Pure Anatase TiO2 Nanoparticles Research Articles

Structural, optical, and electrical characteristics of anatase titanium dioxide tailored by doping of nitrogen and copper ions

Pure anatase TiO2 nanoparticles and its mono–doped and co–doped derivatives [i.e. (TiN0.007O1.993); (Ti0.998Cu0.002O2); (Ti0.998Cu0.002N0.007O1.993)] were prepared by sol–gel auto–combustion technique. Further, the effects of copper (Cu) and nitrogen (N) dopants have been investigated on structural, optical and dielectric properties of nanostructured TiO2 using X–ray diffraction (XRD), Raman spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy and dielectric spectroscopy measurement respectively. The Rietveld refinement analysis of XRD data and Raman spectra revealed that all the synthesized samples have pure anatase phase having tetragonal structure with space group of I41/amd. The pure anatase phase of doped samples illustrate the substitution of Cu ions at Ti4+ sites and N ions at O2− sites in the TiO2 host lattice. The crystallite size of TiO2 and its derivatives has been observed in the range of 11–14 nm. The band gap of TiO2 reduced from 3.2 to 1.9 eV with mono–doping and co–doping of the N and Cu in TiO2 lattice as confirmed by UV–Vis spectroscopy. This red–shift might be occur due to the possible formation of N–2p and Cu–3d localized levels (mono–doping case), and the creation of isolated intermediate states (co–doping case). The dielectric spectroscopy was carried out to investigate the electrical properties in details and explained in terms of structural and intrinsic ionic behaviour of different dopants. The detected band gap energies in N/Cu mono–doped and co–doped anatase TiO2 fall within the visible spectrum, rendering them suitable for harnessing solar energy in photocatalysis and photovoltaic applications.

Development of a low-cost photocatalytic aerogel based on cellulose, carbon nanotubes, and TiO2 nanoparticles for the degradation of organic dyes

A hybrid ultra-light and porous cellulose aerogel was prepared by extracting cellulose fibers from white paper, alkali/urea as a crosslinker agent, and functionalized with CNTs and pure anatase TiO2 nanoparticles. Since CNTs work as mechanical reinforcement for aerogels, physical and mechanical properties were measured. Besides, since TiO2 acts as a photocatalyst for degrading dyes (rhodamine B and methylene blue), UV–Vis spectroscopy under UV light, visible light, and darkroom was used to evaluate the degradation process. XRD, FTIR, and TGA were employed to characterize the structural and thermal properties of the composite. The nanostructured solid network of aerogels was visualized in SEM microscopy confirming the structural uniformity of cellulose and TiO2-CNTs onto fibers. Moreover, CLSM was used to study the nano-porous network distribution of cellulose fibers and porosity, and the functionalization process in a detailed way. Finally, the photocatalytic activity of aerogels was evaluated by degradation of dye aqueous solutions, with the best photocatalytic removal (>97 %) occurring after 110 min of UV irradiation. In addition, HPLC-MS facilitated the proposed mechanism for the degradation of dyes. These results confirm that cellulose aerogels coupled with nanomaterials enable the creation of economic support to reduce water pollution with higher decontamination rates.

Investigational, computational explorations on betanin, lycopene, cyanidin, and peonidin organic photo sensitizers for green energy harvesting

In keeping green energy harvesting as a prime priority and lowering the cost per watt, three potential red-colored organic photosensitizers were separated and employed for proficient titanium dioxide (TiO2) photoanodes. In a prime attempt, Rivina Humilis fruit extract (Betanin) was used for natural dye-sensitized solar cells (NDSSCs). The Prunus cerasus fruits and Solanum lycopersicum fruits (Lycopene) extracts were also successfully employed to fabricate NDSSCs. Cyanidin, Peonidin, and Lycopene are the prominent colorants existent in Prunus cerasus, and their optimized molecular structure was premeditated via Density functional theory. Their thermochemistry and associated physical parameters, Frontier molecular orbitals (FMOs) analyses, theoretical ultraviolet (UV) – visible exploration, and molecular electrostatic potential reactivity analysis were studied. Microwave-assisted sol–gel practice has yielded pure anatase TiO2 nanoparticles (NPs). The pure, red dye-sensitized TiO2 NPs endured needed studies. Environment-friendly, cost-per-watt effective NDSSCs were accomplished by expanding three red-colored organic photoanodes. Among three photosensitizers, Rivina Humilis fruits showed 1.35%, followed by Prunus cerasus at 1.27 % and slightest by Solanum lycopersicum at 0.82%. And, owing to the above performances, these NDSSCs have the potential to be employed in low-power indoor energy harvesting.

