Commercial TiO2 Nanoparticles Research Articles

Synthesis of a TiO2/zeolite composite: Evaluation of adsorption-photodegradation synergy for the removal of Malachite Green

Preparing by a simple method a versatile and sustainable material that can simultaneously perform effectively as an adsorbent/photocatalyst is a real challenge in wastewater treatment technology. In this work, a composite with 10% (wt%) TiO2 nanoparticles supported on zeolite (TiO2-Zeo) was synthesized by a facile-solid-state dispersion method, and characterized for their physicochemical, phase structure, microstructure, and optical properties. Characterization findings, showed that, for TiO2-Zeo catalyst, the zeolitic matrix preserved its initial structure without any alteration, while its gap energy of 3.23 eV was similar to that of the starting TiO2 material, showing that TiO2 nanoparticles were simply deposited on the surface of the zeolite support. TiO2-Zeo photocatalyst, as well as commercial TiO2 nanoparticles, tested here as a photocatalyst model in view of comparison, were used for the removal of Malachite Green dye (MG) from aqueous solution. The adsorption and photodegradation potential of the catalysts was evaluated under the same operating conditions. It was found that the adsorption kinetics for the two materials were relatively slow, and the pseudo-first-order model can describe accurately the adsorption kinetics data. The equilibrium states were reached after 140 min and 150 min for MG/TiO2-Zeo and MG/TiO2 systems. At 0.5 g.L-1 dose of TiO2-Zeo, the adsorption capacity of MG at equilibrium, and the removal efficiency obtained with 25 mg.L-1 and 35 mg.L-1 were 41.2 mg.g-1 (82.3%), and 46.9 mg.g-1 (65.6%), respectively. Whereas, after 240 min UV irradiation, the obtained values in synergistic adsorption-photodegradation dye removal were superior, namely 47.4 mg.g-1 (92.7%) and 63.6 mg.g-1 (90.2%), respectively. On the other hand, within the range of operating conditions considered, the overall kinetic rate of synergistic adsorption-photodegradation was also simulated using the modified Elovich heterogeneous kinetic model in the two following scenarios: for strong and weak adsorption. Based on the goodness-of-fit criteria values obtained with the two used catalysts, the model appeared globally very consistent with kinetic data in both cases, with a perfect agreement in the strong adsorption case.

Self-Cleaning Highly Porous TiO2 Coating Designed by Swelling-Assisted Sequential Infiltration Synthesis (SIS) of a Block Copolymer Template.

Photocatalytic self-cleaning coatings with a high surface area are important for a wide range of applications, including optical coatings, solar panels, mirrors, etc. Here, we designed a highly porous TiO2 coating with photoinduced self-cleaning characteristics and very high hydrophilicity. This was achieved using the swelling-assisted sequential infiltration synthesis (SIS) of a block copolymer (BCP) template, which was followed by polymer removal via oxidative thermal annealing. The quartz crystal microbalance (QCM) was employed to optimize the infiltration process by estimating the mass of material infiltrated into the polymer template as a function of the number of SIS cycles. This adopted swelling-assisted SIS approach resulted in a smooth uniform TiO2 film with an interconnected network of pores. The synthesized film exhibited good crystallinity in the anatase phase. The resulting nanoporous TiO2 coatings were tested for their functional characteristics. Exposure to UV irradiation for 1 h induced an improvement in the hydrophilicity of coatings with wetting angle reducing to unmeasurable values upon contact with water droplets. Furthermore, their self-cleaning characteristics were tested by measuring the photocatalytic degradation of methylene blue (MB). The synthesized porous TiO2 nanostructures displayed promising photocatalytic activity, demonstrating the degradation of approximately 92% of MB after 180 min under ultraviolet (UV) light irradiation. Thus, the level of performance was comparable to the photoactivity of commercial anatase TiO2 nanoparticles of the same quantity. Our results highlight a new robust approach for designing hydrophilic self-cleaning coatings with controlled porosity and composition.

Photocatalytic Activity and Self-Cleaning Effect of Coating Mortars with TiO2 Added: Practical Cases in Warm Sub-Humid Climates.

