TiO2 photocatalysis: Design and applications

Effects of nanomaterials on metal toxicity: Case study of graphene family on Cd

The risk of heavy metal cadmium (Cd) on aquatic organisms has drawn widespread attentions, but the effects of nanomaterials (e.g. graphene (G)) on Cd toxicity are rarely clarified. It was known that mixture of contaminants may exhibit more severe impact than the individual metal. Here, we conducted a study systematically on the effects of nanomaterials on the toxicity of Cd to Scenedesmus Obliquus (S. obliquus) with or without the presence of graphene family materials (GFMs) derived from G, such as graphene oxide (GO) and amine-modified graphene (GNH). Our results showed that the influence of GFMs on the acute toxicity of Cd to S. obliquus is in the order of GO > G > GNH based on their EC₅₀ of Cd-GFMs. The effects of GFMs on the cytotoxicity and oxidative damage of Cd to S. obliquus are varied with the concentrations of GFMs. The differences between the effects of GFMs on Cd toxicity may attribute to their different surface oxygen-containing functional groups contained in the nanomaterials. The adsorption capacity of nanomaterials on metal ions, their dispersibility in water and their interaction mode with organisms, may dominate main contributions to their effects on Cd toxicity. Our study aids to clarify the interference of nanoparticles on the ecotoxicity of metals, to avoid the misunderstanding of the potential risk of metals in the complicate water environments.

Photocatalytic Bi2O3/TiO2:N Thin Films with Enhanced Surface Area and Visible Light Activity

Bi2O3 nanocone films functionalized with an overlayer of TiO2 were deposited by d.c. reactive magnetron sputtering. The aforementioned nanocone structures were formed via a vapour-liquid-solid (VLS) growth, starting from a catalytic bismuth seed layer. The resultant nanocones exhibit an improved surface area, measured by atomic force microscopy, when compared to non-VLS deposition of the same metal oxide. X-ray diffraction texture analysis enabled the determination of the crystallographic β-phase of Bi2O3. A very thin TiO2 overlayer (6 nm thick), undoped and doped with nitrogen, was deposited onto the nanocones template, in order to functionalize these structures with a photocatalytic, self-cleaning, cap material. N-doped TiO2 overlayers increased the selective absorption of visible light due to nitrogen doping in the anatase cell, thus, resulting in a concomitant increase in the overall photocatalytic efficiency.

Diatom Frustule Silica Exhibits Superhydrophilicity and Superhemophilicity

Special surface wettability attracts significant attention. In this study, dramatic differences in wettability are demonstrated for microparticles with the same chemical composition, SiO₂. One is natural silica prepared from the diatom, Melosira nummuloides, and the other is synthetic silica. We found that surface properties of synthetic silica are hydro- and hemophobic. However, diatom frustule silica exhibits superhydrophilicity and even superhemophilicity. Interestingly, such superhydrophilicity of natural silica is not solely originated from nanoporous structures of diatoms but from the synergy of high-density silanol anions and the nanoarchitecture. Furthermore, the observation of superhemophilicity of natural silica is also an interesting finding, because not all superhydrophilic surfaces show superhemophilicity. We demonstrate that superhemowettability is a fundamental principle for developing micropowder-based hemostatic materials despite existing hemorrhaging studies using diatoms.

Plasma Nitriding of TiO2 Nanotubes: N-Doping in Situ Investigations Using XPS

The nitrogen doping of titanium dioxide nanotubes (TiO₂ NTs) was investigated as a result of well-controlled plasma nitriding of TiO₂ NTs at a low temperature. This way of nitrogen doping is proposed as an alternative to chemical/electrochemical methods. The plasma nitriding process was performed in a preparation chamber connected to an X-ray photoelectron spectroscopy (XPS) spectrometer, and the nitrogen-doped TiO₂ NTs were next investigated in situ by XPS in the same ultrahigh vacuum (UHV) system. The collected high-resolution (HR) XPS spectra of N 1s, Ti 2p, O 1s, C 1s, and valence band (VB) revealed the formation of chemical bonds between titanium, nitrogen, and oxygen atoms as substitutional or interstitial species. Moreover, the results provided a characterization of the electronic states of N-TiO₂ NTs generated by various plasma nitriding and annealing treatments. The VB XPS spectrum showed a reduction in the TiO₂ band gap of about 0.6 eV for optimal nitriding and heat-treated conditions. The TiO₂ NTs annealed at 450 or 650 °C in air (ex situ) and nitrided under UHV conditions were used as reference materials to check the formation of Ti-N bonds in the TiO₂ lattice with a well-defined structure (anatase or a mixture of anatase and rutile). Scanning electron microscopy microscopic observations of the received materials were used to evaluate the morphology of the TiO₂ NTs after each step of the nitriding and annealing treatments.

Fabrication of Ag2O/WO3 p-n heterojunction composite thin films by magnetron sputtering for visible light photocatalysis

Semiconductor-based nanostructures which are photo-catalytically active upon solar light irradiation were extensively used for environmental remediation due to the potential decomposition of various kinds of pollutants. In this work, we report the preparation of a sustainable thin film composite, i.e. Ag2O/WO3 p-n heterojunction, and investigation of its photocatalytic activity. To achieve the composite structure, WO3/Ag-WO3 layers were deposited over a quartz substrate by magnetron sputtering at room temperature and subsequently annealed at 823 to 923 K. The thin film structure, morphology, and chemical states were thoroughly characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron spectroscopy, and X-ray photoelectron spectroscopy. The obtained results revealed that the amorphous Ag-doped WO3 was crystallized into monoclinic WO3 and Ag2O, in which nanocrystalline Ag2O was diffused towards the surface of WO3. Optical transmittance spectra recorded by UV-vis-NIR spectroscopy revealed that the WO3/Ag-WO3 films became transparant in the visible region after annealing at high temperature (873 K and 923 K). The Ag2O/WO3 p-n heterojunction composite thin films showed high photocatalytic activity (0.915 × 10-3 min-1) under visible light irradiation, which is attributed to the efficiency of effective photogenerated charge-carrier formation and the reduced recombination rate of photogenerated electron-hole pairs. Unlike the powder-based photocatalysts, the reported thin film-based heterojunction photocatalyst could be very sustainable, and cost-effective.