Multi-antibiotics removal under UV-A light using sol-gel prepared TiO2: Central composite design, effect of persulfate addition and degradation pathway study

The removal of three antibiotics i.e., metronidazole (MNZ), ciprofloxacin (CIP) and tetracycline (TET), from aqueous system via TiO2 photocatalysis under UV-A light was investigated. Photocatalyst(s) were prepared using sol-gel method under different calcination temperatures (400–800 °C) and water-alcohol ratio. The spherical shaped catalyst (mean particle size ∼ 61 nm) was characterized via FTIR, XRD, BET, SEM, Raman, XPS, UV-DRS, and Fluorometry, and point of zero charge was also determined (pHPZC ∼ 6.6). Batch photo-catalytic degradation studies have shown complete degradation of MNZ, CIP and TET after 50, 75 and 20 min with a TOC removal of 37%, 44% and 31%, respectively. The activity of sol-gel prepared TiO2 was comparatively higher than commercially available pure anatase TiO2 nanoparticles due to lesser mean particle size. The ratio of water to alcohol in the preparation of TiO2 catalyst was found to have significant effect on antibiotic removal. Moreover, persulfate (PS) addition of 0.1 g/L amplified the pseudo-first-order removal-rate constant by 2.75, 3.3 and 1.6 times for MNZ, CIP and TET, respectively. The higher initial pH values (8 and 10) have shown the best removal efficiency for all antibiotics. Subsequently, central composite design (CCD) experiments were conducted under multi-antibiotic conditions. Near complete removal of all antibiotics were observed within 120 min. Scavenging studies revealed that hydroxyl and superoxide radicals play major roles in photo-catalytic degradation of MNZ, CIP and TET. During photocatalysis, MNZ degradation was initiated by hydroxylation reaction, CIP by piperazine ring opening by hydroxyl attack and TET by multiple hydroxylation process. Overall, TiO2 showed good efficiency at degrading multiple antibiotics and has the potential for practical application on a larger scale.

Structural, optical and magnetic studies of sol-gel synthesized Mg-doped pure anatase TiO2 nanoparticles for spintronic and optoelectronics applications

Here in we reported the synthesis of MgxT1−xO2 (for x = 0.00, 0.01, 0.02, 0.03, 0.04) nanoparticles via simple sol-gel technique. Mg-doped TiO2 is a hopeful material for the study of the origin of room-temperature ferromagnetism (RTFM) in dilute magnetic semiconductors (DMS) systems, but very scanty work on this material has been reported. The as-synthesized samples were subjected to X-ray diffraction (XRD) which shows that the samples aligned with tetragonal anatase phase of TiO2. UV\\Vis\\NIR diffuse reflectance spectroscopy analysis showed a slight increase in TiO2 energy band gap with Mg doping from 3.25eV to 3.33 eV as a result of blue shift in absorbance edge of the sample. The obtained recombination of photo-generated electrons and holes is excellently curbed by Mg doping which was examined by the photoluminescence study and the blue shift in the most intense Eg (3) Raman mode confirms integrated Mg in TiO2 lattice. As revealed by Field Emission Scanning Electron Microscopy (FESEM), the morphology of the samples showed irregularly distributed nanoparticles and to examine elemental composition of the samples, Energy Dispersive X-ray (EDX) were carried out which stipulates all elements like Ti and Mg are in the sample. Soft ferromagnetism at low magnetic field with hysteresis loop was noticed in all the samples, with values of coercivity in the range 206–309Oe. Maximum value of saturation magnetization was evident by the 2% doped sample. These materials can find applications in electronics, spintronics and magneto-optics devices.

