P25 TiO2 Nanoparticles Research Articles

Quantifying Titanium Exposure in Lung Tissues: A Novel Laser‐Induced Breakdown Spectroscopy Elemental Imaging‐Based Analytical Framework for Biomedical Applications

Occupational and environmental exposures, particularly those related to urban and suburban atmospheres, are increasingly linked to a range of pulmonary diseases. While diagnostic methods for these diseases are well established, analytical tools for assessing elemental contamination in lung tissue remain underutilized. This study introduces a novel framework based on laser‐induced breakdown spectroscopy (LIBS) for the in situ quantification of elemental titanium (Ti) in lung tissues from both animal models and human specimens. Rigorous validation is conducted using animal models exposed to TiO2 P25 nanoparticles and a comparative analysis with inductively coupled plasma mass spectrometry. The novel quantitative metric demonstrates robust correlation with elemental concentrations, expanding LIBS utility to volumetric organ analysis. This validated methodology is subsequently applied to human lung specimens preserved in paraffin. The research holds significant promise as a diagnostic tool for assessing exposure levels to environmental or occupational hazards, thereby offering valuable contributions to the fields of toxicology and respiratory medicine.

A H2O2 Oxidation Approach to Ti3C2/TiO2 for Efficient Photocatalytic Removal of Distinct Organic Pollutants in Water.

To develop versatile photocatalysts for efficient degradation of distinct organic pollutants in water is a continuous pursuit in environment remediation. Herein, we directly oxidize Ti3C2 MXene with hydrogen peroxide to produce C-doped anatase TiO2 nanowires with aggregates maintaining a layered architecture of the MXene. The Ti3C2 MXene provides a titanium source for TiO2, a carbon source for in situ C-doping, and templates for nanowire aggregates. Under UV light illumination, the optimized Ti3C2/TiO2 exhibits a reaction rate constant 1.5 times that of the benchmark P25 TiO2 nanoparticles, toward photocatalytic degradations of trace phenol in water. The mechanism study suggests that photogenerated holes play key roles on the phenol degradation, either directly oxidizing phenol molecules or in an indirect way through oxidizing first the surface hydroxyl groups. The unreacted Ti3C2 MXene, although with trace amounts, is supposed to facilitate electron transfer, which inhibits charge recombination. The unique nanostructure of layered aggregates of nanowires, abundant surface oxygen vacancies arising from the carbon doping, and probably the Ti3C2/TiO2 heterojunction guarantee the high photocatalytic efficiency toward removals of organic pollutants in water. The photocatalyst also exhibits an activity superior to, or at least comparable to, the benchmark P25 TiO2 toward photodegradations for typical persistent organic pollutants of phenol, dye molecule of rhodamine B, antibiotic of tetracycline, pharmaceutical wastewater of ofloxacin, and pesticide of N,N-dimethylformamide, when evaluated in total organic carbon removal.

Enhanced photocatalytic removal of bromate in drinking water by Au/TiO2 under ultraviolet light.

The photo-reduction of bromate (BrO3 -) has attracted much attention due to the carcinogenesis and genotoxicity of BrO3 - in drinking water. In this study, a heterojunction photocatalyst was developed by depositing Au nanoparticles (NPs) onto P25 TiO2 NPs through a one-pot, solvent-thermal process. Due to the unique properties of Au, the Au NPs deposited on the TiO2 surface created a Schottky barrier between the metal and the semiconductor, leading to an effective separation of photo-generated charge carriers as the Au nanoparticles served as electron sinks. The Au/TiO2 photocatalyst demonstrated efficient reduction of BrO3 - under UV light illumination without the need for sacrificial agents. The effect of different Au loading of Au/TiO2 was systematically investigated for its influence on the generation of electrons and the reduction ability of BrO3 -. The results indicate that the 1% Au/TiO2 catalyst exhibited a higher concentration of localized electrons, rendering it more effective in BrO3 - removal. The photocatalytic efficiency for BrO3 - reduction decreased upon the addition of K2S2O8 as an electron quencher, suggesting that the primary factor in this photo-reduction process was the availability of electrons. These findings hold promise for the potential application of the Au/TiO2 catalyst in the removal of BrO3 - from drinking water through photo-reduction.

