Publications by authors named "Anna Ilnicka"

19 Publications

  • Page 1 of 1

The effect of nitrogen species on the catalytic properties of N-doped graphene.

Sci Rep 2021 Dec 14;11(1):23970. Epub 2021 Dec 14.

Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100, Toruń, Poland.

The production of effective catalysts in the oxygen reduction reaction (ORR) continues to be a great challenge for scientists. A constant increase in demand for energy storage materials is followed by a proportionate increase in the number of reports on electrocatalyst synthesis. The scientific world focuses on environmentally friendly materials synthesized in accordance with the safest possible. In this work, we developed a facile method of obtaining heavy-metal-free electrode materials that are effective in ORR. Graphene-based catalysts were doped using azodicarbonamide (ADC) as the source of nitrogen, then carbonized at high temperatures in the range of 700-900 °C under inert gas flow. The produced materials were tested as catalysts for ORR, which is the most important reaction for Zn-air batteries and fuel cells. All obtained nitrogen-doped graphene foams showed increased catalytic activity in ORR owing to active sites created by nitrogen functional groups on the graphene surface. This paper shows that carbonization temperature has a significant impact on nitrogen content and that a small percentage of nitrogen may have a positive effect on the catalytic activity of the obtained materials. The number of transferred electrons in ORR was found to range from three to the maximal theoretical value, i.e., four.
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http://dx.doi.org/10.1038/s41598-021-03403-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8671485PMC
December 2021

High surface area micro-mesoporous graphene for electrochemical applications.

Sci Rep 2021 Nov 11;11(1):22054. Epub 2021 Nov 11.

Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, 87-100, Torun, Poland.

The manuscript presents results on the influence of external pressure on graphene exfoliation and subsequent 3D structuring by means of liquid-phase exfoliation. In contrast to known and applied exfoliation methods, the current study exploits the enhancement of splitting forces caused by the application of high pressure. The manufacturing pathway allowed to increase the surface area from 750 m/g (nanoplatelets) to ca. 1100 m/g (after 3D structuring). Electrochemical studies revealed that the 3D graphene materials were active in the oxygen reduction reaction (ORR). The outstanding ORR activity of 3D structured graphene materials should not be ascribed to heteroatom catalytic centers since such heteroatoms were successively removed upon increasing the carbonization temperature. XPS data showed that the presence of transition metals and nitrogen (usually regarded as catalytic centers) in G-materials was marginal. The results highlight the importance of structural factors of electrodes in the case of graphene-based materials for Zn-air batteries and ORR.
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http://dx.doi.org/10.1038/s41598-021-01154-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8585976PMC
November 2021

Linking the Defective Structure of Boron-Doped Carbon Nano-Onions with Their Catalytic Properties: Experimental and Theoretical Studies.

ACS Appl Mater Interfaces 2021 Nov 22;13(43):51628-51642. Epub 2021 Oct 22.

Department of Organic Chemistry, Faculty of Pharmacy with the Division of Laboratory Medicine, Medical University of Bialystok, Mickiewicza 2A, 15-222 Bialystok, Poland.

Defects are widely present in nanomaterials, and they are recognized as the active sites that tune surface properties in the local region for catalysis. Recently, the theory linking defect structures and catalytic properties of nanocatalysts has been most commonly described. In this study, we prepared boron-doped carbon nano-onions (B-CNOs) by applying an annealing treatment of ultradispersed nanodiamond particles and amorphous boron. These experimental conditions guarantee doping of CNOs with boron atoms in the entire carbon nanostructure, thereby ensuring structural homogeneity. In our research, we discuss the correlations between defective structures of B-CNOs with their catalytic properties toward SO and -butanol dehydration. We show that there is a close relationship between the catalytic properties of the B-CNOs and the experimental conditions for their formation. It is not only the mass of the substrates used for the formation of B-CNOs that is crucial, that is, the mass ratio of NDs to amorphous B, but also the process, including temperature and gas atmosphere. As it was expected, all B-CNOs demonstrated significant catalytic activity in HSO oxidation. However, the subsequent annealing in an air atmosphere diminished their catalytic activity. Unfortunately, no direct relationship between the catalytic activity and the presence of heteroatoms on the B-CNO surface was observed. There was a linear dependence between catalytic activity and Raman reactivity factors for each of the B-CNO materials. In contrast to SO oxidation, the B-CNO-a samples showed higher catalytic activity in -butanol dehydration due to the presence of Brønsted and Lewis acid sites. The occurence of three types of boron-Lewis sites differing in electron donor properties was confirmed using quantitative infrared spectroscopic measurements of pyridine adsorption.
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http://dx.doi.org/10.1021/acsami.1c12126DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8569677PMC
November 2021