Nanowires-Assembled TiO2 Nanorods Anchored on Multilayer Graphene for High-Performance Anodes of Lithium-Ion Batteries.

Multilayer graphene (MLG) prepared via ultrasonic exfoliation has many advantages such as its low-cost and defect-free nature, high electronic conductivity, and large specific surface area, which make it an apt conductive substrate for TiO2 composites. To synthesize graphene/TiO2 hybrids, traditional methods that greatly depend on the chemical bond of oxygen-containing functional groups on graphene with titanium cations are not applicable due to the absence of these functional groups on MLG. In this work, a facile chemical method is developed to directly deposit TiO2 on the MLG surface without the introduction of chemically active groups. With this method, four types of TiO2 materials, that is pure anatase TiO2 nanoparticles, a mixture of anatase TiO2 nanoparticles and rutile TiO2 nanoflowers, pure rutile TiO2 nanoflowers, and pure rutile TiO2 nanorods, are homogeneously anchored on the MLG surface by controlling the amount of HCl in the reactant. Interestingly, the rutile TiO2 nanorods in the TiO2/MLG composite are assembled by many TiO2 nanowires with an ultra-small diameter and ultra-long length, which provides a better synergetic effect for high performances as LIB anodes than other composites. A specific capacity of 631.4 mAh g−1 after 100 cycles at a current density of 100 mA g−1 is delivered, indicating it to be a valuable LIB anode material with low cost and high electrochemical performances.

Computational assisted tuning of Co-doped TiO2 nanoparticles for ammonia detection at room temperatures

Improved gas sensors based on pure anatase TiO2 and Co-doped TiO2 nanoparticles were evaluated. A cobalt-doped TiO2 nanoparticle with a diameter of 40 nm was first synthesized. The morphology of the nanoparticles was analyzed by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. The doped Co ion was confirmed to have entered the TiO2 lattice. Subsequently, gas sensors with different Co-doping concentrations were developed to investigate gas sensitivity to NH3. Compared with pure anatase TiO2 operating at 180 °C, Co-doped TiO2 samples were developed as NH3 gas sensors operating at room temperature. The 20% Co-doped sample exhibited the best performance, with a response value of 14 for 50 ppm NH3, which was 7 times higher than that of pure TiO2. The response and recovery times of the sensor were only 25 and 48 s, respectively, and exhibited both good stability and selectivity. Based on density functional theory (DFT), the calculated bandgap of Co-doped TiO2 decreased by 72% compared to pure TiO2. Structural simulation and mechanism analysis elucidated the good gas-sensing performance at room temperature and the property enhancement of the Co-doped TiO2 gas sensor.

Development of photo-induced Ag0/TiO2 nanocomposite coating for photocatalysis, self-cleaning and antimicrobial polyester fabric

Materials with multifunctional surface, such as UV shielding, self-cleaning or antimicrobial properties have been highly desirable. Titanium dioxide (TiO2) and nanocomposite nanoparticles (NPs) composed of metallic silver/titanium dioxide (Ag0/TiO2) were prepared. Both of TiO2 nanoparticles and Ag0/TiO2 nanocomposite were coated onto the surface polyester fabric utilizing the straightforward pad-dry-curing technique. The morphological properties and elemental composition were determined utilizing X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX). The resultant materials demonstrated photocatalytic and antimicrobial properties. The photocatalytic performance was studied using the photochemical destruction of methylene blue, while the antimicrobial activity was recorded against Escherichia coli. The performance of polyester fabrics comprising Ag0/TiO2 nanocomposite particles was much better than those containing pure anatase TiO2 nanoparticles.