What could be the low-temperature limit of atomic layer deposition of platinum using MeCpPtMe3 and oxygen?

We explore the low-temperature limit of atomic layer deposition of Pt using MeCpPtMe3 and O2. We reveal that by supplying a sufficiently high O2 exposure, highly dispersed and thermally stable Pt sub-nanometer clusters can be deposited onto the surface of P25 TiO2 nanoparticles even at room temperature by atmospheric-pressure ALD.

Optimisation, modelling and mechanism of photocatalytic degradation of sofosbuvir antiviral by TiO2 nanoparticles coupled with biological treatment

ABSTRACT The overarching objective of this research endeavour was to develop an integrated approach to the complete removal and breakdown of the antiviral compound sofosbuvir. To accomplish this, a two-fold strategy was employed, involving a heterogeneous photocatalysis process coupled with subsequent biological treatment. Leveraging the versatile TiO2-P25 nanoparticles, a meticulous optimisation was carried out using the Box-Behnken methodology, strategically considering the interplay of three pivotal independent variables: pH, initial molecule concentration, and catalyst concentration. This optimisation aimed not only to augment the degradation of sofosbuvir but also to enhance its COD removal. The complex influence of these factors was mathematically encapsulated in a second-order polynomial equation, offering valuable insights into the process dynamics. COD removal and optimal parameters for degradation were a pH of 6.8, a catalyst dosage of 1 g L−1, and an initial molecule concentration of 0.1 mM under a 125 W high-pressure mercury lamp. The efficiency of elimination for the degradation was 100% at 120 min and for the COD removal extinguished 99.44% at 6 h. Sofosbuvir has a rapid degradation, COD removal degree is lower, which means the presence of intermediate compounds more difficult to treat by photocatalysis. Thus, the viability of implementing a link between the nanoparticles TiO2-photocatalysis as a biodegradability improvement pretreatment with the biological process has been studied as an essential activity to enhance treatment efficiency while reducing energy use and treatment times. combination of photocatalysis with a biological treatment improves the treatment. The density functional theory (DFT) approach was applied to better understand the mechanism of sofosbuvir degradation and to examine the impact of different degradation sites. Mechanism Analysis of the photoproducts and photoproduct intermediates was identified by HPLC-MS. However, a 120 min BOD5/COD ratio (COD, chemical oxygen demand; BOD, biochemical oxygen demand) of ≥0.4 results from the degradation of sofosbuvir by TiO2.

Exceptional tribo-catalytic degradation of concentrated methyl orange and methylene blue solutions by DXN-RT30 TiO2 nanoparticles

As tribo-catalysis gains increasing attention to harness mechanical energy for environmental remediation, it is time to explore its application to those organic pollutants that have been challenging to degrade. In this study, four commercial metal oxide nanoparticles, BaTiO3, ZnO, P25 TiO2, and DXN-RT30 TiO2 nanoparticles, were stimulated through magnetic stirring to degrade 20 mg/L methyl orange (MO) and 30 mg/L methylene blue (MB) solutions. While all the other nanoparticles showed rather poor performance, DXN-RT30 TiO2 nanoparticles performed exceptionally well: With Teflon magnetic disks rotating at 400 rpm, 98.2% of MO and 100% of MB were degraded within 330 and 420 min, respectively. DXN-RT30 TiO2 nanoparticles demonstrated a unique absorption for MB molecules, yielding significantly different outcomes in active species trapping experiments between degradation of MO and MB solutions by DXN-RT30 TiO2. Complemented by electron paramagnetic resonance analysis, our findings suggest that for DXN-RT30 TiO2 nanoparticles under magnetic stirring, MO molecules are degraded by h+, ·OH, and e− in solution, while MB molecules are absorbed and degraded via h+ and e− on the surface of DXN-RT30 TiO2 nanoparticles. This study identifies DXN-RT30 TiO2 nanoparticles as a cost-effective, high-performance, and environmentally friendly tribo-catalyst for environmental remediation, stimulating further exploration for more excellent tribo-catalysts.

