① 0.004 M CTAB was mixed with distilled deionized water. ② Then 10 mL NH3·H2O was added into the CTAB solution. ③ 0.04 M LaCl3·7H2O was added into it and stirred for 2 h.
① La(NO3)3 was dissolved (solution A). ② Diethylenetriamine was dissolved (solution B). ③ The solution A was heated at 90°C and solution B was dropped into solution A and then kept for 3 h.