Enhancement mechanism of surface-enhanced Raman spectroscopy and plasmon photoelectrochemical reactions

<p indent="0mm">Electrochemical interfaces are important places for energy conversion and chemical transformation. The interaction of light with metallic nanostructures at electrochemical interfaces can significantly change the surface spectroscopic properties, as well as the thermodynamics and kinetics of chemical reactions at the interfaces. Surface plasmon resonance (SPR) effect in chemical reactions with metal nanostructures as a medium redistribute and convert the photon energy into localized photoelectric field, hot electrons, hot holes and photothermal energy, which not only produces surface-enhanced spectroscopy, especially surface-enhanced Raman spectroscopy (SERS), but also induces the interface to occur in new mechanisms of chemical reactions and energy conversion. Meanwhile, SERS can be used as a characterization method to study the surface physical and chemical processes on nanostructures. In this review article, the electromagnetic enhancement mechanism and chemical enhancement mechanism of SERS are firstly introduced to reflect the basic principle of SERS as a means of high sensitivity characterization of interfaces. Secondly, the action mechanism of hot carriers (hot holes and hot electrons)-induced chemical reactions is specifically discussed in three model systems of para-thiophenol, adenine derivatives and 8-bromoadenine, and the selectivity and photon quantum efficiency of plasmon photoelectrochemical realizations to modulate the chemical reaction process are analyzed with respect to the fact that plasmon photoelectrochemical reactions exhibit distinctions and potential advantages over the conventional chemical reactions. Finally, in view of the challenges of selectivity and low photon quantum efficiency of the plasmon photoelectrochemical reaction, combined with the current research progress in this research direction at home and abroad, two outlooks are put forward based on the resonance effect of surface plasmons and their structural features, which will provide a new way of thinking for the conversion and utilization of light energy.