Johannes Skotte - Profile on Academia.edu (original) (raw)
Papers by Johannes Skotte
A series of V 2 O 5 -ZrO 2 -SO 4 2− -sepiolite mixtures were extruded, calcined and characterised... more A series of V 2 O 5 -ZrO 2 -SO 4 2− -sepiolite mixtures were extruded, calcined and characterised. NH 3 -SCR activity was found to be related to the content of the active VO X -ZrO 2 -SO 4 2− phase (VSZ). The distribution of sepiolite and VSZ at the surface of the mechanical mixtures was studied by the electrophoretic migration technique. The samples were further characterised by nitrogen adsorption, NH 3 -TPD, XRD and scanning electron micrography techniques. The electrophoretic migration results showed that the addition of sepiolite to VSZ, by kneading in water, had a dramatic effect on the quantity of VO X -ZrO 2 -SO 4 2− present at the support's surface, both strongly decreasing the molar fraction of zirconia at the surface, and altering the electrophoretic properties of the mixtures.
Novel Fe-based Zeolites with Improved NH< sub> 3-SCR Activity
V< sub> 2 O< sub> 5-based NH< sub> 3-SCR Catalysts Doped with Potassium
Alkali-Resistant Denox Catalysts
... Page 3. Acknowledgements First of all, I would like to thank my advisors: Professor Rasmus Fe... more ... Page 3. Acknowledgements First of all, I would like to thank my advisors: Professor Rasmus Fehrmann and Professor Claus Hviid Christensen for their support, guidance, and encouragement over the past year. ... Doc. Søren Birk Rasmussen for ideas and discussions. iii Page 4. ...
Fe-BEA Zeolite Catalysts for NH₃-SCR of NOx
Reversible gas absorption by ionic liquids
DeNOx SCR catalysts–mechanism of deactivation and alternative alkali-resistant catalysts
Monitoring catalysts at work in their final form: spectroscopic investigations on a monolithic catalyst
Physical Chemistry Chemical Physics, 2012
A monolithic vanadia-titania based catalyst has been subjected to studies with in situ FTIR spect... more A monolithic vanadia-titania based catalyst has been subjected to studies with in situ FTIR spectroscopy coupled with mass spectrometry, during the SCR (Selective Catalytic Reduction) reaction. A device based on a transmission reactor cell for monolithic samples was constructed, dedicated to the study of surface species during reaction. After analysing the steady state SCR activity under industrially relevant conditions, NH(3) chemisorption phenomena as a function of temperature and the subsequent SCR reaction of NO + O(2) with chemisorbed ammonia and ammonium ion species were also investigated. The observations reported here serve as a demonstration of the great potential for the application of operando spectroscopy on monolithic systems. This cross disciplinary approach aims to identify reaction pathways, active sites, intermediate- and spectator-species for catalytic reactions under truly industrial conditions in a shaped monolithic catalyst based on monitoring chemical profiles along its channels. In particular, by demonstrating the feasibility of the approach using the technically challenging operando transmission FTIR spectroscopy methodology, we foresee easy future adaption of this approach with other surface or bulk sensitive techniques, e.g. Raman and UV-vis spectroscopy.
Journal of Catalysis, 2007
A series of vanadium-based SCR catalysts supported on sulfated or tungstated ZrO 2 were synthesiz... more A series of vanadium-based SCR catalysts supported on sulfated or tungstated ZrO 2 were synthesized and characterized by means of N 2 -BET, XRD, NH 3 -TPD and in situ Raman spectroscopy. The effect of potassium doping on the properties of vanadia species was studied in detail. A number of catalyst preparation parameters were examined, including the choice of precipitant, variation of carrier surface area, potassium poisoning, crystallinity, and ZrO 2 -phase composition. The results show that the catalyst structure and SCR activity are affected from the synthesis route by the support crystallinity and morphology, the surface composition, and the molecular configuration of the dispersed vanadates. It was observed that poisoning with potassium had a negligible effect on the surface vanadate species (especially the V=O stretching frequency observed by in situ Raman spectroscopy) if supported on the sulfated zirconia. Conversely, a more pronounced influence on the structure of surface vanadate was observed for the corresponding unsulfated samples, in which a significant red shift in the V=O stretching frequency was observed on potassium doping. Computational studies suggested that potassium was responsible for both the observed decrease in V=O stretching frequency and the higher proportion of dimers and higher polymers through coordination between K + and two neighbouring V=O. The results suggest an increased resistance toward potassium doping for the vanadia-based catalysts supported on sulfated zirconia.
