The detection of single Pd, Pt, and Rh metal nanoparticles (MNPs) was achieved by monitoring their collisions with Au or Hg ultramicroelectrodes (UMEs). Using their chloride salts, Pd, Pt, and Rh nanoparticles were synthesized using sodium citrate as the capping agent. In the single MNP detection experiments, MNPs were injected to a solution containing a Au or Hg UME and a redox species which could undergo a kinetically limited electron transfer reaction. When the catalytic MNPs collided with the nearly inert Au or Hg UME, a sharp increase in current was observed as the MNP catalyzed the redox reaction. The reactions used in this work were the oxidation of hydrazine and the reduction of protons. Using TEM, the size distribution of the MNPs was obtained and then correlated to the sizes of the current increases observed upon MNP/UME collisions. Collision results obtained for the different MNPs at the two UME materials, Au and Hg, will be compared.

Electrocatalytic detection of single Pd, Pt, and Rh nanoparticles at Au and Hg ultramicroelectrodes

255th National Meeting (2018)

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