Effect of copper on thermal stability of nanocrystalline ceria

Cerium (IV) oxide (CeO2) is extensively used as a catalyst because it has numerous advantages over conventional catalysts, like low cost, better poisoning resistance, high catalytic activity due to the facile Ce4+ / Ce3+ redox reaction and high oxygen storage capacity. CeO2 nanoparticles have higher specific surface area and better redox properties, and thus an increased catalytic activity in comparison to bulk materials. However, at elevated temperatures ceria nanoparticles are very prone to coarsening. In order to increase the thermal stability of CeO2 nanoparticles, but also improve its catalytic properties, metal ions are incorporated into the CeO2 crystal structure. The aim of this study was to compare coarsening kinetics of nanocrystalline CeO2 and nanocrystalline CeO2 doped with 10 mol. % of copper in order to determine the effect of doping on thermal stability. Samples were prepared by hydrothermal synthesis and thermally treated at different temperatures and processing times. The samples were analyzed by X-ray diffraction analysis and the crystallite sizes were calculated using the Scherrer’s equation. Based on the obtained crystallite sizes, kinetic parameters were determined and it was found that copper addition has a positive effect on the thermal stability of CeO2

Effect of copper on thermal stability of nanocrystalline ceria

Cerium (IV) oxide (CeO2) is extensively used as a catalyst because it has numerous advantages over conventional catalysts, like low cost, better poisoning resistance, high catalytic activity due to the facile Ce4+ / Ce3+ redox reac-tion and high oxygen storage capacity. CeO2 nanoparticles have higher specific surface area and better redox properties, and thus an increased catalytic activity in comparison to bulk materials. However, at elevated tem-peratures ceria nanoparticles are very prone to coarsening. In order to increase the thermal stability of CeO2 na-noparticles, but also improve its catalytic properties, metal ions are incorporated into the CeO2 crystal structure. The aim of this study was to compare coarsening kinetics of nanocrystalline CeO2 and nanocrystalline CeO2 doped with 10 mol. % of copper in order to determine the effect of doping on thermal stability. Samples were prepared by hydrothermal synthesis and thermally treated at different temperatures and processing times. The samples were analyzed by X-ray diffraction analysis and the crystallite sizes were calculated using the Scherrer’s equation. Based on the obtained crystallite sizes, kinetic parameters were determined and it was found that cop-per addition has a positive effect on the thermal stability of CeO2

Grain growth kinetics of nanocrystalline Cu-doped CeO2

Cilj ovog rada bio je istražiti kinetiku rasta nanokristalnog cerijevog (IV) oksida (CeO2) te utjecaj dopiranja bakrom na kinetiku rasta. Čvrsta otopina cerijevog oksida i 10 mol. % bakra dobivena je hidrotermalnom sintezom te je termički obrađivana na različitim temperaturama i vremenima obrade. Neobrađeni uzorak i obrađeni uzorci analizirani su rendgenskom difrakcijskom analizom praha te je na temelju dobivenih difraktograma pomoću Scherrerove jednadžbe izračunavana veličina kristalita. Na temelju dobivenih veličina kristalita određeni su kinetički parametri rasta i doneseni zaključci o utjecaju dopiranja bakrom na stabilnost cerijevog oksida.The aim of this research was to determine the growth kinetics of nanocrystalline cerium (IV) oxide (CeO2, ceria) and the influence of copper doping on the growth kinetics. Solid solution of ceria and 10 mol.% of copper was prepared by hydrothermal synthesis and further thermally processed at different temperatures and various durations. The samples were then analysed by X-ray diffraction. Using the Scherrer equation, the crystal size was calculated from the obtained diffractograms. Based on the crystallite sizes, the conclusions about the influence of copper doping on kinetic parameters of growth and stability of the ceria can be derived

Grain growth kinetics of nanocrystalline Cu-doped CeO2

Cilj ovog rada bio je istražiti kinetiku rasta nanokristalnog cerijevog (IV) oksida (CeO2) te utjecaj dopiranja bakrom na kinetiku rasta. Čvrsta otopina cerijevog oksida i 10 mol. % bakra dobivena je hidrotermalnom sintezom te je termički obrađivana na različitim temperaturama i vremenima obrade. Neobrađeni uzorak i obrađeni uzorci analizirani su rendgenskom difrakcijskom analizom praha te je na temelju dobivenih difraktograma pomoću Scherrerove jednadžbe izračunavana veličina kristalita. Na temelju dobivenih veličina kristalita određeni su kinetički parametri rasta i doneseni zaključci o utjecaju dopiranja bakrom na stabilnost cerijevog oksida.The aim of this research was to determine the growth kinetics of nanocrystalline cerium (IV) oxide (CeO2, ceria) and the influence of copper doping on the growth kinetics. Solid solution of ceria and 10 mol.% of copper was prepared by hydrothermal synthesis and further thermally processed at different temperatures and various durations. The samples were then analysed by X-ray diffraction. Using the Scherrer equation, the crystal size was calculated from the obtained diffractograms. Based on the crystallite sizes, the conclusions about the influence of copper doping on kinetic parameters of growth and stability of the ceria can be derived