Catalysis Today, 2011
A series of V 2 O 5 -ZrO 2 -SO 4 2− -sepiolite mixtures were extruded, calcined and characterised... more A series of V 2 O 5 -ZrO 2 -SO 4 2− -sepiolite mixtures were extruded, calcined and characterised. NH 3 -SCR activity was found to be related to the content of the active VO X -ZrO 2 -SO 4 2− phase (VSZ). The distribution of sepiolite and VSZ at the surface of the mechanical mixtures was studied by the electrophoretic migration technique. The samples were further characterised by nitrogen adsorption, NH 3 -TPD, XRD and scanning electron micrography techniques. The electrophoretic migration results showed that the addition of sepiolite to VSZ, by kneading in water, had a dramatic effect on the quantity of VO X -ZrO 2 -SO 4 2− present at the support's surface, both strongly decreasing the molar fraction of zirconia at the surface, and altering the electrophoretic properties of the mixtures.
Catalysis Letters, 2009
Iron-containing zeolites are known to be promising catalysts for the NH 3 -SCR reaction. Here, we... more Iron-containing zeolites are known to be promising catalysts for the NH 3 -SCR reaction. Here, we will investigate the catalytic activity of iron-based BEA catalysts, which was found to exhibit improved activities compared to previously described iron-containing zeolite catalysts, such as ZSM-5 and ZSM-12. Series of Fe-BEA zeolite catalysts were prepared using a range of different preparation methods. Furthermore, we found that an iron concentration around 3 wt% on BEA showed a small optimum in SCR activity compared to the other iron loadings studied.
Catalysis Communications, 2009
A series of WO 3 -promoted zirconia supports were synthesized and calcined between 400 and 800°C.... more A series of WO 3 -promoted zirconia supports were synthesized and calcined between 400 and 800°C. Subsequently vanadium oxide was introduced to obtain 3.5 wt% V 2 O 5 . The influence of the calcination temperature and potassium-poisoning (K/V = 0.2, molar ratio) on the catalytic activity in the selective catalytic reduction (SCR) of NO with NH 3 was previously studied. Here, we focus on the influence of these parameters on the catalytic activity for the undesirable oxidation of ammonia, which decrease the N 2 selectivity of the SCR process. It is found that potassium doping of the catalysts results in a considerable decrease in the overall ammonia conversion while selectivity to NO increases.
On the importance of the phase distribution and acidity of VOX-ZrO2-SO4-sepiolite catalysts for the NH3-SCR process in relation to biomass fueled power plants
orbit.dtu.dk
A series of V2O5-ZrO2-SO4 2--sepiolite mixtures were extruded, calcined and characterized. NH3-SC... more A series of V2O5-ZrO2-SO4 2--sepiolite mixtures were extruded, calcined and characterized. NH3-SCR activity was related to the phase distribution of the agglomerant and active VOX-ZrO2-SO4 ... 2-phase, as well as the acidity of the ... In recent years [1], the use of ...
Tungstated zirconia as promising carrier for DeNOX catalysts with improved resistance towards alkali poisoning
Applied Catalysis B: Environmental, 2006
Use of biomass as an alternative to fossil fuels has achieved increasing interest since it is con... more Use of biomass as an alternative to fossil fuels has achieved increasing interest since it is considered neutral regarding CO 2 accumulation in the atmosphere. The by far most energy-efficient use of solid bio-resources in energy production is combustion in combined biomass and coal ...
