TY - JOUR AU - Chodkowski, Michał AU - Terpiłowski, Konrad AU - Románszki, Loránd AU - Klébert, Szilvia AU - Mohai, Miklós AU - Károly, Zoltán TI - Effect of Non‐Thermal Sulfur Hexafluoride Cold Plasma Modification on Surface Properties of Polyoxymethylene JF - CHEMPHYSCHEM: A EUROPEAN JOURNAL OF CHEMICAL PHYSICS AND PHYSICAL CHEMISTRY J2 - CHEMPHYSCHEM PY - 2024 PG - 14 SN - 1439-4235 DO - 10.1002/cphc.202300709 UR - https://m2.mtmt.hu/api/publication/34762097 ID - 34762097 AB - X‐ray photoelectron spectroscopy was employed to reveal the differences in the chemical structure of the topmost layer after plasma modification. It was found out that changes in the surface properties of the polymer could be observed even after 20 seconds of treatment. The surface becomes hydrophobic or superhydrophobic, with the water contact angles up to 160 degrees. Morphological changes and increased roughness can be observed only in the nanoscale, whereas the structure seems to be unaffected in the microscale. As a result of plasma modification a permanent hydrophobic effect was obtained on the polyoxymethylene surface. LA - English DB - MTMT ER - TY - JOUR AU - Rácz, Anita AU - Nagyné László, Krisztina AU - Klébert, Szilvia TI - Qualitative and quantitative chemometric modelling of nanostructured carbon samples based on infrared spectroscopy JF - CARBON J2 - CARBON VL - 218 PY - 2024 PG - 7 SN - 0008-6223 DO - 10.1016/j.carbon.2023.118743 UR - https://m2.mtmt.hu/api/publication/34448239 ID - 34448239 N1 - Plasma Chemistry Research Group, HUN-REN Research Centre for Natural Sciences, Magyar Tudósok Krt. 2, Budapest, H-1117, Hungary Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Budapest, 1521, Hungary Export Date: 19 January 2024 CODEN: CRBNA Correspondence Address: Rácz, A.; Plasma Chemistry Research Group, Magyar Tudósok Krt. 2, Hungary; email: racz.anita@ttk.hu Correspondence Address: László, K.; Department of Physical Chemistry and Materials Science, Hungary; email: laszlo.krisztina@vbk.bme.hu Funding details: Hungarian Scientific Research Fund, OTKA, K 134260, K 143571, PD 134416 Funding details: Magyar Tudományos Akadémia, MTA Funding details: Nemzeti Kutatási, Fejlesztési és Innovaciós Alap, NKFIA Funding text 1: The work was supported by project no. OTKA K 134260 , K 143571 and PD 134416 of the Ministry of Innovation and Technology of Hungary from the National Research, Development, and Innovation Fund , financed under the K and PD type funding scheme , respectively. The work was supported by the Hungarian Academy of Sciences: János Bolyai Research Scholarship . The work was supported by the ÚNKP-23-5 New National Excellence Program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund . LA - English DB - MTMT ER - TY - JOUR AU - Rácz, Anita AU - Renkeczné Tátraaljai, Dóra AU - Klébert, Szilvia TI - Determination of melt flow index and polymer additives in polyethylene based on IR spectra and multivariate modeling JF - MATERIALS TODAY CHEMISTRY J2 - MATER TODAY CHEM VL - 33 PY - 2023 PG - 7 SN - 2468-5194 DO - 10.1016/j.mtchem.2023.101671 UR - https://m2.mtmt.hu/api/publication/34110212 ID - 34110212 N1 - Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, Budapest, H-1117, Hungary Laboratory of Plastics and Rubber Technology, Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem Rkp. 3, Budapest, H-1111, Hungary Export Date: 14 September 2023 Correspondence Address: Rácz, A.; Institute of Materials and Environmental Chemistry, Magyar Tudósok Körútja 2, Hungary; email: racz.anita@ttk.hu LA - English DB - MTMT ER - TY - JOUR AU - Samaniego Andrade, Samantha Kathiuska AU - SHIVA SHANKAR, LAKSHMI AU - Bakos, István AU - Klébert, Szilvia AU - Kun, Róbert AU - Mohai, Miklós AU - Nagy, Balázs AU - Nagyné László, Krisztina TI - The Influence of Reduced Graphene Oxide on the Texture and Chemistry of N,S-Doped Porous Carbon. Implications for Electrocatalytic and Energy Storage Applications JF - NANOMATERIALS J2 - NANOMATERIALS-BASEL VL - 13 PY - 2023 IS - 16 PG - 22 SN - 2079-4991 DO - 10.3390/nano13162364 UR - https://m2.mtmt.hu/api/publication/34106212 ID - 34106212 N1 - Department of Physical Chemistry and Materials Science, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Budapest, 1521, Hungary Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Magyar Tudósok Körútja 2, Budapest, 1117, Hungary Department of Chemical and Environmental Process Engineering, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Budapest, 1521, Hungary H-Ion Research, Development and Innovation Ltd, Konkoly-Thege út 29-33, Budapest, 1121, Hungary Export Date: 4 September 2023 Correspondence Address: László, K.; Department of Physical Chemistry and Materials Science, Hungary; email: laszlo.krisztina@vbk.bme.hu AB - In this work, we study the influence of reduced graphene oxide (rGO) on the morphology and chemistry of highly porous N,S-doped carbon cryogels. Simultaneously, we propose an easily upscalable route to prepare such carbons by adding graphene oxide (GO) in as-received suspended form to the aqueous solution of the ι-carrageenan and urea precursors. First, 1.25–5 wt% GO was incorporated into the dual-doped polymer matrix. The CO2, CO, and H2O emitted during the thermal treatments resulted in the multifaceted modification of the textural and chemical properties of the porous carbon. This facilitated the formation of micropores through self-activation and resulted in a substantial increase in the apparent surface area (up to 1780 m2/g) and pore volume (up to 1.72 cm3/g). However, adding 5 wt% GO led to overactivation. The incorporated rGO has an ordering effect on the carbon matrix. The evolving oxidative species influence the surface chemistry in a complex way, but sufficient N and S atoms (ca. 4 and >1 at%, respectively) were preserved in addition to the large number of developing defects. Despite the complexity of the textural and chemical changes, rGO increased the electrical conductivity monotonically. In alkaline oxygen reduction reaction (ORR) tests, the sample with 1.25 wt% GO exhibited a 4e− mechanism and reasonable stability, but a higher rGO content gradually compromised the performance of the electrodes. The sample containing 5 wt% GO was the most sensitive under oxidative conditions, but after stabilization it exhibited the highest gravimetric capacitance. In Li-ion battery tests, the coulombic efficiency of all the samples was consistently above 98%, indicating the high potential of these carbons for efficient Li-ion insertion and reinsertion during the charge–discharge process, thereby providing a promising alternative for graphite-based anodes. The cell from the 1.25 wt% GO sample showed an initial discharge capacity of 313 mAh/g, 95.1% capacity retention, and 99.3% coulombic efficiency after 50 charge–discharge cycles. LA - English DB - MTMT ER - TY - JOUR AU - Samaniego Andrade, Samantha Kathiuska AU - Kállay-Menyhárd, Alfréd AU - Klébert, Szilvia AU - Mohai, Miklós AU - Nagy, Balázs AU - Nagyné László, Krisztina TI - Effect of Carbon Nanoparticles on the Porous Texture of ι-Carrageenan-Based N-Doped Nanostructured Porous Carbons and Implications for Gas Phase Applications JF - C: JOURNAL OF CARBON RESEARCH J2 - C-J CARBON RES VL - 9 PY - 2023 IS - 3 PG - 16 SN - 2311-5629 DO - 10.3390/c9030068 UR - https://m2.mtmt.hu/api/publication/34065321 ID - 34065321 N1 - Funding Agency and Grant Number: We extend our warm thanks to A. Farkas for his invaluable assistance in Raman spectroscopy and to G. Bosznai for his technical assistance. Funding text: We extend our warm thanks to A. Farkas for his invaluable assistance in Raman spectroscopy and to G. Bosznai for his technical assistance. AB - S and N double-doped high surface area biomass-derived carbons were obtained from marine biomass-derived ι-carrageenan. Adding carbon nanoparticles (CNPs), namely graphene oxide (GO) or carbon nanotubes (CNTs), in the early stage of the synthesis leads to a modified porous texture and surface chemistry. The porous textures were characterized by N2 (−196.15 °C) and CO2 (0 °C) isotherms. The best GO- and CNT-added carbons had an apparent surface area of 1780 m2/g and 1170 m2/g, respectively, compared to 1070 m2/g for the CNP-free matrix. Analysis of the Raman spectra revealed that CNT was more efficient in introducing new defects than GO. Based on XPS, the carbon samples contain 2–4.5 at% nitrogen and 1.1 at% sulfur. The Dubinin–Radushkevich (DR) and Henry models were used to assess the strength of the interactions between various gases and the surface. The N2/H2 and CO2/CH4 selectivities were estimated with ideal adsorbed solution theory (IAST). While the CNPs, particularly GO, had a remarkable influence on the porous texture and affected the surface chemistry, their influence on the separation selectivity of these gases was more modest. LA - English DB - MTMT ER - TY - PAT AU - Bódis, Eszter AU - Fazekas, Péter AU - Károly, Zoltán AU - Keszler, Anna Mária AU - Klébert, Szilvia AU - Kótai, László AU - Szépvölgyi, János TI - Eljárás mikroméretű nikkel-cink-ferrit (NixZn1-xFe2O4, 0 < x < 1) előállítására CY - Country:10001(1) PY - 2023 UR - https://m2.mtmt.hu/api/publication/33620312 ID - 33620312 AB - Jelen találmány tárgya eljárás nikkel-cink-ferrit (NixZn1-xFe2O4, 0