Figure 5.

(A) Bar plot showing the pH change occurring in solution after the addition of KNO₃ and AgNO₃. 30 mL of dialyzed AuNPs was centrifugation precipitated and split into two equal volume portions. Those two are AuNP-free top layer and AuNP-containing bottom layer. pH measurements were conducted 1 h after incubating top and bottom layer with 10 mM KNO₃ and AgNO₃. (B) Photograph of the pH papers used to check the pH of the Ag⁺ treated (i) top and (ii) bottom layers, respectively. (C) Time-dependent proton concentration as a function of the (AgNO₃/AuNP) incubation time. The sample was prepared by mixing 10 mM of AgNO₃ with 30 mL of dialyzed AuNPs that were centrifugation precipitated before AgNO₃ addition.