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The electronic structure, surface properties, and in situ N2O decomposition of mechanochemically synthesised LaMnO3

The electronic structure, surface properties, and in situ N2O decomposition of mechanochemically synthesised LaMnO3
The electronic structure, surface properties, and in situ N2O decomposition of mechanochemically synthesised LaMnO3
The use of mechanochemistry to prepare catalytic materials is of significant interest; it offers an environmentally beneficial, solvent-free, route and produces highly complex structures of mixed amorphous and crystalline phases. This study reports on the effect of milling atmosphere, either air or argon, on mechanochemically prepared LaMnO3 and the catalytic performance towards N2O decomposition (deN2O). In this work, high energy resolution fluorescence detection (HERFD), X-ray absorption near edge structure (XANES), X-ray emission, and X-ray photoelectron spectroscopy (XPS) have been used to probe the electronic structural properties of the mechanochemically prepared materials. Moreover, in situ studies using near ambient pressure (NAP)-XPS, to follow the materials during catalysis, and high pressure energy dispersive EXAFS studies, to mimic the preparation conditions, have also been performed. The studies show that there are clear differences between the air and argon milled samples, with the most pronounced changes observed using NAP-XPS. The XPS results find increased levels of active adsorbed oxygen species, linked to the presence of surface oxide vacancies, for the sample prepared in argon. Furthermore, the argon milled LaMnO3 shows improved catalytic activity towards deN2O at lower temperatures compared to the air milled and sol–gel synthesised LaMnO3. Assessing this improved catalytic behaviour during deN2O of argon milled LaMnO3 by in situ NAP-XPS suggests increased interaction of N2O at room temperature within the O 1s region. This study further demonstrates the complexity of mechanochemically prepared materials and through careful choice of characterisation methods how their properties can be understood.
1463-9076
18774-18787
Blackmore, Rachel Hazel
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Rivas, Maria Elena
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Tierney, George
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Mohammed, Khaled Mohammed Hassan
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Decarolis, Donato
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Hayama, Shusaku
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Venturini, Federica
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Held, Georg
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Arrigo, Rosa
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Amboage, Monica
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Hellier, Pip
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Lynch, Evan William
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Amri, Mahrez
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Casavola, Marianna
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Erden, Tugce Eralp
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Collier, Paul
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Wells, Peter P.
bc4fdc2d-a490-41bf-86cc-400edecf2266
Blackmore, Rachel Hazel
3584b852-92ac-4341-b303-786f67e41f77
Rivas, Maria Elena
08dfefa0-544f-4c89-a1c8-7a58560a59e1
Tierney, George
5a1b1e97-5868-4933-a321-9b2cdfb69c5a
Mohammed, Khaled Mohammed Hassan
f50a275b-4588-43b0-ba9c-5f108f23d3fc
Decarolis, Donato
aa002823-ac92-4afe-aa03-83562110dd3c
Hayama, Shusaku
dbaecfbe-b0a6-4b21-9030-b2942d42b33c
Venturini, Federica
a4ddd918-9bbf-450a-b8e6-558d30301bb2
Held, Georg
ad070380-ba97-42db-9a0d-9e5d73b62cd0
Arrigo, Rosa
0998a17a-56f9-49c6-8a47-bdd9099c523a
Amboage, Monica
f1f91840-c149-4732-b396-0c20e11aaeb6
Hellier, Pip
c3bd090a-2f8d-45ec-8ee6-781c034eb9b9
Lynch, Evan William
6eecfe8a-33be-44bb-9498-e1d378d526ff
Amri, Mahrez
e468ed70-db5e-447f-a174-8afa413922af
Casavola, Marianna
a5a1b50c-6fa4-40e8-a155-9df4426f60cd
Erden, Tugce Eralp
758531fc-bdd2-4122-bc1b-2e4438b1a282
Collier, Paul
35e8d4e9-9569-48f9-9e98-43076647796e
Wells, Peter P.
bc4fdc2d-a490-41bf-86cc-400edecf2266

Blackmore, Rachel Hazel, Rivas, Maria Elena, Tierney, George, Mohammed, Khaled Mohammed Hassan, Decarolis, Donato, Hayama, Shusaku, Venturini, Federica, Held, Georg, Arrigo, Rosa, Amboage, Monica, Hellier, Pip, Lynch, Evan William, Amri, Mahrez, Casavola, Marianna, Erden, Tugce Eralp, Collier, Paul and Wells, Peter P. (2020) The electronic structure, surface properties, and in situ N2O decomposition of mechanochemically synthesised LaMnO3. Physical Chemistry Chemical Physics, 22 (34), 18774-18787. (doi:10.1039/D0CP00793E).

Record type: Article

Abstract

The use of mechanochemistry to prepare catalytic materials is of significant interest; it offers an environmentally beneficial, solvent-free, route and produces highly complex structures of mixed amorphous and crystalline phases. This study reports on the effect of milling atmosphere, either air or argon, on mechanochemically prepared LaMnO3 and the catalytic performance towards N2O decomposition (deN2O). In this work, high energy resolution fluorescence detection (HERFD), X-ray absorption near edge structure (XANES), X-ray emission, and X-ray photoelectron spectroscopy (XPS) have been used to probe the electronic structural properties of the mechanochemically prepared materials. Moreover, in situ studies using near ambient pressure (NAP)-XPS, to follow the materials during catalysis, and high pressure energy dispersive EXAFS studies, to mimic the preparation conditions, have also been performed. The studies show that there are clear differences between the air and argon milled samples, with the most pronounced changes observed using NAP-XPS. The XPS results find increased levels of active adsorbed oxygen species, linked to the presence of surface oxide vacancies, for the sample prepared in argon. Furthermore, the argon milled LaMnO3 shows improved catalytic activity towards deN2O at lower temperatures compared to the air milled and sol–gel synthesised LaMnO3. Assessing this improved catalytic behaviour during deN2O of argon milled LaMnO3 by in situ NAP-XPS suggests increased interaction of N2O at room temperature within the O 1s region. This study further demonstrates the complexity of mechanochemically prepared materials and through careful choice of characterisation methods how their properties can be understood.

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Accepted/In Press date: 7 April 2020
e-pub ahead of print date: 30 June 2020

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Local EPrints ID: 442910
URI: http://eprints.soton.ac.uk/id/eprint/442910
ISSN: 1463-9076
PURE UUID: ca48923c-f962-4c27-8a4d-4493cbb07aed
ORCID for Peter P. Wells: ORCID iD orcid.org/0000-0002-0859-9172

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Date deposited: 31 Jul 2020 16:30
Last modified: 18 Feb 2021 17:05

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