Artykuły naukowe (WTiICh)

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https://oa.zut.edu.pl/handle/20.500.12539/91

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Przeglądaj Artykuły naukowe (WTiICh) wg Autor "Ćmielewska, Katarzyna"

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  • Miniatura
    PozycjaOpen Access
    CO2 Reduction to Valuable Chemicals on TiO2-Carbon Photocatalysts Deposited on Silica Cloth
    (MDPI, 2021-12-28) Morawski, Antoni Waldemar; Ćmielewska, Katarzyna; Witkowski, Kordian; Kusiak-Nejman, Ewelina; Pełech, Iwona; Staciwa, Piotr; Ekiert, Ewa; Sibera, Daniel; Wanag, Agnieszka; Gano, Marcin; Narkiewicz, Urszula
    A new photocatalyst for CO2 reduction has been presented. The photocatalyst was prepared from a combination of a commercial P25 with a mesopore structure and carbon spheres with a microporous structure with high CO2 adsorption capacity. Then, the obtained hybrid TiO2-carbon sphere photocatalysts were deposited on a glass fiber fabric. The combined TiO2-carbon spheres/silica cloth photocatalysts showed higher efficiency in the two-electron CO2 reduction towards CO than in the eight-electron reaction to methane. The 0.5 g graphitic carbon spheres combined with 1 g of TiO2 P25 resulted in almost 100% selectivity to CO. From a practical point of view, this is promising as it economically eliminates the need to separate CO from the gas mixture after the reaction, which also contains CH4 and H2.
  • Miniatura
    PozycjaOpen Access
    Effective green ammonia synthesis from gaseous nitrogen and CO2 saturated-water vapour utilizing a novel photocatalytic reactor
    (ScienceDirect, 2022-10-15) Morawski, Antoni Waldemar; Ćmielewska, Katarzyna; Ekiert, Ewa; Kusiak‐Nejman, Ewelina; Pełech, Iwona; Staciwa, Piotr; Sibera, Daniel; Wanag, Agnieszka; Kapica‐Kozar, Joanna; Gano, Marcin; Lendzion-Bieluń, Zofia; Narkiewicz, Urszula
    The ammonia synthesis from nitrogen and hydrogen derived from water vapor in the photocatalytic process performed under mild conditions is presented. A new solution of a gas-phase photocatalytic reactor with the bed in the form of a UV transparent glass fiber cloth coated with AEROXIDE® P25 TiO2 was applied. The bed in the reactor is located just above the water surface. The gases circulate from above towards the water surface, where the produced ammonia is easily absorbed and continuously separated from the gas phase, shifting the ammonia synthesis equilibrium towards the product. The highest amount of ammonia (about 1.3 mmol NH4+/g TiO2 after 6 h) was obtained at 20 °C, and with the use of the gaseous mixture containing CO2 (15%), N2 (85%), and water vapour derived from water located at the bottom of the reactor. Carbon dioxide in the reaction environment is simultaneously reduced to carbon monoxide and methane.
  • Miniatura
    PozycjaOpen Access
    The influence of the addition of carbon spheres on photoactivity of TiO2 and ZnO in CO2 reduction process
    (Elsevier, 2023-09-09) Morawski, Antoni W.; Ćmielewska, Katarzyna; Kusiak-Nejman, Ewelina; Staciwa, Piotr; Kapica-Kozar, Joanna; Ekiert, Ewa; Pełech, Iwona; Narkiewicz, Urszula; Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydział Technologii i Inżynierii Chemicznej. Katedra Technologii Chemicznej Nieorganicznej i Inżynierii Środowiska; West Pomeranian University of Technology in Szczecin. Faculty of Chemical Technology and Engineering. Department of Inorganic Chemical Technology and Environment Engineering
