brönsted and Lewis acid sites. Furthermore, the crystalline structure of the as-prepared mesoporous GO@TiO2 material remains unaltered after the post-sulfonation treatment. In addition, the synthesized mesoporous SO3H-GO@TiO2 catalyst showed high stability for ten consecutive esterification reactions without additional treatments.

Combination of microwave discharge electrodeless lamp and a TiO2/HZSM-5 composite for the photocatalytic degradation of dimethyl sulphide

In this study, an integrated photocatalytic system consisting of a microwave discharge electrodeless lamp (MDEL) and TiO2/HZSM-5 was established to investigate the intensified degradation of dimethyl sulphide (DMS). The system targets optimisation of the reactive oxygen species (ROS) and photocatalytic degradation pathways without catalyst deactivation. TiO2/HZSM-5, containing highly dispersed TiO2 nanoparticles, was prepared through the sol-gel method. TiO2/HZSM-5 exhibits strong acidity and can adsorb DMS in multiple adsorption forms. Thus, the adsorption capacity of TiO2/HZSM-5 is 20 and 53 times higher than that of Aeroxide TiO2 (P25) in dry and highly humid air, respectively. UV–Vis analysis was performed to investigate the ROS in the gas phase. The results show that the concentrations of the ROS increased by 8% and 62.7% in dry and highly humid air, respectively. 1O2 and O (1D), as well as ·OH are the major ROS, accounting for 73.6% and 61.6% in dry and highly humid air, respectively. A total of 92.5% DMS was removed over 600 min in dry air. Microwaves have strong desorption effects on absorbed substances, promoting the degradation of DMS via ROS in the gas phase. Moreover, 1O2, O (1D), and ·OH can mineralise more DMS molecules into SO2 and SO3 through methanesulfonic acid. The highest mineralisation rate of 89.48% was obtained at 90% humidity over 600 min without catalyst deactivation. Therefore, this integrated system induced by microwave radiation can improve ROS production and prevent catalyst deactivation, providing an alternative to achieve higher photocatalytic performances in dry and highly humid air.

A study of water-based lubricant with a mixture of polyphosphate and nano-TiO2 as additives for hot rolling process

Hot rolling is one of the most widely used hot metal forming processes by shaping the hot workpiece with cylindrical rolls. Its harsh working conditions, including high loading (up to 0.5 GPa), elevated temperature (600–1100 °C) and high speed (above 10 m/s), lead to the problems of high friction, severe wear, oxidation at the tool/workpiece rubbing surfaces. Lubricants are essential to reduce the rolling force, prolong the service life of work rolls, and improve overall process efficiency. In this work, the mixture of sodium polyphosphate and nano-TiO2 as water-based hot rolling lubricants were studied using a laboratory hot rolling mill. Aqueous lubricant with 2 wt.% TiO2 in 20 wt.% sodium polyphosphate demonstrates an excellent lubrication performance with a reduction of a rolling force of 10% compared to pure water lubrication condition. The sodium polyphosphate can not only act as a surfactant to improve the dispersibility of TiO2 nanoparticles in water, but also form an easily sheared glass melt at high temperature to lubricate the workpiece/roller. Focused ion beam and transmission electron microscope analysis of the sliding interface demonstrate that some nano-TiO2 were contained in the polyphosphate melt. The concept that combines the inorganic polymer with nanoparticles to produce the synergy effects of glass lubrication and nanoparticle lubrication can provide new insight into the design of lubricants for the hot metal forming process.

Pan‐Milling: Instituting an All‐Solid‐State Technique for Mechanical Metastable Oxides as High‐Performance Lithium‐Ion Battery Anodes

AbstractAll‐solid‐state mechanochemistry is experiencing an exciting period of renaissance, thanks in part to the recent discovery of its ability to realize chemical synthesis that is inaccessible to solution‐based methods. Among them, high‐energy ball‐milling is widely used in large‐scale preparation of metal oxide composites for lithium‐ion batteries (LIBs). However, ball‐milling‐induced high‐energy mechanical activation may destroy crystalline structure, and thus the electrochemical activity of many metastable oxides such as anatase titanium dioxide (TiO2). Herein, the mechanism that anatase TiO2 undergoes the crystalline‐amorphous phase transformation subject to ball‐milling is reported and a new pan‐milling mechanochemical technique for preparation of stable anatase TiO2/graphene (TiO2/GNS) composites is demonstrated. The pan‐milling technique not only preserves the original crystal structure of TiO2 but also realizes a good dispersion of TiO2 nanoparticles on graphene nanosheets through its unique 3D shear force. When used as anode for LIBs, the pan‐milled TiO2/GNS demonstrates high reversible specific capacity, excellent rate capability, and long cycle stability, in comparison to the ball‐milled TiO2/GNS that shows no capacity. By tapping into the huge potential of pan‐milling mechanochemistry, this work opens the door to large‐scale all‐solid‐state preparation of mechanical metastable oxides with desired electrochemical performance for energy storage.

Novel Surfactant-Free Water Dispersion Technique of TiO2 NPs Using Focused Ultrasound System.