In this study, the photocatalytic activity of coating mortars with synthetized and commercial TiO2 nanoparticles added has been evaluated at 2, 3 and 5% by weight of cement by calculating the degradation efficiency of methyl orange and red wine dyes exposed to both visible-light and UV radiation; also, the self-cleaning effect of coatings exposed to weather conditions (warm sub-humid climate) was assessed. TiO2 nanoparticles were synthesized via the sol-gel method to a low synthesis temperature and characterized via X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The results show synthesized TiO2 particles in anatase phase with a crystallite size of 14.69 nm, and hemispherical particles with sizes of submicron order. The addition percentage with the best performance in the coating mortars was 3%, with both commercial and synthesized TiO2; however, coating mortars with synthesized TiO2 exhibited the highest degradation efficiency for both dyes when they were exposed to visible light, while mortars with commercial TiO2 exhibited the highest degradation efficiency when exposed to UV radiation. In addition, in coating mortars with synthesized TiO2, the self-cleaning effect was evident from the beginning of exposure to weather, reaching the largest dye-free surface at the end of exposure. The compressive strength increased significantly in mortars with TiO2 addition.

Superior single-atom Pt/TiO2 mesoporous microspheres via microdrops-confined pyrolysis/deposition for low-temperature CO oxidation

This work demonstrate a polymer micelle-induced mesoporous single-atom Pt1/TiO2 microspheres with a mixed mother solution of triblock copolymer (Pluronic F127), H2PtCl6 and tetrabutyl titanate (TBT). The specific surface area and pore volume of mesoporous single-atom Pt1/TiO2 microspheres reach 179 m2/g and 0.39 cm3/g, respectively. The synthesis reaction is spatially confined in microdrops via aerosol spray. The obtained catalysts present superior activity for CO oxidation at low temperature. Typically, T100 (Temperature required to reach 100% conversion) of CO conversion (1.0% CO + 1.0% O2) is achieved at 120 °C with 0.5 at% Pt1/TiO2 catalysts, 50–60 °C lower than that with the same Pt loaded non-mesoporous catalysts from conventional photo-deposition and immersion-deposition of Pt on commercial TiO2 nanoparticles. Thus, this work paves a way to access efficient single-atom catalysts for CO oxidation.

Controlled electrodeposition of brookite TiO2 for photoelectroanalysis at printed carbon electrodes

TiO2-based photoelectrochemical (PEC) (bio)sensors have high photoactivity, chemical stability, and biocompatibility. However, their performance depends on multiple factors, including deposition method, morphology, and interaction with the target analyte. Herein, we describe a PEC platform based on TiO2 electrodeposition directly onto printed carbon electrodes (without heat treatment), designed for point-of-care (POC) applications. Brookite TiO2 nanocrystals were synthesized via electrodeposition in an acidic solution containing TiCl3, and parameters such as pH and temperature were optimized to improve photoelectrocatalytic activity. Photoelectrooxidation of ascorbic acid (AA) with electrodes prepared under optimal conditions (pH 2.5, 80 °C) had 10.5 times higher photocurrents than electrodes modified with commercial TiO2 nanoparticles via drop casting. The resulting sensor was highly sensitive and selective for AA, with a linear range from 10 to 1000 µM and a limit of detection of 3.25 µM (S/N = 3). Since brookite TiO2 electrodeposition does not require thermal treatment, printed carbon electrodes on polymer substrates can be used in producing miniaturized devices for sensitive, selective PEC (bio)sensors.

Acetone sensing characteristics of TiO2-LaFeO3 nanocomposites

To enhance the acetone sensing capabilities of LaFeO3 nanoparticles for practical applications in breath analysis, commercial n-type rutile TiO2 nanoparticles were utilized as additives and directly mixed with LaFeO3 nanoparticles synthesized via a sol–gel method. The obtained TiO2-LaFeO3 nanocomposites were characterized by XRD, SEM, BET, and XPS. Compared to pure LaFeO3 nanoparticles, the resulting TiO2-LaFeO3 nanocomposites exhibited higher surface reactivity, as evidenced by their larger specific surface areas and higher oxygen vacancy contents. The introduction of TiO2 also facilitated the formation of p-n heterojunctions, which enhanced the regulation of acetone molecules on internal carrier conduction within the nanocomposites. Therefore, the TiO2-LaFeO3 nanocomposites demonstrated improved acetone sensing performance, including higher vapor response values, selectivity, and faster response/recovery speeds. Among the series of nanocomposites, those with an addition of 10 wt% TiO2 exhibited the highest vapor response value (37.3 to 100 ppm) and the greatest selectivity against methanol and ethylene glycol at the prime operating temperature of 144 °C.

