The Effects of Various Parameters of the Microwave-Assisted Solvothermal Synthesis on the Specific Surface Area and Catalytic Performance of MgF2 Nanoparticles

Yawen Wang; Zahra Gohari Bajestani; Jérôme Lhoste; Sandy Auguste; Annie Hémon-Ribaud; Monique Body; Christophe Legein; Vincent Maisonneuve; Amandine Guiet; Sylvette Brunet

doi:10.3390/ma13163566

The Effects of Various Parameters of the Microwave-Assisted Solvothermal Synthesis on the Specific Surface Area and Catalytic Performance of MgF₂ Nanoparticles

Materials (Basel). 2020 Aug 12;13(16):3566. doi: 10.3390/ma13163566.

Affiliations

¹ Institut de Chimie et Matériaux de Poitiers UMR 7285, University of Poitiers, Cedex 9, 86073 Poitiers, France .
² Institut des Molécules et Matériaux du Mans (IMMM), UMR 6283 CNRS, Le Mans Université, Cedex 9, 72085 Le Mans, France.

Abstract

High-specific-surface-area MgF₂ was prepared by microwave-assisted solvothermal synthesis. The influences of the solvent and the magnesium precursors, and the calcination atmospheres, on the nanoparticle sizes and specific surface areas, estimated by X-Ray Powder Diffraction, N₂ sorption and TEM analyses, were investigated. Nanocrystallized (~7 nm) magnesium partially hydroxylated fluorides (MgF_2-x(OH)_x) with significant specific surface areas between 290 and 330 m²∙g^-1 were obtained. After activation under gaseous HF, MgF_2-x(OH)_x catalysts underwent a large decrease of both their surface area and their hydroxide, rates as shown by their ¹⁹F and ¹H solid-state NMR spectra. Expect for MgF₂ prepared from the acetate precursor, an activity of 30-32 mmol/h∙g was obtained which was about 40% higher compared with that of MgF₂ prepared using Trifluoroacetate method (21.6 mmol/h∙g).

Keywords: BET surface area; TEM data; XRPD data; catalytic performance; inorganic fluorides; microwave synthesis; nanoparticle size; nanoparticles; solid-state NMR; solvothermal route.