Loredana Mantarosie
Research Subjects
Research Interests
Loredana Mantarosie has a total of 16 co-authors. Here are the top co-authors by number of shared publications:
- David Thompsett
Johnson Matthey (United Kingdom)
2 shared publications - Feng Ryan Wang
Department of Chemical Engineering, University College London, London, UK
2 shared publications - Xuze Guan
Department of Chemical Engineering University College London London WC1E 7JE UK
2 shared publications - Bolun Wang
University College London
1 shared publication - Furio Corà
Department of Chemistry, University College London, London WC1H 0AJ, UK
1 shared publication - Jasper Berry-Gair
University College London
1 shared publication
Latest Publications
- Open Access
- 6 November 2023
- Published by American Chemical Society (ACS) in ChemRxiv
Cu speciation in CHA framework and its impact in selective catalytic reduction of NO
The selective reduction of NO with NH3 (SCR) is an important reaction for emission control. The mobility of a metal cation in a confined space is a classic problem in transport phenomena. When the metal cation is an active centre of a chemical reaction, its mobility will be decisive to its catalytic performance, such as the Cu in chabazite (CHA) zeolite catalyst for selective catalytic reduction of NO (SCR) in diesel exhaust. Here we identify electron paramagnetic resonance (EPR) as an effective tool to quantify Cu2+ at different locations of CHA, and study the mobility of hydrated Cu2+. The Cu2+ transfers from one adjacent Al3+ site (1AlCu) to two adjacent Al3+ site (2AlCu) during dehydration. In the hydrothermal aging process, the transition is recorded from CuOx clusters to isolated Cu2+ sites and from Cu at 8-O member ring to 6-O member ring. The result indicates that the Cu – framework (fw) O interaction is thermodynamic drive for the migration of Cu species. For SCR, this means that the reduced Cu-Ofw interaction will lead to mobile Cu species in the catalytic circle.
- 6 November 2023
- Published by American Chemical Society (ACS) in ChemRxiv
Open AccessCu speciation in CHA framework and its impact in selective catalytic reduction of NO
The selective reduction of NO with NH3 (SCR) is an important reaction for emission control. The mobility of a metal cation in a confined space is a classic problem in transport phenomena. When the metal cation is an active centre of a chemical reaction, its mobility will be decisive to its catalytic performance, such as the Cu in chabazite (CHA) zeolite catalyst for selective catalytic reduction of NO (SCR) in diesel exhaust. Here we identify electron paramagnetic resonance (EPR) as an effective tool to quantify Cu2+ at different locations of CHA, and study the mobility of hydrated Cu2+. The Cu2+ transfers from one adjacent Al3+ site (1AlCu) to two adjacent Al3+ site (2AlCu) during dehydration. In the hydrothermal aging process, the transition is recorded from CuOx clusters to isolated Cu2+ sites and from Cu at 8-O member ring to 6-O member ring. The result indicates that the Cu – framework (fw) O interaction is thermodynamic drive for the migration of Cu species. For SCR, this means that the reduced Cu-Ofw interaction will lead to mobile Cu species in the catalytic circle.
- Open Access
- 12 October 2023
- Published by American Chemical Society (ACS) in ChemRxiv
The decisive role of CuI-framework O binding in oxidation half cycle of selective catalytic reduction
Cu-exchanged zeolite is an efficient catalyst to remove harmful nitrogen oxides from diesel exhaust gas through the selective catalytic reduction (SCR) reaction. The SCR performance is structure dependent, in which a Cu with one adjacent framework Al (1AlCu) has lower activation energy in oxidative half-cycle than Cu with two adjacent framework Al (2AlCu). Using a combination of operando X-ray absorption spectroscopy, valence to core - X-ray emission spectroscopy and density functional theory calculations, here we showed that 1AlCu proceeds with nitrate mechanism, in which side-on coordination of O2 at a CuI(NH3)xOfw (fw = framework) is the rate-limiting step in the oxidation half-cycle. As a result, the CuI(NH3)xOfw at 1AlCu can easily yield a transient CuIINOx intermediate upon breaking of Cu-Ofw after interaction with NO. In the meantime, 2AlCu has high barriers for Cu-Ofw bond breaking and proceeds with dimer mechanism. Our results show the coexisting of both dimer and nitrate mechanism, in particular at high Cu loadings, in which controlling the strength of the Cu-Ofw coordination is key for the O-O split in the nitrate pathway.
- 12 October 2023
- Published by American Chemical Society (ACS) in ChemRxiv
Open AccessThe decisive role of CuI-framework O binding in oxidation half cycle of selective catalytic reduction
Cu-exchanged zeolite is an efficient catalyst to remove harmful nitrogen oxides from diesel exhaust gas through the selective catalytic reduction (SCR) reaction. The SCR performance is structure dependent, in which a Cu with one adjacent framework Al (1AlCu) has lower activation energy in oxidative half-cycle than Cu with two adjacent framework Al (2AlCu). Using a combination of operando X-ray absorption spectroscopy, valence to core - X-ray emission spectroscopy and density functional theory calculations, here we showed that 1AlCu proceeds with nitrate mechanism, in which side-on coordination of O2 at a CuI(NH3)xOfw (fw = framework) is the rate-limiting step in the oxidation half-cycle. As a result, the CuI(NH3)xOfw at 1AlCu can easily yield a transient CuIINOx intermediate upon breaking of Cu-Ofw after interaction with NO. In the meantime, 2AlCu has high barriers for Cu-Ofw bond breaking and proceeds with dimer mechanism. Our results show the coexisting of both dimer and nitrate mechanism, in particular at high Cu loadings, in which controlling the strength of the Cu-Ofw coordination is key for the O-O split in the nitrate pathway.