Au@Ag nanorod horizontal arrays: Self-assembly preparation and in situ monitoring SERS of plasmonic catalytic reaction.

Here, we successfully synthesized silver-coated gold nanorods (Au@Ag NRs) via a facile wet chemical method. The catalytic property of Au@Ag NRs in water solution was much better than that of Au NRs in water solution. To obtain high catalytic properties, we self-assembled a single-layer Au@Ag NR array by evaporation on a silicon wafer. The catalytic activity of the Au@Ag NR array was probed using the reduction of 4-nitrothiophenol. The reaction processes were monitored and identified through in situ surface-enhanced Raman spectroscopy based on the confocal Raman microscope system. This study provides a simple and fast method to improve the catalytic property of the noble nanoparticles. • Ag@Au nanorods(NRs) are rationally designed and fabricated via a facile wet chemical method, which have better catalytic property than Au NRs. • A single-layer Au@Ag NRs array is successfully self-assembled by evaporation on a silicon wafer. • The catalytic performance of Au@Ag NRs array using the reduction of 4-nitrothiophenol (4NTP) is chosen as a model reaction. • The reaction processes are real-time monitored through in situ SERS spectroscopy with the confocal Raman microscope system. [ABSTRACT FROM AUTHOR]