Year: 2026
α-FeOOH-Intercalated Ti3C2Tx MXene as a new and stable heterogeneous Fenton catalyst for caffeine degradation in water
Shalu Atri, Hamidreza Behtooei, Mário Kotlár, Frantisek Zazimal, Dana Dvoranova, Tomas Roch, Leonid Satrapinskyy, Tomas Zelenka, Tomas Homola, Olivier Monfort
In: Catalysis Today, Volume 470, 2026, 115764
https://doi.org/10.1016/j.cattod.2026.115764
Abstract
This study demonstrates a simple and scalable synthesis of α-FeOOH (goethite) intercalated Ti3C2Tx MXene through TMAOH treatment, targeting efficient degradation of emerging micropollutants in wastewater via an advanced oxidation process (AOP). Such a α-FeOOH-intercalated MXene stabilizes heterogeneous Fenton-based reactions which usually suffer from decreased efficiency over time due to Fe leaching, thus highlighting the novelty of the work. The successful integration of goethite particles in the MXene interlayer space was evidenced by X-ray diffraction (XRD), Fourier-transform infrared spectrometer (FTIR) and Transmission Electron Microscopy (TEM) analysis. X-ray photoelectron analysis (XPS) revealed notable surface oxidation along with minor TiFx and TiO2-xFx impurities formed via TMAOH treatment. Increased concentration of surface functional groups along with enhanced BET area (71.2 m2 g−1) and porosity after TMAOH treatment enabled complete degradation of caffeine in ⁓ 90 min, by activation of peroxymonosulfate (PMS) under UVA light. Scavenging experiments, electron paramagnetic resonance (EPR) and XPS analysis indicated the degradation mechanism driven by Fenton-based reactions, electron transfer and interfacial surface charge transfers, with hydroxyl (•OH) and sulfate () radicals identified as predominant reactive oxygen species (ROS). The assessment of the α-FeOOH-intercalated MXene as stable Fenton catalyst was confirmed with minimal iron leaching (3.07 wt%) during catalytic reactions and robust reusability over ten cycles, thus being more efficient and sustainable than conventional Fenton-based catalysts. Post-reaction XRD,FTIR and TEM analyses further confirmed excellent structural stability of the new catalyst. These findings establish α-FeOOH-intercalated Ti3C2Tx MXene as a promising and durable catalyst for heterogeneous Fenton-based reactions applied to wastewaters treatment.
Novel Nb4C3Tx-Co3O4 nanohybrid as AOP catalyst for potential quaternary treatment of wastewaters containing pharmaceuticals
Shalu Atri, Hamidreza Behtooei, Frantisek Zazimal, Arshitha Madhusudhan, Mário Kotlár, Jana Makukova, Andrea Sevcovicova d, Tomas Roch, Marcello Brigante, Michael Naguib, Olivier Monfort
In:Chemical Engineering Journal, 174993, 534, 2026
https://doi.org/10.1016/j.cej.2026.174993
Abstract
The increasing occurrence of pharmaceutical residues in treated wastewaters, together with the emergence of MXene-based composites as novel and promising catalysts for advanced oxidation processes (AOP), motivates the development of more efficient and selective treatment technologies. In this study, a novel Nb4C3Tx-Co3O4 nanohybrid AOP catalyst was synthesized for peroxymonosulfate (PMS) activation under dark conditions to degrade four pharmaceutical pollutants including caffeine (CAF), ibuprofen (IBU), paracetamol (PAR), and sulfamethoxazole (SMX). Structural and morphological characterization confirmed successful integration of Co3O4 nanoparticles onto the Nb4C3Tx MXene surface. Under optimized conditions, complete degradation of the pharmaceuticals was obtained within 60 min, except for IBU, which required >100 min due to steric hindrance in its molecular structure, resulting in fewer sites available for attack by reactive species. The contribution of reactive species differs among the pharmaceutical where degradation of IBU and PAR was predominantly governed by sulfate radicals (), contributing over 50% while CAF and SMX followed a degradation mechanism involving singlet oxygen (1O2, up to 30%), (20–40%) and (20–40%). The AOP involved a redox-mediated PMS activation mechanism predominantly on Co and Nb surface sites. The Nb4C3Tx-Co3O4 catalyst exhibited robust performance in cocktail of pollutants and maintained satisfactory degradation efficiency, especially for SMX and PAR in tertiary effluents from wastewaters treatment plant (WWTP) collected in Bratislava. In addition, the chemical structure of degradation by-products was characterized by LC-MS analysis and a degradation mechanism was proposed. Colorimetric MTT assays of the treated waters showed no acute cytotoxicity from either the PhACs or their degradation products on short-term exposure. This study provides new insights into pollutant-specific oxidation mechanisms and reactive species profiles in PMS-based AOPs, establishing Nb4C3Tx-Co3O4 as a promising non-conventional catalyst for potential quaternary treatment in WWTP technology.