Mechanism of Action of TiO2: Recommendations to Reduce Uncertainties Related to Carcinogenic Potential

The Risk Assessment Committee of the European Chemicals Agency issued an opinion on classifying titanium dioxide (TiO₂) as a suspected human carcinogen upon inhalation. Recent animal studies indicate that TiO₂ may be carcinogenic through the oral route. There is considerable uncertainty on the carcinogenicity of TiO₂, which may be decreased if its mechanism of action becomes clearer. Here we consider adverse outcome pathways and present the available information on each of the key events (KEs). Inhalation exposure to TiO₂ can induce lung tumors in rats via a mechanism that is also applicable to other poorly soluble, low-toxicity particles. To reduce uncertainties regarding human relevance, we recommend gathering information on earlier KEs such as oxidative stress in humans. For oral exposure, insufficient information is available to conclude whether TiO₂ can induce intestinal tumors. An oral carcinogenicity study with well-characterized (food-grade) TiO₂ is needed, including an assessment of toxicokinetics and early KEs.

Enhancement of Photocatalytic Oxidation of Glucose to Value-Added Chemicals on TiO2 Photocatalysts by A Zeolite (Type Y) Support and Metal Loading

TiO2-based photocatalysts synthesized by the microwave-assisted sol-gel method was tested in the photocatalytic glucose conversion. Modifications of TiO2 with type-Y zeolite (ZeY) and metals (Ag, Cu, and Ag-Cu) were developed for increasing the dispersion of TiO2 nanoparticles and increasing the photocatalytic activity. Effects of the TiO2 dosage to zeolite ratio (i.e., TiO2/ZeY of 10, 20, 40, and 50 mol %) and the silica to alumina ratio in ZeY (i.e., SiO2:Al2O3 of 10, 100, and 500) were firstly studied. It was found that the specific surface area of TiO2/ZeY was 400–590 m2g−1, which was higher than that of pristine TiO2 (34.38 m2g−1). The good properties of 20%TiO2/ZeY photocatalyst, including smaller particles (13.27 nm) and high surface area, could achieve the highest photocatalytic glucose conversion (75%). Yields of gluconic acid, arabinose, xylitol, and formic acid obtained from 20%TiO2/ZeY were 9%, 26%, 4%, and 35%, respectively. For the effect of the silica to alumina ratio, the highest glucose conversion was obtained from SiO2:Al2O3 ratio of 100. Interestingly, it was found that the SiO2:Al2O3 ratio affected the selectivity of carboxylic products (gluconic acid and formic acid). At a low ratio of silica to alumina (SiO2:Al2O3 = 10), higher selectivity of the carboxylic products (gluconic acid = 29% and formic acid = 32%) was obtained (compared with other higher ratios). TiO2/ZeY was further loaded by metals using the microwave-assisted incipient wetness impregnation technique. The highest glucose conversion of 96.9 % was obtained from 1 wt. % Ag-TiO2 (40%)/ZeY. Furthermore, the bimetallic Ag-Cu-loaded TiO2/ZeY presented the highest xylitol yield of 12.93%.

Insights into the Photocatalytic Bacterial Inactivation by Flower-Like Bi2WO6 under Solar or Visible Light, Through in Situ Monitoring and Determination of Reactive Oxygen Species (ROS)

This study addresses the visible light-induced bacterial inactivation kinetics over a Bi2WO6 synthesized catalyst. The systematic investigation was undertaken with Bi2WO6 prepared by the complexation of Bi with acetic acid (carboxylate) leading to a flower-like morphology. The characterization of the as-prepared Bi2WO6 was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), specific surface area (SSA), and photoluminescence (PL). Under low intensity solar light (<48 mW/cm2), complete bacterial inactivation was achieved within two hours in the presence of the flower-like Bi2WO6, while under visible light, the synthesized catalyst performed better than commercial TiO2. The in situ interfacial charge transfer and local pH changes between Bi2WO6 and bacteria were monitored during the bacterial inactivation. Furthermore, the reactive oxygen species (ROS) were identified during Escherichia coli inactivation mediated by appropriate scavengers. The ROS tests alongside the morphological characteristics allowed the proposition of the mechanism for bacterial inactivation. Finally, recycling of the catalyst confirmed the stable nature of the catalyst presented in this study.

Photocatalyzed preferential oxidation of CO under simulated sunlight using Au-transition metal oxide-sepiolite catalysts

In the present study a series of Au-transition metal oxides supported on a clay mineral such as sepiolite were tested in the preferential oxidation of CO in an excess of H₂ under simulated solar light irradiation and in the absence of light, at 30 °C and atmospheric pressure. Transition metal oxides (ZnO, Fe₂O₃, NiO, MnO₂, and Co₃O₄) were dispersed over the sepiolite surface where, subsequently, Au nanoparticles with an average particle size between 2 and 3 nm were successfully deposited-precipitated. The obtained photocatalysts were characterized by XRD, XRF, DRUV-Vis, N₂ adsorption-desorption and HRTEM in order to evaluate the optical, structural and chemical properties of the prepared samples. Despite the low amount of gold (nominal 1.0 wt%), the catalysts exhibited an outstanding behavior under light irradiation, with reaction rates between 4.5 and 5.2 mmol CO_ox g_cat^-1 h^-1 for the Au-NiSep, Au-CoSep and Au-ZnSep samples. These photocatalysts exhibited a high dispersion of the respective transition metal oxides over the sepiolite support and the presence of low-coordinated hemispherical gold nanoparticles. The superior photocatalytic efficiency of these samples was ascribed to the reduction of the electron-hole pair recombination of photogenerated charge carriers by the excitation of the localized surface plasmon resonance of the Au nanoparticles. The BET surface area and the gold particle size seemed to be relevant factors affecting the catalytic performance.