Ferroelectric barium titanate microspheres with superior light-scattering ability for the performance enhancements of flexible polymer dye sensitized solar cells and photodetectors

In this study, barium titanate microspheres (BTMS) comprising 10 to 20 nm thick one-dimensional (1D) nanorods have been synthesized via a dual-stage hydrothermal process and used as photoelectrode material for the fabrications of high-performance flexible dye sensitized solar cells (FDSSCs) and photodetectors. Crystal structure and morphological analyses have indicated a rutile phase TiO2 microspheres (RTMS) intermediate is transformed as tetragonal BTMS during the hydrothermal process. Because of the superior light-scattering ability and reduced charge recombination at the BTMS/TiO2 nanoparticles film/electrolyte interface by the ferroelectric dipoles of BaTiO3, BTMS/TiO2 nanocomposite based FDSSC photoanode has demonstrated ~1.7-fold higher power conversion efficiency (PCE = 4.53%) than the pure anatase TiO2 nanoparticles based FDSSC photoanode (PCE = 2.66%). A high dielectric permittivity (ɛr = 3114 at 25 °C) and tangent loss (ɛ˝) obtained for the BTMS at low AC frequencies have confirmed their superior dielectric and ferroelectric characteristics over RTMS (ɛr = 888 at 25 °C), created by the strain induced ferroelectric polarization of 1D BaTiO3 nanorods. Similarly, the BTMS coated PET based flexible photodetector has produced quantum efficiency (QE) of 1.1% with an excellent photoresponse, which further indicated the ferroelectric polarization aided photocurrent generation in the BTMS based photoactive materials.

Biosynthesized TiO2 nanoparticles an efficient biogenic material for photocatalytic and antibacterial applications

A simple one-step biosynthesis route has been adopted for the synthesis of high crystalline phase pure anatase TiO2 nanoparticles. The structural conformation and functional group analysis of the synthesized nanoparticles were made through X-Ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR), respectively. The optical property and the band gap were estimated by using UV-Visible diffuse reflectance spectroscopy (UV-DRS). The surface morphological properties of the anatase TiO2 nanoparticles were confirmed using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) and the size of the synthesized nanoparticles are 8 nm. The element analysis was evaluated by using EDS and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the prepared sample was investigated by the decolourization of Methylene blue dye under UV and solar light irradiation. The maximum dye removal efficiency of 99.2% was observed for solar light irradiation. Besides, the prepared samples also exhibit excellent antibacterial activity against Klebsilla Pneumoniae and Streptococcus Pneumoniae. The antibacterial activity for the synthesized TiO2 nanoparticles show maximum zone of inhibition (23.5 mm). Thus, the biogenic property of the bioprocessed TiO2 nanoparticles is a potential material for environmental and biomedical applications. [Formula: see text]

Phthalocyanine-Grafted Titania Nanoparticles for Photodegradation of Ibuprofen

The natural environment is constantly under threat from man-made pollution. More and more pharmaceuticals are recognized as emerging pollutants due to their growing concentration in the environment. One such chemical is ibuprofen which has been detected in processed sewage. The ineffectiveness of water methods treatment currently used raises the need for new remediation techniques, one of such is photodegradation of pollutants. In the present study, zinc(II) and copper(II) phthalocyanines were grafted onto pure anatase TiO2 nanoparticles (5 and 15 nm) to form photocatalysts for photodecomposition of ibuprofen in water. The nanoparticles were subjected to physicochemical characterization, including: thermogravimetric analysis, X-ray powder diffraction, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller surface area analysis and particle size measurements. In addition, they were assessed by means of electron spin resonance spectroscopy to evaluate the free radical generation. The materials were also tested for their photocatalytic activity under either UV (365 nm) or visible light (665 nm) irradiation. After 6 h of irradiation, almost complete removal of ibuprofen under UV light was observed, as assessed by liquid chromatography coupled to mass spectrometry. The reaction kinetics calculations revealed that the copper(II) phthalocyanine-containing nanoparticles were acting at a faster rate than those with zinc(II) derivative. The solutions after the photoremediation experiments were subjected to Microtox® acute toxicity analysis.

