Herein, we investigated how the introduction of different metal salts during the synthesis of bismuth oxychloride affects its electronic structure, revealing that the nature of the metal salt plays a key role in determining the resulting  properties. Several species (Mo, Se, W, V, Ti, Mn, Hg, and Pb) were added to affect the precipitation of the BiOCl photocatalysts. Prepared samples were investigated concerning their crystal structure, elemental composition, morphology, surface area, and optical properties, which were discussed considering possible effects of Bi substitution from the density functional theory calculations. Ti and Hg influence only the crystal growth and morphology. Mo, W, and V, as metallates, shift the absorption to the visible region, but the resulting photocatalytic activity was hindered. Pb2+ and Mn2+ ions substitute for Bi, acting as acceptor defects. Moreover, MnCl2 lead to significant crystal growth and formation of well-defined {100}, {110}, {101}, and {111} facets. The BiOCl:Mn sample shows increased activity, connected with conduction band (CB) shift and enhanced O2 reduction to ∙O2 -. Introduction of SeO3 2- deposits Se4+/S0 species on the surface, leading to the formation of smaller, well-defined rectangular BiOCl crystals. Surface selenium acts as electron traps, increasing the charge carriers lifetime and promoting 2-electron reduction of O2 to H2O2.

This study reports for the first time how the combination of crystal facet exposure and surface non-stoichiometry enhances the photocatalytic activation of peroxymonosulfate (PMS) by bismuth orthovanadate (BiVO4). Three distinct BiVO4 crystal types: octahedral BiVO4 (BVO-O) with dominant {1 2 0} facets, decahedral BiVO4 (BVO-D) featuring {0 1 0} and {0 1 1} facets, and multifaceted BiVO4 (BVO-M) with {0 1 1} and {1 1 1} facets, were thoroughly investigated. X-ray photoelectron spectroscopy (XPS) revealed a surface non-stoichiometry of BiVO4 crystals synthesised by hydrothermal method. Among facet-engineered photocatalysts, octahedral BVO-O sample was the most active one from the series, and BVO-O/PMS/Vis420 system was the most efficient for both naproxen (NPX) oxidation and & sdot;OH radicals production. On the other hand, the highest degradation enhancement due to the presence of PMS was observed for the decahedral BVO-D. DFT simulations revealed possible structures of the Bi-rich {0 1 0}, {0 1 1} and {1 2 0} facets, characterised by excess BiO2-like surface sites. The geometry of these sites had a significant impact on work function values. This parameter was found to directly control the reduction of PMS to active radicals, with experimental results showing the highest synergy on the {0 1 0}-Bi facets and the lowest on the {0 1 1}-Bi. Moreover, on the {0 1 0}-Bi facets, the desorption of radicals was found to be unfavourable, potentially creating a bottleneck in the overall degradation process. These findings underscore the structure-activity relationship of PMS activation and open new pathways for understanding the role of the surface structure in facet-engineered photocatalysts.

Controlling the oxidation state and chemical environment of photodeposited metal species remains a fundamental challenge in photocatalysis, as these are dictated by complex and poorly understood metal-support interactions. Here, we suggest a general mechanism by which doping of a photocatalyst substrate (anatase {0 0 1} facets) modulates the local chemical potential and oxygen activation pathways, thereby directing the oxidation, coordination and reactivity of photodeposited CuOX clusters. Using shallow donor (Nb5+) and acceptor (Ga3+) species as model systems, a combined DFT, spectroscopy and reactivity analysis reveals that Nb-induced electron-rich environment promote O2 adsorption and O-O dissociation at NbTi-Cu interfacial sites, accelerating Cu+/Cu2+ cycling, while Ga-induced electron withdrawal suppresses O2 dissociation and stabilizes hydrogen peroxide. Further validation confirmed similar effects for Sc3+ and Al3+ as alternative acceptors. As a proof-of-concept we used the 2% Nb-doped material with deposited 0.5% Cu for achieving state-of-the-art 400 nmol min-1 rate of the hydroxyl radicals generation (probed by coumarin in neutral pH) with 0.5 mM PMS assistance. Finally, we presented high quantum efficiencies/relative photonic efficiencies of this material in degradation of selected pollutants: phenol (20/299%), naphthalene (56/706%), EE2 (18/170%) and methomyl (100/1043%).