The comparative effects of visible light and UV-A radiation on the combined toxicity of P25 TiO2 nanoparticles and polystyrene microplastics on Chlorella sp.

The ubiquitous presence of TiO2 nanoparticles (nTiO2) and microplastics (MPs) in marine ecosystems has raised serious concerns about their combined impact on marine biota. This study investigated the combined toxic effect of nTiO2 (1 mg/L) and NH2 and COOH surface functionalized polystyrene MPs (PSMPs) (2.5 and 10 mg/L) on Chlorella sp. All the experiments were carried out under both visible light and UV-A radiation conditions to elucidate the impact of light on the combined toxicity of these pollutants. Growth inhibition results indicated that pristine nTiO2 exhibited a more toxic effect (38%) under UV-A radiation when compared to visible light conditions (27%). However, no significant change in the growth inhibitory effects of pristine PSMPs was observed between visible light and UVA radiation conditions. The combined pollutants (nTiO2 + 10 mg/L PSMPs) under UV-A radiation exhibited more growth inhibition (nTiO2 + NH2 PSMPs 66%; nTiO2 + COOH PSMPs 50%) than under visible light conditions (nTiO2 + NH2 PSMPs 55%; TiO2 + COOH PSMPs 44%). Independent action modeling indicated that the mixture of nTiO2 with PSMPs (10 mg/L) exhibited an additive effect on the algal growth inhibition under both the light conditions. The photoactive nTiO2 promoted increased production of reactive oxygen species under UV-A exposure, resulting in cellular damage, lipid peroxidation, and impaired photosynthesis. The effects were more pronounced in case of the mixtures where PSMPs added to the oxidative stress. The toxic effects of the binary mixtures of nTiO2 and PSMPs were further confirmed through the field emission electron microscopy, revealing specific morphological abnormalities. This study provides valuable insights into the potential risks associated with the combination of nTiO2 and MPs in marine environments, considering the influence of environmentally relevant light conditions and the test medium.

Effectiveness of Light Scattering Layer Using Mesoporous SiO2‐TiO2 Core‐Shell on Dye‐Sensitized Solar Cells

The photoanode of dye‐sensitized solar cells (DSSCs) was investigated. P25 TiO2 nanoparticles were used to fabricate the active layer, on which a light scattering layer was coated using SiO2‐TiO2 core‐shell particles. SiO2‐TiO2 core‐shell particles with and without mesoporous (MP) surface structure were fabricated and evaluated separately for the scattering layer. MP surface helped increase the surface area and the amount of adsorbed dye. As a result, the light absorption rate of the photoanode with the MP‐SiO2‐TiO2 scattering layer increased, leading to improving the DSSC performance by about 50%. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

Preparation of Titanium Dioxide Nanoparticles Films by Air-Compressed Spray Method for Supercapacitor Device

In this work, the titanium dioxide (TiO2) nanoparticle films were prepared from commercial Degussa P25-TiO2 nanoparticles by air-compressed spray. The properties of the prepared films were characterized by X-ray diffraction, FTIR, Raman spectroscopy, and scanning electron microscope, respectively. In addition, the prepared TiO2 film on a metal substrate (stainless steel, SS304) was used to fabricate the electrode of the electrochemical supercapacitor device. The electrochemical storage performance of the fabricated device was obtained by cyclic voltammetry measurement in aqueous 1 M Na2SO4 with an Ag/AgCl reference electrode (platinum as a counter electrode). The optimum specific capacitance of the fabricated device was found at 3.014 F/g at a scan rate of 50 mV/s.

Photocatalytic degradation of bisphenol A in aqueous solution using TiO2/clinoptilolite hybrid photocatalyst.

