Adsorption and advanced oxidation processes, especially photocatalysis, are amongst the most common water treatment methodologies. Unfortunately, using each of these techniques independently does not fully eliminate the pollutants of diverse nature, which are present in wastewater. Here, an avenue for multifunctional materials for water treatment is opened by reporting for the first time the preparation, characterization, and study of the properties of a novel multifunctional nanocomposite with both adsorption and visible-light-driven photocatalysis abilities. These multifunctional nanocomposites, namely iron (II, III) oxide/poly(N-isopropylacrylamide-co-methacrylic acid)/silver-titanium dioxide (Fe3O4/P(NIPAM-co-MAA)/Ag-TiO2), are prepared by combining magnetic polymeric microspheres (Fe3O4/P(NIPAM-co-MAA)) with silver-decorated titanium dioxide nanoparticles (Ag-TiO2 NPs). Cationic dyes, such as basic fuchsin (BF), can be adsorbed by the nanocomposites thanks to the carboxylic groups of Fe3O4/P(NIPAM-co-MAA) microspheres. Concomitantly, the presence of Ag-TiO2 NPs endows the system with the visible-light-driven photocatalytic degradation ability toward antibiotics such as ciprofloxacin (CIP) and norfloxacin (NFX). Furthermore, the proposed nanocomposites show antibacterial activity toward Escherichia coli (E. coli), thanks to the presence of silver nanoparticles (Ag NPs). Due to the superparamagnetic properties of iron (II, III) oxide nanoparticles (Fe3O4 NPs), the nanocomposites can be also recycled and reused, after the cleaning process, by using an external magnetic field.

• Klíčová slova
• adsorption, dyes and antibiotics, multifunctionality, recycling, visible‐light‐driven photocatalysis,
• Publikační typ
• časopisecké články MeSH

Micro/nanomotors are capable of a wide variety of tasks related, i.e., to biomedical or environmental applications. Light-driven semiconductor-based micromotors are especially appealing, as they can split surrounding water via light irradiation, and therefore, they can move infinitely. However, their motion is typically limited to in-plane motion with four degrees of freedom (4DoF) or even pseudo-1D motion with 2DoF. Herein, magnetically steerable tubular TiO2 /Fe3 O4 /CdS micromotors, termed microsubmarines, with 6DoF motion, based on a fuel-free design where surrounding water acts as fuel upon visible light irradiation, are presented, with an average velocity of 7.9 µm s-1 . Besides, the generation of radicals via such water splitting aids the photocatalytic chemicals degradation with the potential to use solar radiation. A light-induced self-electrophoretic mechanism is responsible for the self-propulsion and can be used to predict the motion direction based on the structure and composition. Finally, the TiO2 /Fe3 O4 /CdS microsubmarines are tested in a proof-of-concept application of high-energy explosive, e.g., picric acid, photocatalytic degradation, with the best performance owing to the versatility of 6DoF motion, the surface coating with amorphous TiO2 layer, and UV light. The results can help optimize light-active micromotor design for potential national security and environmental application, hydrogen evolution, and target cargo delivery.

• Klíčová slova
• explosive decontamination, micromotor, six degrees of freedom, visible-light-driven, water fuel,
• MeSH
• dekontaminace MeSH
• světlo MeSH
• voda * MeSH
• vodík MeSH
• výbušné látky * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• voda * MeSH
• vodík MeSH
• výbušné látky * MeSH

Visible light-driven proton transfer is crucial in nature and catalysis. Here, we report that protic merocyanine-based photoswitches act as efficient and recyclable homogeneous Brønsted acid catalysts under blue or green light irradiation. Photo-promoted proton release efficiently enables Friedel-Crafts reactions with easy catalyst recovery and reuse. Furthermore, by leveraging the high two-photon absorption cross-section of merocyanines, we successfully promote the reaction using near-IR light (λ ∼ 975 nm).