Black mass from spent lithium-ion batteries (LIBs) primarily derived from portable electronics was investigated as a waste-derived functional material for advanced oxidation applications. A novel mobile pilot system was applied for the direct recycling of spent LIBs, containing predominantly lithium cobalt oxide (LCO) and lithium manganese oxide (LMO). Subsequently, the black mass powders were evaluated as catalytic activators of peroxymonosulfate (PMS) in sulfamethoxazole (SMX) degradation. Among the investigated spent LIB powders, the fraction with the smallest particles exhibited the highest activity, enabling the most efficient PMS-assisted catalytic SMX degradation within only 2.5 min (kapp = 1.815 min-1) accompanied by substantial mineralization. Moreover, this catalytic system demonstrated rapid kinetics in the degradation of 21 micropollutants detected in wastewater effluent. Spin trapping experiments, analysis of PMS consumption, selective methyl phenyl sulfoxide (PMSO) oxidation and center dot OH radical generation revealed that PMS activation proceeds predominantly via a nonradical pathway with formed singlet oxygen (1O2). The reusability tests of the catalysts confirmed that the black mass materials revealed high mineralization efficiency over consecutive reaction cycles. This study highlights the benefits of combining direct recycling with size fractionation to improve the catalytic performance of materials derived from e-waste, supporting black mass valorization as a potential sustainable materials resource.

Organic-inorganic hybrid compounds based on quinuclidinium and metal bromides, (C7H14N)2MBr4 (M = Co, Mn, Cd), have been synthesized. Differential scanning calorimetry measurements indicate that all compounds undergo a reversible phase transition at 251 K (Co), 205 K (Mn), and 363 K (Cd) upon heating. The respective temperature dependences of the dielectric permittivity reveal anomalies, confirming the occurrence of phase transitions. Although the crystals are isostructural at room temperature, as confirmed by X-ray diffraction data, the mechanism of the phase transitions varies in each compound. The main driving force is the reorientation of quinuclidinium, resulting in the rearrangement of hydrogen bonds. Satisfactory dielectric and thermal stability properties of these materials have been demonstrated, highlighting their potential for applications in temperature sensors and switch devices.

Polypropylene-based composites reinforced with xylite filler, a natural carbonaceous material derived from brown coal, were investigated with a focus on their recyclability and structural integrity after multiple processing cycles. The study aimed to evaluate the effects of six mechanical recycling cycles on the thermal, mechanical, and structural properties of polypropylene composites containing 25 wt

Extensive peripheral nerve injuries often lead to the loss of neurological function due to slow regeneration and limited recovery over large gaps. Current clinical interventions, such as nerve guidance conduits (NGCs), face challenges in creating biomimetic microenvironments that effectively support nerve repair. The developedGrooveNeuroTubeis composed of hyaluronic acid methacrylate and gelatin methacrylate hydrogel, incorporating active agents (growth factors and antibacterial agents) encapsulated within an NGC conduit made of 3D-printed PCL grid fibers.In vitrostudies showed thatGrooveNeuroTubesignificantly promoted migration of dorsal root ganglion (DRG) neuronal cells, 3D bioprinted at the far ends of the conduit to imitate a proximal nerve injury as a novelex vivomodel. A long-term culture of up to 60 d was employed to better mimicin vivoconditions. This model tested the effects of pulsed electromagnetic field stimulation on neural tissue development. After 60 d,GrooveNeuroTubeshowed a 32% cell migration increase compared to the growth-factor-group and 105% compared to the no-growth-factor condition. These results confirm that theGrooveNeuroTubesystem can effectively support sustained neural cell migration and maturation over extended periods, proving a new technology for testing peripheral nerve injuryex vivo.

