Enhanced Electrochemiluminescence Behavior of Gold–Silver Bimetallic Nanoclusters and Its Sensing Application for Mercury(II)

Bimetallic nanoclusters (NCs) with superior performance to that of monometallic nanoclusters have attracted extensive research interest due to the synergetic effect of the two atoms. Inspired from the silver effect on the enhanced fluorescence intensity of Au NCs, a series of bovine serum albumin-protected Au–Ag bimetallic NCs were prepared by regulating the molar ratios of HAuCl4/AgNO3 and their electrochemiluminescence (ECL) property was investigated using triethylamine as co-reactant. Notably, multifold higher efficiency was achieved with Au–Ag bimetallic NCs in reference to the monometallic nanoclusters. Moreover, the doping of Ag atoms not only made the ECL emission of the Au NCs blue shift but also decreased the peak potential and onset potential, which provided an efficient and facile way to improve the ECL behavior. Based on the ECL quenching effect of Hg2+ toward Au–Ag bimetallic NCs via the formation of metallophilic bond, an ECL sensor for Hg2+ detection was proposed with good stability and high selectivity and sensitivity. These results indicated that the as-prepared Au–Ag bimetallic NCs with enhanced ECL properties can be served as an ideal luminescent material in sensing application.