pH-Response Mechanism of a Redox Reaction between Silver Ions and Hydroquinone

Studying chemical reactions at the nanoscale level could aid to better understand and control reaction processes. In this paper, the redox reaction between hydroquinone and Ag+ via gold nanoparticles as a suitable surface was taken as an example, where its thermochemical values were computed by using density functional theory (DFT) methods with the 6-31G(d) basis set. The calculated results exhibited that the reaction kinetics was related to pH values and concluded as three different kinds of processes. Assisted by the gold nanoparticles, we tracked the reduction of Ag+ in real time by plasmon resonance Rayleigh scattering spectroscopy and dark-field microscopy. Moreover, discrete dipole approximation and transmission electron microscope images were also conducted, and the calculated results were in good agreement with the experimental ones. In addition, we utilized the pH response of the redox reaction to distinguish cancer cells from the normal ones, which showed promising applications in promoting the development of disease diagnosis.