Direct synthesis of hydrogen fluoride-free multilayered Ti3C2/TiO2 composite and its applications in photocatalysis

Ti3C2/TiO2 hybrids are environment-friendly and exhibit excellent photocatalytic and hydrogen-generating power characteristics. Herein, a novel single-step method is proposed for fabricating multilayer structures in which TiO2, generated from (NH4)2TiF6, wraps the Ti3C2 MXene by etching Ti3AlC2 with (NH4)2TiF6. The optimal reaction conditions for the etching of Ti3AlC2 with (NH4)2TiF6 were systematically studied. The phase composition, morphology, and photophysical properties of the Ti3C2/TiO2 hybrids were investigated using X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and UV–vis spectrophotometry. The thermal stability of the hybrids was investigated using thermogravimetric and differential thermal analyses. Along with the formation of Ti3C2 MXene, Ti3AlC2 reacted with (NH4)2TiF6 at 60 °C for 24 h to form hybrids surrounded by NH4TiOF3 crystals. Subsequent reactions of these hybrids with H3BO3 resulted in the conversion of NH4TiOF3 crystals into TiO2 and eventually into Ti3C2/TiO2 hybrids. Furthermore, the photocatalytic activity of the Ti3C2/TiO2 hybrids was measured by monitoring the photodegradation of methylene blue under ultraviolet light, which showed that the photocatalytic activity of the Ti3C2/TiO2 hybrids was higher than that of the commercial anatase TiO2 nanoparticles.

Voltammetric determination of arbutin using carbon paste electrode modified with low crystalline home-prepared rutile TiO2 nanoparticles

Carbon paste electrodes (CPE) were modified with commercial (Degussa P25, BDH, Merck, Hombikat) and home-prepared rutile TiO2 (HPRT) nanoparticles for the electrochemical determination of arbutin (AR) by differential pulse voltammetry technique. The optimization experiments were performed in Britton-Robinson buffer at pH 2–7 using modified CPEs. 15%-HPRT(25 °C)/CPE and 15%-HPRT(400 °C)/CPE showed the highest current values among all electrodes at optimum pH, accumulation potential, and duration time values (pH 2, 0.70V and 45 s); consequently, the electrodes were characterized by SEM-EDX, while TiO2 samples by BET and XRD techniques. Electrochemical surface areas of the electrodes were also determined. HPRT(25 °C) and HPRT(400 °C) samples have the lowest crystallinity which is the reason for their high performance. The linear working range of 15%-HPRT(25 °C)/CPE and 15%-HPRT(400 °C)/CPE electrodes was 0.5–120 μM. The detection limit for these electrodes was 32 and 40 nM, and the quantification limit was 107 and 135 nM, respectively. Interference studies, repeatability, reproducibility and the stability of the electrodes were examined, and a reaction mechanism for AR oxidation was proposed and promising results were obtained. The AR determination in a real sample, in the anti-blemish skin serum, was also performed successfully.

Efficient dye degradation and concurrent electricity generation using silver bromide-embedded titanium dioxide

Removal of dissolved organic matters, like dyes, from industrial wastewater is challenging due to complexity with their exceptional stability and ability to pass through filters. In this study, we have synthesized silver bromide nanoparticles-embedded polycrystalline titania (AgBr-x/TiO2) by a simple one-pot synthesis route. The degradation of reactive green dye with simultaneous electrical energy generation is demonstrated with developed AgBr-x/TiO2 photo-anodes. The structural and morphological analyses reveal that the fine AgBr nanocrystals are embedded in submicron sized TiO2 particles. The composite particles with various AgBr compositions were synthesized. The embedded-structure gives better heterojunction between AgBr and TiO2, and facilitates the transfer of photogenerated electrons compared to simple mixture. The visible light absorption of the composite was monotonically increased with AgBr composition. A flat optical absorption profile was obtained at 50% AgBr composition. The developed AgBr-x/TiO2 photo-anode shows the initial rate of dye degradation four-fold higher than the commercial grade TiO2 nanoparticles, where the generated power was 2.6 times high. The degradation by-product contains water-insoluble sludge which has the similar optical absorption profile of feed water. It is observed that the dye removal is predominantly through decolourization and coagulation. Conclusively, the developed AgBr-x/TiO2 photo-anode could realize a self-sustained wastewater treatment unit where the required electricity is produced by dye degradation.