Exposition of a specific crystal facets and modification with co-catalysts are often used in order to improve photocatalytic activity of a material. However, considering complexity of these interactions, it is still challenging to fully understand and predict activity of a specific system. Here, we report combination of the {0 0 1} and {1 0 1} crystal facets of anatase TiO2 with CuXO co-catalyst, applied for diclofenac degradation, center dot OH generation and 4-nitrophenol reduction. Interestingly, we observed opposite effect of Cu for center dot OH generation and DCF degradation, with clear enhancement of the activity observed only for the {0 0 1} facets. EPR measurements further proved that for the most active material in this series, Cu exist as an atomically-scattered Cu2+ species at the surface, achieved as the result of high surface development and high adsorption energy (from DFT). Based on the absorbance measurements and XPS analysis, these species are shown to be further reduced to Cu2O during degradation process. Compared to this, all other systems ({1 0 1} and all results for nitrophenol) showed reduction of the activity due to the CuXO presence. In this regard, CuXO cannot be seen as an universal reduction co-catalyst for TiO2, with final effect being clearly dependent on exposed facet and reaction. This is despite TiO2/ CuXO was found to form analogical, well-known Z-scheme junction in case of both surfaces. Ultimately, we showed that specifically {0 0 1} with CuXO make highly synergistic combination for ROS generation.

We report applying the autoclaved hydrothermal method for obtaining conductive reduced graphene oxide (rGO) fibers for potential flexible electronic applications, such as supercapacitors, transistors, or sensing applications. The reduction of GO was performed in the temperature range 120 to 180 °C under increased pressure of ca. 8 bar in a sealed Teflon lined up, stainless steel autoclave. The fiber’s diameter and length were defined by the glass tube used as the mold for reducing GO water suspension (diameter of 600 µm and length of 8 cm). After drying, in an ambient atmosphere, the hydrogel fiber shrinks to ca. 50 µm in diameter and 6 cm in length (collapsed pore structure). The drying process, in addition to enhancing electrical conductivity, also increases the mechanical strength of the fibers due to the stronger overlapping of the graphene flakes. The best performance was observed in the fiber reduced at the highest temperature studied, 180 °C, and a minimum temperature of 120 °C is necessary to obtain a fiber. Electrical conductivity was measured using the 4-probe method. The results were analyzed within the framework of variable range hopping and Arrhenius models to pinpoint the best model describing electrical conductivity in dry rGO fibers.

Imidazole molecules entrapped in porous materials can exhibit high and stable proton conductivity suitable for elevated temperature (>373 K) fuel cell applications. In this study, new anhydrous proton conductors based on imidazole and mesoporous KIT-6 were prepared. To explore the impact of the acidic nature of the porous matrix on proton conduction, a series of KIT-6 materials with varying Si/Al ratios and pure silica materials were synthesized. These materials were additionally modified with cerium atoms to enhance their Brønsted acidity. TPD-NH3 and esterification model reaction confirmed that incorporating aluminum into the silica framework and subsequent modification with cerium atoms generated additional acidic sites. UV-Vis and XPS identified the presence of Ce3+ and Ce4+ in the KIT-6 materials, indicating that high-temperature treatment after cerium introduction may lead to partial cerium incorporation into the framework. EIS studies demonstrated that dispersing imidazole within the KIT-6 matrices resulted in composites showing high proton conductivity over a wide temperature range (300–393 K). The presence of weak acidic centers, particularly Brønsted sites, was found to be beneficial for achieving high conductivity. Cerium-modified composites exhibited conductivity surpassing that of molten imidazole, with the highest conductivity (1.13 × 10−3 S/cm at 393 K) recorded under anhydrous conditions for Ce-KIT-6. Furthermore, all tested composites maintained high stability over multiple heating and cooling cycles.

The present study highlights the importance of the net density of charge carriers at the ground state on photocatalytic activity of the faceted particles, which can be seen as a highly underexplored problem. To investigate it in detail, we have systematically doped {1 0 1} enclosed anatase nanoparticles with Gd3+ ions to manipulate the charge carrier concentration. Furthermore, control experiments using an analogical Nb5+ doped sample were performed to discuss photocatalytic activity in the increased range of free electrons. Overall results showed significant enhancement of phenol degradation rate and coumarin hydroxylation, together with an increase of the designed Gd/Ti ratio up to 0.5 at. %. Simultaneously, the mineralization efficiency, measured as a TOC reduction, was controlled between the samples. The observed activity enhancement is connected with the controlled decrease of the donor state density within the materials, being the net effect of the spontaneously present defects and introduced dopants, witch reduce hydroxylation and the hole trapping ability of the {1 0 1} facets. This allows to fine-tune multi-/single-electron processes occurring over the prepared samples, leading to clear activity maxima for 4-nitrophenol reduction, H2O2 generation, and ·OH formation observed for different donor densities. The optimized material exceeds the activity of the TiO2 P25 for phenol degradation by 52% (377% after surface normalization), showing its suitable design for water treatment. These results present a promising approach to boost photocatalyst activity as the combined result of the exposed crystal facet and dopant-optimized density of ground-state charge carriers.