• Publikační typ
• časopisecké články MeSH

Light-driven micro/nanomotors represent the next generation of automotive devices that can be easily actuated and controlled by using an external light source. As the field evolves, there is a need for developing more sophisticated micromachines that can fulfill diverse tasks in complex environments. Herein, we introduce single-component BiVO4 micromotors with well-defined micro/nanostructures that can swim both individually and as collectively assembled entities under visible-light irradiation. These devices can perform cargo loading and transport of passive particles as well as living microorganisms without any surface functionalization. Interestingly, after photoactivation, the BiVO4 micromotors exhibited an ability to seek and adhere to yeast cell walls, with the possibility to control their attachment/release by switching the light on/off, respectively. Taking advantage of the selective motor/fungal cells attachment, the fungicidal activity of BiVO4 micromotors under visible illumination was also demonstrated. The presented star-shaped BiVO4 micromotors, obtained by a hydrothermal synthesis, contribute to the potential large-scale fabrication of light-powered micromotors. Moreover, these multifunctional single-component micromachines with controlled self-propulsion, collective behavior, cargo transportation, and photocatalytic activity capabilities hold promising applications in sensing, biohybrids assembly, cargo delivery, and microbiological water pollution remediation.

• Klíčová slova
• bismuth vanadate, cargo transport, fungicidal activity, micromotors, visible light,
• MeSH
• bismut chemie   MeSH
• elektrochemické techniky MeSH
• nanostruktury chemie   MeSH
• povrchové vlastnosti MeSH
• Saccharomyces cerevisiae cytologie   izolace a purifikace   MeSH
• světlo * MeSH
• vanadáty chemická syntéza   chemie   MeSH
• velikost částic MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• bismut MeSH
• bismuth vanadium tetraoxide MeSH Prohlížeč
• vanadáty MeSH

To improve the efficiency of photocatalytic oxidative degradation of antibiotic pollutants, it is essential to develop an efficient and stable photocatalyst. In this study, a polymer-assisted facile synthesis strategy is proposed for the polymorph-controlled α-Bi2O3/Bi2O2CO3 heterojunction retained at elevated calcination temperatures. The p-n heterojunction can effectively separate and migrate electron-hole pairs, which improves visible-light-driven photocatalytic degradation from tetracycline (TC). The BO-400@PAN-140 photocatalyst achieves the highest pollutant removal efficiency of 98.21% for photocatalytic tetracycline degradation in 1 h (λ > 420 nm), and the degradation efficiency was maintained above 95% after 5 cycles. The morphology, crystal structure, and chemical state of the composites were analysed by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Ultraviolet-visible diffuse reflection, transient photocurrent response, and electrochemical impedance spectroscopy were adopted to identify the charge transfer and separation efficiency of photogenerated electron-hole pairs. The EPR results verified h+ and ˙OH radicals as the primary active species in the photocatalytic oxidation reactions. This observation was also consistent with the results of radical trapping experiments. In addition, the key intermediate products of the photocatalytic degradation of TC over BO-400@PAN-140 were identified via high-performance liquid chromatography-mass spectrometry, which is compatible with two possible photocatalytic reaction pathways. This work provides instructive guidelines for designing heterojunction photocatalysts via a polymer-assisted semiconductor crystallographic transition pathway for TC degradation into cleaner production.

• Publikační typ
• časopisecké články MeSH

Light-driven microrobots based on organic semiconductors have received tremendous attention in the past few years due to their unique properties, such as ease of reactivity tunability, band-gap modulation, and low cost. However, their fabrication with defined morphologies is a very challenging task that results in amorphous microrobots with poor motion efficiencies. Herein, we present hybrid inorganic-organic photoactive microrobots with a tubular shape and based on the combination of a mesoporous silica template with an active polymer containing thiophene and triazine units (named as Tz-Th microrobots). Owing to their well-defined tubular structure, such Tz-Th microrobots showed efficient directional motion under fuel-free conditions. Depending on the accumulation of the polymer coating, these microdevices also exhibited stand-up and rotation motion. As a proof-of-concept, we use these hybrid microrobots for the capture and degradation of toxic psychoactive drugs commonly found in wastewater effluents such as methamphetamine derivatives. We found that the microrobots were able to decompose the drug into small organic fragments after 20 min of visible light irradiation, reaching total intermediates removal after 2 h. Therefore, this approach represents a versatile and low-cost strategy to fabricate structured organic microrobots with efficient directional motion by using inorganic materials as the robot chassis, thereby maintaining the superior photocatalytic performance usually associated with such organic polymers.