Application of the statistical analysis methodology for photodegradation of methyl orange using a new nanocomposite containing modified TiO2 semiconductor with SnO2

ABSTRACT Pure anatase TiO2 nanoparticles and two kinds of TiO2–SnO2 nanocomposite with different amounts of SnO2 nanoparticles (A-S (1-1) and A-S (1-2)) are synthesised. The X-ray diffraction (XRD) pattern is used for the characterisation of the synthesised samples. The XRD results confirmed that synthesised TiO2 nanoparticles have an anatase structure and SnO2 nanoparticles possess a tetragonal structure. The results of TEM reveal that the particle size of the TiO2 nanoparticles is less than 30 nm. Meanwhile, the SnO2 nanoparticle is successfully introduced onto the outer surface of TiO2 nanoparticles. The variation in the removal efficiency of methyl orange as an organic pollutant with UV irradiation time, weight fraction of synthesised photocatalysts and pH is investigated. The obtained results confirm that the removal efficiency of methyl orange increases in respect of the UV irradiation time and weight fraction. In addition, it is observed that the highest and lowest removal efficiencies occur at pH = 3 and pH = 11, respectively. Meanwhile, the results reveal that the removal efficiency of methyl orange is enhanced in respect of the SnO2 nanoparticles content in the synthesised nanocomposite. The analysis of variance investigation reveals that all the main factors have a significant effect on the removal efficiency of pollutant. Meanwhile, the proposed models can accurately predict the variation of the removal efficiency with studied parameters.

Hydrothermal and sol-gel low-temperature synthesis of tin, silver co-doped TiO2 nanoparticles with enhanced photocatalytic efficiency: artificial neural network modelling

Pure anatase TiO2 nanoparticles with various Ag and Sn contents were synthesized by hydrothermal and sol-gel low-temperature methods. Structural and morphological characterizations of synthesized nanoparticles were performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and N2 adsorption/desorption isotherm and brunauer-emmett-teller (BET) techniques. The effect of synthesis procedure on the crystalline structure, crystal size, surface area, pore size distribution and photocatalytic activity of synthesized samples were studied. The photocatalytic activity was tested vs. degradation of methylene blue (MB) under black light radiation. Ag/Sn-TiO2 nanoparticles synthesized by hydrothermal method showed higher photoactivity during the degradation of MB under black light irradiation because of being enhanced in the specific surface area, total pore volume, and its reduction in the crystallite size. An artificial neural network (ANN) comprising four input variables (mol% of dopant ions, photocatalyst dosage, initial dye concentration, and pH of the solution), eight neurons and an output variable (degradation efficiency %) was optimized, tested and validated for MB degradation by Ag/Sn-TiO2 nanoparticles synthesized via hydrothermal method. The results showed that the predicted data from the designed ANN model are in good agreement with the experimental data with a correlation coefficient (R2) of 0.979. A 98.9% photodegradation efficiency of MB was achieved by utilizing 0.07 mol% Ag and 0.03 mol% Sn co-doped TiO2 at pH = 12.

Ultra-trace (parts per million-ppm) W6+ dopant ions induced anatase to rutile transition (ART) of phase pure anatase TiO2 nanoparticles for highly efficient visible light-active photocatalytic degradation of organic pollutants

A series of novel photocatalysts were synthesized by incorporating tungsten (W6+) ions in to the lattice of pure anatase TiO2 nanoparticles with ultra-trace concentrations (ppm) such as 10 ppm, 50 ppm, 90 ppm and 120 ppm using a simple one-step hydrothermal method under identical conditions. X-ray diffraction (XRD) studies, revealed a spectacular structural phase transformation from anatase to rutile on doping and associated morphological changes are seen by scanning electron microscopy (SEM). The phase transformation is promoted with the increase of W concentration up to 50 ppm and inhibited thereafter. Microstructural lattice distortions due to the presence of W6+ ions are monitored by high-resolution transmission electron microscopy (HR-TEM). The valence band X-ray photoelectron spectra (XPS), Ultraviolet photoelectron spectra (UPS) and UV–Vis absorption studies confirm the reduction of band gap for W doped TiO2 mixed phase nanoparticles. The doping causes an enhanced visible light absorption. Room temperature photoluminescence (PL) spectroscopy ensures an oxygen vacancy mediated phase transformation. The photocatalytic performances of the W doped TiO2 catalysts are evaluated for the degradation of Rhodamine B (RhB), Methylene blue (MB) and Methyl orange (MO) aqueous solutions under visible-light irradiation. The efficiency of photocatalytic degradation of the dyes gradually increased with the content of W6+ ions (till 50 ppm) and then decreased which is consistent with the structural and optical studies. The control experiments, showed possible oxidative species, are hydroxyl (·OH-) and oxygen (·O2-) radicals while the earlier plays a dominant role. The resuability tests performed for five cycles demonstrate high stability and reusability of the photocatalysts. A possible synergistic mechanism based on the impurity energy levels of W6+ ions, oxygen vacancies and anatase-rutile heterojunction for the enhancement of the photocatalytic activity under visible-light irradiation is proposed.

