Abstract Corrosion of metals is producing huge costs by the depreciation of corroded structures w... more Abstract Corrosion of metals is producing huge costs by the depreciation of corroded structures with major impact on environment and human safety. It requires the proper selection of a specific protecting coating material. Innovative ways of counteracting corrosion by use of electrospun polymeric nanofibers will be reviewed. The use and benefits of single-component nanofibers for improving the mechanical properties of organic coatings are described. A further approach is the incorporation of corrosion inhibitors within the nanofiber structure in order to increase corrosion coatings performance. Attention is given to core-shell nanofibers using coaxial electrospinning setups for providing self-healing capabilities. The self-healing performance of various composite coatings reinforced with core-shell nanofibers is discussed. Literature results of improved corrosion resistance by nanofiber introduction into coatings are summarized. An outlook is provided for future potential ideas and possible applications of this emerging field. The commercial viability of those innovative processes is discussed and evaluated.
Abstract The use of smart nanocontainers as carriers of corrosion inhibitors offers good alternat... more Abstract The use of smart nanocontainers as carriers of corrosion inhibitors offers good alternatives to the classical corrosion protection methods. This chapter aims to give a concise review on the most important recent achievements in the field of development and fabrication of protective coatings based on corrosion inhibitor loaded–smart nanocontainers, as well as explanation of the different corrosion inhibition mechanisms. The most significant types of smart nanocontainers have been demonstrated from polymer nanocapsules, nanofibers, nanotubes, and nanolayers to the porous nanoparticles. The commercial viability of those innovative materials and processes, as well as the advantages and limitations associated with their practical applications are discussed and evaluated in the chapter.
Two types of Cu-modified Pd catalysts supported on high area carbon were prepared: Pd nanoparticl... more Two types of Cu-modified Pd catalysts supported on high area carbon were prepared: Pd nanoparticles modified with a sub-monolayer of underpotentially deposited Cu (Cu@Pd/C) and Pd-Cu alloy nanoparticles (Pd-Cu/C), and examined for the ethanol oxidation reaction (EOR) in alkaline solution. The catalysts were characterized by energy-dispersive X-ray spectroscopy, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy, as well as cyclic voltammetry. As reference catalysts, Pd/C and Pt/C were used. The electrochemically active surface area of all samples was determined from CO ads and Cu upd desorption and Pd oxide reduction, and used to assess their intrinsic activity for EOR. Intimate contact of Pd with Cu atoms enhanced its activity, regardless of the type of bimetal catalyst. The atomic Pd:Cu ratio between 2:1 and 4:1 appears to be optimal for high activity. The most active catalyst under the potentiodynamic conditions was Cu@Pd/C with θ(Cu) = 0.21,although Pd-Cu/C was superior during the potentiostatic test. All bimetallic catalysts surpassed Pd/C in mass activity. The EOR activity of Pt/C was higher compared to Pd-based catalysts at low potentials, both in terms of specific and mass activity, but with a significant decline over a 30-min potentiostatic stability test.
Two types of Cu-modified Pd catalysts supported on high area carbon were prepared: Pd nanoparticl... more Two types of Cu-modified Pd catalysts supported on high area carbon were prepared: Pd nanoparticles modified with a sub-monolayer of underpotentially deposited Cu (Cu@Pd/C) and Pd-Cu alloy nanoparticles (Pd-Cu/C), and examined for the ethanol oxidation reaction (EOR) in alkaline solution. The catalysts were characterized by energy-dispersive X-ray spectroscopy, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy, as well as cyclic voltammetry. As reference catalysts, Pd/C and Pt/C were used. The electrochemically active surface area of all samples was determined from CO ads and Cu upd desorption and Pd oxide reduction, and used to assess their intrinsic activity for EOR. Intimate contact of Pd with Cu atoms enhanced its activity, regardless of the type of bimetal catalyst. The atomic Pd:Cu ratio between 2:1 and 4:1 appears to be optimal for high activity. The most active catalyst under the potentiodynamic conditions was Cu@Pd/C with θ(Cu) = 0.21,although Pd-Cu/C was superior during the potentiostatic test. All bimetallic catalysts surpassed Pd/C in mass activity. The EOR activity of Pt/C was higher compared to Pd-based catalysts at low potentials, both in terms of specific and mass activity, but with a significant decline over a 30-min potentiostatic stability test.