The spectroscopic and electrical properties of poly(pyrrole-3-carboxylic acid) doped with p-TSA- (p-toluenesul- fonate) and AQS- (anthraquinone sulfonate) were investigated. The variation in electrical conductivity as a function of temperature shows that the systems have semiconductor -like electrical characteristics. The investigated polymers exhibit 3D conductivity and less than 0.6 eV energy gaps. The IR and Raman spectra show that the charge carriers are polarons and bipolarons. Doping the poly(pyrrole-3-carboxylic acid) increases the number of charge carriers. Electron paramagnetic resonance has shown that localized polarons and bipolarons are formed within these polymers.

There is a need for a stable and economical solid proton-conducting electrolyte capable of operating at elevated temperatures (>373 K), suitable for high-performance hydrogen fuel cells. In its search, imidazole (Im) or 1,2,4-triazole (Tri) is introduced into the channels of BEA zeolites with different porosity (i.e. the conventional microporous BEA (BEA-O) and two hierarchical materials with structural (BEA-C) or interparticle (BEA-TF) mesoporosity). The proton conductivity of obtained composites increases with increasing azole loading and temperature. The generation of mesopores in BEA zeolites leads to a decrease in the activation energy of proton conductivity in composites and favors the dispersion of a large amount of azoles. Zeolites with structural porosity (BEA-C) allow to introduce the highest amount of the azole molecules (0.29 wt% of imidazole), however the highest proton conductivity and the lowest activation energy is recorded for BEA-TF-0.25Im (s = 5.86 x 10(-4) S cm(-1) at 393 K). A comparison of azole composites (with Im and Tri) of equal azole loadings shows that imidazole-containing materials exhibit significantly higher proton conductivity, regardless of the type of zeolite matrix. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

The present work concerns proton-conducting composites obtained by replacing the water molecules present in aluminophosphate and silicoaluminophosphate AFI-type molecular sieves (AlPO-5 and SAPO-5) with azole molecules (imidazole or 1,2,4-triazole). Both the introduction of azoles and the generation of Brønsted acid centers by isomorphous substitution in aluminophosphate materials were aimed at improving the proton conductivity of the materials and its stability. In the presented study, AlPO-5 and several SAPO-5 materials differing in silicon content were synthesized. The obtained porous matrices were studied using PXRD, low-temperature nitrogen sorption, TPD-NH3, FTIR, and SEM. The proton conductivity of composites was measured using impedance spectroscopy. The results show that the increase in silicon content of the porous matrices is accompanied by an increase in their acidity. However, this does not translate into an increase in the conductivity of the azole composites. Triazole composites show lower conductivity and significantly higher activation energies than imidazole composites; however, most triazole composites show much higher stability. The different conductivity values for imidazole and triazole composites may be due to differences in chemical properties of the azoles.

Nanocrystalline powders of LiCoO2 were synthesized using a modified solution combustion method, and the effects of the annealing temperature (450–900 °C) on structure and composition were investigated using various methods, including XRD, SEM, EPR, and electrical studies. It was found that, as the process temperature increases, the value of the specific surface area decreases, and, hence, the size of the crystallites increases. XRD analysis showed that phase-pure LiCoO2 material was maintained without additional phases. EPR studies revealed the presence of two Ni3+ complexes resulting from Ni impurities. The electrical properties of the studied LiCoO2 samples were investigated by using impedance spectroscopy. Comparison of the effect of annealing temperature on electrical conductivity shows a very interesting behavior. As the annealing temperature increases, the DC conductivity value increases, reaching a maximum at a temperature of 500 °C. However, further increase in the annealing temperature causes a steady decrease in the DC conductivity.