Combined effect of nitrogen-doped functional groups and porosity of porous carbons on electrochemical performance of supercapacitors.

Sci Rep 2021 09 15;11(1):18387. Epub 2021 Sep 15.

Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100, Torun, Poland.

In this work, nitrogen-doped porous carbons obtained from chitosan, gelatine, and green algae were investigated in their role as supercapacitor electrodes. The effects of three factors on electrochemical performance have been studied-of the specific surface area, functional groups, and a porous structure. Varying nitrogen contents (from 5.46 to 10.08 wt.%) and specific surface areas (from 532 to 1095 m g) were obtained by modifying the carbon precursor and the carbonization temperature. Doping nitrogen into carbon at a level of 5.74-7.09 wt.% appears to be the optimum for obtaining high electrochemical capacitance. The obtained carbons exhibited high capacitance (231 F g at 0.1 A g) and cycle durability in a 0.2 mol L KSO electrolyte. Capacitance retention was equal to 91% at 5 A g after 10,000 chronopotentiometry cycles. An analysis of electrochemical behaviour reveals the influence that nitrogen functional groups have on pseudocapacitance. While quaternary-N and pyrrolic-N nitrogen groups have an enhancing effect, due to the presence of a positive charge and thus improved electron transfer at high current loads, the most important functional group affecting energy storage performance is graphite-N/quaternary-N. The study points out that the search for the most favourable organic precursors is as important as the process of converting precursors to carbon-based electrode materials.
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http://dx.doi.org/10.1038/s41598-021-97932-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8443607PMC
September 2021

The Improvement of Energy Storage Performance by Sucrose-Derived Carbon Foams via Incorporating Nitrogen Atoms.

Nanomaterials (Basel) 2021 Mar 17;11(3). Epub 2021 Mar 17.

Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland.

This paper addresses the problem of improving electrochemical energy storage with electrode materials obtained from common raw ingredients in a facile synthesis. In this study, we present a simple, one-pot route of synthesizing microporous carbon via a very fast reaction of sucrose and graphene (carbon source), chitosan (carbon and nitrogen source), and HPO. Porous carbons were successfully produced during high temperature carbonization, using nitrogen as a shielding gas. Samples were characterized using X-ray powder diffractometry, elemental analysis, N adsorption-desorption measurements, scanning electron microscopy, and Raman spectroscopy. The developed carbon material possessed a high surface area, up to 1313 m g, with no chemical or physical activators used in the process. The structural parameters of the microporous carbons varied depending on the ratio of reagents and mass composition. Samples were prepared both with and without chitosan. The present synthesis route has the advantages of being a single-step approach and only involving low-cost and environmentally friendly sources of carbon. More importantly, microporous carbon was prepared without any activators and potentially offers great application in supercapacitors. Cyclic voltammetry and constant current charge-discharge tests show that sucrose-based porous carbons show excellent electrochemical performance with a specific capacitance of up to 143 F g at a current density of 1 A g in a 6 M KOH electrolyte.
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http://dx.doi.org/10.3390/nano11030760DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8002957PMC
March 2021

Green algae and gelatine derived nitrogen rich carbon as an outstanding competitor to Pt loaded carbon catalysts.

Sci Rep 2021 Mar 29;11(1):7084. Epub 2021 Mar 29.

Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100, Torun, Poland.

The development of effective catalysts for the oxygen reduction reaction (ORR) is a significant challenge in energy conversion systems, e.g., Zn-air batteries. Herein, green-algae- and gelatine-derived porous, nitrogen-rich carbons were extensively investigated as electrode materials for electrochemical catalytic reactions. These carbon-based catalysts were designed and optimized to create a metal-free catalyst via templating, carbonization, and subsequent removal of the template. The additional incorporation of graphene improved electronic conductivity and enhanced the electrochemical catalytic reaction. Porous carbons with heteroatoms were used as effective platinum-free ORR electrocatalysts for energy conversion; the presence of nitrogen in the carbon provided more active sites for ORR. Our catalyst also displayed notable durability in a rechargeable Zn-air battery energy system. More importantly, the nitrogen-containing porous carbons were found to have comparable ORR performance in alkaline media to commercially available electrocatalysts. The manuscript demonstrates that nitrogen atom insertion is an appropriate approach when aiming to eliminate noble metals from the synthesis route. N-doped carbons are competitive materials compared to reference platinum-based catalysts.
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http://dx.doi.org/10.1038/s41598-021-86507-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8007801PMC
March 2021

N-doped graphene foam obtained by microwave-assisted exfoliation of graphite.

Sci Rep 2021 Jan 21;11(1):2044. Epub 2021 Jan 21.

Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100, Torun, Poland.

The synthesis of metal-free but electrochemically active electrode materials, which could be an important contributor to environmental protection, is the key motivation for this research approach. The progress of graphene material science in recent decades has contributed to the further development of nanotechnology and material engineering. Due to the unique properties of graphene materials, they have found many practical applications: among others, as catalysts in metal-air batteries, supercapacitors, or fuel cells. In order to create an economical and efficient material for energy production and storage applications, researchers focused on the introduction of additional heteroatoms to the graphene structure. As solutions for functionalizing pristine graphene structures are very difficult to implement, this article presents a facile method of preparing nitrogen-doped graphene foam in a microwave reactor. The influence of solvent type and microwave reactor holding time was investigated. To characterize the elemental content and structural properties of the obtained N-doped graphene materials, methods such as elemental analysis, high-resolution transmission electron microscopy, scanning electron microscopy, and Raman spectroscopy were used. Electrochemical activity in ORR of the obtained materials was tested using cyclic voltamperometry (CV) and linear sweep voltamperometry (LSV). The tests proved the materials' high activity towards ORR, with the number of electrons reaching 3.46 for tested non-Pt materials, while the analogous value for the C-Pt (20 wt% loading) reference was 4.
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http://dx.doi.org/10.1038/s41598-021-81769-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7820460PMC
January 2021

3D hierarchical porous hybrid nanostructure of carbon nanotubes and N-doped activated carbon.

Sci Rep 2020 11 2;10(1):18793. Epub 2020 Nov 2.

Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100, Torun, Poland.

In this work, carbon nanotubes (CNTs)/nitrogen-doped activated carbon (AC) hybrids were designed and fabricated using a facile and one-step synthesis. The synthesis of CNTs is based on the recently discovered phenomenon of thermally-induced polyfurfuryl alcohol (PFA) conversion. Hybrid materials are fabricated through the in-situ free growth of closed carbon nanotubes on low-cost activated carbon substrates which were obtained from green algae or amino acids. Herein, three types of carbon nanotubes were observed to freely grow on an activated carbon background from Chlorella vulgaris or L-lysine, types such as multiwalled carbon and bamboo-like nanotubes, whose structure depends on the background used and conditions of the synthesis. Structure type is identified by analyzing transmission electron microscopy images. HRTEM images reveal the tubes' outer diameter to be in the range of 20-120 nm. Because the carbon surface for the growth of carbon tubes contains nitrogen, the final hybrid materials also possess pyridinic-N and quaternary-N groups, as indicated by X-ray photoelectron spectra.
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http://dx.doi.org/10.1038/s41598-020-75831-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608594PMC
November 2020

Synthesis of Hybrid Carbon Materials Consisting of N-Doped Microporous Carbon and Amorphous Carbon Nanotubes.