Decolorization and biodegradability of a real pharmaceutical wastewater treated by H2O2-assisted photoelectrocatalysis on TiO2 meshes

In recent years, photoelectrocatalysis (PEC) for the treatment of industrial wastewaters (IWWs) has been repeatedly proposed. However, despite the number of tests reported in literature, only a few of them were conducted on real IWWs. In this study, real pharmaceutical IWWs showing an intense recalcitrant color were treated by PEC and H₂O₂-assisted PEC (UV/TiO₂/Bias and UV/H₂O₂/TiO₂/Bias, respectively) on TiO₂ meshes having sub-micrometric features obtained by Plasma Electrolytic Oxidation. Photolysis (UV), chemical oxidation (H₂O₂) and H₂O₂-assisted photolysis (UV/H₂O₂) were tested in the same reactor for comparison. The configuration UV/H₂O₂/TiO₂/bias showed the best results in term of decolorization efficiency and rate, where decolorization was 55 % (single-step H₂O₂ dosing) and 44 % (three-step H₂O₂ dosing), after 2 h of contact time. In the same contact time, UV and UV/TiO₂/Bias processes did not give decolorization. A more effective COD removal was measured for the PEC processes, UV/H₂O₂/TiO₂/Bias (-24 %) and UV/TiO₂/Bias (-20 %), while COD removal by UV was almost 0 %. Correspondingly, the SOUR values showed that PEC combined with a single-step H₂O₂ dosage was the most effective configuration, leading to the highest biodegradability of the treated IWW with respect to the other processes. The energy consumption analysis demonstrated that PEC+H₂O₂ (single-step dosage) optimized energy costs.

WO3-ZnO and CuO-ZnO nanocomposites as highly efficient photoanodes under visible light illumination

We prepared ZnO nanocomposites with WO₃ or CuO nanostructures to improve the photocatalytic performance of ZnO nanostructures. Characterization of the nanocomposites using scanning electron microscopy, x-ray diffraction, UV-vis spectrometry and photoluminescence revealed the morphologies and wide light absorption range of the materials. The highest current densities of WO₃/ZnO and CuO/ZnO nanocomposites were 1.28 mA cm^-2 and 2.49 mA cm^-2 at 1.23 V (versus a reversible hydrogen electrode) under AM 1.5 100 mW cm^-2, which are ~1.2- and 3.5-fold greater than those of bare ZnO nanostructures, respectively. The easy fabrication process suggests that nanocomposites with narrow bandgap materials, such as WO₃ and CuO, will improve the performance of electrochemical and optoelectrical devices such as dye-sensitized solar cells and biosensors.

Influence of TiO2 Morphology and Crystallinity on Visible-Light Photocatalytic Activity of TiO2-Bi2O3 Composite in AOPs

Solution combustion synthesis was used to produce a junction between different TiO2 supports (anatase TiO2 nanorods (TNR) and nanoparticles (TNP) and TiO2 with anatase core and amorphous shell (a-TNR)) and narrow bandgap (BG) semiconductor β-Bi2O3. β-Bi2O3 acted as a visible-light photosensitizer and enabled us to carry out photocatalytic oxidation of water dissolved bisphenol A (BPA) with TiO2 based catalysts under visible-light illumination. Heterojunction between TiO2 and β-Bi2O3 in TNR + Bi and TNP + Bi composites enables the transfer of visible-light generated holes from the β-Bi2O3 valence band (VB) to the upper lying TiO2 VB. A p–n junction, established upon close chemical contact between TiO2 and β-Bi2O3, enables the transfer of visible-light generated electrons in the β-Bi2O3 conduction band (CB) to the TiO2 CB. In TNR + Bi and a-TNR + Bi composites, the supplied heat energy during the synthesis of samples was not sufficient to completely transform (BiO)2CO3 into β-Bi2O3. A p–n junction between (BiO)2CO3 and β-Bi2O3 enables the transfer of electrons generated by β-Bi2O3 to (BiO)2CO3. Hindered charge carrier recombination originating from the crystallinity of TiO2 is a more important factor in the overall kinetics of BPA degradation than high specific surface area of the amorphous TiO2 and reduction/oxidation of surface adsorbed substrates.

Green Fabrication of Tannic Acid-Inspired Magnetic Composite Nanoparticles toward Cationic Dye Capture and Selective Degradation

An environmental strategy for developing sustainable materials presents an attractive prospect for wastewater remediation. Herein, a facile, green, and economical strategy is proposed to fabricate magnetic composite nanoparticles (NPs) toward cationic dye adsorption and selective degradation. To prepare the composite TiO2-PEI-TA@Fe3O4 NPs, tannic acid (TA) and polyethyleneimine (PEI) were first used to decorate Fe3O4 NPs at aqueous solution, and then TiO2 NPs were anchored onto the surfaces of Fe3O4 NPs based on the catecholamine chemistry. The chemical composition and microstructure of the obtained NPs were systematically characterized. The NPs not only exhibited adsorption ability for the cationic dye of methylene blue (MB) but also responded to ultraviolet light to selectively degrade the adsorbed MB, and the removal (adsorption and/or degradation) ratio for MB could reach 95%. In addition, cyclic experiments showed that the removal ratio of the composite NPs for MB could still be maintained more than 85% even after five cycles. Given by the above-mentioned advantages, such a green and facile strategy for combining the adsorption and degradation methods to construct magnetic nanocomposites exhibits potential applications in cationic dye selective removal and sustainable wastewater remediation.

Electrospun Ag-TiO2 Nanofibers for Photocatalytic Glucose Conversion to High-Value Chemicals

TiO₂ nanofibers were fabricated by combination of sol-gel and electrospinning techniques. Ag-doped TiO₂ nanofibers with different Ag contents were prepared by two different methods (in situ electrospinning or wetness impregnation of Ag on TiO₂ nanofibers) and heat treated at 500 °C for 2 h under an air or N₂ atmosphere. The obtained catalysts were characterized by field emission scanning electron microscopy, X-ray diffraction, photoluminescence, and N₂ adsorption analyzed by the Brunauer-Emmett-Teller (BET) method. Photocatalytic glucose conversions with electrospun TiO₂ and Ag-doped TiO₂ nanofibers for production of high-value products were carried out. From different doping methods, the results indicated that 1 wt % Ag-TiO₂ nanofibers prepared by an in situ method with calcination under N₂ achieved the highest glucose conversion (85.49%). From several Ag loading contents (i.e., 0, 1, 2, and 4 wt %) in Ag-doped TiO₂ nanofibers, the nanofibers exhibited different glucose conversions [in order of 2 wt % (99.65%) > 1 wt % (85.49%) > 4 wt % (77.72%) > 0 wt % (29.64%)]. Arabinose, xylitol, gluconic acid, and formic acid were found as the high-value chemicals with the photocatalytic reaction of TiO₂ and Ag-doped TiO₂ nanofibers under UVA irradiation. Product yields of each converted chemicals from different photocatalysts from different Ag loading contents showed relatively same trends with the glucose conversion. From all results, it can be concluded that the good characteristics of 2 wt % Ag-TiO₂ nanofibers such as the smallest anatase crystallite size (8.25 nm) and the highest specific surface area (S _BET = 53.69 m²/g) promoted the highest photocatalytic activity. Additionally, TiO₂ and Ag-doped TiO₂ nanofibers exhibited higher photocatalytic performance for glucose conversion than commercial TiO₂ (P25) and synthesized TiO₂ nanoparticles. Finally, Ag-doped TiO₂ nanofibers showed recycling ability with high photocatalytic glucose conversion after four-time use.