• Klíčová slova
• conjugated polymer, donor−acceptor, drugs of abuse, microrobots, photocatalyst,
• MeSH
• katalýza MeSH
• lékové transportní systémy MeSH
• polovodiče MeSH
• polymery * chemie   MeSH
• světlo * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• polymery * MeSH

This contribution reports on the preparation, characterization, and biological evaluation of electrospun polystyrene nanofiber materials engineered with a covalently grafted NO photodonor and ionically entangled tetracationic porphyrin and phthalocyanine photosensitizers. These photofunctional materials exhibit an effective and simultaneous photogeneration of two antibacterial species such as nitric oxide (NO) and singlet oxygen, O2((1)Δg) under illumination with visible light, as demonstrated by their direct detection using amperometric and time-resolved spectroscopic techniques. Dual-mode photoantibacterial action is demonstrated by antibacterial tests carried out on Escherichia coli.

• Klíčová slova
• antibacterial, nanofiber, nitric oxide, photogeneration, singlet oxygen,
• MeSH
• antibakteriální látky farmakologie   MeSH
• elektrochemické techniky MeSH
• fluorescence MeSH
• iontová výměna MeSH
• kyslík chemie   MeSH
• nanovlákna chemie   ultrastruktura   MeSH
• oxid dusnatý chemie   MeSH
• polystyreny chemie   MeSH
• roztoky MeSH
• spektrofotometrie ultrafialová MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• světlo * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky MeSH
• kyslík MeSH
• oxid dusnatý MeSH
• polystyreny MeSH
• roztoky MeSH

Upgrading of biomass wastes to value-added materials has been incessantly pursued worldwide with diverse applications, especially deploying photocatalytic composites encompassing metal oxides with acidic and carbon compounds. Herein, the fabrication of a morphologically unique acidic catalyst encompassing a two-dimensional (2D) TiO2/g-C3N4 heterojunction feature is described for the generation of 5-hydroxymethylfurfural (5-HMF), which exploits the acidic/ionic liquid (IL) bifunctional photocatalysis under visible light. The structural integrity of the synthesized TiO2/g-C3N4/SO3H(IL) was corroborated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy-energy-dispersive spectroscopy (EDX-EDS), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), UV-vis, Tauc plots, transmission electron microscopy (TEM), and Brunauer-Emmett-Teller-Barrett-Joyner-Halenda (BET-BJH) analyses. Keeping environmental impact in mind, there are compelling advantages in the development of bio-derived pathways to access ILs from natural renewable resources. The outcomes of environmental assessments have revealed that the incorporation of TiO2 in g-C3N4 and ClSO3H can reduce the probability of recombination due to ionic charges present, therefore enhancing the photocatalytic activity via the transformation of cellulose and glucose to produce 5-HMF in higher yields, with the optimum conditions being reaction in water under a blue light-emitting diode (LED), at 100 °C, for 1-1.5 h. The main advantages of this production method include minimum number of synthetic steps as well as ample availability of and easy access to primary ingredients. While a significant volume of 5-HMF was produced under blue light-emitting diode (LED) radiation, the selectivity was drastically reduced in the dark. The salient attributes of the catalyst comprise stability in air, robustness, reusability, and its overall superior activity that is devoid of hazardous additives or agents. This inimitable method has uncovered a newer strategy for enhancing the photocatalytic attributes of deployed semiconducting materials for numerous photocatalytic functions while adhering to the tenets of environmental friendliness.

• Klíčová slova
• 5-hydroxymethylfurfural, TiO2, blue LED, g-C3N4, ionic liquid,
• Publikační typ
• časopisecké články MeSH

