Preparation of AuPd bimetallic nanoparticles by plasma in a microreactor and their SERS properties

To overcome the limitations of current bimetallic nanoparticle preparation methods, such as complex procedures, long reaction times, excessive use of chemical reducing agents, and inconsistent product uniformity, a continuous microreactor-based method was developed to prepare AuPd bimetallic nanoparticles using chloroauric acid and sodium tetrachloropalladate as precursors. The surface-enhanced Raman scattering （SERS） performance of the products was systematically studied using crystal violet （CV） as probe molecule. In such a manner, plasma can simultaneously reduce Au³⁺ and Pd²⁺, enabling efficient and continuous production of AuPd bimetallic nanoparticles. The resulting products exhibited excellent crystalline structure, high dispersion, and tunable composition through reactant flow rate adjustments. In addition, the AuPd-based SERS substrates exhibited significant signal enhancement capabilities, enabling highly sensitive and stable detection of trace CV analytes. The results of this study offer valuable guidance for the efficient and controllable synthesis of multimetallic nanoparticles.