Selective flue gas cleaning with ionic liquids
Regeneration of Pt-Catalysts Deactivated In Municipal Waste Flue Gas With H2/N2 and the Effect of Regeneration Step on the SCR Catalyst
orbit.dtu.dk
Introduction Burning municipal waste or sludges instead of landfill depositing is an important is... more Introduction Burning municipal waste or sludges instead of landfill depositing is an important issue from an environmental point of view, since this waste to energy conversion also implies several benefits such as control of toxic emissions and heavy metal waste, etc. In this ...
Applied Catalysis B: Environmental, 2011
A series of experiments was conducted to reveal the impact on the catalyst and NH 3 -SCR activity... more A series of experiments was conducted to reveal the impact on the catalyst and NH 3 -SCR activity of an industrial deNO x catalyst from Haldor Topsøe A/S (V 2 O 5 -WO 3 /TiO 2 ) by exposure to H 2 and H 2 /O 2 . Treatment of the SCR catalyst was done by exposure for 60 min with three different concentrations of H 2 (0-2%) in an 8% O 2 /N 2 mixture, where the SCR activity was measured before and after the hydrogen treatment. The results show that the activity of the SCR catalyst is only negligibly affected during exposure to the H 2 /O 2 gas and in all cases it returned reversibly to the initial NO x conversion rate after reexposure to the standard NH 3 -SCR gas. In situ electron paramagnetic resonance (EPR) and UV-vis spectroscopy at 250 • C suggest that a significant part of V 4+ present during SCR conditions was oxidized to V 5+ during exposure to 2% H 2 + 8% O 2 . However, the distribution of vanadium in oxidation states V 4+ and V 5+ returned to the initial redox equilibrium in less than an hour after the hydrogen-oxygen treatment, emphasizing the reversibility of the V 4+ -V 5+ system.
SCR activity of conformed CuOX/ZrO2-SO4 catalysts
Studies in Surface …, 2010
The use of biomass in fossil fuel based power plants is of increasing interest, since it is consi... more The use of biomass in fossil fuel based power plants is of increasing interest, since it is considered as a CO 2 neutral fuel, having zero human impact on the carbon release to the atmosphere. Simultaneously, continuous efficient selective catalytic reduction of NO with ammonia (NH ...
A series of V 2 O 5 -ZrO 2 -SO 4 2− -sepiolite mixtures were extruded, calcined and characterised... more A series of V 2 O 5 -ZrO 2 -SO 4 2− -sepiolite mixtures were extruded, calcined and characterised. NH 3 -SCR activity was found to be related to the content of the active VO X -ZrO 2 -SO 4 2− phase (VSZ). The distribution of sepiolite and VSZ at the surface of the mechanical mixtures was studied by the electrophoretic migration technique. The samples were further characterised by nitrogen adsorption, NH 3 -TPD, XRD and scanning electron micrography techniques. The electrophoretic migration results showed that the addition of sepiolite to VSZ, by kneading in water, had a dramatic effect on the quantity of VO X -ZrO 2 -SO 4 2− present at the support's surface, both strongly decreasing the molar fraction of zirconia at the surface, and altering the electrophoretic properties of the mixtures.
Novel Fe-based Zeolites with Improved NH< sub> 3-SCR Activity
V< sub> 2 O< sub> 5-based NH< sub> 3-SCR Catalysts Doped with Potassium
Alkali-Resistant Denox Catalysts
... Page 3. Acknowledgements First of all, I would like to thank my advisors: Professor Rasmus Fe... more ... Page 3. Acknowledgements First of all, I would like to thank my advisors: Professor Rasmus Fehrmann and Professor Claus Hviid Christensen for their support, guidance, and encouragement over the past year. ... Doc. Søren Birk Rasmussen for ideas and discussions. iii Page 4. ...
