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Dive into the research topics where A. Cvetkovs is active.

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Featured researches published by A. Cvetkovs.


Key Engineering Materials | 2014

Selective Oxidation of Glycerol to Glyceraldehyde over Novel Monometallic Platinum Catalysts

Svetlana Chornaja; Elina Sproge; Konstantins Dubencovs; Lidija Kulikova; Vera Serga; A. Cvetkovs; Valdis Kampars

Several novel monometallic platinum catalysts supported on metal oxides (Al2O3, Y2O3, γ-Al2O3, Lu2O3, ZrO2-Y2O3 TiO2, SiO2, γ-AlO(OH)) and activated carbon (C) were synthesized by extractive-pyrolytic method and tested in glycerol oxidation processes without base addition to obtain glyceraldehyde. It was found that Pt catalyst activity is strongly influenced by support nature, oxygen partial pressure and Pt loading. Pt/Al2O3 and Pt/SiO2 catalysts exhibited the highest activity but selectivity to glyceraldehyde significantly decreased when glycerol conversion increased.


IOP Conference Series: Materials Science and Engineering | 2013

Novel fine-disperse bimetallic Pt-Pd/Al2O3 catalysts for glycerol oxidation with molecular oxygen

Konstantins Dubencovs; Svetlana Chornaja; Elina Sproge; Valdis Kampars; D Markova; Lidija Kulikova; Vera Serga; A. Cvetkovs

Using extractive-pyrolytic method several Pt-Pd bimetallic catalysts supported on plasma-processed alumina nanopowder were synthesized. Pt-Pd loading and glycerol oxidation process parameter influence on catalyst activity and selectivity was determined oxidizing glycerol in mild conditions. Novel bimetallic catalysts in neutral water solutions were practically inactive (glycerol conversion was only 3%) whereas in alkaline solutions they were active and selective to glyceric acid. Using 1.2%Pt-1.2%Pd/Al2O3 catalyst glyceric acid was obtained with 65% selectivity (glycerol conversion was 96%). It was shown that novel fine-disperse bimetallic Pt-Pd/Al2O3 catalysts were more active compared to analogous monometallic Pt/Al2O3 and Pd/Al2O3 catalysts.


Latvian Journal of Physics and Technical Sciences | 2016

Production of ZnO AND CdO-ZnO Thin Films by Extraction–Pyrolytic Method

A. Cvetkovs; O. Kiselova; Uldis Rogulis; Vera Serga; R. Ignatans

Abstract The extraction-pyrolytic method has been applied to produce the ZnO and CdO-ZnO thin films on glass and quartz glass substrates. According to X-ray diffraction measurements, the ZnO and CdO phases have been produced with an average size of crystallites about 8–42 nm in the films. The thickness of the layers measured by a profilometer has been up to 150 nm. The surface morphology measurements show that the surface of the films may be rough and non-continuous. The SEM results confirm the dependence between the preparation procedure and the quality of the thin film.


Chemija | 2018

Fabrication and characterization of magnetic FePt nanoparticles prepared by extraction–pyrolysis method

Vera Serga; M. Maiorov; A. Cvetkovs; A. Krumina; A.I. Popov


publication.editionName | 2016

Production of CeO2/NiO and CeO2/NiO-Pt Nanocomposites by EPM

Vera Serga; A. Cvetkovs; Aija Krumina; Svetlana Čornaja; Janis Kunakovs; Mikhail Maiorov


publication.editionName | 2015

New Methods of Glyceric and Lactic Acid Production by Catalytic Oxidation of Glycerol. New Method of Synthesis of a Catalyst with Enhanced Activity and Selectivity

Svetlana Čornaja; Svetlana Žižkuna; Konstantīns Dubencovs; Olga Stepanova; Valdis Kampars; Lidiya Kulikova; Vera Serga; A. Cvetkovs; Eriks Palcevskis; Elīna Sproģe


31.Zinātniskā konference | 2015

Cinka oksīdu plāno kārtiņu sintēze ar ekstrakcijas-pirolītisko metodi

Olga Kiseļova; A. Cvetkovs; Uldis Rogulis; Vera Serga; Reinis Ignatāns; Kārlis Kundziņš


31.Zinātniskā konference | 2015

Synthesis of Zinc Oxide Thin Films by Extraction-Pyrolytic Method

Olga Kiseļova; A. Cvetkovs; Uldis Rogulis; Vera Serga; Reinis Ignatāns; Kārlis Kundziņš


30.Zinātniskā konference | 2014

Studies of ZnxCd1-xO Thin Films

Olga Kiseļova; A. Cvetkovs; Uldis Rogulis; Vera Serga; R. Ignatans


30. Zinātniskā konference | 2014

Noble Metals-Oxide Nanocomposites: Preparation, Characteristics

Eriks Palcevskis; Vera Serga; L. Kuļikova; A. Cvetkovs; Daniela Karashanova

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Vera Serga

Riga Technical University

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Valdis Kampars

Riga Technical University

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Elina Sproge

Riga Technical University

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Lidija Kulikova

Riga Technical University

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Olga Stepanova

Riga Technical University

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Daniela Karashanova

Bulgarian Academy of Sciences

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