Photocatalytic degradation of bisphenol A (BPA) was investigated using commercial TiO2 P25 nanoparticles supported on natural zeolite clinoptilolite (Cli). Employing ultrasound assisted solid-state dispersion method hybrid photocatalyst containing 20 wt% of TiO2, marked TCli-20, was prepared. The structural, morphological and surface properties, and particle size distribution of TCli-20 were studied by X-ray powder diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, scanning electron microscopy with energy dispersive spectroscopy, atomic force microscopy, Brunner-Emmet-Teller method and laser diffraction. The results revealed a successful loading of TiO2 P25 nanoparticles on Cli surface and the preservation of both zeolitic structure and optical properties of TiO2. The influence of catalyst dose, pH value and the addition of hydrogen peroxide (H2O2) was evaluated. The optimal reaction conditions were 2g/L of catalyst at near-neutral conditions (pH = 6.4) for complete BPA (5mg/L) photodegradation after 180min of exposure to simulated solar light. The addition of H2O2 was beneficial for the degradation process and led to the removal of BPA after 120min of irradiation. BPA removal (60% for 180min of irradiation) was reduced when TCli-20 was tested in bottled drinking water due to the presence of bicarbonate ions which acted as scavengers for hydroxyl radicals. Even though the photocatalytic activity of TCli-20 decreased after several cycles of usage, 70% of BPA was still successfully degraded during the fourth cycle. The reusability study showed easy separation, stability and good photocatalytic ability of investigated cost-effective hybrid photocatalyst.

Simple two-step development of TiO2/Fe2O3 nanocomposite for oxygen evolution reaction (OER) and photo-bio active applications

The simultaneous incorporation of iron (III) oxide (Fe2O3) and titanium oxide (TiO2) forms a noteworthy composite for oxygen evolution reactions, photocatalytic, and antimicrobial applications. TiO2/Fe2O3 nanocomposite was deposited utilizing a patented, single-step altered pseudo-successive ionic layer adsorption and reaction (p-SILAR) process for the deposition of oxides, which was employed in this study to form Fe2O3 for the first time. The developed nanocomposite exhibits improved electrocatalytic water splitting, photocatalytic activity, and antimicrobial performance. Controlled deposition and heat treatment enable the formation of Fe2O3 and TiO2, as verified by SEM, EAM, and XPS analysis. Incorporation of Fe2O3 significantly enhances the photocatalytic activity of P25 TiO2 nanoparticles, demonstrated by the visible light dye degradation test. The nanocomposite degrades 58% of the Rhodamine B dye in 100 min, while pure TiO2 degrades only 26%. The NC also shows higher antibacterial activity against E. coli and S. aureus compared to pure TiO2. Water splitting performance is evaluated using Electro Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), and Tafel Slopes. The results show that TiO2/Fe2O3 NCs exhibit improved oxygen evolution reaction compared to pure TiO2.

Preparation of a new green magnetic Fe3O4 @TiO2-P25 photocatalyst for solar advanced oxidation processes in water

A novel green method has been investigated to obtain a magnetic recoverable photocatalyst. Fe3O4 particles formed in situ by aerial oxidative precipitation of aqueous Fe(II) in the presence of terephthalate were bonded to TiO2-P25 nanoparticles, giving rise to a coupled semiconductor heterostructure with superparamagnetic behavior at room temperature (Fe3O4 @TiO2-P25). The synthesis method is carried out in water at room temperature with almost full recovery and recycling of terephtalic acid. The prepared samples were fully characterized by XRD, TGA-DTA-MS, ATR-FTIR, WDXRF, TEM, SEM/EDX, N2 adsorption-desorption, elemental analysis, XPS, DRS, PL spectroscopy and SQUID. Photo-stability tests showed that Fe3O4 @TiO2-P25 does not undergo photodissolution under simulated solar radiation. The photocatalytic performance of Fe3O4 @TiO2-P25 was examined based on its ability to degrade aqueous metoprolol under UV–vis radiation in the presence of O2 and O3/O2. Also, the catalyst was successfully reused in six solar photocatalytic ozonation runs with negligible loss of photocatalytic activity.

