2.2. Preparation of PBNPs.
PB NPs were synthesized according to the previous method developed by
our group. In brief, 264 mg
K3[Fe(CN)6]•3H2O and
3 g PVP were dissolved in 40 mL of 0.01 M HCl solution under stirring
for 1 h at room temperature. Then, the mixture solution was heated at 80
°C for 20 h with oil bath. After centrifugation and water washing for 3
times, the precipitate was dried under vacuum for the preparation of PB
NPs.
2.3 Preparation
of HMPB NPs.
HMPB NPs were prepared following the previous method with little
modification32. 100 mg PVP and 20 mg PB NPs were
dissolved in 20 mL of 1 M HCl solution under magnetic stirring for 3 h.
Then, the mixture solution was transferred into a stainless autoclave
and heated at 140 °C for 4 h. After acid etching, HMPB NPs is collected
by centrifugation and washed three times with deionized water.