Component‐Controlled Synthesis of Small‐Sized Pd‐Ag Bimetallic Alloy Nanocrystals and Their Application in a Non‐Enzymatic Glucose Biosensor

Small‐sized monodisperse Pd‐Ag alloy nanocrystals (NCs) are synthesized via a solid‐liquid and solid‐solid phase chemical route, i.e., sequential reduction of Pd(NO₃)₂ and AgNO₃ solid precursors in the liquid mixture of dodecylamine and 1‐octadecene, followed by fusion of formed Pd and Ag NCs at 250 °C. By controlling the addition sequence and molar ratio of the metallic precursors, a series of Pd‐Ag alloy NCs, including Pd₅Ag, Pd₂Ag, PdAg, PdAg₂, and PdAg₅, is obtained. The alloy NCs are highly crystallized and exhibit a strong atomic ensemble in addition to component‐dependent electronic effects. Pd₂Ag NCs have unique structure and electronic properties, showing a much faster electron transfer process at a modified glassy carbon electrode interface compared with that of other alloys. Therefore, the Pd₂Ag NCs are chosen as the electrocatalyst to evaluate the performance of Pd‐Ag nanoalloy and a novel non‐enzymatic glucose biosensor is fabricated. The biosensor exhibits an acceptable reproducibility, a good stability and low interferences, which can be used to examine glucose in clinic blood serum samples. This work provides a simple multiphasic reaction system to synthesize binary alloy NCs with well‐controlled componential ratio and opens the avenue to utilize them in biosensing or other advanced technological fields.