Fe-BEA Zeolite Catalysts for NH₃-SCR of NOx
Reversible gas absorption by ionic liquids
DeNOx SCR catalysts–mechanism of deactivation and alternative alkali-resistant catalysts
Monitoring catalysts at work in their final form: spectroscopic investigations on a monolithic catalyst
Physical Chemistry Chemical Physics, 2012
A monolithic vanadia-titania based catalyst has been subjected to studies with in situ FTIR spect... more A monolithic vanadia-titania based catalyst has been subjected to studies with in situ FTIR spectroscopy coupled with mass spectrometry, during the SCR (Selective Catalytic Reduction) reaction. A device based on a transmission reactor cell for monolithic samples was constructed, dedicated to the study of surface species during reaction. After analysing the steady state SCR activity under industrially relevant conditions, NH(3) chemisorption phenomena as a function of temperature and the subsequent SCR reaction of NO + O(2) with chemisorbed ammonia and ammonium ion species were also investigated. The observations reported here serve as a demonstration of the great potential for the application of operando spectroscopy on monolithic systems. This cross disciplinary approach aims to identify reaction pathways, active sites, intermediate- and spectator-species for catalytic reactions under truly industrial conditions in a shaped monolithic catalyst based on monitoring chemical profiles along its channels. In particular, by demonstrating the feasibility of the approach using the technically challenging operando transmission FTIR spectroscopy methodology, we foresee easy future adaption of this approach with other surface or bulk sensitive techniques, e.g. Raman and UV-vis spectroscopy.
Journal of Catalysis, 2007
A series of vanadium-based SCR catalysts supported on sulfated or tungstated ZrO 2 were synthesiz... more A series of vanadium-based SCR catalysts supported on sulfated or tungstated ZrO 2 were synthesized and characterized by means of N 2 -BET, XRD, NH 3 -TPD and in situ Raman spectroscopy. The effect of potassium doping on the properties of vanadia species was studied in detail. A number of catalyst preparation parameters were examined, including the choice of precipitant, variation of carrier surface area, potassium poisoning, crystallinity, and ZrO 2 -phase composition. The results show that the catalyst structure and SCR activity are affected from the synthesis route by the support crystallinity and morphology, the surface composition, and the molecular configuration of the dispersed vanadates. It was observed that poisoning with potassium had a negligible effect on the surface vanadate species (especially the V=O stretching frequency observed by in situ Raman spectroscopy) if supported on the sulfated zirconia. Conversely, a more pronounced influence on the structure of surface vanadate was observed for the corresponding unsulfated samples, in which a significant red shift in the V=O stretching frequency was observed on potassium doping. Computational studies suggested that potassium was responsible for both the observed decrease in V=O stretching frequency and the higher proportion of dimers and higher polymers through coordination between K + and two neighbouring V=O. The results suggest an increased resistance toward potassium doping for the vanadia-based catalysts supported on sulfated zirconia.
Catalysis Today, 2011
A series of V 2 O 5 -ZrO 2 -SO 4 2− -sepiolite mixtures were extruded, calcined and characterised... more A series of V 2 O 5 -ZrO 2 -SO 4 2− -sepiolite mixtures were extruded, calcined and characterised. NH 3 -SCR activity was found to be related to the content of the active VO X -ZrO 2 -SO 4 2− phase (VSZ). The distribution of sepiolite and VSZ at the surface of the mechanical mixtures was studied by the electrophoretic migration technique. The samples were further characterised by nitrogen adsorption, NH 3 -TPD, XRD and scanning electron micrography techniques. The electrophoretic migration results showed that the addition of sepiolite to VSZ, by kneading in water, had a dramatic effect on the quantity of VO X -ZrO 2 -SO 4 2− present at the support's surface, both strongly decreasing the molar fraction of zirconia at the surface, and altering the electrophoretic properties of the mixtures.
Catalysis Letters, 2009
Iron-containing zeolites are known to be promising catalysts for the NH 3 -SCR reaction. Here, we... more Iron-containing zeolites are known to be promising catalysts for the NH 3 -SCR reaction. Here, we will investigate the catalytic activity of iron-based BEA catalysts, which was found to exhibit improved activities compared to previously described iron-containing zeolite catalysts, such as ZSM-5 and ZSM-12. Series of Fe-BEA zeolite catalysts were prepared using a range of different preparation methods. Furthermore, we found that an iron concentration around 3 wt% on BEA showed a small optimum in SCR activity compared to the other iron loadings studied.
