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SnS-Ti/TiO2photoanode for anticancer drug degradation.

Titanium(IV) oxide, titania, photocatalyst particles were prepared from titanium alkoxide in the presence of several kinds of ionic liquids, and it was clarified that a group of samples exhibited photocatalytic activity for phenol degradation under the irradiation of light of wavelength >400 nm higher than those of the other group of samples. Although the conventional structural analytical results could not be related to the activity, electron-trap distribution measured by reversed double-beam photoacoustic spectroscopy suggested that a part of the ionic liquid induced the creation of a surface amorphous layer covered with hydrophobic organic residues to enhance the adsorption of phenol on the surface.

The evolution of the analytical techniques allowed the detection of pollutants so called contaminants of emerging concern (CEC). Water scarcity is a reality lived by some populations. Thus, water reuse is mandatory to minimize this problematic. This implies that wastewater treatments must be improved. The Advanced Oxidation Processes (AOP) such as photocatalysis and ozonation can be suitable solutions for CECs abatement. Also, TiO2 powder catalyst is an important material in this field. However, its powder form presents a huge obstacle for industrial application, and the solution may be to support this material. This work studies the degradation of a mixture of 3 parabens by photocatalysis, catalytic and photocatalytic ozonation using TiO2 nanotube arrays (NTs). The studied catalysts were produced using electrolyte solutions with different ages, so the nanotubes growth ocurred at 5 (NTs_5) and 20 (NTs_20) anodization cycles. The toxicological assessment for the initial mixture, final samples and along the reaction time was performed using the cress seeds Lepidium sativum and the bacteria Aliivibrio fischeri. The photocatalysis with UVA radiation led to 50 % and 35 % parabens removal for NTs_5 and NTs_20 catalysts. This can be related to the different dimensional characteristics of the nanotubes. Ozone technologies led to total parabens degradation with an improvement when catalytic ozonation was applied. The use of NTs as catalysts in ozonation also reduced the transferred ozone dose (TOD) required for total parabens abatement when compared to single ozonation. The main parabens degradation mechanism seems to be via direct pathway by molecular ozone. Regarding the toxicity assessment, the toxicity did not change significatively, which can be explained by the intermediate’s formation.

We compared the activity enhancement effect of noble metal deposited on TiO2 in photocatalytic nitrogen oxides oxidation. Titanium dioxide was decorated with Ag, Au, Pt or Pd in the sol-gel process. Synthesized catalysts were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller measurement (BET), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDX). All catalysts together with pure TiO2 obtained by sol-gel (SG) technique were tested for their photocatalytic activity towards nitrogen oxide oxidation (high concentrations of 50, 150 and 250 ppm). FTIR spectrometry was used to determine the gas phase composition and identify TiO2 surface species. The Ag0.1 sample turned out to be deactivated within 60 min of UV/Vis irradiation. Photocatalytic oxidation rate towards NO2 turned to be the highest over SG (photocatalyst without metal deposition). NO2 formation was also observed for Au0.1, Au0.5, Pt0.1, Pt0.5 and Pd0.1. The best NOx removal, i.e., conversion to final product HNO3 was obtained with the Au0.5 photocatalyst.

A new and active material in the form of ZnIn2S4 microspheres decorated by CuInS2 quantum dots have been obtained by hydrothermal method for the first time. The optimum amount of CuInS2 quantum dots (1.13 wt.%) introduced into rection medium during ZnIn2S4 microspheres synthesis increased the photocatalytic H2 generation rate by 2.5 times than that of bare ZnIn2S4 photocatalysis under visible light irradiation. This sample exhibited strong photoactivity in the extended visible range up to 540 nm with 30.6% apparent quantum efficiency (λ = 420 nm).

Applied cutting-edge electronic structure and phonon simulations provide a reliable knowledge about the stability of perovskite structures and their electronic properties, which are crucial for des...

