Modulating Plasmon-mediated Chemical Reaction by Electrode Potential on Copper Nanoelectrode

Plasmon-mediated chemical reaction (PMCRs) is a promising approach for facilitating light-driven chemical reactions by utilizing solar energy. PMCR is an emerging field of research whereby the chemical reactions are triggered by the plasmonic metals which facilitate the conversion and redistribution of the photon energy into hot electrons and/or thermal energy. The molecular fingerprint of the PMCR-derived surface species can be characterized by Surface-enhanced Spectroscopy (SERS) in situ and in real-time with a sensitivity down to a single molecule. Plasmonic noble metals such as gold (Au) or silver (Ag) are typically used as SERS substrates owing to their extraordinary plasmonic properties associated with their high chemical stability. However, due to their limited amount in the continental crust, there’s a constant need to develop an alternative SERS substrate. Copper (Cu) is an attractive and cheaper alternative with its high catalytic activities combined with its strong plasmonic properties. In this talk, I will present the SERS studies of PMCRs on electrochemically etched copper nanoelectrodes (CuNE) as tunable, reliable, and efficient electrochemical SERS (EC-SERS) substrates. The catalytic reactions on the CuNE surface can be tuned by three factors: (i) the surface plasmons, (ii) the electrode potential, and (iii) the redox states of Cu. By using the time-resolved EC-SERS, the reversible conversion of 4-aminothiophenol(4-ATP)/4-nitrothiophenol(4-NTP) to 4,4′-dimercaptoazobenzene (DMAB) is studied.