Materials (Basel) 2020 Jul 6;13(13). Epub 2020 Jul 6.

Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland.

The N-doped hybrid carbon materials containing amorphous carbon nanotubes (ACNTs) were obtained by free growth of a polymer at 200 °C. The improvement of electrical conductivity was achieved by a final carbonization at 600-800 °C under the flow of nitrogen. The microstructure of ACNT/N-doped hybrids was characterized using a transmission electron microscope and X-ray diffusion. Furthermore, their elemental composition was measured using energy-dispersive X-ray spectroscopy and an elemental analyzer. The experimental results indicated that the ACNTs had a diameter in the range of 40-60 nm and the N-doped carbon background contained nitrogen atoms in most bonded pyrrolic-N and quaternary-N groups. The results revealed that the microstructure of the as-grown nanotubes, prepared by the proposed method, is mainly amorphous. This technique introduces the advantages of low cost and process simplicity, which may redeem some drawbacks of the methods commonly used in ACNT synthesis.
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http://dx.doi.org/10.3390/ma13132997DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7372370PMC
July 2020

Photosensitizing potential of tailored magnetite hybrid nanoparticles functionalized with levan and zinc (II) phthalocyanine.

Appl Surf Sci 2020 Sep 7;524:146602. Epub 2020 May 7.

Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland.

Phototherapies, including photodynamic therapy (PDT), have been widely used in the treatment of various diseases, especially for cancer. However, there is still a lack of effective, safe photosensitizers that would be well tolerated by patients. The combination of several methods (like phototherapy and hyperthermia) constitutes a modern therapeutic approach, which demands new materials based on components that are non-toxic without irradiation. Therefore, this study presents the synthesis and properties of novel, advanced nanomaterials in which the advantage features of the magnetic nanoparticles and photoactive compounds were combined. The primary purpose of this work was the synthesis of magnetic nanoparticles coated with biocompatible and antitumor polysaccharide - levan, previously unknown from scientific literature, and the deposition of potent photosensitizer - zinc(II) phthalocyanine on their surface. In order to better characterize the nature of the coating covering the magnetic core, the atomic force microscope analysis, a contact angle measurement, and the mechanical properties of pure levan and its blend with zinc(II) phthalocyanine films were investigated. This magnetic nanomaterial revealed the ability to generate singlet oxygen upon exposure to light. Finally, preliminary toxicity of obtained nanoparticles was tested using the Microtox® test - with and without irradiation.
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http://dx.doi.org/10.1016/j.apsusc.2020.146602DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7204711PMC
September 2020

Improving the Performance of Zn-Air Batteries with N-Doped Electroexfoliated Graphene.

Materials (Basel) 2020 May 2;13(9). Epub 2020 May 2.

Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland.

The constantly growing demand for active, durable, and low-cost electrocatalysts usable in energy storage devices, such as supercapacitors or electrodes in metal-air batteries, has triggered the rapid development of heteroatom-doped carbon materials, which would, among other things, exhibit high catalytic activity in the oxygen reduction reaction (ORR). In this article, a method of synthesizing nitrogen-doped graphene is proposed. Few-layered graphene sheets (FL-graphene) were prepared by electrochemical exfoliation of commercial graphite in a NaSO electrolyte with added calcium carbonate as a separator of newly-exfoliated FL-graphene sheets. Exfoliated FL-graphene was impregnated with a suspension of green algae used as a nitrogen carrier. Impregnated FL-graphene was carbonized at a high temperature under the flow of nitrogen. The N-doped FL-graphene was characterized through instrumental methods: high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. Electrochemical performance was determined using cyclic voltamperometry and linear sweep voltamperometry to check catalytic activity in ORR. The N-doped electroexfoliated FL-graphene obeyed the four-electron transfer pathways, leading us to further test these materials as electrode components in rechargeable zinc-air batteries. The obtained results for Zn-air batteries are very important for future development of industry, because the proposed graphene electrode materials do not contain any heavy and noble metals in their composition.
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http://dx.doi.org/10.3390/ma13092115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7254366PMC
May 2020

Alternative Synthesis Method for Carbon Nanotubes.