Catalysis Communications, 2009
A series of WO 3 -promoted zirconia supports were synthesized and calcined between 400 and 800°C.... more A series of WO 3 -promoted zirconia supports were synthesized and calcined between 400 and 800°C. Subsequently vanadium oxide was introduced to obtain 3.5 wt% V 2 O 5 . The influence of the calcination temperature and potassium-poisoning (K/V = 0.2, molar ratio) on the catalytic activity in the selective catalytic reduction (SCR) of NO with NH 3 was previously studied. Here, we focus on the influence of these parameters on the catalytic activity for the undesirable oxidation of ammonia, which decrease the N 2 selectivity of the SCR process. It is found that potassium doping of the catalysts results in a considerable decrease in the overall ammonia conversion while selectivity to NO increases.
On the importance of the phase distribution and acidity of VOX-ZrO2-SO4-sepiolite catalysts for the NH3-SCR process in relation to biomass fueled power plants
orbit.dtu.dk
A series of V2O5-ZrO2-SO4 2--sepiolite mixtures were extruded, calcined and characterized. NH3-SC... more A series of V2O5-ZrO2-SO4 2--sepiolite mixtures were extruded, calcined and characterized. NH3-SCR activity was related to the phase distribution of the agglomerant and active VOX-ZrO2-SO4 ... 2-phase, as well as the acidity of the ... In recent years [1], the use of ...
Tungstated zirconia as promising carrier for DeNOX catalysts with improved resistance towards alkali poisoning
Applied Catalysis B: Environmental, 2006
Use of biomass as an alternative to fossil fuels has achieved increasing interest since it is con... more Use of biomass as an alternative to fossil fuels has achieved increasing interest since it is considered neutral regarding CO 2 accumulation in the atmosphere. The by far most energy-efficient use of solid bio-resources in energy production is combustion in combined biomass and coal ...
Selective flue gas cleaning with ionic liquids
Regeneration of Pt-Catalysts Deactivated In Municipal Waste Flue Gas With H2/N2 and the Effect of Regeneration Step on the SCR Catalyst
orbit.dtu.dk
Introduction Burning municipal waste or sludges instead of landfill depositing is an important is... more Introduction Burning municipal waste or sludges instead of landfill depositing is an important issue from an environmental point of view, since this waste to energy conversion also implies several benefits such as control of toxic emissions and heavy metal waste, etc. In this ...
Applied Catalysis B: Environmental, 2011
A series of experiments was conducted to reveal the impact on the catalyst and NH 3 -SCR activity... more A series of experiments was conducted to reveal the impact on the catalyst and NH 3 -SCR activity of an industrial deNO x catalyst from Haldor Topsøe A/S (V 2 O 5 -WO 3 /TiO 2 ) by exposure to H 2 and H 2 /O 2 . Treatment of the SCR catalyst was done by exposure for 60 min with three different concentrations of H 2 (0-2%) in an 8% O 2 /N 2 mixture, where the SCR activity was measured before and after the hydrogen treatment. The results show that the activity of the SCR catalyst is only negligibly affected during exposure to the H 2 /O 2 gas and in all cases it returned reversibly to the initial NO x conversion rate after reexposure to the standard NH 3 -SCR gas. In situ electron paramagnetic resonance (EPR) and UV-vis spectroscopy at 250 • C suggest that a significant part of V 4+ present during SCR conditions was oxidized to V 5+ during exposure to 2% H 2 + 8% O 2 . However, the distribution of vanadium in oxidation states V 4+ and V 5+ returned to the initial redox equilibrium in less than an hour after the hydrogen-oxygen treatment, emphasizing the reversibility of the V 4+ -V 5+ system.
SCR activity of conformed CuOX/ZrO2-SO4 catalysts
Studies in Surface …, 2010
The use of biomass in fossil fuel based power plants is of increasing interest, since it is consi... more The use of biomass in fossil fuel based power plants is of increasing interest, since it is considered as a CO 2 neutral fuel, having zero human impact on the carbon release to the atmosphere. Simultaneously, continuous efficient selective catalytic reduction of NO with ammonia (NH ...