MRC-5 Human Lung Fibroblasts Alleviate the Genotoxic Effect of Fe-N Co-Doped Titanium Dioxide Nanoparticles through an OGG1/2-Dependent Reparatory Mechanism

The current study was focused on the potential of pure P25 TiO2 nanoparticles (NPs) and Fe(1%)-N co-doped P25 TiO2 NPs to induce cyto- and genotoxic effects in MRC-5 human pulmonary fibroblasts. The oxidative lesions of P25 NPs were reflected in the amount of 8-hydroxydeoxyguanosine accumulated in DNA and the lysosomal damage produced, but iron-doping partially suppressed these effects. However, neither P25 nor Fe(1%)-N co-doped P25 NPs had such a serious effect of inducing DNA fragmentation or activating apoptosis signaling. Moreover, oxo-guanine glycosylase 1/2, a key enzyme of the base excision repair mechanism, was overexpressed in response to the oxidative DNA deterioration induced by P25 and P25-Fe(1%)-N NPs.

A multifunctional heterogeneous superwettable coating for water collection, oil/water separation and oil absorption.

Herein, inspired by desert beetles, we fabricated a multifunctional heterogeneous superwettable coating (MHSC) for water collection and oily wastewater cleanup. The selective modifications of 1-octadecanethiol (ODT) treated CoO and P25 TiO2 nanoparticles (NPs) were prepared, so hydrophobic CoO NPs and superhydrophilic P25 NPs were combined on the MHSC, showing the water contact angle (WCA) of 156.5° and rolling-off angle (RA) of 6.4°. With the aid of waterborne polyurethane (WPU), five kinds of substrates (i.e., glass slide, dish, wood, fabric, sponge) spray-coated by MHSC displayed high-efficiency water collection rates (WCRs) of 18.1±0.7mgmin-1 cm-2. Moreover, MHSC coated fabric manifested robust oil/water separations with separation efficiencies (SEs) >99.7 % and fluxes ranged from 9.7 to 11.0Lm-2 s-1. Efficient oil sorption from oily water was obtained by MHSC coated sponge with oil absorption capacities (OACs) of 6.5-29.5gg-1. Further, even dealt with the treatments of mechanical destructions, extreme temperature and UV illumination, the coated materials remained stable performances.

Combined effects of P25 TiO2 nanoparticles and disposable face mask leachate on microalgae Scenedesmus obliquus: analysing the effects of heavy metals.

Disposable surgical face masks extensively used during the COVID-19 outbreak would release microplastics into the aquatic environment. The increasing usage of titanium dioxide nanoparticles (nTiO2) in various consumer items has led to its ubiquitous presence in freshwater systems. This study determined the quantity and kind of microplastics discharged from disposable surgical face masks. The mask-leached microplastics were identified to be polypropylene of varying shapes and sizes, spanning from 1 μm to 15 μm. In addition, heavy metals like Cd, Cr, and Hg leached from the face masks were quantified. Four concentrations of nTiO2, 0.5, 1, 2, and 4 mg L-1, were mixed with leached solution from the face masks to perform the combined toxicity test on freshwater algae, Scenedesmus obliquus. A dose-dependent decrease in algal cell viability was observed upon treatment with various concentrations of nTiO2 individually. The mixtures of nTiO2 and the leached solution from the face masks exhibited significantly more toxicity in the algal cells than in their pristine forms. nTiO2 promoted increased production of oxidative stress and antioxidant enzyme activities resulting in cellular damage and decreased photosynthesis. These impacts were elevated when the algal cells were treated with the binary mixture. Furthermore, the heavy metal ions leached from face masks also contributed to the toxic effects. Our study shows that the leachates from disposable surgical face masks, combined with nTiO2, may pose a severe environmental threat.