Small 2019 Dec 21;15(51):e1904132. Epub 2019 Nov 21.

Faculty of Chemistry, Nicolaus Copernicus University in Torun, ul. Gagarina 7, 87-100, Torun, Poland.

It is demonstrated that carbon nanotubes (CNTs) can be synthetized on the surface of an example carbon background, activated carbon, using the thermal conversion of poly(furfuryl alcohol) (PFA). This newly discovered CNTs synthesis method is an alternative solution to previously known methods, e.g., chemical vapor deposition, arc discharge, and laser ablation. Scanning electron microscopy and high-resolution transmission electron microscopy images deliver direct evidence of CNT formation through the thermal degradation of PFA in a temperature range of 500-700 °C. The discovered process consists of the free growth of CNTs from PFA without any mechanical patterning, casting, or molding. CNTs obtained in this manner resemble MWCNTs in size, though according to microscopic investigation the tubes do not possess the well-developed layered structure of MWCNTs. Nonetheless, X-ray photoelectron spectroscopy and Raman spectroscopy studies fully confirm that carbon (C) is the main elemental constituent of the tubes (C atomic content above 85%) and C atoms are structured in a manner typical of defected CNTs (D, G, and G' intensity ratios).
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http://dx.doi.org/10.1002/smll.201904132DOI Listing
December 2019

Effective Synthesis of Carbon Hybrid Materials Containing Oligothiophene Dyes.

Materials (Basel) 2019 Oct 15;12(20). Epub 2019 Oct 15.

Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, 87-100 Torun, Poland.

This paper shows the first study of the synthesis of hybrid materials consisting of commercial Norit carbons and oligothiophenes. The study presents the influence of surface oxidation on dye deposition as well as changes of pore structure and surface chemistry. The hybrid materials were characterised using Raman spectroscopy, and scanning and transmission electron microscopy (SEM and HR-TEM, respectively). Confocal microscopy was employed to confirm the immobilization of oligomers on the surface of the carbons being investigated. Confocal microscopy measurements were additionally used to indicate whether dye molecules covered the entire surface of the selected commercial Norit samples. Specific surface area and pore structure parameters were determined by low-temperature nitrogen adsorption. Additionally, elemental content and surface chemistry were characterised by means of X-ray photoelectron spectroscopy (XPS) and combustion elemental analysis. Experimental results confirmed that oligothiophene dyes were adsorbed onto the internal part of the investigated pores of the carbon materials. The pores were assumed to have a slit-like shape, a set of 82 local adsorption isotherms was modelled for pores from 0.465 nm to 224 nm. Further, XPS data showed promising qualitative results regarding the surface characteristics and chemical composition of the hybrid materials obtained (sulphur content ranged from 1.40 to 1.45 at%). It was shown that the surface chemistry of activated carbon plays a key role in the dye deposition process. High surface heterogeneity after hydrothermal oxidation did not improve dye adsorption due to specific interactions between surface oxygen moieties and local electric charges in the oligothiophene molecules.
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http://dx.doi.org/10.3390/ma12203354DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6829365PMC
October 2019

Electro-Exfoliation of Graphite to Graphene in an Aqueous Solution of Inorganic Salt and the Stabilization of Its Sponge Structure with Poly(Furfuryl Alcohol).

Nanomaterials (Basel) 2019 Jul 3;9(7). Epub 2019 Jul 3.

Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, 87-100 Torun, Poland.