Ionic liquids (ILs) containing distinct nitrogen-bearing organic cations (pyridinium, pyrrolidinium, imidazolium, ammonium, morpholinium) were first used for the preparation of 23 IL-TiO2 types of composites by ionic liquid assisted solvothermal synthesis. These 23 optimal ILs structures (i.e. compounds exhibiting an optimal combination of specific properties, functionality, and safety) for synthesis and experimental validation were selected by computational high-throughput screening from a combinatorically created library containing 836 ILs theoretically designed and characterized candidates. Then, selected IL-TiO2 structures with potential photocatalytic activity were synthesized with the use of solvothermal reaction. Then, the decomposition level, the role of the individual IL cation structure on the morphology, thermal stability, surface and photocatalytic properties of the IL-TiO2 microparticles were determined experimentally. The chemoinformatic analysis of the relationship between the structure of the ionic liquid, its thermal stability under the conditions of synthesis and photocatalytic activity was applied for the first time. The results presented here are the first step in the development of methodology (combined experimental and theoretical) that may simplify the procedure of designing safer and more efficient TiO2-based photocatalyst. The developed computational methodology makes it possible to predict properties of newly synthesized IL-TiO2 materials before synthesis and identifies structural features of ILs that influence the efficiency of IL-TiO2 system. The presented approach reduces the number and cost of necessary experiments, as well as increases the success ratio of efficient TiO2-based photocatalyst design by a selection of optimal IL structures (i.e. ionic liquid characterized by a combination of most promising physicochemical features).

Graphitic carbon nitride (g-C3N4) is a promising catalyst for contaminants of emerging concern removal applications, especially as a visible-light-driven material. In this study, g-C3N4 catalysts were effectively synthesized through a simple thermal polymerization method, using melamine, urea, and thiourea as precursors to elucidate the influence of these compounds on the final product’s photocatalytic performance. The degradation of a mixture of three parabens was investigated under different types of radiation: two artificial, ultraviolet-A (UVA) and visible LED, and natural sunlight. The urea-based catalyst (UCN) presented better results under all radiation sources, followed by thiourea, and finally, melamine. Among the artificial light sources, the degradation of parabens under UVA was considerably higher than visible—up to 51% and 21%, respectively—using UCN; however, the broader spectrum of natural sunlight was able to achieve the highest removals, up to 92%, using UCN. Comparing artificial radiation sources, UVA lamps presented 45% lower energy consumption and associated costs. Photocatalytic ozonation was tested using UCN and MCN, with UCN once more possessing superior performance and a synergetic effect between photocatalysis and ozonation, with complete removal under 12 min. The use of g-C3N4 was then successfully tested in initial screening and found to be an efficient alternative in more low-cost and feasible solar photocatalysis water treatment.

Microplastics (MPs) pollution is one of the most important problems of the Earth. They have been found in all the natural environments, including oceans and the atmosphere. In this study, the concentrations of both atmospheric and marine MPs were measured over the Baltic along a research cruise that started in the Gdansk harbour, till the Gotland island, and the way back. A deposition box (based on a combination of active/passive sampling) was used to collect airborne MPs while, marine MPs concentrations were investigated during the cruise using a dedicated net. Ancillary data were obtained using a combination of particle counters (OPC, LAS and CPC), Aethalometer (AE33 Magee Scientific), spectrofluorometer (sea surface samples, Varian Cary Eclipse), and meteorological sensors. Results showed airborne microplastics average concentrations higher in the Gdansk harbour (161 ± 75 m-3) compared to the open Baltic Sea and to the Gotland island (24 ± 9 and 45 ± 20 m-3). These latter values are closer to the ones measured in the sea (79 ± 18 m-3). The MPs composition was investigated using μ-Raman (for the airborne ones) and FTIR (for marine ones); similar results (e.g. polyethylene, polyethylene terephthalates, polyurethane, polystyrene) were found in the two environmental compartments. The concentrations and similar composition in air and sea suggested a linkage between the two compartments. For this purpose, the atmospheric MPs' equivalent aerodynamic diameter was calculated (28 ± 3 μm) first showing the capability of atmospheric MPs to remain suspended in the air. At the same time, the computed turnover times (0.3-90 h; depending on MPs size) limited the transport distance range. The estimated MPs sea emission fluxes (4-18 ∗ 106 μm3 m-2 s-1 range) finally showed the contemporary presence of atmospheric transport together with a continuous emission from the sea surface enabling a grasshopper long-range transport of microplastics across the sea.

The increasing air pollution taking place in virtue of human activity has a novel impact in our health. Heterogeneous photocatalysis is a promising way of degrading volatile organic compounds (VOCs) that makes the quest of new and improved photocatalysts of great importance. Herein, perovskite-related materials ATiO3 with A = Mg, Ni, Co, Zn were synthesized through an ethylene glycol-mediated root, with ethylene glycol being used as a solvent and ligand. Characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy, and energy dispersive X-ray spectroscopy (SEM/EDX), transmission electron microscopy (TEM), UV-vis spectroscopy, Raman spectroscopy, Fourier transform infrared (FT-IR), and photoluminescence spectroscopy (PL) were used in order to confirm the structure, the nanorod morphology, their absorption in UV-vis, and the separation efficiency of photogenerated charge carriers. The highest photoactivity was observed for ZnTiO3 in which 62% of toluene was decomposed after 60 min under LED illumination (54 mW/cm2).

Self-organized TiO 2 nanotubes as immobilized photocatalysts were evaluated in detail for the photocatalytic degradation of parabens mixtures from ultrapure water. This kind of approach can be a very suitable option for emerging contaminants degradation considering the possibility of the catalyst reuse and recovery which will be simpler than when catalytic powders are used. The anodization method was applied for the TiO 2 nanotubes production under different preparation voltages (20, 30 and 40 V). These preparation conditions are important on the morphological characteristics of nanotubes such as length, as well as internal and external diameters. The photocatalytic efficiency was dependent on the materials preparation voltages. The photocatalytic oxidation was evaluated using two different irradiation sources, namely UVA and sunlight. These irradiation sources were evaluated for parabens mixture degradation using different number of catalytic plates. The increase of the number of plates improved the parabens degradation possibly due to the availability of more active sites which can be relevant for the hydroxyl radical's generation. The effect of the reactor design was also evaluated using sunlight irradiation. The configuration, position and solar concentrators can be important for the performance of degradation. The mechanism of degradation was analysed through by-products formation under sunlight irradiation. The main responsible for parabens degradation was hydroxyl radical. Decarboxylation, dealkylation and hydroxylation seem to be the most important reactional steps for the mixture decontamination.

Photocatalytic water splitting has great potential in solar-hydrogen production as a low-cost and environmentally friendly method. Different unique techniques used to obtain photocatalysts with various modifications to improve H2 generation have been introduced. In the present work, SrTiO3 was successfully synthesized via the solvothermal method in the presence of ionic liquid (IL) - 1-butyl-3-methylimidazolium bromide ([BMIM][Br]) followed by surface decoration with Pt particles using the photodeposition method. The effect of the noble metal content and presence of IL on the morphology, optical and surface properties of SrTiO3, thereby the effectiveness of hydrogen generation, has been thoroughly examined and presented. Unexpectedly, the presence of [BMIM][Br] at the SrTiO3 surface affected the interaction between the semiconductor surface and platinum particles formed throughout photodeposition. Platinum particles at the surface of SrTiO3_IL were found to be in the form of 2D clusters with a size of 1 nm. In comparison, Pt deposited on SrTiO3 photocatalyst without application of IL created larger, three-dimensional structures with a diameter exceeding 5 nm. This is the reason why the total amount of platinum deposited on the SrTiO3_IL sample is smaller than that on SrTiO3 and justifies a higher efficiency of hydrogen generation of Pt modified SrTiO3 photocatalyst in comparison to SrTiO3 prepared in the presence of IL. The mechanism of H2 generation in the water-splitting reaction in the presence of SrTiO3_Pt photocatalyst was discussed.

