Influence of various anions (Cl~-, NO_3~-, and CH_3COO~-) of europium salts on the thermal decomposition behavior of Eu~(3+)-modified 1,8-naphthalic anhydride hybrid mesoporous silica

摘要

Hybrid bimodal mesoporous silica grafted 1,8-naphthalic anhydride (NA) as a luminescent tracer was modified by Eu~(3+) ions, whereas the influence of the interaction between europium salts with various anions (Cl~-, NO_3~-, and CH_3COO~-) and NA molecules grafted onto the mesopores on their thermal decomposition behaviors and kinetic properties were studied in detail in accordance with the thermogravimetric analyzer (TGA) profiles obtained at different heating rates under flowing N_2 atmosphere. Meanwhile, Kissinger and Flynn-Wall-Ozawa algorithms were used to calculate the apparent activation energies of Eu~(3+)-modified NA existing in the mesoporous channels and therefore the thermal decomposition mechanism was discussed on the basis of the Coats-Redfern method. Moreover, XRD, TEM, N2 adsorption-desorption isotherms and FT-IR techniques were employed to analyze the structural characteristics and textural properties of the resultant samples.