Self-cleaning solar water evaporation device based on polyaniline/TiO2/natural cellulose fibers for contaminant water

Wastewater accounts for a large part of the water body on the earth. Solar water evaporation is an effective way to produce fresh water from seawater or polluted water. However, the co-evaporation or deposition of contaminants may reduce the efficiency and freshwater quality during water evaporation. In this work, a self-cleaning solar water evaporator is developed based on the natural lignocellulose fibers (NCF), polyaniline (PANI), and TiO2, which shows great advantages of wide-range light absorption, super hydrophilicity, and low thermal conductivity. Nanofibrous PANI is polymerized on the surface of NCF to form a mesoporous network by adding the NCF to the polymerization solution. P25 TiO2 nanoparticles as photocatalysts are dispersed into the above reaction to form the hybrid PANI/TiO2/NCF composite disc by simply filtration. Owing to the synergistic effect between the photothermal PANI and the photocatalytic degradation of TiO2 nanoparticles in the solar water evaporator device, the water evaporation rate can reach 2.36 kg m−2 h−1 (under 1 sun irradiation), and the contaminant (100 ppm tetracycline) can be efficiently degraded. Interestingly, the solar water evaporator device still maintains a constant solar evaporation rate after working for 10 h, and no contaminant is accumulated. The bifunctional solar water evaporation device, which combines photocatalytic and photothermal effects, has great potential application in organic contaminant water with a self-cleaning effect.

Photocatalytic removal of cefazolin in a photoreactor packed with TiO2-P25 nanoparticles supported on glass beads: an artificial neural network modeling

ABSTRACT To operationalise the heterogeneous photocatalysis process, the present study investigated the efficiency of TiO2-P25 nanoparticles immobilised on glass beads using the heat attachment method to remove cefazolin (CEF) as an antibiotic contaminant. The characteristics of the glass beads coated with TiO2-P25 nanoparticles were probed by the Scanning Electron Microscopy (SEM) technique. The immobilised TiO2-P25 nanoparticles manifested considerable efficiency in CEF removal in different operational conditions. The impact of various parameters, such as the ultraviolet light radiation time, initial concentration of CEF, light source power, inlet liquid volumetric flow rate, and pH of the solution, on the efficiency of CEF removal were examined. The results reveal that the removal percentage goes up as the irradiation time, volumetric flow rate, pH of the solution, and light source power increase while declining with a rise in the initial concentration of CEF. According to the findings, an initial CEF concentration of 20 mg L−1 is entirely removed by 40 min UV irradiation with a 16 W light source, the volumetric flow rate of 300 mL min−1, and the pH of 9.5. The reaction rate constant and adsorption coefficient of CEF on immobilised TiO2 were estimated at 0.622 mg L−1 min−1 and 0.095 mg−1 L via Langmuir- Hinshelwood kinetics. The outcomes of the mineralisation studies also display a considerable reduction of TOC and evolution of significant mineralisation products, like N O 3 − , N O 2 − , N H 4 + , and S O 4 2 − . The experimental results were modelled by artificial neural networks (ANN). Comparing the experimental results with the ANN-predicted data shows the acceptable efficiency of modelling with ANN. The minimum MSE, R2 value for all data (validation, training, and test), and R2 value for simulated data were obtained at 0.00027811, 0.9971, and 0.9809, respectively. The relative importance of the parameters affecting the process evaluated by the ANN weights indicates that the irradiation time is the most important factor in the photocatalytic removal of CEF.