Enhancement of photocatalytic activity by Z-scheme heterojunction of CaTiO3 nanocuboids and P25

Photocatalysis is an interesting approach to convert solar energy into chemical energy. To achieve efficient energy conversion, a mixed photocatalyst of CaTiO3 nanocuboids and commercial anatase TiO2 nanoparticles P25 were used. This is due to the formation of a heterostructure between CaTiO3 nanocuboids and P25, which enhances the photocatalytic activity. Experiments on the degradation of methylene blue under black light irradiation showed that the hybrid photocatalyst exhibited 11 % higher degradation performance than P25 only. Moreover, a photocatalyst film was formed on FTO glass and used as an electrode for a photoelectrochemical cell (PEC). This is the first time CaTiO3 nanocuboids were mixed with P25 and used as electrodes of PECs.

Cellulose mineralization with in-situ synthesized amorphous titanium dioxide for enhanced adsorption and auto-accelerating photocatalysis on water pollutant

It is a daunting task to balance the catalyst stability and exposure of active site of highly efficient immobilizing photocatalyst system for wastewater treatment. In this study, an in-situ mineralization method based on homogeneous system was proposed to directly construct amorphous TiO2 into cellulose hydrogel network as the crosslinker for efficiently and safely processing wastewater. This unique structure not only endowed TiO2/cellulose microsphere (TMS) with an adsorption capacity of 91.7 mg/g on methylene blue, which was approximately 14 times to cellulose microsphere containing commercial TiO2 nanoparticles, but also made TMS reusable due to its pH sensitive adsorption capacity. More interestingly, TMS exhibited an auto-accelerating process in decomposing Rhodamine B where the degradation intermediate could act as the receptor of photo-regenerated holes to improve photocatalytical activity. In further cyclic test, the degradation rate constant of intermediate-adsorbed TMS was up to 0.02 mg−1min−1. Moreover, the intermediate-adsorbed TMS obtained visible light responsive property, including a removal ratio of 86.3 % against tetracycline (c0 = 20 mg/L) in 120 min. This in-situ cellulose mineralization provides a new sight into the design of hydrogel immobilized catalyst system with high dispersion and active site exposure for efficient and safe water treatment.

Fretting behavior of piston ring-cylinder liner components of a diesel engine running on TiO2 nanolubricant

This experimental research presents the friction and wear characteristics of piston ring-cylinder liner component of a diesel engine running on commercial engine oil (5W-30) and TiO2 nanoparticle (~20 nm, ≥99.5% trace metals basis) incorporated 5W-30 engine oil (nanolubricant) to observe the performance parameters in terms of mean effective pressures and smoke emissions. Dynamic light scattering was utilized to examine the nanoparticle dispersion in the lubricant. Thermo-gravimetric analysis on nanoparticles was conducted to examine the thermal endurance during abrasion tests. The samples directly cut from the spare piston ring of the test engine underwent severe friction and wear tests via linear friction module. Coefficient of friction was considered as comparison param-eter to understand the tribological behavior of friction pairs submerged in two different lubricants. Scanning electron microscopy analysis was conducted to observe morphology of the nanoparticle and to analyze the surface structure of the samples before and after the abrasion tests. Atomic force microscopy analysis was done to obtain the 3D images of the worn surfaces and to make a comprehensive comparison of tribological performance between engine lubricant and nanolubricant. The results depicted that, TiO2 is effective in reducing coefficient of friction by an average of 10.37% and wear rate by 33.58% as well as improving brake mean effective pressure by an average of 4.95% and reducing friction mean effective pressure by an average of 9.34% when compared to those of the engine oil. In parallel with reduced friction, TiO2 incorporation in engine oil yielded an average reduction of 9.11% in smoke opacity. The experiments suggest promising results in terms of utilization of low friction, fuel efficient and environmental friendly internal combustion engines fulfilling strict emission regulations.