The utilization of solar light to induce a photocatalytic reaction in the presence of wide band gap semiconductors requires the modification of their surface and optical properties. The Vis-to-UV up-conversion process (UCP) that occurs in lanthanide ions could be employed to induce TiO2. Thus, having in mind solar-forced photocatalysis, nanostructured TiO2 co-modified with Tm and Li was prepared via a hydrothermal method. In addition to the exhaustive surface characterization of the as-prepared samples, the partial density of states (PDOS) was computed to better understand the electronic structure and physicochemical properties of the prepared photocatalysts. It was demonstrated that Tm ions were beneficial for phenol degradation in the aqueous phase under visible irradiation, whereas the co-presence of Tm and Li ions was profitable for enhanced luminescence. Although action spectra revealed that excitation of Tm-TiO2 in the range from 400 to 490 nm led to the photodegradation of phenol and 2-propanol, the UCP was not responsible for the photocatalytic activity under Vis irradiation. Therefore, it is proposed that the formation of sub-band gap states from the lanthanide 4f level played a key role in the phenol degradation process.

Modifying the geometric and surface parameters of oriented TiO2 nanotubes (NTs) is beneficial to the utilization of solar energy for chemical reactions, and this performance may be further improved. Thus, the effects of adding an ionic liquid (IL), 1-butylpiridinium chloride [BPy][Cl], and the effects of the water content and preparation conditions on the surface morphological, physicochemical, photocatalytic, and photoelectrochemical properties of TiO2 NTs were thoroughly examined and presented. The anodic oxidation of Ti foil in an organic electrolyte containing a small amount of [BPy][Cl] allowed for obtaining IL_NTs with a well-ordered structure, even at low voltages (10 V). Additionally, the application of [BPy][Cl] enabled one of the geometric parameters of the IL_NTs, namely, the diameter, to be tuned, whereas the length remained the same (i.e., control over the diameter was first noted). Improvements in the photocatalytic and photoelectrochemical activities of the IL_NTs in comparison with those o...

Due to their photon up-converting capability, lanthanide ions are ideal candidates dopants for semiconductors for developing visible light-driven photocatalytic activity. Of particular relevance, the low luminescence efficiency of Ln-based nanoparticles is one of the main factors that limits their further applications. Carbon, which is present on the surface of all TiO2 photocatalysts, can be responsible for luminescence quenching processes and, thus, decreasing the photocatalytic activity of TiO2. This article presents a systematic experimental and theoretical study of the effects of carbon on the photocatalytic performance of Ho3+-modified TiO2. Ho3+-TiO2 photocatalysts modified with various carbon contents (from 0.5 to 20 mol.%) were successfully prepared using a simple hydrothermal method. As-obtained samples were characterized by UV–Vis diffuse reflectance spectroscopy (DRS/UV–Vis), X-ray diffraction (XRD), X-ray photoelectron emission spectroscopy (XPS), N2 adsorption measurements, photoluminescent spectroscopy (PL), field-emission scanning electron microscopy (FE-SEM) and scanning transmission microscopy (STEM). The photodegradation efficiency of phenol was estimated for visible light (λ > 420 nm and λ > 455 nm). The XPS and XRD analyses and theoretical calculations revealed that the substitutional doping of holmium and carbon in the TiO2 anatase structure resulted in the appearance of a new sub-band-gap. Changes in the material texture, BET surface area and pore volume can be easily controlled via carbon content in samples. Doping of the Ho3+-TiO2 photocatalysts with carbon resulted in quenching of the emission of Ho3+ and, thus, the photodegradation of phenol, was observed in samples containing smaller amounts of carbon. Sixty minutes of irradiation resulted in 89% of phenol degradation under visible light (λ > 420 nm).

The efficient and safe degradation of drugs present in wastewater requires the design of a new material possessing high activity for that process. In addition to other methods, photoelectrocatalysis (PEC) merges the strengths of both photocatalytic and electrochemical methods, and the efficiency could be enhanced by the type of photoelectrode material. To address this challenge, three Ti/TiO2 nanotube-based photoelectrodes, differing in their tube morphology, were prepared by anodic oxidation and employed for the degradation of the 5-fluorouracil (5-FU) drug by the PEC process. The highest efficiency for 5-fluorouracil (5-FU) degradation by PEC was observed for the photoelectrode with a 1.7 μm length, 65 nm diameter and 8 nm wall thickness of TiO2 nanotubes, which were prepared by Ti foil anodization at 30 V. The effects of applied potential, irradiation intensity, initial pH and 5-FU concentration on PEC were investigated. Furthermore, our findings showed that the mechanism of photoelectrocatalysis in the presence of TiO2 nanotubes is based on ∙OH and h+ activity. To determine the 5-FU degradation pathway, the organic byproducts were identified by LC-MS analysis. Furthermore, the ecotoxicity evaluated during PEC dropped with decreasing 5-FU concentration.

