Silver nitrate

The following materials were used as received: potassium tetrachloroplatinate(II) (K₂PtCl₄; 98%), silver nitrate (AgNO₃; 99%), gold(III) chloride trihydrate [HAuCl₄·3H₂O; ACS reagent; 49.0% Au basis), palladium(II) acetylacetonate [Pd(acac)₂; 99%], acetic acid (CH₃COOH; 98%), sulfur powder (S; chemical grade), and oleylamine (primary amine; 95.4%) from J&K Scientific; aqueous HClO₄ solution (ACS reagent; 70%) and Nafion 117 solution (5% in a mixture of lower aliphatic alcohols and water) from Aladdin Reagents; ethanol (99%), methanol (99%), and toluene (99.5%) from Beijing Chemical Works; and Vulcan XC 72 carbon powders (XC 72C) with a BET (Brunauer–Emmett–Teller) surface area of ca. 250 m² g⁻¹ and average particle sizes of ca. 40 to 50 nm from Cabot Corporation. Commercial Pd/C and Pt/C catalysts were purchased from Johnson Matthey. All glassware and Teflon-coated magnetic stir bars were cleaned with aqua regia, followed by copious washing with deionized water before drying in an oven.

Cetyl trimethyl ammonium bromide (CTAB, >98.0%), tetraethylorthosilicate (TEOS, GR), 5-bromosalicylicacid (>98.0%), hydrogen tetrachloroaurate trihydrate (HAuCl₄∙3H₂O), silver nitrate (AgNO₃, >99%), sodium borohydride (NaBH₄, 99%), bismuth acetate (99.5%), bismuth nitrate pentahydrate (Bi(NO₃)₃·5H₂O), sodium sulfide nonahydrate (Na₂S·9H₂O), sodium hydroxide (NaOH, 96%), AA, hexamethylenetetramine, DOX, PVP, TAA and 4′,6-diamidino-2-phenylindole (DAPI) were purchased from J&K Scientific Ltd. (Shanghai, China) and used without further purification. 3-(4, 5)-dimethylthiahiazo-2-yl)-2,5-diphenyltetrazolium bromide (MTT) was obtained from Sigma (cat. M2003). Fresh doubly distilled water was used to make all aqueous solutions. All relevant glassware was immersed in aqua regia and thoroughly washed with doubly distilled water, then dried in an air dry oven.