In-Situ Functionalization of Cotton Fabric by TiO2: The Influence of Application Routes

The desirable chemical, physical, electronic, and optical properties of TiO2, as well as its high availability, non-toxicity, and low price, make it very popular in the modern functional textile industry. Here, TiO2 from titanium tetraisopropoxide (TTIP) precursors at concentrations of 2, 4, and 6% and commercial TiO2 nanoparticles (NPs) in dispersion form were applied to cotton textiles using low-temperature application methods (i.e., sol–gel pad–dry–cure, pad–hydrothermal, and exhaustion–hydrothermal methods) to provide a systematic study of the influence of low-temperature application processes and TIIP concentration and on the overall properties of TiO2-functionalized textile materials. The treated cotton fabric samples were characterized using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction spectroscopy (XRD) to determine their surface morphology, chemical composition, and crystal structure, while the optical properties of the synthesized TiO2 were determined using the absorption method and Tauc plotting. Afterwards, corresponding UV protection properties and photocatalytic self-cleaning activity were evaluated. In contrast to commercial TiO2, a relatively thin TiO2 deposition with an amorphous structure and a blue-shifted band gap between 3.18 and 3.28 eV was formed when applied at low temperatures. A sol with a TIIP concentrations of 2 and 4% applied using the exhaustion–hydrothermal and sol–gel dry-cure method, respectively, proved to be optimal. Both applied sol concentrations provided good UV protection and excellent photocatalytic performance, which exceeded that of commercial TiO2, even though the Ti contents in the samples were two- to three-times lower and the synthesized TiO2 exhibited an amorphous structure.

Comparative Study of Platinum Nanoparticle Deposition on TiO2/BP and SnO2/BP Nanocomposites for the Oxygen Reduction Reaction

Proton exchange membrane fuel cells (PEMFCs), in their low temperature (LT, 60-80 °C) and high temperature (HT, 120-200 °C) variants, can be used for broad applications in the automotive and stationary sector. However, the most commonly used PEMFC catalyst, consisting of platinum nanoparticles supported on a carbon black, suffers from degradation under the relevant working conditions e.g. low pH environment and potentials in the range of 0.6-1.5 V vs. RHE. These processes include carbon corrosion, Pt dissolution and detachment as well as agglomeration.[1-3] Especially, carbon corrosion leads to an increase of the support hydrophilicity, decreased conductivity and loss of Pt particles resulting in an overall performance loss of PEMFCs.[1] Different studies already reported a positive effect of metal oxide-carbon composite supports using TiO2-Vulcan®XC-72[1,2], SnO2-Vulcan®XC-72[2,3], or fluorine-doped SnO2 on reduced graphene oxide[4] on the carbon and Pt stability. Moreover, Ruiz Camacho et al. showed higher ORR activity for Pt/TiO2-Vulcan and Pt/SnO2-Vulcan compared to Pt/C and a lower potential for CO oxidation during stripping experiments.[2] This can be beneficial for PEMFC operation with reformate.To further push the activity and stability of Pt/metal oxide-carbon catalysts homogeneous distribution of metal oxide and Pt nanoparticles is necessary. In contrast to previous studies, that uses low surface area Vulcan®XC-72[1-3] the implementation of high surface area Black Pearls (BPs) can enable more homogenous distribution of metal oxides and Pt nanoparticles which can positively impact the activity. In this comparative study, Pt/metal oxide-carbon catalysts using SnO2 and TiO2 nanoparticles on BPs are analyzed towards their physical properties and electrochemical ORR activity and stability. Metal oxide/carbon composites were fabricated by deposition of 50 wt.% commercial SnO2 or TiO2 nanoparticles on Black Pearls® 2000. Thermogravimetric analysis (TGA) reveals the successful deposition of metal oxides TiO2 (41 wt.%) and SnO2 (47 wt.%) on BP. Next, deposition of 40 wt.% Pt nanoparticles with diameters between 1-2 nm on the metal oxide-BP composites is done. Transmission electron microscope (TEM) images display successful deposition of Pt with uniform distribution of Pt for both composite catalysts in Figure 1 a) and c). The elemental mapping of Pt and Sn or Ti, using scanning TEM with energy dispersive spectroscopy (EDS) for analysis of the interaction between metal oxide displays homogenous distribution of Pt over the metal oxide-BP supports (Fig 1, b), d)). In the case of Pt/SnO2-BP also uniform Sn distribution is observed whereas for Pt/TiO2-BP partial agglomeration of TiO2 is found.Further analysis of Pt and metal oxides will be given using high resolution-TEM for analysis of lattice distance and ICP-MS for determination of Pt content. Moreover, electrochemical characterization using rotating ring disc electrode will be carried out for comparison of ORR activity and selectivity. Furthermore, an accelerated stress test including 5000 cycles in the range of 0.6-1.5 V vs. RHE in N2-saturated 0.1 mol L-1 HClO4 is applied to analyze the overall catalyst stability. The results will reveal the most promising candidate in terms of activity and stability for future application in HT-PEM half- and single-cell setups.