The water scarcity, the presence of different contaminants in the worldwide waters and wastewaters and their impacts should motivate their good elimination and water management. With this, photocatalysis and photocatalytic ozonation are strong solutions to obtain good quality reclaimed water, for different applications. Nanostructured supported photo-active catalysts, such as the TiO

The design of an active, stable and efficient photocatalyst that is able to be used for hydrogen production is of great interest nowadays. Therefore, four methods of AgTaO3 perovskite synthesis, such as hydrothermal, solvothermal, sol-gel and solid state reactions, were proposed in this study to identify the one with the highest hydrogen generation efficiency by the water splitting reaction. The comprehensive results clearly show that the solid state reaction (SSR) led to the obtainment of a sample with an almost seven times higher photocatalytic activity than the other methods. Furthermore, four ionic liquids, all possessing nitrogen in the form of organic cations (two imidazoliums with different anions, ammonium and tetrazolium), were used for the first time to prepare composites consisting of AgTaO3 modified with IL and Pt, simultaneously. The effect of the ionic liquids (ILs) and Pt nanoparticles&rsquo, presence on the structure, morphology, optical properties, elemental composition and the effectiveness of the hydrogen generation was investigated and discussed. The morphology investigation revealed that the AgTaO3 photocatalysts with the application of [OMIM]-cation based ILs created smaller granules (&lt, 500 nm), whereas [TBA] [Cl] and [TPTZ] [Cl] ILs caused the formation of larger particles (up to 2 &mu, m). We found that various ILs used for the synthesis did not improve the photocatalytic activity of the obtained samples in comparison with pristine AgTaO3. It was detected that the compound with the highest ability for hydrogen generation under UV-Vis irradiation was the AgTaO3_0.2% Pt (248.5 &mu, mol∙g&minus, 1), having an almost 13 times higher efficiency in comparison with the non-modified pristine sample. It is evidenced that the enhanced photocatalytic activity of modified composites originated mainly from the presence of the platinum particles. The mechanism of photocatalytic H2 production under UV-Vis light irradiation in the presence of an AgTaO3_IL_Pt composite in the water splitting reaction was also proposed.

Taking our current environmental situation in the world into consideration, people should face growing problems of air and water pollution. Heterogeneous photocatalysis is a highly promising tool to improve both air and water quality through decomposition/mineralization of contaminants directly into harmless CO2 and H2O under ambient conditions. In this contribution, we focused on the synthesis of self-assembly WO3 thin films via an electrochemical approach in the aqueous electrolyte containing fluoride ions toward air purification. The effect of preparation conditions such as applied potential (10–50 V), anodization time (15–120 min), concentration of H2SO4 (0.5–1.5 M) and NaF (0.1–1.0 wt.%) on the morphology, photocurrent response, and photocatalytic activity addressed to removal of air pollutant in the presence of as-prepared WO3 samples were thoroughly examined and presented. The results revealed the growth of nanoplatelets and their gradual transformation into flower-like structures. The oxide layers and platelet thickness of the WO3 samples were found to be proportionally related with the synthesis conditions. The photocatalytic ability toward air purification was evaluated by degradation of toluene from air mixture using low-powered LEDs as an irradiation source (λmax = 415 nm). The highest photoactivity was achieved in presence of the sample which possessed a well-ordered, regular shape and repeatable distribution of flower buds (100% of degradation). The results have confirmed that the oxide layer thickness of the anodic WO3 significantly affected the photocatalytic activity, which increased with the increasing thickness of WO3 (to 1.05 μm) and then had a downward trend. The photocurrent response evidenced that the well-organized sample had the highest ability in photocurrent generation under UV-Vis and Vis irradiation. Finally, a possible growth mechanism of WO3 NFs was also discussed.