Titanium dioxide (TiO2) nanoparticles are used in a wide variety of products, such as renewable energy resources, cosmetics, foods, packaging materials, and inks. However, large quantities of surfactants are used to prepare waterborne TiO2 nanoparticles with long-term dispersion stability, and very few studies have investigated the development of pure water dispersion technology without the use of surfactants and synthetic auxiliaries. This study investigated the use of focused ultrasound to prepare surfactant-free waterborne TiO2 nanoparticles to determine the optimal conditions for dispersion of TiO2 nanoparticles in water. Under 395–400 kHz and 100–105 W conditions, 1 wt% TiO2 colloids were prepared. Even in the absence of a surfactant, in the water dispersion state, the nanoparticles were dispersed with a particle size distribution of ≤100 nm and did not re-agglomerate for up to 30 days, demonstrating their excellent dispersion stability.

Influence of TiO2 film thickness on photovoltaic properties of dye-sensitized solar cells

Generally, the dye-sensitized solar cells DSSCs are composed of a photoanode, a redox-coupled electrolyte, and a counter electrode. The nanocrystalline porous TiO2 film is one of the most employed frequently photoanode materials in this type of solar cells due to its excellent optoelectronic properties. It significantly influences the photon-electron conversion efficiency of the solar cell, because of its good photo-excited electron transportation and dye adsorption. The surface morphology, crystalline phase, particle size, surface area, porosity, and dispersion of TiO2 nanoparticles are the various influencing factors which determine the properties of DSSCs. In particular, the thickness of the photoanode is known to be one of the crucial factors determining the efficiency of solar cells. These properties strongly relate to the TiO2 electrode method of fabrication and its parameters. Dye-sensitized solar cells based on TiO2 films with different printing layers were fabricated by screen printing method. The prepared samples were characterized by scanning electron microscopy SEM and UV-Vis absorption spectroscopy. The effects of film thickness on the current-voltage characteristics of DSSCs were also investigated.

Performance enhancement in tribological properties of lubricants by dispersing TiO2 nanoparticles

Nano-lubricants have attracted many investigators since past decade due to their better anti-wear and friction reducing abilities. Still a major challenge lies in preparation of stable nano-lubricants with uniform nanoparticles suspension. In research studies synthesis of nanoparticle, preparation of nano-lubricants, characterization, and their performance are generally reported. Every single study has reported the enhancement in tribological capabilities of the nano-lubricants. TiO2 nanoparticle based nano-lubricants are specially focused which are either used after surface modification with acids or directly dispersed in base oil. Nano-lubricants with water and paraffin oil as base lubricant is rarest and common respectively. Several hybrid combination of nano-particles with TiO2 have also proved to be efficient. What further challenges is the optimization of the nano-lubricants performances with better stability and less preparation cost. No mathematical model yet exists to predict the properties and tribological behavior of the nano-lubricants.

Stabilizing effects of zinc(II)-benzene-1,3,5-tricarboxylate metal organic frameworks on the performance of TiO2 photoanodes for use in dye-sensitized solar cells

This work reports on the effect of zinc(II)-benzene-1,3,5-tricarboxylate metal organic frameworks (Zn-BTC MOFs) towards enhancing the power conversion efficiency of titanium dioxide (TiO2) based dye-sensitized solar cells (DSSCs). Zn-BTC MOFs and TiO2 nanoparticles were synthesized via a modified hydrothermal method. This was followed by the addition of an extrinsic mixture of TiO2 powder and MOFs to form TiO2-Zn-BTC MOF(2%), TiO2-Zn-BTC MOF(4%) and TiO2-Zn-BTC MOF(6%) nanocomposites with varying concentrations. The structure, morphology, optical properties and thermal stability of the MOF powders were subsequently evaluated. XRD analysis demonstrated that the incorporation of MOFs into TiO2 decreases the crystallinity of TiO2 due to the poor crystalline structure of MOFs. The presence of the Ti-C bond and the induced redshift of the E1g peak suggesting the migration of electrons between TiO2 and MOFs was confirmed by FTIR and Raman spectroscopy, respectively. Microscopic studies showed the formation of irregularly shaped nanoparticles with a size range of 5–40 nm. Additionally, the BET surface area improved with an increase in Zn-BTC loadings, leading to the uniform dispersion of TiO2 nanoparticles in the nanocomposites. The optical properties of the nanocomposites were enhanced by the incorporation of Zn-BTC MOFs resulting to low band gap values. The TiO2-Zn-BTC MOF(2%) exhibited a lower band gap of 2.9 eV in comparison to TiO2-Zn-BTC MOF(4%) with a band gap of 3.1 eV and TiO2-Zn-BTC MOF(6%) which also had a band gap of 3.1 eV. Hence, TiO2-Zn-BTC MOF(2%) exhibited reduced recombination rates of the electron-hole pairs and increased photoactivity as confirmed by the photoluminescence (PL) spectroscopy data, as well as reduced charge-transfer kinetics shown by electrochemical impedance results. The I–V results showed that TiO2-Zn-BTC MOF(2%) has a strong ability to act as an effective electron transporter which significantly enhanced the photoefficiency of TiO2 thus leading to better photoanodes for DSSCs.