Preparation of anatase TiO2 nanoparticles using low hydrothermal temperature for dye-sensitized solar cell

One device being developed as an alternative source of renewable energy by utilizing solar energy source is dye-sensitized solar cells (DSSC). This device works using simple photosynthetic-electrochemical principle in the molecular level. In this device, the inorganic oxide semiconductor of titanium dioxide (TiO2) has a great potential for the absorption of the photon energy from the solar energy source, especially in the form of TiO2 nanoparticle structure. This nanoparticle structure is expected to improve the performance of DSSC because the surface area to weight ratio of this nanostructures is very large. In this study, the synthesis of TiO2 nanoparticle from its precursors has been performed along with the fabrication of the DSSC device. Effort to improve the size of nanocrystalline anatase TiO2 was accomplished by low hydrothermal treatment at various temperatures whereas the crystallinity of the anatase phase in the structure was performed by calcination process. Characterization of the materials was performed using X-ray Diffraction (XRD) and scanning electron microscope (SEM), while the DSSC performance was examined through a high precision current versus voltage (I-V) curve analyzer. The results showed that pure anatase TiO2 nanoparticles could be obtained at low hydrothermal of 100, 125, and 150 °C followed by calcination at 450 °C. The best performance of photocurrent-voltage characteristic was given by TiO2 hydrothermally synthesized at 150 °C with power conversion efficiency (PCE) of 4.40 %, whereas the standard TiO2 nanoparticles has PCE only 4.02 %. This result is very promising in terms low temperature and thus low cost of anatase TiO2 semiconductor preparation for DSSC application.

Effect of a pulsed electric field on the synthesis of TiO2 and its photocatalytic performance under visible light irradiation

Pure anatase TiO2 nanoparticles were synthesized by sol-gel method under a pulsed electric field (PEF). The morphology and properties of the prepared materials were characterized by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy (TEM) and UV–vis absorption spectra. The surface area was also analyzed by BET method. Oxalic acid and formic acid were used as model pollutants, and the degradation performance of the TiO2 was examined using the as-prepared samples as photocatalysts. Enhanced photocatalytic activity under visible light irradiation was observed on the PEF-assisted synthesized TiO2. Higher photocatalytic efficiency was obtained with either higher pulse frequency (949Hz) and shorter treatment time (12min), or lower frequency (50Hz) and longer treatment time (24min).

Development of a photoelectrochemical sensor for detection of TBHQ antioxidant based on LiTCNE-TiO2 composite under visible LED light

In this work, a novel photoelectrochemical sensor for detection of tert-butylhydroquinone (TBHQ) based on anatase titanium dioxide (TiO2) nanoparticles sensitized with lithium tetracyanoethylenide (LiTCNE/TiO2) was developed. The LiTCNE/TiO2 photoelectrochemical sensor showed high anodic photocurrent to TBHQ under visible LED light irradiation in comparison to pure anatase TiO2 nanoparticles or pure LiTCNE. The LiTCNE/TiO2 composite shows a photocurrent to TBHQ about 28 times higher than that observed to TiO2 nanoparticles and 4-fold higher than that observed to LiTCNE modified electrode. The LiTCNE/TiO2 composite showed a low charge transfer resistance in comparison to their individual components. Under optimized conditions, the photoelectrochemical sensor shows a linear response range from 0.4 up to 500μmolL−1 with a sensitivity of 0.01μALμmol−1 and limit of detection of 100nmolL−1 for the detection of TBHQ. The photoelectrochemical sensor showed high photocurrent to TBHQ in comparison to photocurrent response to butylated hydroxyanisole (BHA) and butyl-hydroxytoluene (BHT). The present LiTCNE/TiO2 photoelectrochemical sensor was successfully applied to biodiesel samples, with recovery values between 96.8% and 98.2%. The results obtained were found to be similar to those obtained using the spectrophotometric method with agreement at 95% confidence level.