Preparing of CdSe quantum dots

Cilj ovog rada bio je provesti sintezu kadmij-selenidnih (CdSe) kvantnih točaka, te pokazati ovisnost zabranjene zone materijala o rastu čestica tj. o trajanju reakcije. Prethodno pripremljene prekursorske otopine selenija i kadmija istovremeno se dodaju u otopinu za rast, vrući oktadecen, čime trenutačno započinje proces nastajanja i rasta kvantnih točaka. Kinetičkom analizom na temelju spektroskopskih podataka određeni su parametri rasta nanočestica. Reakcijska smjesa uzorkovana je u određenim vremenskim razmacima kako bi se pripravile kvantne točke u širokom rasponu veličina tj. svojstava koja se očituju u različitim spektrima. Modelna solarna ćelija na bazi fotoaktivnog sloja kadmij-selenidnih kvantnih točaka pripravljena je u sastavu ITO - ZnO – CdSe – PEDOT:PSS -Ag.The aim of this research was to synthesise cadmium selenide (CdSe) quantum dots, determine the dependence of the band gaps and to determine how reaction time influences the particle growth. Previously prepared cadmium and selenium precursor solutions were simultaneously introduced into the growth solution, hot octadecene, instantly initiating the reaction of formation and growth of the quantum dots. The parameters of the nanoparticle growth were determined by kinetic analysis based on spectroscopy data. Reaction mixture was sampled at certain time intervals in order to achieve a broad spectrum of quantum dot sizes and characteristics. Model solar cell based on photoactive layer made of cadmium selenide quantum dots was prepared as ITO – ZnO – CdSe – PEDOT:PSS – Ag

Preparing of CdSe quantum dots

Cilj ovog rada bio je provesti sintezu kadmij-selenidnih (CdSe) kvantnih točaka, te pokazati ovisnost zabranjene zone materijala o rastu čestica tj. o trajanju reakcije. Prethodno pripremljene prekursorske otopine selenija i kadmija istovremeno se dodaju u otopinu za rast, vrući oktadecen, čime trenutačno započinje proces nastajanja i rasta kvantnih točaka. Kinetičkom analizom na temelju spektroskopskih podataka određeni su parametri rasta nanočestica. Reakcijska smjesa uzorkovana je u određenim vremenskim razmacima kako bi se pripravile kvantne točke u širokom rasponu veličina tj. svojstava koja se očituju u različitim spektrima. Modelna solarna ćelija na bazi fotoaktivnog sloja kadmij-selenidnih kvantnih točaka pripravljena je u sastavu ITO - ZnO – CdSe – PEDOT:PSS -Ag.The aim of this research was to synthesise cadmium selenide (CdSe) quantum dots, determine the dependence of the band gaps and to determine how reaction time influences the particle growth. Previously prepared cadmium and selenium precursor solutions were simultaneously introduced into the growth solution, hot octadecene, instantly initiating the reaction of formation and growth of the quantum dots. The parameters of the nanoparticle growth were determined by kinetic analysis based on spectroscopy data. Reaction mixture was sampled at certain time intervals in order to achieve a broad spectrum of quantum dot sizes and characteristics. Model solar cell based on photoactive layer made of cadmium selenide quantum dots was prepared as ITO – ZnO – CdSe – PEDOT:PSS – Ag

Grain growth kinetics of nanocrystalline Cu-doped CeO2

Cilj ovog rada bio je istražiti kinetiku rasta nanokristalnog cerijevog (IV) oksida (CeO2) te utjecaj dopiranja bakrom na kinetiku rasta. Čvrsta otopina cerijevog oksida i 10 mol. % bakra dobivena je hidrotermalnom sintezom te je termički obrađivana na različitim temperaturama i vremenima obrade. Neobrađeni uzorak i obrađeni uzorci analizirani su rendgenskom difrakcijskom analizom praha te je na temelju dobivenih difraktograma pomoću Scherrerove jednadžbe izračunavana veličina kristalita. Na temelju dobivenih veličina kristalita određeni su kinetički parametri rasta i doneseni zaključci o utjecaju dopiranja bakrom na stabilnost cerijevog oksida.The aim of this research was to determine the growth kinetics of nanocrystalline cerium (IV) oxide (CeO2, ceria) and the influence of copper doping on the growth kinetics. Solid solution of ceria and 10 mol.% of copper was prepared by hydrothermal synthesis and further thermally processed at different temperatures and various durations. The samples were then analysed by X-ray diffraction. Using the Scherrer equation, the crystal size was calculated from the obtained diffractograms. Based on the crystallite sizes, the conclusions about the influence of copper doping on kinetic parameters of growth and stability of the ceria can be derived

Preparing of CdSe quantum dots

Cilj ovog rada bio je provesti sintezu kadmij-selenidnih (CdSe) kvantnih točaka, te pokazati ovisnost zabranjene zone materijala o rastu čestica tj. o trajanju reakcije. Prethodno pripremljene prekursorske otopine selenija i kadmija istovremeno se dodaju u otopinu za rast, vrući oktadecen, čime trenutačno započinje proces nastajanja i rasta kvantnih točaka. Kinetičkom analizom na temelju spektroskopskih podataka određeni su parametri rasta nanočestica. Reakcijska smjesa uzorkovana je u određenim vremenskim razmacima kako bi se pripravile kvantne točke u širokom rasponu veličina tj. svojstava koja se očituju u različitim spektrima. Modelna solarna ćelija na bazi fotoaktivnog sloja kadmij-selenidnih kvantnih točaka pripravljena je u sastavu ITO - ZnO – CdSe – PEDOT:PSS -Ag.The aim of this research was to synthesise cadmium selenide (CdSe) quantum dots, determine the dependence of the band gaps and to determine how reaction time influences the particle growth. Previously prepared cadmium and selenium precursor solutions were simultaneously introduced into the growth solution, hot octadecene, instantly initiating the reaction of formation and growth of the quantum dots. The parameters of the nanoparticle growth were determined by kinetic analysis based on spectroscopy data. Reaction mixture was sampled at certain time intervals in order to achieve a broad spectrum of quantum dot sizes and characteristics. Model solar cell based on photoactive layer made of cadmium selenide quantum dots was prepared as ITO – ZnO – CdSe – PEDOT:PSS – Ag