Green synthesis of cavity-containing manganese oxides with superior catalytic performance in toluene oxidation

10 Figuras.- 2 Tablas.- Datos suplementarios disponibles en línea en la página web del editor.-- © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Manganese oxide prepared by a simple hydrothermal method is highly active and stable in both lab and quasi industrial conditions for the total oxidation of toluene, achieving total conversion at only 175 °C in the absence of water and at 150 °C in the presence of 4 mol % water. Moreover, this performance is stable for at least 6 cycles. The enhanced catalytic performance has been related to the presence of highly reactive oxygen surface species. This species are probably promoted by Mn3O4 nanoparticles with Mn3+ at the tetragonal distorted cationic sites, likely compensated by structural water at the anionic sites. The presence of structural water can be related to the formation of internal cavities/vesicles in the Mn3O4 crystalline structure.AM and YZ acknowledge The Centre for High-resolution Electron Microscopy (CħEM), supported by SPST of ShanghaiTech University under contract No. EM02161943. Electron microscopy analyses were performed at Centre for High-Resolution Electron Microscopy (CћEM), ShanghaiTech University. AM acknowledges the National Natural Science Foundation of China through the projects NSFC NFSC-21850410448 and NSFC- 21835002. Authors from UCM thank Santander-UCM institution (PR41/17-20951 project) and MINECO (MAT2017-84118-C2-2-R project) and UCM CAI centers (XRD and EM). TG and JML thank Regional Aragon Government (DGA) under the research groups support programme. Some of the STEM analyses were conducted at the Laboratorio de Microscopias Avanzadas, Universidad de Zaragoza, Spain. R. A. acknowledges support from Spanish MINECO grant MAT2016-79776-P (AEI/FEDER, UE), from the Government of Aragon and the European Social Fund (E13_17R, FEDER) and from the European Union H2020 program “ESTEEM3” (grant 823717) Authors from UV thank MINECO (MAT2017-84118-C2-1-R project) for funding.Peer reviewe