A Simple Approach To Develop Tailored Mesoporosity in Nanostructured Heteropolysalts

In this study, we describe a very simple approach to the development of tailored mesoporosity in any nanostructured heteropolysalt with control over both the mesoporous volume and the pore size. This approach, which consists in the treatment of a solid microporous precursor with a basic agent, has been tested on the ammonium salt of the Keggin-type [PMo12O40]3− heteropolyanion and constitutes a novel procedure for the preparation of mesoporous solids with no precedents. The results obtained in this study allow two main conclusions to be drawn: 1) the micro- and mesoporous structures in the heteropolysalt nanoparticles are independent from each other and 2) the development of mesoporosity in the solid material must be related to a process of alkaline degradation within the core of the nanocrystals that aggregate into the particles. These results afford valuable additional information to the present model of porosity that has been established for heteropolysalts.This work was financially supported by Generalitat Valenciana (grant PROMETEO2/2014/010) and Ministerio de Economia y Competitividad (grant CTQ2015-64801-R) through FEDER funds. S.R. acknowledges financial support from the program “Ayudas para la Captación del Talento adscritas a los Institutos de Investigación de la Universidad Pública de Navarra” funded by a collaboration agreement between Universidad Pública de Navarra, Fundación Bancaria la Caixa and Fundación Bancaria Caja Navarra