    The development of an effective photocatalyst for CO2 reduction is currently being addressed by many scientists. This study concerns the influence of the addition of carbon spheres (CS) on photoactivity of TiO2 and ZnO. The photocatalysts were tested in a liquid phase system in an alkaline environment. The suspensions of the tested materials were irradiated with UV–Vis light for 6 h. Then, the amount of the obtained products in the gas phase was analysed by gas chromatography. The identified products of CO2 photoreduction were hydrogen, carbon monoxide, and methane. Based on the results, it was found that CS/TiO2 and CS/ZnO showed similar activity in carbon dioxide reduction processes, however, more product amounts were obtained in experiments with the use of CS/TiO2 materials. The addition of carbon spheres to titanium dioxide improved its activity in carbon monoxide production. The maximum photoactivity of CS/TiO2 was observed for the addition of 0.1 g of CS. On the other hand, in the case of CS/ZnO materials, carbon spheres did not positively affect their performance. Nevertheless, their activity increased with the CS amount.
  • Miniatura
    PozycjaOpen Access
    New Insight on Carbon Dioxide–Mediated Hydrogen Production
    (Chemistry Europe, 2022-04-03) Morawski, Antoni Waldemar; Kusiak-Nejman, Ewelina; Pełech, Iwona; Ćmielewska, Katarzyna; Sibera, Daniel; Staciwa, Piotr; Wanag, Agnieszka; Gano, Marcin; Ekiert, Ewa; Kapica‐Kozar, Joanna; Witkowski, Kordian; Narkiewicz, Urszula
    A new approach to hydrogen production from water is described. This simple method is based on carbon dioxide-mediated water decomposition under UV radiation. The water contained dissolved sodium hydroxide, and the solution was saturated with gaseous carbon dioxide. During saturation, the pH decreased from about 11.5 to 7–8. The formed bicarbonate and carbonate ions acted as scavengers for hydroxyl radicals, preventing the recombination of hydroxyl and hydrogen radicals and prioritizing hydrogen gas formation. In the presented method, not yet reported in the literature, hydrogen production is combined with carbon dioxide. For the best system with alkaline water (0.2 m NaOH) saturated with CO2 under UV-C, the hydrogen production amounted to 0.6 μmol h−1 during 24 h of radiation.
  • Miniatura
    PozycjaOpen Access
    Photocatalytic Reduction Efficiency of CO2 Depending on ZnO Particle Size
    (MDPI, 2023-09-03) Morawski, Antoni Waldemar; Gano, Marcin; Ćmielewska, Katarzyna; Kusiak-Nejman, Ewelina; Pełech, Iwona; Staciwa, Piotr; Ekiert, Ewa; Narkiewicz, Urszula; Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydział Technologii i Inżynierii Chemicznej. Katedra Technologii Chemicznej Nieorganicznej i Inżynierii Środowiska; Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydział Technologii i Inżynierii Chemicznej. Katedra Technologii Chemicznej Organicznej i Materiałów Polimerowych; West Pomeranian University of Technology in Szczecin. Faculty of Chemical Technology and Engineering. Department of Inorganic Chemical Technology and Environment Engineering; West Pomeranian University of Technology in Szczecin. Faculty of Chemical Technology and Engineering. Department of Organic Chemical Technology and Polymer Materials
    In the face of increasing global carbon dioxide emissions and the urgent need to mitigate climate change, the development of efficient and sustainable strategies for CO2 conversion has gained significant attention. One of the methods of eliminating the harmful effects of CO2 is its photoreduction. In this paper, ZnO was used as an effective photocatalyst for the photoreduction of CO2 in a gas-phase system. The influence of particle size on the process efficiency was investigated. The ZnO materials applied in the studies were characterized using XRD, SEM, and low-temperature nitrogen adsorption (BET) methods. The pore volume distribution was calculated based on the DFT method. The investigation confirmed that it had a significant impact on the formation of the product of photocatalysis carbon dioxide. The main identified product was carbon monoxide. Hydrogen and methane were detected as well. Based on the results, it was found that the process efficiency was enhanced with decreasing ZnO particle size, and the most effective catalyst for the photoreduction of CO2 was the ZnO sample with the smallest particle size (18 nm).