Cu-modified SrTiO3 as a perspective material for environmental catalysis

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Cu-modified SrTiO3 as a perspective material for environmental catalysis

Popis výsledku v původním jazyce

This contribution was presented on 15th Pannonian International Symposium on Catalysis. SrTiO3 is a perovskite-structure compound whose properties can be significantly modified by the relatively easy incorporation of other elements into this structure, which makes strontium titanate a rerspective material with a wide range of potential applications. The materials based on strontium titanate differing with the level of non-stoichiometry in the strontium sublattice and Cu content were synthesized by a modified sol-gel method. The final materials in the form of powders were received by the proper thermal treatment finalized by calcination at 900oC for 3 hours performed in the flow of air. The nominal composition of the materials was as follow: SrTi0.98Cu0.02O3, Sr0.95Ti0.98Cu0.02O3 and Sr0.90Ti0.90Cu0.10O3. It is expected that copper can be incorporated into the perovskite structure and/or can be formed on the surface of the perovskite in the form of oxide. The presence of these two different types of Cu-bonding in the materials can result in various materials&apos; functional properties especially the ability to participate in the redox reaction.These properties can also be affected by the oxidation state of copper incorporated into the perovskite structure. It should be underlined, that an introduction of non-stoichiometry in the Sr-sublattice in the SrTiO3 structure leads to an increase in the amount of dopant which can be incorporated in the Ti- sublattice.The obtained materials were characterized in terms of their structure (XRD analysis and Rietveld refinement) and microstructure (SEM observations, the specific surface area measurements (BET), and dynamic light scattering (DLS) analysis). To observe the copper distribution the energy-dispersive X-ray spectroscopy (EDS) analysis in the mapping mode was performed. X-ray photoelectron spectroscopy (XPS) was applied to evaluate the copper oxidation state and the temperature-programmed reduction (TPR) and temperatureprogrammed oxidation (TPOx) measurements were performed to evaluate the material&apos;s redox properties. As a final part of the research, the catalytic tests for the synthesized materials were performed. The selective catalytic oxidation of ammonia (NH3-SCO) and selective catalytic reduction of NOx with ammonia (NH3-SCR) were chosen as the test reactions.The results of XRD measurements showed that materials with 2 mol.% of introduced copper (SrTi0.98Cu0.02O3, Sr0.95Ti0.98Cu0.02O3) were single-phase - only strontium titanate with tausonite structure was observed, while for the material with the higher copper content(Sr0.90Ti0.90Cu0.10O3) also copper oxide was observed as an additional phase. However, the EDS analysis implied the presence of a Cu-rich phase also in the SrTi0.98Cu0.02O3 sample. For all materials, a relatively small specific surface area (4-11 m2 g-1) was observed, neverthelessthe performed catalytical test showed the high values of ammonia conversion. Also, the materials with the assumed non-stoichiometry in strontium sublattices exhibited better catalytic properties than stoichiometric material, especially in NH3-SCR reaction.

Název v anglickém jazyce

Cu-modified SrTiO3 as a perspective material for environmental catalysis

Popis výsledku anglicky

This contribution was presented on 15th Pannonian International Symposium on Catalysis. SrTiO3 is a perovskite-structure compound whose properties can be significantly modified by the relatively easy incorporation of other elements into this structure, which makes strontium titanate a rerspective material with a wide range of potential applications. The materials based on strontium titanate differing with the level of non-stoichiometry in the strontium sublattice and Cu content were synthesized by a modified sol-gel method. The final materials in the form of powders were received by the proper thermal treatment finalized by calcination at 900oC for 3 hours performed in the flow of air. The nominal composition of the materials was as follow: SrTi0.98Cu0.02O3, Sr0.95Ti0.98Cu0.02O3 and Sr0.90Ti0.90Cu0.10O3. It is expected that copper can be incorporated into the perovskite structure and/or can be formed on the surface of the perovskite in the form of oxide. The presence of these two different types of Cu-bonding in the materials can result in various materials&apos; functional properties especially the ability to participate in the redox reaction.These properties can also be affected by the oxidation state of copper incorporated into the perovskite structure. It should be underlined, that an introduction of non-stoichiometry in the Sr-sublattice in the SrTiO3 structure leads to an increase in the amount of dopant which can be incorporated in the Ti- sublattice.The obtained materials were characterized in terms of their structure (XRD analysis and Rietveld refinement) and microstructure (SEM observations, the specific surface area measurements (BET), and dynamic light scattering (DLS) analysis). To observe the copper distribution the energy-dispersive X-ray spectroscopy (EDS) analysis in the mapping mode was performed. X-ray photoelectron spectroscopy (XPS) was applied to evaluate the copper oxidation state and the temperature-programmed reduction (TPR) and temperatureprogrammed oxidation (TPOx) measurements were performed to evaluate the material&apos;s redox properties. As a final part of the research, the catalytic tests for the synthesized materials were performed. The selective catalytic oxidation of ammonia (NH3-SCO) and selective catalytic reduction of NOx with ammonia (NH3-SCR) were chosen as the test reactions.The results of XRD measurements showed that materials with 2 mol.% of introduced copper (SrTi0.98Cu0.02O3, Sr0.95Ti0.98Cu0.02O3) were single-phase - only strontium titanate with tausonite structure was observed, while for the material with the higher copper content(Sr0.90Ti0.90Cu0.10O3) also copper oxide was observed as an additional phase. However, the EDS analysis implied the presence of a Cu-rich phase also in the SrTi0.98Cu0.02O3 sample. For all materials, a relatively small specific surface area (4-11 m2 g-1) was observed, neverthelessthe performed catalytical test showed the high values of ammonia conversion. Also, the materials with the assumed non-stoichiometry in strontium sublattices exhibited better catalytic properties than stoichiometric material, especially in NH3-SCR reaction.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

20700 - Environmental engineering

Projekt

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Návaznosti

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Rok uplatnění

2022

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů