Integrated metal ion-mediated coordination strategy gives bimetallic silver nano-secondary materials unique properties

Metastable precious metal nanoparticles as precursors and self-templates with uniform atomic distribution provide unlimited possibilities for the construction of nano-secondary materials. Bimetallic nanomaterials with unexpected physical and chemical properties can be fabricated through a metal ion-mediated strategy. However, the interior functionalization of metastable precious metal nanoparticles so as to achieve synergistic interaction between precursors and external ions thus enhance the performance of bimetallic nanomaterials remains a challenge. Herein, the metal ion-mediated bimetallic nanomaterials such as Cr@Ag NPs, Ni@Ag NPs, Mn@Ag NPs, Cd@Ag NPs, and Pb@Ag NPs were precisely constructed on the basic of the seeds of silver nanoparticles (Ag NPs). More importantly, the integrated bimetallic nanomaterials Cr@Ag NPs could serve as the potential mimetic-peroxidase to sensitively and rapid identify Hg²⁺ in TMB-H₂O₂ systems. Furthermore, the developed colorimetric assay platform exhibits satisfying performances in real water samples. The present study opens a new horizon for the design and construct novel nanomaterials with extraordinary opto-physical and chemical properties in colorimetric sensing.