Fabrication of Popcorn-Like Silver Microparticles Film Array for in Situ Detection of Plasmonic Catalytic Reaction by Sers Spectroscopy Technique

Surface-enhanced Raman scattering (SERS) spectroscopy has tremendous significance in the fields of ultrasensitive detection and real-time in situ monitoring in catalysis. However, simultaneously obtaining higher-quality SERS and better plasmonic catalytic properties in single nano/microstructure remains difficult. Here, popcorn-like silver (Ag) microparticles (MPs) with special surface topography were designed and fabricated by a modified polyol method. Popcorn-like Ag MPs exhibit a broad range of electromagnetic (EM) spectra from the red to infrared regions, approximating a full spectrum. Moreover, these popcorn-like Ag MPs were used to construct a monolayer film array substrate on silicon wafer with a high reproducibility and good homogeneity over large areas by an interfacial self-assembly method. The single-layer Ag MPs film array is utilized as an effective SERS substrate, which can realize trace detection for in situ monitoring the plasmonic catalytic reaction about the conversion of 4-nitrothiophenol (4-NTP) to 4,4’-dimercaptoazobenzene (DMAB) under excitation by 532 nm and 785 nm lasers, respectively. The mechanism on SERS response and plasmonic catalytic reaction of the popcorn-like Ag MPs was systemically investigated through experimental and theoretical simulations aspect. This work will be widely used in the fields of SERS, sensors and photocatalysis.