A novel octahedral distorted coordination complex was formed from a copper transition metal with a bidentate ligand (1,10-Phenanthroline) and characterized by Ultraviolet-visible spectroscopy, Ultraviolet-visible diffuse reflectance spectroscopy, Fourier-transform infrared spectroscopy, Brunauer-Emmett-Teller, Field emission scanning electron microscopy, and Single-crystal X-ray diffraction. The Hirshfeld surface and fingerprint plot analyses were conducted to determine the interactions between atoms in the Cu(II) complex. DFT calculations showed that the central copper ion and its coordinated atoms have an octahedral geometry. The Molecular electrostatic potential (MEP) map indicated that the copper (II) complex is an electrophilic compound that can interact with negatively charged macromolecules. The HOMO-LUMO analysis demonstrated the π nature charge transfer from acetate to phenanthroline. The band gap of [Cu(phen)2(OAc)]·PF6 photocatalyst was estimated to be 2.88 eV, confirming that this complex is suitable for environmental remediation. The photocatalytic degradation of erythrosine, malachite green, methylene blue, and Eriochrome Black T as model organic pollutants using the prepared complex was investigated under visible light. The [Cu(phen)2(OAc)]·PF6 photocatalyst exhibited degradation 94.7, 90.1, 82.7, and 74.3 % of malachite green, methylene blue, erythrosine, and Eriochrome Black T, respectively, under visible illumination within 70 min. The results from the Langmuir-Hinshelwood kinetic analysis demonstrated that the Cu(II) complex has a higher efficiency for the degradation of cationic pollutants than the anionic ones. This was attributed to surface charge attraction between photocatalyst and cationic dyes promoting removal efficiency. The reusability test indicated that the photocatalyst could be utilized in seven consecutive photocatalytic degradation cycles with an insignificant decrease in efficiency.

• Klíčová slova
• Band gap engineering, DFT calculation, Molecular electrostatic potential, Organic pollutants, Photocatalytic degradation, Visible light,
• MeSH
• barvicí látky chemie   MeSH
• erythrosin MeSH
• katalýza MeSH
• kinetika MeSH
• látky znečišťující životní prostředí * MeSH
• měď * chemie   MeSH
• methylenová modř chemie   MeSH
• světlo MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• barvicí látky MeSH
• Eriochrome Black T MeSH Prohlížeč
• erythrosin MeSH
• látky znečišťující životní prostředí * MeSH
• malachite green MeSH Prohlížeč
• měď * MeSH
• methylenová modř MeSH

TiO2 is one of the most widely used semiconductors for photocatalytic reactions. However, its wide bandgap energy and fast charge recombination limit its catalytic activity. Thus, herein, a new Ru(ii) polypyridyl complex, [Ruii(tptz)(CH3CN)Cl2] (tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine), was synthesized and used as a visible-light photosensitizer dye for improving the light harvesting and quantum efficiency of TiO2. Accordingly, a well-designed nanostructured photocatalyst was proposed using mesoporous TiO2 nanocrystals coupled with reduced graphene oxide (rGO) and the polypyridyl Ru(ii) complex, which was tested for the photocatalytic degradation of atrazine (ATZ) as a model of emerging water contaminants. Specifically, the Ru complex (Ru-CMP) served as an electron donor, while rGO acted as an electron acceptor, and the synergistic effect between them promoted the separation of electron-hole pairs and suppressed the charge recombination in the hybridized species. Structural analysis indicated that the TiO2 nanoparticles with an anatase crystal structure had a mesoporous texture and were homogeneously coated on the rGO sheets. The detailed FT-IR, Raman, XPS and UV-vis absorption spectroscopic analyses combined with EDS mapping clearly confirmed the successful loading of the Ru complex onto the catalyst. The PL and EIS results revealed that the addition of the Ru-CMP photosensitizer enhanced the charge separation and transport. The gas-phase geometry and energies of the molecular orbitals of the Ru complex were evaluated via DFT calculations. The results from the DFT calculations were consistent with the experimental results. Compared to pure TiO2, the as-synthesized Ru-CMP-TiO2/rGO hybrid exhibited significantly enhanced photocatalytic activity for the degradation of ATZ. The rate of ATZ degradation in the developed photocatalytic process with the Ru-CMP-TiO2/rGO hybrid was 9 times that with commercial TiO2. The enhanced photocatalytic activity of the prepared catalyst can be attributed to its better light harvesting and efficient electron transportation due to its more suitable LUMO position than the conduction band of TiO2. Moreover, the excellent conductivity and adsorption capacity of graphene contributed to the increase in photocatalytic activity. Thus, these features make the Ru-CMP-TiO2/rGO hybrid nanomaterial an excellent candidate for the photocatalytic purification of contaminated water.

• Publikační typ
• časopisecké články MeSH