Controlling synthesis of Au@AgPd core–shell nanocubes and in situ monitoring SERS of their enhanced catalysis

Abstract

Surface-enhanced Raman spectroscopy (SERS) displays extraordinary application value in studying chemical reaction mechanism catalyzed by noble metal nanocomposites in recent years by identifing ‘‘fingerprint” information of molecules from their vibrational transitions. Herein, we successfully fabricated Au@AgPd core-shell nanocomposites with integration of catalytic and SERS activities, via a facile process by simultaneously reducing Ag and Pd precursors (AgNO3 and PdCl2) in the presence of Au nanocubes. By easily adjusting the amount of AgNO3 and PdCl2, we can optimize the SERS and catalytic activities of Au@AgPd core-shell nanocomposites. Various spectroscopic and microscopic techniques were employed to characterize the nanocomposites. The optimal Au@AgPd core-shell nanocomposites were used to follow the catalytic reduction process of 4-nitrothiophenol in the presence of NaBH4 by SERS. The prepared Au@AgPd core-shell nanocomposites are effective and suitable for sensitively investigating the catalytic reaction process by in situ SERS.