Understanding the ensemble electrochemistry of random-walk nanoparticles: Improved reaction efficiency and mechanistic insights

Abstract Dispersing nanoparticles into solution instead of utilizing conventional nanoparticle modified electrodes can improve the reaction efficiency of electrochemical systems by orders of magnitude. A theoretical model was built describing the ensemble electrochemistry of multiple random-walk nanoparticles via Monte Carlo simulation. It was found that solution-phase nanoparticles broke the mass transport limitation via pre-adsorbing substrates from solution. Even not all the nanoparticles can be “recycled” during the reaction, the renewal of a small portion of nanoparticles greatly improved the overall reaction rate. Proof-of-concept experiments of the reduction reaction of arsenic(III) at gold nanoparticles were implemented, which confirmed our theoretical predictions. This work revealed the mechanisms of reaction enhancement in nanoparticle solutions, verifying the feasibility of employing the random-walk nanoparticle technique for engineering electrochemical reactions in general.