Issue 34, 2020

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

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.

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

Supplementary files

Article information

Article type
Paper
Submitted
12 feb 2020
Accepted
07 apr 2020
First published
30 jun 2020
This article is Open Access
Creative Commons BY license

Phys. Chem. Chem. Phys., 2020,22, 18774-18787

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

R. H. Blackmore, M. E. Rivas, G. F. Tierney, K. M. H. Mohammed, D. Decarolis, S. Hayama, F. Venturini, G. Held, R. Arrigo, M. Amboage, P. Hellier, E. Lynch, M. Amri, M. Casavola, T. Eralp Erden, P. Collier and P. P. Wells, Phys. Chem. Chem. Phys., 2020, 22, 18774 DOI: 10.1039/D0CP00793E

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements