Photocatalytic activity induced by zinc phthalocyanine synthesized by microwave irradiation

Zinc phthalocyanine, synthesized under microwave irradiation proved to be an interesting photocatalyst. The degradation of Rose Bengal, as model organic dye, under visible light irradiation was used to study the adsorption/photocatalytic activity. The huge potential of the synthesized molecule for the removal of organic pollutants was demonstrated by its absorption capacity, which was far larger than that of dye degradation

Synthesis of bile acid amines via microwave irradiation

Herein, we present microwave-assisted reductive amination of oxo derivative of deoxycholic acid with morpholine in the presence of sodium-cyanoborohydride. These chemical transformation produces a majority of the 3β-amino isomer 5 as a new compound after five minutes of irradiation. In addition, formylated bile acid have been proved as excellent starting material for the synthesis of bile acid`s N-morpholino amine. Microwave-assisted reactions of formylation in the absence of catalyst, selective deformylation, as well as further oxidation with N-bromosuccinimide gained 3-oxo derivatives of deoxycholic acid acid in high yield. Compared to the conventional protocol a remarkable reduction in overall processing time from hours to a few minutes was achieved

Graphene thin films syntehesis by rapid thermal annealing method from different carbon sources and their characterisantion.

Dobijanje uniformnog tankog sloja grafena je od izuzetnog znaĉaja za njegovu primenu u razliĉitim oblastima, pre svega elektronici i medicini. Stoga je dobijanje kontinualnih, homogenih grafenskih tankih slojeva cilj mnogih istraživaĉa u oblasti ugljeniĉnih nanomaterijala. Predmet prouĉavanja ove doktorske disertacije je sinteza tankih slojeva jednoslojnog i višeslojnog grafena metodom brzog termalnog odgrevanja (eng. Rapid Thermal Annealing – RTA). Sinteza tankih slojeva grafena vršena je na razliĉitim podlogama i iz razliĉitih ugljeniĉnih prekursora. Kao podloge za sintezu grafena korišteni su silicijum, bakarna folija i grafitna elektroda. Kao ugljeniĉni prekursor korištene su grafenske kvantne taĉke, fulerol, amorfni ugljenik i grafit. Za sintezu grafena RTA metodom, sloj metala je deponovan na dva naĉina: autokatalitiĉki na silicijumsku i bakarnu foliju i fiziĉkim putem na grafit. Ispitan je uticaj podloge, ugljeniĉnog prekursora, temperature i vremena odgrevanja na sintezu grafena. U cilju sinteze grafenskih tankih slojeva, prethodno je uraĊena sinteza grafenskih kvantnih taĉaka i fulerola kao ugljeniĉnih prekursora. Radi karakterizacije sintetisanih grafenskih tankih slojeva korištena je ramanska spektroskopija kojom je potvrĊena sinteza grafenskog sloja, odreĊen broj sintetisanih grafenskih slojeva i njihov kvalitet. Mikroskopija atomskih sila, skenirajuća i transmisiona elektronska mikroskopija omogućile su vizualizaciju i ispitivanje morfoloških karakteristika formiranih grafenskih tankih slojeva. Na osnovu dobijenih rezultata potvrĊeno je da temperatura i vreme odgrevanja imaju veliki uticaj na broj formiranih slojeva grafena, dok sam ugljeniĉni prekursor i podloga utiĉu na kvalitet dobijenih grafenskih tankih slojeva.Synthesis of uniform graphene thin film is of great importance for its application in different fields, such as electronics and medicine. Therefore, synthesis of continuous and homogenous graphene is the goal of many researches in the field of carbon nanomaterials. The aim of this doctoral dissertation is synthesis of mono– and multi–layer graphene thin films by rapid thermal annealing (RTA) process. Graphene synthesis was performed on different substrates from different carbon precursors. As substrates for graphene synthesis we used silicon, copper foil and graphite electrode, and as carbon precursors we used graphene quantum dots, fullerol, amorphous carbon and graphite. For graphene synthesis by RTA method the metal layer was deposited by electroless deposition on top of the silicon and copper surface and by sputtering on top of the graphite as substrate. During graphene synthesis, we investigated the influence of substrate type, carbon source, annealing temperature and time on graphene synthesis. For graphene synthesis, we previously performed synthesis of graphene quantum dots and fullerol. For graphene thin films characterisation Raman spectroscopy was used to distinguish the number of formed graphene layers and their level of defects. Atomic force microscopy, scanning and transmission electron microscopy enabled the visualization and the examination of morphological characteristics of formed graphene layers. Based on the results we confirmed that annealing temperature and time have a great influence on the number of formed graphene layers, while substrate and chosen carbon source affect the quality of formed graphene layers

Photocatalytic Activity Induced by Zinc Phthalocyanine Synthesized by Microwave Irradiation

Zinc phthalocyanine, synthesized under microwave irradiation proved to be an interesting photocatalyst. The degradation of Rose Bengal, as model organic dye, under visible light irradiation was used to study the adsorption/photocatalytic activity. The huge potential of the synthesized molecule for the removal of organic pollutants was demonstrated by its absorption capacity, which was far larger than that of dye degradation.29th International Symposium on Analytical and Environmental Problems : Proceedings; November 13-14, 2023; Szeged, Hungary

