Catalytic Single-Particle Nano-Impacts: Theory and Experiment. Poly(vinylferrocene)-Modified Graphene Nanoplatelet Mediated l‑Cysteine Oxidation

The theory of catalytic nano-impacts is developed specifically for the case of a single particle in contact with an electrode for a short period of time in which it mediates electron transfer to or from a species in homogeneous solution. The theory is applied to impacts of chemically modified graphene nanoplatelets in which the immobilized ferrocene/ferrocenium couple is used to mediate the oxidation of l-cysteine in aqueous solution. Theory and experiment are in good agreement, and the catalytic rate constant is found to be (2.4 ± 1.2) × 10³ M^–1 s^–1.