Direct Observation of the Reactivity of Electrons\ntoward Gold Nanoparticles in Aqueous Solution

The catalytic activity\nof gold nanoparticles (AuNPs) has been widely\nacknowledged; however, Au NPs are considered to be highly inert as\nradiosensitizers in biological systems. This apparent discrepancy\nacross different fields complicates the understanding of their interfacial\nreactivity, particularly in terms of electron transfer reactions.\nHere, we employ pulse radiolysis to determine the rate constants for\nthe reactions of electrons with AuNPs in aqueous solution. Our investigation\nof AuNPs with different sizes and surface modifications demonstrates\nthe potential influence of the AuNPs design on electron transfer reactions.\nThese findings address long-standing mechanistic contradictions and\nunderscore the significance of interfacial electron dynamics on AuNPs\nin both catalytic and biological processes.