Synthesis and Characterization of Mesoporous Europium (Ⅲ) Silicate Molecular Sieves

The luminescent nanosized Eu-MCM (1:10) was synthesized by means of sol-gel-assisted self-assembly under basic conditions at room temperature. The results of 29Si-MAS NMR show that the peaks are Q4, Q3, Q2 [(SiO)4-mSi-(OH)m (m=0, 1, 2), at -δ111, -δ103, -δ90], and q3, q2, q1, q0 [(SiO)4-nSi-(O-Eu)n (n=1, 2, 3, 4 ), at -δ83, -δ72, -δ55, -δ47]. The result proves Eu3+ doped Si-O framework. The HRTEM image shows that the regular uniform nanoparticles with a diameter of 15 nm possess large pore with Φ8 nm, which is consistent with the result of N2 adsorption. The patterns of selected-area electron diffraction, XRD, and pore-size distribution plot of Eu-MCM (1:10) show that the sample of Eu-MCM (1:10) possesses the both of crystal and amorphous phases. The FT IR results indicate that the peaks near 970 cm-1 are assigned to the deformation vibration of silanol group. The as-product was calcined at 800 ℃ and the mesoporous material possesses enormous specific areas and large pores, which shows that the mesoporous material is ultrastable.