TiO2 superstructures with oriented nanospaces: a strategy for efficient and selective photocatalysis

Highly ordered superstructures of semiconductor nanocrystals contain abundant nanometer-scale pores between the crystals; however, there have been difficulties in controlling the size and orientation of these nanospaces without the use of a template or a capping reagent. This constraint has affected their development and applications in potential fields including catalysis and optoelectronics adversely. In this study, we synthesized a rod-shaped TiO2 mesocrystal (TMC) having a length of a few hundreds of micrometers and comprising regularly ordered anatase TiO2 nanocrystals that form oriented nanospaces by exposed {001} facets. Finite-difference time-domain (FDTD) calculations of electric fields and in situ fluorescence imaging with a polarization sensitive dye on a single mesocrystal were performed to reveal anisotropic adsorption and excitation of the dyes. Furthermore, the photodegradation of the dyes was found to be more facilitated in nanospaces formed by the specific facets, as compared with the dyes randomly adsorbed on the outer surfaces. Consequently, the selectivity of photocatalytic reactions based on the molecular size and redox was enhanced by introducing the concept of oriented nanospace.

Photocatalysts for H2 Generation from Starburst Triphenylamine/Carbazole Donor-Based Metal-Free Dyes and Porous Anatase TiO2 Cube

A series of novel triphenylamine/carbazole-based D-D-π-π-A dyes DH1-4 and a mesoporous anatase cubic "microcage" TiO₂ material (denoted as MC-TiO₂ ) were synthesized and combined to obtain dye-sensitized photocatalysts (denoted as DHn/Pt/MC-TiO₂ , n=1-4). These catalysts showed better performances in visible-light-driven H₂ evolution from water than DHn/Pt/P25-TiO₂ catalysts based on commercial P25-TiO₂ bulk semiconductor under similar conditions. Compared with P25-TiO₂ particles, the porous MC-TiO₂ had a large Brunauer-Emmett-Teller surface area, porosity, and exposed {0 0 1} crystal plane, which greatly contributed to the photocatalytic activity. The optimized DH2/Pt/MC-TiO₂ photocatalyst exhibited an attractive H₂ production rate (16.28 mmol g^-1  h^-1 based on catalyst mass), and the optimized DH4/Pt/MC-TiO₂ photocatalyst showed good stability [turnover number (TON) of 16 699 in 105 h based on dye number], which represents one of the best performances among all reported visible-light-driven heterogeneous catalytic systems. Compared with the other dyes in this series, the high H₂ production rate of DH2 on Pt/MC-TiO₂ can be attributed to its size-matching effect and thus high dye loading amount, whereas the high TON and durability of DH4/Pt/MC-TiO₂ are probably related to the rapid regeneration kinetics of DH4.

Manganese and Graphene Included Titanium Dioxide Composite Nanowires: Fabrication, Characterization and Enhanced Photocatalytic Activities

We report the detailed microstructural, morphological, optical and photocatalytic studies of graphene (G) and manganese (Mn) co-doped titanium dioxide nanowires (TiO₂(G–Mn) NWs) prepared through facile combined electrospinning–hydrothermal processes. The as-prepared samples were thoroughly characterized using X-ray diffraction (XRD), transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and diffuse reflectance spectroscopy (DRS). XRD studies reveal the formation of mixed anatase-rutile phases or rutile phase depending on the dopant (Mn) precursor concentrations in the electrospinning dope and calcination temperature. The evaluation of lattice parameters revealed that the incorporation of Mn species and carbon atoms in to the lattice of anatase or rutile TiO₂ could occur through substituting the sites of oxygen atoms. XPS results confirm the existence of Mn²⁺/Mn³⁺ within the TiO₂ NW. Raman spectroscopy provides the evidence for structural modification because of the graphene inclusion in TiO₂ NW. The optical band gap of G–Mn including TiO₂ is much lower than pristine TiO₂ as confirmed through UV-vis DRS. The photocatalytic activities were evaluated by nitric oxide (NOx) degradation tests under visible light irradiation. Superior catalytic activity was witnessed for rutile G–Mn-co-doped TiO₂ NW over their anatase counterparts. The enhanced photocatalytic property was discussed based on the synergistic effects of doped G and Mn atoms and explained by plausible mechanisms.

Amperometric Flow-Injection Analysis of Phenols Induced by Reactive Oxygen Species Generated under Daylight Irradiation of Titania Impregnated with Horseradish Peroxidase

Titanium dioxide (TiO₂) is a unique material for biosensing applications due to its capability of hosting enzymes. For the first time, we show that TiO₂ can accumulate reactive oxygen species (ROS) under daylight irradiation and can support the catalytic cycle of horseradish peroxidase (HRP) without the need of H₂O₂ to be present in the solution. Phenolic compounds, such as hydroquinone (HQ) and 4-aminophenol (4-AP), were detected amperometrically in flow-injection analysis (FIA) mode via the use of an electrode modified with TiO₂ impregnated with HRP. In contrast to the conventional detection scheme, no H₂O₂ was added to the analyte solution. Basically, the inherited ability of TiO₂ to generate reactive oxygen species is used as a strategy to avoid adding H₂O₂ in the solution during the detection of phenolic compounds. Electron paramagnetic resonance (EPR) spectroscopy indicates the presence of ROS on titania which, in interaction with HRP, initiate the electrocatalysis toward phenolic compounds. The amperometric response to 4-AP was linear in the concentration range between 0.05 and 2 μM. The sensitivity was 0.51 A M^-1 cm^-2, and the limit of detection (LOD) 26 nM. The proposed sensor design opens new opportunities for the detection of phenolic traces by HRP-based electrochemical biosensors, yet in a more straightforward and sensitive way following green chemistry principles of avoiding the use of reactive and harmful chemical, such as H₂O₂.