Synthesis, characterization and photocatalytic properties of nanostructured lanthanide doped β-NaYF4/TiO2 composite films

The photocatalytic approach is known to be one of the most promising advanced oxidation processes for the tertiary treatment of polluted water. In this paper, β-NaYF4/TiO2 composite films have been synthetized through a novel sol–gel/spin-coating approach using a mixture of β-diketonate complexes of Na and Y, and Yb3+, Tm3+, Gd3+, Eu3+ as doping ions, together with the TiO2 P25 nanoparticles. The herein pioneering approach represents an easy, straightforward and industrially appealing method for the fabrication of doped β-NaYF4/TiO2 composites. The effect of the doped β-NaYF4 phase on the photocatalytic activity of TiO2 for the degradation of methylene blue (MB) has been deeply investigated. In particular, the upconverting TiO2/β-NaYF4: 20%Yb, 2% Gd, x% Tm (x = 0.5 and 1%) and the downshifting TiO2/β-NaYF4: 10% Eu composite films have been tested on MB degradation both under UV and visible light irradiation. An improvement up to 42.4% in the degradation of MB has been observed for the TiO2/β-NaYF4: 10% Eu system after 240 min of UV irradiation.

TiO2 nanorods doped with g-C3N4 – Polyethylene composite coating for self-cleaning applications

Visible-light-absorbing graphitic carbon nitride–TiO2 nanorod nanomaterials (g-C3N4@TiO2NR) were successfully immobilized using a one-step UVA-induced photocatalytic procedure on commercially obtained flexible low-density polyethylene (LDPE) films. Self-cleaning properties were evaluated in solid–liquid and solid–gas phases using malachite green as a model molecule under UV-A and visible light irradiation. For comparison purpose, LDPE films containing P25 TiO2 nanoparticles was prepared using the same synthetic strategy (P25/LDPE). Among the fabricated films, the g-C3N4@TiO2NR/LDPE films exhibited the highest photocatalytic activity both in solid–liquid and solid–gas phases after 120 min of visible light irradiation (λ > 455 nm) removing efficiently malachite green stains probably due to the attack of photoinduced reactive oxygen species (ROS) such as singlet oxygen (1O2), hydroxyl radical (•OH) and superoxide anion radical (O2−•). Furthermore, the g-C3N4@TiO2NR/LDPE films retained their visible-light-photoinduced photocatalytic properties after four reuse cycles. The g-C3N4@TiO2NR/LDPE films also exhibited significant visible-light-photoinduced hydrophilicity. The high visible-light-photoinduced photocatalytic capacity of g-C3N4@TiO2NR/LDPE films was found to be related to the textural and electronic properties, superior visible-light absorption, and surface roughness of the films.

Hydrophobic agents and pH modification as comparative chemical effect on the hydrophobic and photocatalytic properties in SiO2-TiO2 coating

The SiO2-TiO2 composite has been studied through several techniques obtaining different morphologies and specific properties of SiO2 and TiO2. Nevertheless, the modification of the synthesis pH and the addition of different hydrophobic agents, such as hexamethyldisilazane (HDMS) and polydimethylsiloxane (PDMS), have not been thoroughly studied and reported. This work assessed the presence of two different hydrophobic agents and the pH modification. The SiO2-TiO2 coating was synthesized through two vias, basic and acid environment, employing the sol–gel method coupled to the sonochemistry technique. Moreover, the change of pH and use of P25 TiO2 nanoparticles and TiO2-synthesized nanoparticles allows establishing a relationship with the self-cleaning properties. The samples of SiO2-TiO2 composite were analyzed by AFM, indicating a variation in surface morphology and roughness concerning the PDMS and HMDS hydrophobic agent. ATR-FTIR analysis exhibit changes in intensity in vibrations of the Si-O, PDMS, and HMDS bonds. Raman spectroscopy results show the vibrations of the anatase and rutile phases of the TiO2 and the corresponding vibrations to the hydrophobic agents. The evaluation of self-cleaning properties demonstrated changes from the hydrophobic state to the hydrophilic state due to the addition of the nanoparticles of TiO2 to the SiO2. The photocatalytic activity was modified and improved in the HMDS-1 coating due to the hydrophobic agent and type of nanoparticles. To compare the effect of the pH in the PDMS and HMDS coatings, carried out with cyclic voltammograms and Differential Capacitance spectra. Finally, the storage time of SiO2-TiO2 coating was improved using the HMDS hydrophobic agent.