Ákos Szamosvölgyi

Layered perovskite photoactive bismuth titanate (BT) ternary interface was achieved via a sequential hydrolysis pathway. . Comprehensive analysis of the pH modified BT photocatalyst before and after calcination, was conducted, followed by its application in the photodegradation of organic pollutant methyl orange (MO) dye and photocatalytic carbon dioxide (CO2) hydrogenation. The optimisation of the as fabricated catalysts was conducted at three different pH (3, 7, and 12) levels, followed by their calcination at 700°C. The samples before calcination, with their extraordinarily large surface area, achieved most of the adsorption of MO dye with varying concentration (20, 50, 100, 500 ppm). Furthermore, after calcination, samples demonstrated remarkable photocatalytic performance, indicating their enhanced catalytic efficacy after visible light irradiation. Due to exceptional results up to 500 ppm of MO dye, all analytes were evaluated for CO2 hydrogenation. The results indicated that calcined BT analytes exhibited substantial efficiency in CO2 photoreduction capability due to the presence of three distinct crystal structures of BT family (sillenite Bi12TiO20, perovskite Bi4Ti3O12, pyrochlore Bi2Ti2O7) with continuous electron transport among the interfaces, which possibly enhanced the process for the CO2 conversion and reduction.

Polyaniline serves as a tuneable support for controlling the catalytic performance of platinum nanoparticles, enabling regulation of metal–support interactions and allowing activation of platinum in reactions where it is typically less active.

Magnetically separable TiO₂-based composite photocatalysts have gained significant interest in the past two decades; however, the optimization of their synthesis and the stabilization of the magnetic iron oxide within the composite is still an open challenge. The present study investigates the photocatalytic behavior and recyclability of TiO₂-Fe₃O₄ composites, with emphasis on a possible correlation between pollutant degradation efficiency, recyclability, iron oxide stability, and the phase composition of the chosen TiO₂ base. Magnetite nanoparticles were synthesized under varied temperature and alkaline conditions to identify optimal parameters for achieving the desirable magnetic properties. The magnetic nanoparticles were integrated into composite systems with either commercial TiO₂ (Evonik Aeroxide P25 with anatase–rutile mixed phase) or a hydrothermally synthesized anatase TiO₂. The P25-based composite removed 99% paracetamol from aqueous solutions under UV-A irradiation and demonstrated successful recyclability, maintaining 96% paracetamol degradation efficiency after four uses. In contrast, the anatase TiO₂-based magnetic composite exhibited a lower performance (70%) and a significantly hindered recyclability (45% after four cycles). The difference in performance was attributed to variations in the phase composition of the employed TiO₂ in the composites and, consequently, in their charge separation mechanisms.

Dry reforming of methane is an advantageous technique to produce syngas by using greenhouse gases like CO₂ and CH₄. This study investigated the stability, catalytic effectiveness, and physicochemical characteristics of mono- and trimetallic catalysts based on Ni and supported on γ-Al₂O₃. Adding Co and Fe has been found to modify the structure and surface through the characterizations, including XRD, SEM, TEM, BET, H₂-TPR, and XPS methods. Compared to the monometallic Ni catalyst, the trimetallic catalysts exhibited improved alloy formation, reduced particle size, increased metal dispersion, and enhanced surface area and pore structures. The 10% Ni, 2.5% Co, and 2.5% Fe-Al₂O₃ catalyst exhibits higher CH₄ conversion, surpassing 75%, and also CO₂ conversion around 85% at 700 °C, compared to 15% Ni-Al₂O₃, which showed CH₄ conversion of about 65% and CO₂ conversion of 70%. It also showed comparatively good stability in 24 h testing performed at 700 °C. According to the findings of the research on trimetallic catalysts, their capacity to improve dry reforming of methane (DRM) performance may be attributed to increased stability, which is a crucial challenge in the production of sustainable syngas, as well as higher activity and lower deactivation.