Surface-enhanced Raman Spectroscopy and Plasmon-Assisted Photocatalysis of p-Aminothiophenol

p-Aminothiophenol (PATP) is one of the most important probe molecules in surface-enhanced Raman spectroscopy (SERS). Adsorbed PATP exhibits very unique and abnormally intense SERS signals. However, the understanding toward the abnormal SERS signals is still in debate. In this review, we overview our theoretical and experimental studies to understand the abnormal SERS of PATP. We first introduce the theoretical investigation on the SERS enhancement mechanism of PATP. The theoretical study shows that the abnormal SERS signals of PATP are not from PATP itself but arise from its surface catalytic coupling product p, p'-dimercaptoazobenzene (DMAB). The assumption is supported by carefully designed experiments of PATP and the SERS signal of the synthesized DMAB molecule. Then, we summarize the experimental factors that influence the photochemical conversion of PATP to DMAB on the surfaces of metal nanostructures. We then explore the reaction mechanisms for the surface catalytic coupling reaction of PATP in both experimental and theoretical aspects. Finally, we proposed the further direction of surface plasmon enhanced chemical reaction on the basis of our systematically studies of SERS and plasmon photocatalysis of PATP.