Photocatalytic Degradation of Rhodamine B Dye by TiO2 and Gold Nanoparticles Supported on a Floating Porous Polydimethylsiloxane Sponge under Ultraviolet and Visible Light Irradiation

A combination of plasmonic nanoparticles (NPs) with semiconductor photocatalysts, called plasmonic photocatalysts, can be a good candidate for highly efficient photocatalysts using broadband solar light because it can greatly enhance overall photocatalytic efficiency by extending the working wavelength range of light from ultraviolet (UV) to visible. In particular, fixation of plasmonic photocatalysts on a floating porous substrate can have additional advantages for their recycling after water treatment. Here, we report on a floating porous plasmonic photocatalyst based on a polydimethylsiloxane (PDMS)-TiO₂-gold (Au) composite sponge, in which TiO₂ and Au NPs are simultaneously immobilized on the surface of interconnected pores in the PDMS sponge. This can be easily fabricated by a simple sugar-template method with TiO₂ NPs and in situ reduction of Au NPs by the PDMS without extra chemicals. Its ability to decompose the organic pollutant rhodamine B in water was tested under UV and visible light, respectively. The results showed highly enhanced photocatalytic activity under both UV and visible light compared to the PDMS-TiO₂ sponge and the PDMS-Au sponge. Furthermore, its recyclability was also demonstrated for multiple cycles. The simplicity of fabrication and high photocatalytic performance of our PDMS-TiO₂-Au sponge can be promising in environmental applications to treat water pollution.

Enhancing Ru(II)-Catalysis with Visible-Light-Mediated Dye-Sensitized TiO2 Photocatalysis for Oxidative C-H Olefination of Arene Carboxylic Acids at Room Temperature

Erythrosine B sensitized TiO₂ photocatalysis has been combined with Ru(II)-catalysis to accomplish an oxidative olefination/annulation of benzoic acids with activated olefins under mild conditions that tolerates useful functionalities, such as halides, free hydroxy, acetamido, etc. The morphology of the photocatalyst is unaffected during the reaction and it can be reused. Mechanistic studies favor the involvement of a photo-induced single electron transfer process.

Synergetic treatment of dye contaminated wastewater using microparticles functionalized with carbon nanotubes/titanium dioxide nanocomposites

The highly efficient treatment of azo dye contaminated wastewater from the textile industry is an important but challenging problem. Herein, polydimethylsiloxane (PDMS) microparticles, incorporating multiple-walled carbon nanotubes/titanium dioxide (MWCNTs/TiO2) nanocomposites, were successfully synthesized to treat wastewater containing Rhodamine B (RhB) dyes in a synergetic approach, by combining sorption and photocatalytic degradation. The surfactant wrapping sol-gel method was applied to synthesize MWCNTs/TiO2 nanocomposites with TiO2 nanoparticles evenly distributed on the surface of the MWCNTs. The PDMS microparticles were fabricated with an oil-in-water (O/W) single emulsion template, using needle-based microfluidic devices. MWCNTs/TiO2 nanocomposites (at a weight ratio of 1%, and 2%, respectively) were mixed with the PDMS precursor as the dispersed phase, and an aqueous solution of polyvinyl alcohol (PVA) was used as the continuous phase. Highly monodispersed microparticles, with average diameters of 692.7 μm (Coefficient of Variation, CV = 0.74%) and 678.3 μm (CV = 1.04%), were formed at an applied flow rate of the dispersed and continuous phase of 30 and 200 μL min-1, respectively. The fabricated hybrid microparticles were employed for the treatment of RhB, involving a dark equilibrium for 5 hours and UV irradiation for 3 hours. The experimental conditions of applied PDMS type, mass loading amount, treatment duration, photodegradation kinetics, initial concentration of pollutants and environmental pH values were investigated in this work. The PDMS microparticles with 2 wt% MWCNTs/TiO2 nanocomposites can exhibit a removal efficiency of 85%. Remarkably, an efficiency of 70% can be retained after the microparticles have been recycled and reused for 3 cycles. The PDMS-MWCNTs/TiO2 microparticles possess a superior performance over conventional treatment approaches for dye contaminated wastewater, especially in recyclability and the prevention of secondary pollution. This work provides a feasible and eco-friendly route for developing an efficient and low-cost microfluidic method for treating complicated water environmental systems.

Electricity generation in fuel cell with light and without light and decomposition of tetracycline hydrochloride using g-C3N4/Fe0(1%)/TiO2 anode and WO3 cathode

Visible-light-driven photocatalytic Fuel Cell (PFC) is of great interest in the environmental pollutant remediation with energy recovering. Herein, enhancement in photocatalytic degradation of Tetracycline Hydrochloride (TC) with electricity generation was achieved in a single reactor of PFC with paired stainless-steel mesh electrode loaded with anodic g-C₃N₄/Fe⁰(1%)/TiO₂ and cathodic WO₃ catalyst (at various pH, 0.05 M Na₂SO₄, 10 Ω external resistance) with visible light and without light. With light, TC molecules were successfully removed (97.3% in 90 min, at initial and optimal pH 5), while generating 0.98 V cell voltage and 24 W m^-2 power density, simultaneous removal of COD (chemical oxygen demand) and TOC (total organic carbon) was 91.3% and 95%, respectively, suggesting superior mineralization that can be explained by the excitation of the anodic triple component g-C₃N₄/Fe⁰(1%)/TiO_2. In contrast, without light, the removal of COD, TOC and the cell voltage were much lower (48.8%, 65.3%, 0.78 V). In dark, the fuel cell is self-driven and self-biased, forming potential gradient and degrading pollutants. The effects of solution pH, initial TC concentration on degradation and power generation were evaluated. This PFC degrading TC can maintain high photocatalytic activity and high power output capacity after 5 cycles with light. Without light, the electricity generation capacity was 50-70% that in visible light PFC. These features reveal that fuel cell with g-C₃N₄/Fe⁰(1%)/TiO₂ photo anode and WO₃ photocathode has great application potential for removing refractory pollutants from wastewater.

