All chemicals were of analytical grade and used asreceived
without further purification. All experiments were conducted
under air atmosphere. A typical synthesis experiment occurredas
follows:0.236gAgNO3 and 0.337gAlCl3 6H2O were added into
the deionizedwater(20mL)under vigorous stirring for 10min.7g
NaOH and 12gurea were added into the deionizedwater(100mL)
under vigorous stirring to form NaOH/urea solution.Then,the
above two solution were mixed together and were transformed
intoa50-mLTeflon-lined stainlesssteelautoclave.Theautoclave
wasmaintainedat140,160,and180 °C for12h.Theproductwas
separatedfromthesolutionbycentrifugation,washedwithwater
and ethanolthreetimesanddriedat60 °C forfurther
characterization