Manganese oxidation states repartition in a channel-like mesoporous zirconium oxide

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Manganese oxidation states repartition in a channel‑like mesoporous zirconium oxide Nelly Couzon1 · Laurence Bois1   · Clémentine Fellah2 · Cristian Loestean3 · Fernand Chassagneux1 · Rodica Chiriac1 · François Toche1 · Lhoussain Khrouz4 · Arnaud Brioude1 · Ovidiu Ersen6 · Lucian Roiban5

© Springer Science+Business Media, LLC, part of Springer Nature 2020

Abstract Here, we present a characterization of mesoporous mixed manganese zirconium oxide (MnZr) synthesized by evaporation induced self-assembly method involving a block copolymer self-assembly method. The MnZr oxide has been fully characterized by X-ray diffraction, transmission electronic microscopy, analytical electronic tomography, nitrogen adsorption/ desorption isotherms, thermogravimetric analysis, X-ray photoelectron spectroscopy and electronic paramagnetic resonance. Electronic tomography analysis reveals that a mesoporous solid solution MnZr was successfully obtained by this way, with a homogeneous dispersion of Mn. X-ray diffraction, X-ray photoelectron spectroscopy, thermal analysis and electronic paramagnetic resonance inform about the manganese oxidation states present (­ Mn2+, ­Mn3+, ­Mn4+) and their location within the sample. Keywords  Manganese · Zirconium · Mesoporous · Analytical electron tomography · Self-assembly block copolymer

1 Introduction The development of catalysis area during last decades has led to an increase interest in the use of transition metals as catalysts, proposing a great alternative to noble metals, being * Laurence Bois Laurence.bois@univ‑lyon1.fr 1



Univ. Lyon, Université Claude Bernard Lyon 1, Laboratoire Des Multimatériaux Et Interfaces, UMR CNRS 5615, 69622 Villeurbanne, France

2



Université de Lyon, ENS Lyon, Université Lyon 1, CNRS, LGL-TPE, 69007 Lyon, France

3

Department Physics of Nanostructured Systems, National Institute for Research and Development of Isotopic and Molecular Technologies, 67‑103 Donat St, 400293 Cluj‑Napoca, Romania

4

Univ. Lyon, ENS de Lyon, CNRS UMR 5182, Université Claude Bernard Lyon 1, Laboratoire de Chimie, 69342 Lyon, France

5

Univ. Lyon, INSA-Lyon, Université Claude Bernard Lyon 1, MATEIS, UMR5510 CNRS, 7 avenue Jean Capelle, 69100 Villeurbanne, France

6

Institut de Physique Et Chimie Des Matériaux de Strasbourg (IPCMS), UMR 7504, CNRS - Université de Strasbourg, 23 rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France









cheaper and as efficient [1–3]. Manganese possesses various valence states and five stable stoichiometric oxides (MnO, ­Mn3O4, ­Mn2O3, ­Mn5O8, and ­MnO2) allowing a wide range of applications in catalysis and electro-catalysis, in sensing as cathode in Li-ion batteries and as supercapacitor materials [4–6]. Manganese containing catalysts have received much attention for oxidation reactions such as the oxidation of carbon monoxide or benzene [7–10] or for the combustion of toluene [11]. Also, lot of studies have shown that manganese-based catalysts exhibit good N ­ H3-selective catalytic reduction (SCR) activity at low temperature [12], whi