Band gap engineering of Ce-doped anatase TiO2 through solid solubility mechanisms and new defect equilibria formalism

The present work reports a detailed mechanistic interpretation of the role of the solubility of dopants and resultant midgap defect energies in band gap engineering. While there is a general perception that a single dopant is associated with single solubility and defect mechanisms, in reality, the potential for multiple solubility and defect mechanisms requires a more nuanced interpretation. Similarly, Kröger-Vink defect equilibria assume that stoichiometries during substitutional and interstitial solid solubility as well as Schottky and Frenkel pair formation are compensated by the diffusion of matrix ions to the grain boundaries or surface. However, this approach does not allow the possibility that stoichiometry is uncompensated, where diffusion of the matrix ion to lattice interstices occurs, followed by charge compensation by redox of this ion. Consequently, a modified defect equilibria formalism has been developed in order to allow description of this situation. Experimental data for the structural, chemical, semiconducting, and photocatalytic properties as a function of doping level are correlated with conceptual structural models, a comprehensive energy band diagram, and the corresponding defect equilibria. These correlations reveal the complex mechanisms of the interrelated solubility and defect formation mechanisms, which change significantly and irregularly as a function of small changes in doping level. The analyses confirm that the assumption of single mechanisms of solid solubility and defect formation may be simplifications of more complex processes. The generation of (1) a matrix of complementary characterisation and analytical data, (2) the calculation of a complete energy band diagram, (3) consideration of charge compensation mechanisms and redox beyond the limitations of Kröger-Vink approaches, and (4) the development of models of corresponding structural analogies combine to create a new approach to interpret and explain experimental data. These strategies allow deconstruction of these complex issues and thus targeting of optimal and possibly unique doping levels to achieve lattice configurations that may be energetically and structurally unfavorable. These approaches then can be applied to other doped semiconducting systems.

Development of photocatalytic paint based on TiO2 and photopolymer resin for the degradation of organic pollutants in water

While the use of TiO2 nanoparticles in the form of slurry/suspension requires energy-intensive separation processes, its immobilization in solid support may open new opportunities in the area of sustainable water treatment technologies. In this study, a novel method for the development of photocatalytic paint based on TiO₂ nanoparticles and acrylate-based photopolymer resin is reported. The paint (TiO₂@polymer) was applied on substrates such as plastic petri dish and glass jar, which was polymerized/solidified by ultraviolet light irradiation. The painted petri dish and glass jar were used for the photocatalytic degradation of model organic pollutants viz. methyl orange (MO), methylene blue (MB), and indole in deionized water, simulated fresh drinking water, and tap water matrices. The photocatalytic degradation studies were performed under sunlight and UV-B light were used for. The sunlight-assisted photocatalytic degradation of MO and MB was found to be faster and more efficient than the UV-B light-assisted ones. Under UV-B light irradiation, it took 120 min to degrade about 80% of 6 ppm MB solution, whereas under sunlight irradiation it took 60 min to degrade about 90% of the same MB solution. The photocatalytic paint generated hydroxyl radical (·OH) under the UV-B and sunlight irradiation, which was studied by the terephthalic acid fluorescence tests. Further, the potential release of TiO₂ during the exposure to UV irradiation was studied by single particle ICP-MS analysis.

SnO2-Containing Clinoptilolite as a Composite Photocatalyst for Dyes Removal from Wastewater under Solar Light

Due to their adsorbent, ion exchange and catalytic properties zeolites are suitable for a variety of applications. We report on the photocatalytic activity of a readily available and inexpensive natural zeolite clinoptilolite (Z) containing SnO2 (Sn-Z). The Sn-Z samples with 3–15 wt. % of Sn were prepared by using a precipitation–deposition method. Powder X-ray diffraction analysis showed that the zeolite structure was unaffected by the introduction of the Sn-phase. Diffuse reflectance UV/VIS spectra of the Sn-Z samples confirmed the presence of SnO2 and X-Ray absorption spectroscopy analyses suggested that the SnO2 particles mainly resided on the surface of the clinoptilolite, while ATR-FTIR analysis gave some clues that part of the SnO2 phase was incorporated in the pores of the zeolite. The presence of SnO2 in Sn-Z increased both adsorption capacity and photocatalytic performance which could be partially explained by higher surface area and partially with an increased negative potential of the surface. Adsorption and total degradation of methylene blue (MB) for the Sn-Z with the highest amount of Sn (15 wt.%) was about 30% and 45%, respectively, suggesting a synergetic effect between SnO2 and the clinoptilolite lattice. Reusability tests showed that these catalysts present a promising material for water purification.

NOM (HA and FA) Reduction in Water Using Nano Titanium Dioxide Photocatalysts (P25 and P90) and Membranes

This study examined the removal of natural organic substances (humic acids-HA, and fulvic acids-FA) from model solutions using photocatalysis and ultrafiltration. The effect of two nano titanium dioxide types (P25 and P90) with different active surface areas and two UV lamps (low-pressure and medium-pressure) on the effectiveness of FA and HA removal during photocatalysis was tested. An integrated photocatalytic + ultrafiltration system was also analyzed to determine the effectiveness of FA and HA removal and the changes in the relative permeate flux (Ultrafiltration Membrane Fouling-UF). We observed that photocatalysis using the P90 nano titanium dioxide was more efficient than the P25 due to the larger surface area (2×). The decomposition of organic substances proceeded efficiently up to 30 min of solution exposure, and the use of a medium-pressure lamp accelerated compound decomposition relative to the low-pressure lamp. The applied photocatalysis + ultrafiltration system was characterized by a high degree of FA removal while improved hydraulic efficiency was observed during ultrafiltration.

Influence of Mg, Cu, and Ni Dopants on Amorphous TiO2 Thin Films Photocatalytic Activity

The present study investigates Mg (0 ÷ 17.5 wt %), Cu (0 ÷ 21 wt %) and Ni (0 ÷ 20.2 wt %) dopants (M-doped) influence on photocatalytic activity of amorphous TiO₂ thin films. Magnetron sputtering was used for the deposition of M-doped TiO₂ thin films. According to SEM/EDS surface analysis, the magnetron sputtering technique allows making M-doped TiO₂ thin films with high uniformity and high dopant dispersion. Photocatalysis efficiency analysis was set in oxalic acid under UV irradiation. In accordance with the TOC (total organic carbon) measurements followed by the apparent rate constant (k_app) results, the dopants’ concentration peak value was dopant-dependent; for Mg/TiO₂, it is 0.9% (k_app—0.01866 cm⁻¹), for Cu/TiO₂, it is 0.6% (k_app—0.02221 cm⁻¹), and for Ni/TiO₂, it is 0.5% (k_app—0.01317 cm⁻¹). The obtained results clearly state that a concentration of dopants in TiO₂ between 0.1% and 0.9% results in optimal photocatalytic activity.