Photoelectroanalytical Sensor Based on TiO2 Nanoparticles/Copper Tetrasulfonated Phthalocyanine for Detection of Dopamine Exploiting Light Emitting Diode Irradiation

AbstractIn this manuscript, a novel photoelectroanalytical sensor for detection of dopamine based on anatase TiO2 nanoparticles sensitized with copper tetrasulfonated phthalocyanine (CuTsPc/TiO2) was developed. The CuTsPc/TiO2 photoelectroanalytical sensor shows high anodic photocurrent under visible light emitting diode irradiation in comparison to pure anatase TiO2 nanoparticles. The CuTsPc/TiO2 composite shows a photocurrent about 2.5‐fold higher than those of pure TiO2 nanoparticles or CuTsPc modified electrode. The CuTsPc/TiO2 composite shows a low charge transfer resistance in comparison to its individual components as well as the impedance circle radius decreases significantly under UV light illumination. Under optimized conditions, the photoelectroanalytical sensor shows a linear response range from 4 up to 810 µmol L−1 with a sensitivity of 3.0 nA L µmol−1 and limit of detection of 0.5 µmol L−1 for the detection of dopamine. The photoelectrochemical sensor shows high photocurrent to dopamine in comparison to foreign species such as ascorbic acid, uric acid, glucose, K+, Na+, and Cl−.

Organic-free Anatase TiO₂ Paste for Efficient Plastic Dye-Sensitized Solar Cells and Low Temperature Processed Perovskite Solar Cells.

Recently, the synthesis of fine TiO2 paste with organic-free binder emerged as an indispensable technique for plastic photovoltaics due to the low temperature processing requirement. In this study, pure anatase TiO2 nanoparticles and organic-free TiO2-sol were successfully synthesized individually in organic-free solution. By mixing the pure anatase TiO2 with the newly developed TiO2-sol binder, mechanically robust and well-interconnected TiO2 films were prepared via UV-irradiation at low temperature for applications in plastic dye-sensitized solar cells (p-DSSCs). The structural, electrical, and photovoltaic properties of the films as well as the devices were investigated by various techniques. The dye-loading amount of the obtained film is 2.6 times that of the P25 electrodes. As revealed by electrochemical impedance spectroscopy results, the film derived from the as-prepared anatase TiO2 paste (A-TiO2) exhibits much smaller charge transport resistance and lower electron recombination rate than the P25 film, while the introduction of TiO2-sol into the paste can further remarkably decrease the resistance of the produced film (AS-TiO2). The p-DSSCs employing AS-TiO2 photoanode yield a high efficiency up to 7.51%, which is 86% higher than the P25 reference cells and also 31% higher than the A-TiO2 cell. As a proof of concept, the newly developed AS-TiO2 paste was also applied to low temperature processed perovskite solar cells (PSCs), and a promising high efficiency up to 9.95% was achieved.

Enhanced potocatalytic activity of Pt decorated TiO2 nanoparticles

Pt decorated TiO2 (Pt@TiO2) nanoparticles were synthesised via the sol–gel approach and subsequent thermal decomposition of chloroplatinic acid. Characterisations with scanning electron microscopy and X-ray diffraction showed that the anatase titanium oxide (TiO2) nanoparticles were around 30 nm in diameter. The photocatalytic activities of Pt@TiO2 were investigated by measurement the degradation of methyl orange (MO) solution under ultraviolet light irradiation, the results indicated that the Pt@TiO2 nanoparticles exhibited a markedly enhanced photocatalytic activity in the degradation of MO when compared to pure anatase TiO2 nanoparticles. The improved photocatalytic activity is interpreted in terms of the formation of metal-semiconductor junction at the interface of Pt/TiO2, which is favour of the carrier separation upon photoexcitation. Our results provide an approach to prepare highly efficient photocatalyst to degrade organic pollutants in water.