Synthetic routes to manganese oxoborate and correlations between experimental parameters and properties

Abstract

This study examines manganese oxoborate synthesis in three different routes and the role of process parameters on structure and morphology of the products. Borax or boric acid and simple manganese salts were used as raw materials. In this regard, the samples prepared by hydrothermal, solid-state, and solution combustion methods were characterized by powder X-ray diffraction (XRD), vibrational spectroscopy (FT-IR and Raman), thermal analysis (DSC and TGA), scanning and transmission electron microscopy (SEM and TEM), chemical analysis and BET surface area measurements. It was found that all three strategies yielded warwickite-type Mn2OBO3 nanoparticles, but with significant changes in morphology, size, and surface characteristics. The hydrothermal approach has proven to be a general approach for synthesizing manganese oxoborate nanorods at pH 7.5. Solution combustion technique appeared the most practical and promising not only as a time-saving route but also in the production of ca. 100 nm, quasi-spherical, mesoporous manganese oxoborate nanoparticles.