Enhancement in Photocatalytic Efficiency of Commercial TiO2 Nanoparticles by Calcination: A Case of Doxycycline Removal

In this study, the pure and calcined forms of Degussa TiO2 were applied for photocatalytic removal of doxycycline - a broad-spectrum tetracycline antibiotic. The calcination of TiO2 at 500 °C enhanced the photocatalytic efficiency of the TiO2 under optimal operational conditions of 5 ppm of doxycycline, 0.25 g/L of TiO2, pH 6.5, 120 min, and room temperature. In addition, the changes in morphology, crystal structure, and optical properties of the materials before and after calcination were observed by scanning electron microscopy, X-ray diffraction, and UV-Visible spectroscopy. The reaction kinetics of the doxycycline removal was also investigated based on the Langmuir-Hinshelwood model with a correlation coefficient R2 of >80%. Results showed that the photocatalytic ability of TiO2 is stable and enhanced after being calcined at a suitable temperature of 500 °C. This opens up the potential application of TiO2 in the treatment of emerging organic pollutants in water. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Synthesis of mesoporous TiO2‐MCM‐41 photocatalyst for quinolone antibiotics removal from aqueous solution

AbstractIn this paper, a significant aspect of using TiO2 photocatalyst immobilized on MCM‐41 mesoporous material by sol‐gel method for ciprofloxacin (CIP) and norfloxacin (NOR) antibiotics removals was studied. The structure and morphology of the materials were evaluated by X‐ray diffraction (XRD), energy‐dispersive X‐ray spectrometer analysis combined with field‐emission scanning electron microscopy (FESEM‐EDX), fourier transform infrared spectroscopy (FTIR), transmission electron microscopes (TEM), and N2 adsorption‐desorption isotherms (BET) methods. Characterization results indicated that the presence of TiO2 anatase phase with relatively high TiO2 content (up to 60 % by weight) did not destroy the mesopore system of MCM‐41 substrate. Photoactivity of the catalyst was tested through the degradation of two quinolone antibiotics, CIP, and NOR. In this study, the factors affecting the decomposition efficiency of the above pharmaceutical antibiotics such as, the immobilized content of TiO2 and the concentrations of antibiotics as and catalyst were also evaluated using Langmuir‐Hinshelwood (LH) model. The TiO2 immobilized on MCM‐41 material showed a better ability to remove CIP and NOR antibiotics than the commercial TiO2 nanoparticles (P25) due to the high dispersion of active sites on an MCM‐41 high specific surface area mesoporous substrate.

Solar-driven Photocatalyzed Hydrogen Production from Water cleavage: Evaluation and Process Life Cycle Assessment

Hydrogen is proper chemical storage for solar energy and is considered a green and non-pollution energy. The feasibility of solar-driven hydrogen generation from water cleavage is investigated using commercial TiO2 nanoparticles, and the process of life cycle assessment (LCA) is estimated. TiO2 is fully characterized. The results confirm the efficacy of TiO2 for solar-driven photocatalytic water splitting with the same production rate of H2. The maximum calculated photocatalytic rate of hydrogen over PC was 4.76 µmole/h under sunlight. As well the rate of produced H2 is dependent PC dose. There is a signification corelation between Kapp with PC dose with r2 of 0.96. Reaction rate constant for hydrogen production is significantly dependent concentration of TiO2. The outcome emphasized the practical application of solar-driven, cost-effective technology for production renewable energy. Also, LCA study of solar-driven H2 production is showed that higher carbon dioxide and as well as global warming potential with lower climatic change impact originated from operation of system.

Degradation of pollutants in solid and gas states using waterborne acrylic nanocomposite paints