We demonstrate an accessible and effective technique for exfoliating graphite foil and graphite powder into graphene in a water solution of inorganic salt. In our research, we report an electrochemical cathodic exfoliation in an aqueous solution of NaSO. After electro-exfoliation, the resulting graphene was premixed with furfuryl alcohol (FA) and an inorganic template (CaCO and NaCO). Once FA was polymerized to poly(furfuryl alcohol) (PFA), the mixture was carbonized. Carbon bridges originating in thermally-decomposed PFA joined exfoliated graphene flakes and stabilized the whole sponge-type structure after the nano-template was removed. Gases evolved at the graphite electrode (cathode) played an important role in the process of graphene-flake splitting and accelerated the change of graphite into graphene flakes. Starting graphite materials and graphene sponges were characterized using Raman spectroscopy, SEM, high-resolution transmission electron microscopy (HRTEM), elemental analysis, and low-temperature adsorption of nitrogen to determine their structure, morphology, and chemical composition. The discovered manufacturing protocol had a positive influence on the specific surface area and porosity of the sponges. The SEM and HRTEM studies confirmed a high separation degree of graphite and different agglomeration pathways. Raman spectra were analyzed with particular focus on the intensities of I and I peaks; the graphene-type nature of the sponges was confirmed.
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http://dx.doi.org/10.3390/nano9070971DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6669511PMC
July 2019

Effect of Geometrical Structure, Drying, and Synthetic Method on Aminated Chitosan-Coated Magnetic Nanoparticles Utility for HSA Effective Immobilization.

Molecules 2019 May 18;24(10). Epub 2019 May 18.

Faculty of Chemistry, Nicolaus Copernicus University in Torun, Gagarina 7, 87-100 Torun, Poland.

Human serum albumin (HSA) is one of the most frequently immobilized proteins on the surface of carriers, including magnetic nanoparticles. This is because the drug-HSA interaction study is one of the basic pharmacokinetic parameters determined for drugs. In spite of many works describing the immobilization of HSA and the binding of active substances, research describing the influence of the used support on the effectiveness of immobilization is missing. There are also no reports about the effect of the support drying method on the effectiveness of protein immobilization. This paper examines the effect of both the method of functionalizing the polymer coating covering magnetic nanoparticles (MNPs), and the drying methods for the immobilization of HSA. Albumin was immobilized on three types of aminated chitosan-coated nanoparticles with a different content of amino groups long distanced from the surface FeO-CS-Et(NH). The obtained results showed that both the synthesis method and the method of drying nanoparticles have a large impact on the effectiveness of immobilization. Due to the fact that the results obtained for FeO-CS-Et(NH) significantly differ from those obtained for the others, the influence of the geometry of the shell structure on the ability to bind HSA was also explained by molecular dynamics.
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http://dx.doi.org/10.3390/molecules24101925DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6572529PMC
May 2019

Marine and Freshwater Feedstocks as a Precursor for Nitrogen-Containing Carbons: A Review.

Mar Drugs 2018 Apr 26;16(5). Epub 2018 Apr 26.

Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, 87-100 Torun, Poland.

Marine-derived as well as freshwater feedstock offers important benefits, such as abundance, morphological and structural variety, and the presence of multiple elements, including nitrogen and carbon. Therefore, these renewal resources may be useful for obtaining N- and C-containing materials that can be manufactured by various methods, such as pyrolysis and hydrothermal processes supported by means of chemical and physical activators. However, every synthesis concept relies on an efficient transfer of nitrogen and carbon from marine/freshwater feedstock to the final product. This paper reviews the advantages of marine feedstock over synthetic and natural but non-marine resources as precursors for the manufacturing of N-doped activated carbons. The manufacturing procedure influences some crucial properties of nitrogen-doped carbon materials, such as pore structure and the chemical composition of the surface. An extensive review is given on the relationship between carbon materials manufacturing from marine feedstock and the elemental content of nitrogen, together with a description of the chemical bonding of nitrogen atoms at the surface. N-doped carbons may serve as effective adsorbents for the removal of pollutants from the gas or liquid phase. Non-recognized areas of adsorption-based applications for nitrogen-doped carbons are presented, too. The paper proves that nitrogen-doped carbon materials belong to most of the prospective electrode materials for electrochemical energy conversion and storage technologies such as fuel cells, air⁻metal batteries, and supercapacitors, as well as for bioimaging. The reviewed material belongs to the widely understood field of marine biotechnology in relation to marine natural products.
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http://dx.doi.org/10.3390/md16050142DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5983274PMC
April 2018

Nano-Structured Carbon Matrixes Obtained from Chitin and Chitosan by a Novel Method.