Metallic zirconium has a broad range of potential applications in engineering and in industries t... more Metallic zirconium has a broad range of potential applications in engineering and in industries that are operating under harsh corrosive environments, such as nuclear and chemical industry. Compared to other metals like aluminum, its behavior in electrochemical reactions is poorly understood and so far, there are no larger-scale electrochemical approaches to process zirconium. Ionic liquids are a suitable reaction medium for electrochemical reactions of zirconium. To better understand the electrochemical reactivity of zirconium, different combinations of ionic liquids and zirconium precursors are investigated. It was found that interactions between the Zr precursor and the ionic liquids can have significant influence on the diffusion properties of Zr. Furthermore, mixtures of ionic liquids with other solvents were explored and it could be determined that most of the electrochemical properties of Zr are retained also in solvent mixtures. This could potentially save costs for industri...
AbstractIn our previous paper, we described in detail studies of Sn influence on electrocatalytic... more AbstractIn our previous paper, we described in detail studies of Sn influence on electrocatalytic activity of PtSn catalyst for CO and formic acid oxidation (Stevanović et al., J. Phys. Chem. C, 118 (2014) 278–289). The catalyst was composed of a Pt phase, Pt3Sn alloy and very small SnO2 particles. Different electrochemical treatment enabled studies of PtSn/C having Sn both in surface and subsurface layers and skeleton structure of this catalyst with Sn only in subsurface layers. The results obtained revealed the promotional effect of surface Sn whether alloyed or as oxide above all in preventing accumulation of CO and blocking the surface Pt atoms. As a consequence, in formic acid oxidation, the currents are not entering the plateau but increasing constantly until reaching a maximum. It was concluded that at lower potentials the effect of Sn on formic acid oxidation was predominantly electronic but with increasing the potential bi-functional mechanism prevailed due to the leading role of SnO2. This role of SnO2 is restated in the present study. Therefore, CO and formic acid oxidation were examined at PtSnO2/C catalyst. The catalyst was synthesised by the same microwave-assisted polyol procedure. According to XRD analysis, the catalyst is composed of a Pt phase and SnO2 phase. The reactions were examined on PtSnO2/C catalyst treated on the same way as PtSn/C. Comparing the results obtained, the role of SnO2 is confirmed and at the same time the significance of alloyed Sn and its electronic effect is revealed. Graphical Abstract
Abstract Pd-Ni/C catalyst was synthesized employing a borohydride reduction method. The high area... more Abstract Pd-Ni/C catalyst was synthesized employing a borohydride reduction method. The high area Ni was first dispersed on the carbon support and then modified by Pd nanoparticles. Transmission electron microscopy confirmed relatively even distribution of Ni across the carbon support with discrete palladium particles of about 3.3 nm mean diameter on it. Cyclic voltammetry confirmed the presence of Ni on the catalyst surface. The activity of the Pd-Ni/C catalysts for ethanol oxidation reaction (EOR) in alkaline solution was tested under the potentiodynamic and potentiostatic conditions and the results were compared to those obtained on the Pd/C catalyst. It was found that Pd-Ni/C is more active for the EOR compared to Pd/C by a factor up to 3, depending on the type of experiments and whether specific activity or mass activity are considered. During the potentiodynamic stability test an interesting phenomenon of activation of Pd-Ni/C catalyst was observed. It was found that maximum activity is attained after fifty cycles with the positive potential limit of 1.2 V, regardless of whether they were performed in the electrolyte with or without ethanol. It was postulated that potential cycling of the Pd-Ni surface causes reorganization of the catalyst surface bringing Pd and Ni sites to a more suitable arrangement for the efficient ethanol oxidation.
