Briefly, 0.10 g of Fe3O4 particles (380 nm
in diameter) synthesized by solvothermal reaction were treated
with 0.1 mol L1 HCl aqueous solution (50 mL) by ultrasonication.
Then the Fe3O4 particles were homogeneously dispersed in the
mixture of ethanol, deionized water and concentrated ammonia
aqueous solution, followed by the addition of 0.03 g (0.144 mmol)
TEOS.