Soft Synthesis Route and Characterization of Superparamagnetic Mn_1/2Fe_1/2(H₂PO₄)₂·2H₂O and Its Decomposed Product

Abstract

The superparamagnetic Mn1/2Fe1/2(H2PO4)2·2H2O was synthesized by a soft synthesis method using a Mn(c)−Fe(c)−H3PO4 system in water−acetone medium at ambient temperature. The synthesized Mn1/2Fe1/2(H2PO4)2·2H2O decomposed through the dehydration and the phosphate condensation reactions at high temperature and yielded binary manganese iron cyclotetraphosphate MnFeP4O12. The XRD and FTIR results of the synthesized Mn1/2Fe1/2(H2PO4)2·2H2O and the decomposed MnFeP4O12 indicate the pure monoclinic phase with space group P21/n and C2/c, respectively. The thermal behaviors and superparamagnetic properties of Mn1/2Fe1/2(H2PO4)2·2H2O and MnFeP4O12 in this work differed from the single compounds (M(H2PO4)2 ·2H2O and M2P4O12, where M = Mn, Fe) and the binary compounds (Mn0.5Fe0.5(H2PO4)2·xH2O) reported in previous works. The kinetic and thermodynamic functions for thermal decomposition of Mn1/2Fe1/2(H2PO4)2·2H2O were studied and confirmed as reaction mechanisms. Vibrational frequencies of breaking bonds in two thermal transformation stages were estimated and assigned by comparison with the observed FTIR spectra.

Superior thermal stability and smoke suppression of epoxy resin composites with graphene/LDHphosphorus‐rich hybrids

“…After embedding NaH 2 PO 4 , the peak of C O bond at 1,362 cm −1 disappears, and the symmetric stretching vibration peak of P O bond at 1,080 cm −1 appears. [23] These results demonstrate that CO Figure 3, the GO sample exhibits a corresponding characteristic peak of the (001) crystal planes with 2θ at 11.6 . [24] After grafting HA, the (001) characteristic peak of GO disappears, and a new characteristic diffraction peak attributed to (002) planes appears at 23 , indicating that HA promotes the reduction of GO to graphene and HA was grafted well on graphene layers.…”