Abstract Corrosion of metals is producing huge costs by the depreciation of corroded structures w... more Abstract Corrosion of metals is producing huge costs by the depreciation of corroded structures with major impact on environment and human safety. It requires the proper selection of a specific protecting coating material. Innovative ways of counteracting corrosion by use of electrospun polymeric nanofibers will be reviewed. The use and benefits of single-component nanofibers for improving the mechanical properties of organic coatings are described. A further approach is the incorporation of corrosion inhibitors within the nanofiber structure in order to increase corrosion coatings performance. Attention is given to core-shell nanofibers using coaxial electrospinning setups for providing self-healing capabilities. The self-healing performance of various composite coatings reinforced with core-shell nanofibers is discussed. Literature results of improved corrosion resistance by nanofiber introduction into coatings are summarized. An outlook is provided for future potential ideas and possible applications of this emerging field. The commercial viability of those innovative processes is discussed and evaluated.
Abstract The use of smart nanocontainers as carriers of corrosion inhibitors offers good alternat... more Abstract The use of smart nanocontainers as carriers of corrosion inhibitors offers good alternatives to the classical corrosion protection methods. This chapter aims to give a concise review on the most important recent achievements in the field of development and fabrication of protective coatings based on corrosion inhibitor loaded–smart nanocontainers, as well as explanation of the different corrosion inhibition mechanisms. The most significant types of smart nanocontainers have been demonstrated from polymer nanocapsules, nanofibers, nanotubes, and nanolayers to the porous nanoparticles. The commercial viability of those innovative materials and processes, as well as the advantages and limitations associated with their practical applications are discussed and evaluated in the chapter.
Two types of Cu-modified Pd catalysts supported on high area carbon were prepared: Pd nanoparticl... more Two types of Cu-modified Pd catalysts supported on high area carbon were prepared: Pd nanoparticles modified with a sub-monolayer of underpotentially deposited Cu (Cu@Pd/C) and Pd-Cu alloy nanoparticles (Pd-Cu/C), and examined for the ethanol oxidation reaction (EOR) in alkaline solution. The catalysts were characterized by energy-dispersive X-ray spectroscopy, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy, as well as cyclic voltammetry. As reference catalysts, Pd/C and Pt/C were used. The electrochemically active surface area of all samples was determined from CO ads and Cu upd desorption and Pd oxide reduction, and used to assess their intrinsic activity for EOR. Intimate contact of Pd with Cu atoms enhanced its activity, regardless of the type of bimetal catalyst. The atomic Pd:Cu ratio between 2:1 and 4:1 appears to be optimal for high activity. The most active catalyst under the potentiodynamic conditions was Cu@Pd/C with θ(Cu) = 0.21,although Pd-Cu/C was superior during the potentiostatic test. All bimetallic catalysts surpassed Pd/C in mass activity. The EOR activity of Pt/C was higher compared to Pd-based catalysts at low potentials, both in terms of specific and mass activity, but with a significant decline over a 30-min potentiostatic stability test.
Two types of Cu-modified Pd catalysts supported on high area carbon were prepared: Pd nanoparticl... more Two types of Cu-modified Pd catalysts supported on high area carbon were prepared: Pd nanoparticles modified with a sub-monolayer of underpotentially deposited Cu (Cu@Pd/C) and Pd-Cu alloy nanoparticles (Pd-Cu/C), and examined for the ethanol oxidation reaction (EOR) in alkaline solution. The catalysts were characterized by energy-dispersive X-ray spectroscopy, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy, as well as cyclic voltammetry. As reference catalysts, Pd/C and Pt/C were used. The electrochemically active surface area of all samples was determined from CO ads and Cu upd desorption and Pd oxide reduction, and used to assess their intrinsic activity for EOR. Intimate contact of Pd with Cu atoms enhanced its activity, regardless of the type of bimetal catalyst. The atomic Pd:Cu ratio between 2:1 and 4:1 appears to be optimal for high activity. The most active catalyst under the potentiodynamic conditions was Cu@Pd/C with θ(Cu) = 0.21,although Pd-Cu/C was superior during the potentiostatic test. All bimetallic catalysts surpassed Pd/C in mass activity. The EOR activity of Pt/C was higher compared to Pd-based catalysts at low potentials, both in terms of specific and mass activity, but with a significant decline over a 30-min potentiostatic stability test.