Synthesis of Bile Acid Amines Via Microwave Irradiation

Herein, we present microwave-assisted reductive amination of oxo derivative of deoxycholic acid with morpholine in the presence of sodium-cyanoborohydride. These chemical transformation produces a majority of the 3β-amino isomer 5 as a new compound after five minutes of irradiation. In addition, formylated bile acid have been proved as excellent starting material for the synthesis of bile acid`s N-morpholino amine. Microwave-assisted reactions of formylation in the absence of catalyst, selective deformylation, as well as further oxidation with N-bromosuccinimide gained 3-oxo derivatives of deoxycholic acid acid in high yield. Compared to the conventional protocol a remarkable reduction in overall processing time from hours to a few minutes was achieved.26th International Symposium on Analytical and Environmental Problems : Proceedings; November 23-24, 2020; Szeged, Hungary

Surface chemistry of "boron" doped carbon quantum dots

Carbon quantum dots (CQDs), are a novel class of carbon nanomaterials that exhibit outstanding physical, chemical, and optical characteristics in addition to strong light absorption. By substituting some of the carbon atoms in CQDs for heteroatoms like N, B, P, and S, it is possible to modify the surface chemistry and electronic properties of the structures, boosting their catalytic activity. Adding B dopant to CQDs changes its surface chemistry and morphology, opening up a wide range of potential uses. The presented study illustrates a quick and environmentally friendly method for producing B-CQDs through microwave-assisted method. According to TEM characterization, the generated B-CQDs had a spherical form, an average diameter of 12 nm, and were negatively charged particles with good water dispersibility and no discernible aggregation. The thorough surface chemistry characterization revealed the presence of B-O and B-C bonds, as well as oxygen-containing surface functional groups in the form of hydroxyl, carbonyl, and carboxyl groups. Additionally, using an RB organic dye as a model molecule, the sonocatalytic, photocatalytic, and synergistic effects of the two processes were investigated

The morphology of pani/graphene composites prepared under isothermal conditions

This article investigates the morphology of polyaniline/electrochemically exfoliated graphene composites prepared by oxidative polymerization with ammonium persulfate at a constant temperature (15 °C). During the polymerization, the pH of the reaction mixture decreases, which was used to monitor the rate of the reaction. A granular morphology with the presence of large sheet-like structures is found to be predominant for the composite prepared without added acid, while rod-shaped and tubular morphology is characteristic for the composite prepared with the addition of glacial acetic acid. The nanotubular and nanorod morphology of the sample prepared with the addition of glacial acetic acid was also confirmed by the presence of prominent phenazine structural units in Raman spectra. The composite prepared with the addition of HCl has granular morphology with a small amount of rod-like structures

Antioxidant and prooxidant features of N-CQD in photocatalytic testing of aquatic media

The modern age science is still searching for an effective photocatalytic material for the treatment of colored discharges from different industries which cause severe environmental issues. The excellent properties of nitrogen doped carbon quantum dots (N-CQD) enable their successful application as photocatalytic material in organic dye removal triggered under light absorption. With this in mind we first present a successfully performed microwave-assisted synthesis method, a green, simple and economically affordable method for N-CQD synthesis with high nitrogen percentage incorporated in the form of pyrrolic, pyridinic/NH2 and graphitic/NH3 groups. The pro-oxidant and antioxidant features of the synthesized N-CQD were further presented, with high removal efficiency of synthesized N-CQD towards the methylene blue (MB) organic dye, as one of the leading water pollutants with a major risk to aquatic and human life

Efficient synthesis and detailed thermal studies of zinc phthalocyanine

A facile and efficient, one step synthesis of macrocyclic molecule zinc phthalocyanine (ZnPc), was proposed. Dark violet crystals of ZnPc dye were obtained in high boiling point solvent of dimethylformamide (DMF) in the presence of 2,2,6,6-tetramethylpiperidine (TMP) as a catalyst. Detailed thermogravimetric and kinetic analysis revealed high thermal stability of the investigated compound

Microwave-assisted synthesis of n-doped carbon quantum dots for the photocatalytic removal of methylene blue from wastewater

Wastewater treatment is an emerging problem in the industrialized world. The development of new semiconducting materials with the potential to be used in photocatalysis is the focus of the scientific community. Here, we present the synthesis of N-doped carbon quantum dots (NCQDs) using microwave radiation. N-CQDs were synthesized by irradiation of glucose solution in the presence of ammonia hydroxide as a nitrogen doping agent at low temperature (100 °C), low applied microwave power (100 and 200 W), and for a short period of time (60 s). The possible application of N-CQDs as a catalyst for photocatalytic degradation of Methylene Blue (MB) dye under blue light, green light, red light, and daylight was investigated. The highest values of MB degradation were observed for the samples exposed to red light with a maximum of 58.8 % for N-CQDs sample prepared at the reactor power of 200 W exposed to red light for 2 h