MOS Capacitance Measurements for PEALD TiO2 Dielectric Films Grown under Different Conditions and the Impact of Al2O3 Partial-Monolayer Insertion

In this paper, we report the plasma-enhanced atomic layer deposition (PEALD) of TiO₂ and TiO₂/Al₂O₃ nanolaminate films on p-Si(100) to fabricate metal-oxide-semiconductor (MOS) capacitors. In the PEALD process, we used titanium tetraisopropoxide (TTIP) as a titanium precursor, trimethyl aluminum (TMA) as an aluminum precursor and O₂ plasma as an oxidant, keeping the process temperature at 250 °C. The effects of PEALD process parameters, such as RF power, substrate exposure mode (direct or remote plasma exposure) and Al₂O₃ partial-monolayer insertion (generating a nanolaminate structure) on the physical and chemical properties of the TiO₂ films were investigated by Rutherford backscattering spectroscopy (RBS), Raman spectroscopy, grazing incidence X-ray diffraction (GIXRD), and field emission scanning electron microscopy (FESEM) techniques. The MOS capacitor structures were fabricated by evaporation of Al gates through mechanical mask on PEALD TiO₂ thin film, followed by evaporation of an Al layer on the back side of the Si substrate. The capacitors were characterized by current density-voltage (J-V), capacitance-voltage (C-V) and conductance-voltage (G-V) measurements. Our results indicate that RF power and exposure mode promoted significant modifications on the characteristics of the PEALD TiO₂ films, while the insertion of Al₂O₃ partial monolayers allows the synthesis of TiO₂/Al₂O₃ nanolaminate with well-spaced crystalline TiO₂ grains in an amorphous structure. The electrical characterization of the MOS structures evidenced a significant leakage current in the accumulation region in the PEALD TiO₂ films, which could be reduced by the addition of partial-monolayers of Al₂O₃ in the bulk of TiO₂ films or by reducing RF power.

Activation of peroxymonosulfate by Fe doped g-C3N4 /graphene under visible light irradiation for Trimethoprim degradation

Fe-doped g-C₃N₄ / graphene (rGO) composites were investigated as catalysts for the activation of peroxymonosulfate (PMS) to degrade Trimethoprim (TMP) under visible light irradiation. The rapid recombination of photogenerated electron-hole pairs in g-C₃N₄ may be suppressed by doping with Fe and incorporating rGO. The TMP degradation efficiency using 0.2% Fe-g-C₃N₄/2 wt% rGO/PMS was 3.8 times than that of g-C₃N₄/PMS. The degradation efficiency of TMP increased with higher catalyst dosages and PMS concentrations. Acidic condition (pH = 3) was observed to significantly enhance the TMP degradation efficiency from 61.4% at pH = 6 to nearly 100%. By quenching experiments and electron spin resonance (ESR), O₂^- was found to play an important role for the activation of PMS to accelerate the generation of reactive radicals for the TMP degradation. A total of 8 intermediates derived from hydroxylation, demethoxylation and carbonylation were identified through theoretical calculations and the HRAM/LC-MS-MS technique, and transformation pathways of TMP oxidation were proposed. TOC removal rate of TMP increased as reaction time was prolonged. Acute toxicity estimation by quantitative structure-active relationship analysis indicated that most of the less toxic intermediates were generated. The aim of this study was to elucidate and validate the functionality of a promising polymeric catalyst for the environmental remediation of organic contaminants.

Enhanced UV Light Emission by Core-Shell Upconverting Particles Powering up TiO2 Photocatalysis in Near-Infrared Light

The core-shell NaYb0.99F4:Tm0.01@NaYF4 upconverting particles (UCPs) with a high UV emission to apply in NIR-driven photocatalysis were synthesized. The influence of the Yb3+ doping concentration in NaYxF4:Yb0.99−xTm0.01 core particles, and the role of the NaYF4 shell on the upconversion emission intensity of the UCPs were studied. The absorption of NIR light by the obtained UCPs was maximized by increasing the Yb3+ concentration in the core, reaching the maximum for Y3+-free particles (NaYb0.99F4:Tm0.01). Additionally, covering the NaYb0.99F4:Tm0.01 core with a protective layer of NaYF4 minimized the surface luminescence quenching, which significantly improved the efficiency of upconversion emission. The high intensity of the UV light emitted by the NaYb0.99F4:Tm0.01@NaYF4 under NIR irradiation resulted in a high photocatalytic activity of TiO2 (P25) mixed with the synthesized material.

Continuous-flow synthesis and application of polymer-supported BODIPY Photosensitisers for the generation of singlet oxygen; process optimised by in-line NMR spectroscopy

Commercial polystyrene Merrifield-type resins have been post-synthetically functionalised with BODIPY photosensitisers via a novel aryl ester linking strategy in continuous-flow. A unique synthetic advantage of post-synthetically modifying heterogeneous materials in flow was identified. The homogeneous analogues of the polymer-supported BODIPYs were synthesised and used as reference to assess photophysical properties altered by the polymer-support and linker. The homogeneous and polymer-supported BODIPYs were applied in visible-light photosensitisation of singlet oxygen for the conversion of α-terpinene to ascaridole. Materials produced in flow were superior to batch in terms of functional loading and photosensitisation efficiency. Flow photochemical reactions generally outperformed batch by a factor of 4 with respect to rate of reaction. The polymer-supported BODIPY resins could be irradiated for 96 h without loss of photosensitising ability. Additional material synthetic modification and conditions optimisation using an in-line NMR spectrometer resulted in a 24-fold rate enhancement from the initial material and conditions.

TiO2 Nanostructured Films for Electrochromic Paper Based-Devices

Electrochromic titanium dioxide (TiO2) nanostructured films were grown on gold coated papers using a microwave-assisted hydrothermal method at low temperature (80 °C). Uniform nanostructured films fully covered the paper substrate, while maintaining its flexibility. Three acids, i.e., acetic, hydrochloric and nitric acids, were tested during syntheses, which determined the final structure of the produced films, and consequently their electrochromic behavior. The structural characteristics of nanostructured films were correlated with electrochemical response and reflectance modulation when immersed in 1 M LiClO4-PC (lithium perchlorate with propylene carbonate) electrolyte, nevertheless the material synthesized with nitric acid resulted in highly porous anatase films with enhanced electrochromic performance. The TiO2 films revealed a notable contrast behavior, reaching for the nitric-based film optical modulations of 57%, 9% and 22% between colored and bleached states, at 250, 550 and 850 nm, respectively in reflectance mode. High cycling stability was also obtained performing up to 1500 cycles without significant loss of the electrochromic behavior for the nitric acid material. The approach developed in this work proves the high stability and durability of such devices, together with the use of paper as substrate that aggregates the environmentally friendly, lightweight, flexibility and recyclability characters of the substrate to the microwave synthesis features, i.e., simplicity, celerity and enhanced efficiency/cost balance.

