From Nanoparticle Ensembles to Single Nanoparticles: Techniques for the Investigation of Plasmon Enhanced Electrochemistry.

Plasmon enhanced electrochemistry (PEEC), where specific electrochemical reactions are promoted due to the reduced energy barrier of the reaction processes by the light excited "hot carriers" of the plasmonic nanoparticles, has aroused tremendous interest in recent years. A deep understanding of the PEEC process becomes a key issue for facilitating PEEC catalyst design and improving PEEC performance. This concept article begins with a brief discussion of the macroscopic electrochemical method of PEEC study of the plasmonic nanoparticle ensembles. Following that, we highlight two electrochemical techniques that may possess single nanoparticle sensitivity, i. e., scanning electrochemical microscope and nano-impact electrochemistry. The pros and cons of each technique are discussed and an outlook is given. We hope to provide the readers with the current status of PEEC to evoke reflections regarding the reaction mechanisms, performance improvement, and the utilizations to important systems.