Studies on Sensitization for Electrochemiluminescence of Luminol with Platinum-Gold Bimetallic Nanoparticles Modified Electrode

The present paper reports the researches on sensitization of nano-bimetalic material for the electrochemiluminescence (ECL) of luminol. The platinum-gold bimetallic nanoparticles with different component ratio and size were prepared by chemical reduction. The analytical methods such as UV-Vis spectra, TEM and XRD were applied to characterize the properties of the nanoparticles. The information obtained from these methods revealed that the prepared bimetallic nanoparticles were truly of alloy structure and absolutely not the mixture of two kinds of metallic nanoparticles. The components of the nanoparticles. could be regulated for a series of Pt/Au ratios and the diameters determined by laser-granulometer. In alkaline medium of pH 12.0, the bimetallic Pt-Au nanoparticle modified electrode sensitized the electrochemiluminescence of luminol. The sensitization efficiency reached as high as one order of magnitude with the 6 : 1 of Pt/Au ratio. The specific surface area of nanoparticles would be larger as the size diminishes, resulting in a higher surface activity, so the smallest size of nanoparticles led to the highest efficiency.