Waste-to-resource strategy to fabricate functionalized material from waste brick

Waste brick (WB), as a major type of construction and demolition waste, has posed much potential disasters to the environment and society due to the main disposal method of direct landfill. In this work, we presented a sustainable and promising recycling approach to transform WB into TiO₂ nanoneedles functionalized waste brick grain material (TiO₂/WBG) via a simple physical treatment and in-situ growth technique. The raw WBG can be as promising substrate material due to excellent chemical stability. After surface functionalization of TiO₂ nanoneedles, the obtained TiO₂/WBG exhibits significantly enhanced hierarchical porous structure. Based on the inherent chemical properties and hierarchical structure of TiO₂ nanoneedles coating, TiO₂/WBG shows special wettability of excellent underwater oleophobicity and photodegradability of organic pollutants. Besides, the modified TiO₂/WBG with low-surface-energy chemical obtains fine hydrophobicity. Therefore, the as-prepared TiO₂/WBG is believed to hold potential applications in oil/water separation, pollutant degradation and water purification. This work opens new avenues for effectively utilizing waste brick as resource to fabricate functionalized material with potential application value, showing far-reaching value and significance in fundamental research and environmental protection.

Influence of pH and DO on the ofloxacin degradation in water by UVA-LED/TiO2 nanotube arrays photocatalytic fuel cell: mechanism, ROSs contribution and power generation

The influence of pH and dissolved oxygen (DO) on the degradation of ofloxacin (OFX) in water by UVA-LED/TiO₂ nanotube arrays photocatalytic fuel cell (UVA-LED/TNA PFC) was investigated. The degradation pathway depended on the location of OFX frontier orbital with different ionization states and the role of reactive oxidative species (ROSs) played with varied pH and DO values. In presence of DO, the quencher tests revealed that O₂^- played a key role at pH 3.0, 7.0 and 11.0, while OH made its greatest contribution at pH 3.0 and the effect of h⁺ was largely inhibited at pH 11.0. Hydroxylation for cationic OFX was more significant, while demethylation and piperazinyl ring oxidation for anionic OFX occurred more quickly compared to other forms. Besides, zwitterionic OFX underwent decarboxylation and combination of demethylation & hydroxylation more easily. Much higher power generation was observed in presence of DO at pH 7.0, probably due to the enhanced adsorption of OFX on the TNA, and DO could amplify the electric potential between the two electrodes. The degradation efficiencies were almost the same in presence or absence of DO, but the pathways were different and e-_aq may replace O₂- as the leading ROSs in absence of DO.

Recent developments in MnO2-based photocatalysts for organic dye removal: a review

The textile industry consumes a large volume of organic dyes and water. These organic dyes, which remained in the effluents, are usually persistent and difficult to degrade by conventional wastewater treatment techniques. If the wastewater is not treated properly and is discharged into water system, it will cause environmental pollution and risk to living organisms. To mitigate these impacts, the photo-driven catalysis process using semiconductor materials emerges as a promising approach. The semiconductor photocatalysts are able to remove the organic effluent through their mineralization and decolorization abilities. Besides the commonly used titanium dioxide (TiO₂), manganese dioxide (MnO₂) is a potential photocatalyst for wastewater treatment. MnO₂ has a narrow bandgap energy of 1~2 eV. Thus, it possesses high possibility to be driven by visible light and infrared light for dye degradation. This paper reviews the MnO₂-based photocatalysts in various aspects, including its fundamental and photocatalytic mechanisms, recent progress in the synthesis of MnO₂ nanostructures in particle forms and on supporting systems, and regeneration of photocatalysts for repeated use. In addition, the effect of various factors that could affect the photocatalytic performance of MnO₂ nanostructures are discussed, followed by the future prospects of the development of this semiconductor photocatalysts towards commercialization.

Merits of photocatalytic and antimicrobial applications of gamma-irradiated Co x Ni1-x Fe2O4/SiO2/TiO2; x = 0.9 nanocomposite for pyridine removal and pathogenic bacteria/fungi disinfection: implication for wastewater treatment

In this paper, we report a layer-by-layer approach for the preparation of a concentric recyclable composite (Co x Ni1-x Fe2O4/SiO2/TiO2; x = 0.9) designed for wastewater treatment. The prepared composite was investigated by X-ray diffraction spectroscopy, high-resolution transmission electron microscopy and scanning electron microscopy (SEM) supported with energy dispersive X-ray (EDX) spectroscopy to analyze crystallinity, average particle size, morphology and elemental composition, respectively. The antimicrobial activities of the prepared composite have been investigated against multi-drug-resistant bacteria and pathogenic fungi using a variety of experiments, such as zone of inhibition, minimum inhibitory concentration, biofilm formation and SEM with EDX analysis of the treated bacterial cells. In addition, the effects of gamma irradiation (with different doses) and UV irradiation on the antibacterial abilities of the prepared composite have been evaluated. Moreover, the effect of gamma irradiation on the crystallite size of the prepared composite has been studied under varying doses of radiation (25 kGy, 50 kGy and 100 kGy). Finally, the photocatalytic efficiency of the prepared composite was tested for halogen-lamp-assisted removal of pyridine (artificial wastewater). Various parameters affecting the efficiency of the photocatalytic degradation, such as photocatalyst dose, pyridine concentration, pH, point of zero charge and the presence of hydrogen peroxide, have been studied. Our results show that the synthesized composite has a well-crystallized semi-spherical morphology with an average particle size of 125.84 nm. In addition, it possesses a high degree of purity, as revealed by EDX elemental analysis. Interestingly, the prepared composite showed promising antibacterial abilities against almost all the tested pathogenic bacteria and unicellular fungi, and this was further improved after gamma and UV irradiation. Finally, the prepared composite was very efficient in the light-assisted degradation of pyridine and its degradation efficiency can be tuned based on various experimental parameters. This work provides a revolutionary nanomaterial-based solution for the global water shortage and water contamination by offering a new wastewater treatment technique that is recyclable, cost effective and has an acceptable time and quality of water.