Influence of Nitrogen Pressure on the Adhesion and Scratch Failure Mechanisms of TiMoN/NbN Multilayer Coatings Deposited by Cathodic ARC PVD
O.V. Maksakova, V.M. Beresnev, S.V. Lytovchenko, M. Sahul, Mária Čaplovičová, R.S. Galushkov
In: East Eur. J. Phys., no. 1, pp. 540-547, Mar. 2026
https://doi.org/10.26565/2312-4334-2026-1-62
Abstract:
Multilayer nitride coatings are widely used to improve the mechanical performance and durability of engineering components subjected to severe tribological loading. In the present work, the adhesion behaviour and failure mechanisms of nanolayered TiMoN/NbN multilayer coatings deposited by cathodic arc PVD were investigated as a function of nitrogen working pressure. Two coatings were synthesized at nitrogen pressures of 0.52 Pa and 0.13 Pa under otherwise identical deposition conditions. Microscopy analysis revealed that both coatings exhibit a well-defined nanolayered architecture consisting of alternating TiMoN and NbN layers with a modulation period of approximately 85 nm and a total thickness of about 9.5 μm. The decreasing of nitrogen pressure results in a higher density of macroparticles due to the longer mean free path of cathodic arc plasma species. Scratch adhesion tests performed under progressive loading conditions allowed identification of two characteristic failure events corresponding to buckling crack initiation and buckling spallation. The multilayer coating deposited at 0.13 Pa demonstrated slightly improved resistance to crack initiation (5.41 N) compared with the multilayer coating deposited at 0.52 Pa (4.72 N). However, both coatings exhibited similar values of the second critical load (12.4–12.5 N). The multilayer coating deposited at higher nitrogen pressure mainly undergoes adhesive failure with extensive substrate exposure. In contrast, the multilayer coating deposited at lower nitrogen pressure exhibits predominantly cohesive damage within the multilayer structure. The obtained results demonstrate that nitrogen pressure during cathodic arc deposition significantly affects the microstructure evolution and the mechanisms of adhesion failure in TiMoN/NbN multilayer coatings. The study provides insight into the optimization of deposition parameters for improving the mechanical reliability of multilayer nitride coatings.
Advanced Biomaterials in Tissue Engineering Based on Antibacterial and Antibiofilm Nanocomposites for Multidrug-Resistant Wound PathogensCli
Aizhan B. Talipova, Volodymyr Buranych, Irina S. Savitskaya, Inara Abashidze, Fyodor I. Malchik, Dina H. Shokatayeva, Martin Sahul, Krzysztof Rokosz, Mária Čaplovičová, Alexander D. Pogrebnjak
In: ACS Omega 2026, 11, 9, 14806–14820
https://doi.org/10.1021/acsomega.5c11015
Abstract
The treatment of chronic wounds is critically challenged by resilient biofilms formed by multidrug-resistant (MDR) pathogens, which are largely impervious to conventional antibiotics. This study addresses this challenge by engineering a multifunctional hydrogel dressing that synergistically integrates bacterial cellulose (BC), MXene nanosheets, and hydroxyapatite (HAp). Plays a critical dual role in the composite, significantly boosting bioactivity while also stabilizing the MXene to prevent oxidation and maintain its antibacterial properties. As a result, the BC/MXene/HAp composite achieved a near-total (98%) eradication of viable cells in mature biofilms of challenging MDR pathogens, including MRSA and FQRPA. Such activity is driven by a dual-mechanism that effectively disrupts both the initial attachment of bacteria and the structural scaffold of established biofilms. Complementing this efficacy, in vitro assays with NIH-3T3 fibroblasts confirm that the composite supports excellent cell adhesion, proliferation, and metabolic activity, highlighting its high biocompatibility. This work demonstrates a nonantibiotic strategy to combat biofilms through a synergistically designed biomaterial. Given its robust performance and multifunctionality, this platform is a promising candidate for the development of advanced therapeutic dressings in regenerative wound care.
Anisotropic In-Plane Thermal Transport in Monolayer ReSe2 and Its Modulation through Layer Control and Selenium Vacancies: Experiment vs. Theory
Shipra Aswal, Sirsendu Ghosal, Himanshu Murari, Ravinder Chahal, Viliam Vretenár, Ravi Kumar Biroju, Ľubomír Vančo, Subhradip Ghosh and P. K. Giri
In: Nanoscale, 2025
https://doi.org/10.1039/D5NR03668B
Abstract
Understanding phonon transport and thermal anisotropy in two-dimensional (2D) materials is essential for their integration into electronic and thermal nanoscale devices. In this work, we achieve large-area, contamination-free monolayer Rhenium diselenide (ReSe2) growth via chemical vapor deposition, confirmed by atomic force microscopy and HAADF-STEM imaging. To probe its anisotropic thermal properties, we employ non-contact low-temperature Raman spectroscopy with unpolarized laser excitation to measure its thermal conductivity (κ). We report exceptionally low values of in-plane thermal conductivity κ~25.2 Wm-1K-1 for the pristine monolayer, the lowest among the TMDs. Critically, we find the introduction of more selenium vacancies further suppresses it to κ~20.7 Wm-1K-1. Polarization-dependent Raman analysis reveals a layer-dependent change in anisotropy ratio, with the ratio decreasing from 6.23 (pristine monolayer) to 4.42 (monolayer with vacancies) and further to 3.82 (trilayer), highlighting the distinct effects of both interlayer interactions and point defects on phonon transport. The suppression of κ with increasing thickness suggests enhanced phonon scattering from structural distortions and weak van der Waals coupling. These findings provide critical insights into how both layer thickness and intrinsic defects like Se vacancies can be used to modulate anisotropic transport in low-symmetry 2D materials. In addition, we employed Density Functional Theory and Boltzmann Transport Theory to elucidate the lattice phonon dynamics and thermal transport behaviour of monolayer ReSe2. The computed lattice thermal conductivity (κ_l) exhibits excellent agreement (κ_l^x ≈ 21.5 Wm-1 K-1 and κ_l^y ≈ 23.8 Wm-1 K-1) with the experimental data, thereby providing strong validation for our experimental approach. This work establishes ReSe2 as a strong candidate for thermoelectric and nanoelectronic applications where tunable thermal properties are paramount.