Metallic zirconium has a broad range of potential applications in engineering and in industries t... more Metallic zirconium has a broad range of potential applications in engineering and in industries that are operating under harsh corrosive environments, such as nuclear and chemical industry. Compared to other metals like aluminum, its behavior in electrochemical reactions is poorly understood and so far, there are no larger-scale electrochemical approaches to process zirconium. Ionic liquids are a suitable reaction medium for electrochemical reactions of zirconium. To better understand the electrochemical reactivity of zirconium, different combinations of ionic liquids and zirconium precursors are investigated. It was found that interactions between the Zr precursor and the ionic liquids can have significant influence on the diffusion properties of Zr. Furthermore, mixtures of ionic liquids with other solvents were explored and it could be determined that most of the electrochemical properties of Zr are retained also in solvent mixtures. This could potentially save costs for industri...
AbstractIn our previous paper, we described in detail studies of Sn influence on electrocatalytic... more AbstractIn our previous paper, we described in detail studies of Sn influence on electrocatalytic activity of PtSn catalyst for CO and formic acid oxidation (Stevanović et al., J. Phys. Chem. C, 118 (2014) 278–289). The catalyst was composed of a Pt phase, Pt3Sn alloy and very small SnO2 particles. Different electrochemical treatment enabled studies of PtSn/C having Sn both in surface and subsurface layers and skeleton structure of this catalyst with Sn only in subsurface layers. The results obtained revealed the promotional effect of surface Sn whether alloyed or as oxide above all in preventing accumulation of CO and blocking the surface Pt atoms. As a consequence, in formic acid oxidation, the currents are not entering the plateau but increasing constantly until reaching a maximum. It was concluded that at lower potentials the effect of Sn on formic acid oxidation was predominantly electronic but with increasing the potential bi-functional mechanism prevailed due to the leading role of SnO2. This role of SnO2 is restated in the present study. Therefore, CO and formic acid oxidation were examined at PtSnO2/C catalyst. The catalyst was synthesised by the same microwave-assisted polyol procedure. According to XRD analysis, the catalyst is composed of a Pt phase and SnO2 phase. The reactions were examined on PtSnO2/C catalyst treated on the same way as PtSn/C. Comparing the results obtained, the role of SnO2 is confirmed and at the same time the significance of alloyed Sn and its electronic effect is revealed. Graphical Abstract
Abstract Pd-Ni/C catalyst was synthesized employing a borohydride reduction method. The high area... more Abstract Pd-Ni/C catalyst was synthesized employing a borohydride reduction method. The high area Ni was first dispersed on the carbon support and then modified by Pd nanoparticles. Transmission electron microscopy confirmed relatively even distribution of Ni across the carbon support with discrete palladium particles of about 3.3 nm mean diameter on it. Cyclic voltammetry confirmed the presence of Ni on the catalyst surface. The activity of the Pd-Ni/C catalysts for ethanol oxidation reaction (EOR) in alkaline solution was tested under the potentiodynamic and potentiostatic conditions and the results were compared to those obtained on the Pd/C catalyst. It was found that Pd-Ni/C is more active for the EOR compared to Pd/C by a factor up to 3, depending on the type of experiments and whether specific activity or mass activity are considered. During the potentiodynamic stability test an interesting phenomenon of activation of Pd-Ni/C catalyst was observed. It was found that maximum activity is attained after fifty cycles with the positive potential limit of 1.2 V, regardless of whether they were performed in the electrolyte with or without ethanol. It was postulated that potential cycling of the Pd-Ni surface causes reorganization of the catalyst surface bringing Pd and Ni sites to a more suitable arrangement for the efficient ethanol oxidation.
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Papers by Aleksandra Gavrilovic-Wohlmuther