In this study, TiO2/SiO2 nanoparticles were synthesized using titanium tetraisopropoxide and tetraethoxysilane in a two-step sol-gel route. FTIR, XRD, UV–Vis, and XPS techniques were used to characterize the synthesized nanoparticles. Fe-SEM was utilized to evaluate the particle size of the synthesized nanoparticles (30.35 ± 4.52 nm). Photo-degradation of rhodamine B (Rh.B) as a solid pollutant model and NO2 as a typical gaseous pollutant was assessed on the surface of the waterborne-acrylic coatings containing TiO2/SiO2 nanoparticles (TSC.La) under direct sunlight irradiation and accelerated weathering conditions and the results were compared with a P25–TiO2 nanoparticle (UT.La) embedded coating samples.To evaluate the degradation of Rh.B, color coordinates (L*a*b*) were measured, while the degradation of NO2 was determined in a batch-designed photocatalytic reactor by measuring the reduction in gas concentration. For the TSC.La-sample exposed to accelerated weathering conditions, the changes in a* parameter (Δa*) were about 60%, which was 44 times greater than the changes in this parameter for the sample exposed to sunlight. The surface morphology of the exposed samples to the accelerated weathering conditions was evaluated using AFM and BET measurements. The AFM results indicated that TiO2/SiO2 nanoparticles lead to less surface degradation of the paints compared to the commercial TiO2 nanoparticles. NO2 concentration decreased steadily in the reactor from 30 to 27 ppm, at an RH%<20 in the presence of UT.La or TSC.La-samples after 45 and 60 min of UV exposure. This reduction in gas concentration is equivalent to photocatalytic power of 6 and 8 mLm−2h−1, for the two samples, respectively.

Pt-Modified Interfacial Engineering for Enhanced Photocatalytic Performance of 3D Ordered Macroporous TiO2

Narrowing the band gap and increasing the photodegradation efficiency of TiO2-based photocatalysts are very important for their wide application in environment-related fields such as photocatalytic degradation of toxic pollutants in wastewater. Herein, a three-dimensionally ordered macroporous Pt-loaded TiO2 photocatalyst (3DOM Pt/TiO2) has been successfully synthesized using a facile colloidal crystal-template method. The resultant composite combines several morphological/structural advantages, including uniform 3D ordered macroporous skeletons, high crystallinity, large porosity and an internal electric field formed at Pt/TiO2 interfaces. These unique features enable the 3DOM Pt/TiO2 to possess a large surface for photocatalytic reactions and fast diffusion for mass transfer of reactants as well as efficient suppression of recombination for photogenerated electron-hole pairs in TiO2. Thus, the 3DOM Pt/TiO2 exhibits significantly enhanced photocatalytic activity. Typically, 88% of RhB can be degraded over the 3DOM Pt/TiO2 photocatalyst under visible light irradiation (λ ≥ 420 nm) within 100 min, much higher than that of the commercial TiO2 nanoparticles (only 37%). The underlying mechanism for the enhanced photocatalytic activity of 3DOM Pt/TiO2 has been further analyzed based on energy band theory and ascribed to the formation of Schottky-type Pt/TiO2 junctions. The proposed method herein can provide new references for further improving the photocatalytic efficiency of other photocatalysts via rational structural/morphological engineering.

Epoxy Composites Reinforced with ZnO from Waste Alkaline Batteries.

The zinc alkaline battery is one of the most popular sources of portable electrical energy, with more than 300,000 tons being consumed per year. Accordingly, it is critical to recycle its components. In this work, we propose the use of zinc oxide (ZnO) microparticles recovered from worn-out batteries as fillers of epoxy resins. These nanocomposites can be used as protective coatings or pigments and as structural composites with high thermal stability. The addition of ceramic nanofillers, such as ZnO or/and TiO2, could enhance the thermal and mechanical properties, and the hardness and hydrophobicity, of the epoxy resins, depending on several factors. Accordingly, different nanocomposites reinforced with recycled ZnO and commercial ZnO and TiO2 nanoparticles have been manufactured with different nanofiller contents. In addition to the different ceramic oxides, the morphology and size of fillers are different. Recycled ZnO are“desert roses” such as microparticles, commercial ZnO are rectangular parallelepipeds nanoparticles, and commercial TiO2 are smaller spherical nanoparticles. The addition of ceramic fillers produces a small increase of the glass transition temperature (<2%), together with an enhancement of the barrier effect of the epoxy resin, reducing the water diffusion coefficient (<21%), although the maximum water uptake remains constant. The nanocomposite water absorption is fully reversible by subsequent thermal treatment, recovering its initial thermomechanical behavior. The water angle contact (WCA) also increases (~12%) with the presence of ceramic particles, although the highest hydrophobicity (35%) is obtained when the epoxy resin reinforced with recycled flowerlike ZnO microparticles is etched with acid stearic and acetic acid, inducing the corrosion of the ZnO on the surface and therefore the increment of the surface roughness. The presence of desert rose ZnO particles enhances the de lotus effect.