Nano-impact single-entity electrochemistry enables plasmon-enhanced electrocatalysis

Plasmon-enhanced electrocatalysis (PEEC) based on a combination of localized surface plasmon resonance excitation and electrochemical bias applied to plasmonic material can result in improved electrical-to-chemical energy conversion compared to conventional electrocatalysis. Here, we demonstrate the advantages of nano-impact single-entity electrochemistry (SEE) for investigating the intrinsic activity of plasmonic catalysts at the single-particle level using glucose electrooxidation on gold nanoparticles as a model reaction. We show that in conventional ensemble measurements, plasmonic effects have minimal impact on photocurrent because the Fermi level of the deposited gold nanoparticles continuously equilibrates with the working electrode potential, leading to fast neutralization of hot carriers by the measuring circuit. The photocurrents detected in these measurements are caused by photo-induced heating of carbon-based electrodes. In SEE, the Fermi level of diffused gold nanoparticles is unaffected by the working electrode potential. As a result, plasmonic effects are the dominant source of photocurrents in SEE.