In this study, we report the potential of 2D/2D TiO2-GO-ZnFe2O4 photocatalyst obtained using the fluorine-free lyophilization technique for the degradation of ibuprofen belonging to the group of active pharmaceutical ingredients (API). The improved ibuprofen degradation under simulated solar light was achieved in the presence of a composite of 2D TiO2 combined with GO and embedded ZnFe2O4, which additionally provides superparamagnetic properties and enables photocatalyst separation after the photodegradation process. After only 20 min of the photodegradation process in the presence of 2D/2D TiO2-GO-ZnFe2O4 composite, more than 90% of ibuprofen was degraded under simulated solar light, leading to non-toxic and more susceptible to biodegradation intermediates. At the same time, photolysis of ibuprofen led to the formation of more toxic intermediates. Furthermore, based on the photocatalytic degradation analysis, the degradation by-products and possible photodegradation pathways of ibuprofen were investigated. The photodegradation tests and electronic spin resonance analyses indicated the significant involvement of superoxide radicals and singlet oxygen in the ibuprofen photodegradation process.

In the present study, alkaline earth metal scheelite-type ABO(4) compounds (A = Ca, Sr, and Ba; B = Mo and W) synthesized by a hydrothermal method were systematically studied. The as-obtained photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area analysis, UV-vis diffuse reflectance (DR/UV-vis) spectroscopy, photoluminescence, and thermoluminescence (TL) spectroscopy together with charge carrier lifetime measurements, electron paramagnetic resonance (EPR) spectroscopy, and electrochemical impedance spectroscopy (EIS). The photocatalytic activity was studied in the reaction of phenol degradation under simulated solar light. The obtained tungstates and molybdates revealed excellent photocatalytic activity despite the low surface area and wide bandgap typical for insulators. The mechanism of phenol degradation proceeded through hydroquinone and catechol formation in the presence of hydroxyl and superoxide radicals. The presence of electron traps allowed absorption of light with lower energy than resulting from the absorption edge. BaWO4 and SrWO4, with the most extended average carrier lifetime, were the most efficient photocatalysts from the obtained series. In general, molybdates exhibited lower photocatalytic activity toward phenol degradation due to deeper trap states and lower average charge carrier lifetimes than tungstates. Additionally, electrochemical studies demonstrated that molybdates exhibit more insulating behavior than tungstates. The overall results showed that wide-bandgap semiconductors, mainly tungstates, can be applied as earth-abundant photocatalytic materials for the degradation of persistent organic pollutants.

Inorganic-organic hybrid QMnCl (Q = quinuclidinium) crystals were synthesized and characterized. The X-ray and variable-temperature IR/Raman analysis demonstrate that the crystals undergo a reversible structural phase transition, which originates from an order-disorder process and is related to the dynamics of the organic Q cation. Dielectric function measurements disclose a switchability between low ("OFF") and high ("ON") dielectric states centered at around 285 K. Owing to a remarkable temperature-dependent dielectric function, this type of molecular compound can represent an interesting tunable and switchable dielectric material for a diverse range of applications.

The application of two-dimensional (2D) materials as a building component for aerogels formation allows obtaining three-dimensional (3D) structures featured by remarkable physiochemical properties. One of the most commonly applied 2D materials for the aerogels fabrication is a graphene oxide (GO), which can undergo chemical or thermal reduction forming a reduced graphene oxide (rGO) porous network. Interestingly, the influence of the reduction process on the magnetic properties of rGO-based aerogels is still uncharted. This article sheds a light onto interdependence between reducing agents (hydrazine, sodium borohydride, ethane-1,2-diamine, citric acid, ascorbic acid), which were applied during GO hydrothermal reduction, and the magnetic properties of thereby formed rGO aerogels. The magnetic characterization was performed by vibration magnetometer (VSM) and electron paramagnetic resonance (EPR) in the temperature range of 4-300 K. It was found that the choice of reducing agent significantly affects the resulting magnetic properties of aerogels. This is directly linked to the spatial organization of the defects and localization of conduction electrons in rGO hexagonal lattice.