The mixture was then discharged using a unipolar pulsed power supply under conditions
of 500 V applied voltage, 20 kHz frequency, 70–25% duty ratio, and
0.3 mm electrode gap for 3 min. For Ag nanoparticle-embedded mesoporous
silica, 0.13–1.3 ml silver nitrate (AgNO3 1M, Sam Chun) solutions
were dropped into mixture of P123 and TEOS in HCl solution
before discharge to prepare 1, 5, and 10mM AgNO3 solutions, named
as 1, 5, and 10AgNP@SiO2. The collected precipitates were washed several
times with deionized water and dried in ambient condition. Mesoporous
silica prepared by SPP wasweighed to be 5.11 gwith the yeild of
74.4% w/w, comparing with the initial weight of Si precursor (TEOS).