J Nanosci Nanotechnol 2016 Mar;16(3):2623-31

A series of porous carbon matrixes was prepared by phosphoric (V) acid activation of unconventional precursors chitin and chitosan: impregnation with H3PO4 at concentrations ranging from 1.34 to 5.53 mole dm(-3), followed by carbonization at 600 degrees C. The obtained carbons demonstrated well-developed porosity that declined steadily in the micropore and mesosopore ranges, depending on both the kind of the precursor and the concentration of activator. The surface area and pore volume of the carbons prepared from chitin increased upon the rising impregnation ratio. The surface area and total pore volume reached their maximum values (1257 m2g(-1) and 1.007 cm3g(-1), respectively) for the acid concentration of 3.40 mole dm(-3). The chars obtained from chitosan showed the values of the BET surface area ranging from 970 to 1484 m2g(-1). Chemical analysis indicated that the activation with phosphoric acid led to the chars of exceptionally high concentration of nitrogenated functionalities and a typical amount of oxygenated surface groups.
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http://dx.doi.org/10.1166/jnn.2016.10839DOI Listing
March 2016

The fungicidal properties of the carbon materials obtained from chitin and chitosan promoted by copper salts.

Mater Sci Eng C Mater Biol Appl 2015 24;52:31-6. Epub 2015 Mar 24.

Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarina St., 87-100 Torun, Poland.

Renewable raw materials chitin and chitosan (N-deacetylated derivative of chitin) were subjected to action of different copper modifiers that were carbonized in the atmosphere of the N2 inert gas. As a result of the novel manufacturing procedure, a series of carbon materials was obtained with developed surface area and containing copper derivatives of differentiated form, size, and dispersion. The copper modifier and manufacturing procedure (concentration, carbonization temperature) influence the physical-chemical and fungicide properties of the carbons. The received carbons were chemically characterized using several methods like low-temperature adsorption of nitrogen, X-ray diffraction analysis, scanning electron microscopy, cyclic voltammetry, elemental analysis, and bioassay. Besides chemical testing, some biological tests were performed and let to select carbons with the highest fungicidal activity. Such carbons were characteristic of the specific form of copper derivatives occurring in them, i.e., nanocrystallites of Cu(0) and/or Cu2O of high dispersion on the surface of carbon. The carbons may find an application as effective contact fungistatic agents in cosmetology, medicine, food industry, etc.
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http://dx.doi.org/10.1016/j.msec.2015.03.037DOI Listing
February 2016

Biologically active constituents from Salix viminalis bio-oil and their protective activity against hydrogen peroxide-induced oxidative stress in Chinese hamster ovary cells.

Appl Biochem Biotechnol 2014 Nov 30;174(6):2153-61. Epub 2014 Aug 30.

Faculty of Chemistry, Nicolaus Copernicus University, ul. Gagarina 7, 87-100, Torun, Poland.

The protective antioxidative effect of the phenolic extract (PE) isolated from Salix viminalis pyrolysis derived bio-oil was shown in vitro on the Chinese hamster ovary (CHO) cells exposed to hydrogen peroxide (H2O2). Cells pretreated with 0.05 μg/ml PE after exposure to different concentrations of H2O2 (300-900 μM) showed up to 25 % higher viability than the unpretreated ones. The antioxidative effect of PE was also observed in a time-dependent manner. The results were confirmed by visual examination of the specimens using microscopy. Finally, superoxide dismutase (SOD) activity modulation was shown by SOD assay, designed to determine the activity of enzymes removing free radicals.
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http://dx.doi.org/10.1007/s12010-014-1171-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4207959PMC
November 2014
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