Analytical Sciences

Scanning Electrochemical Microscopic Study of Hydrogen Oxidation and Evolution at Electrochemically Deposited Pt Nanoparticulate Electrode Incorporated in Polyaniline

Samina AHMED, Shan JI, Leslie PETRIK, and Vladimir M. LINKOV

Department of Chemistry, University of the Western Cape, Private Bag X12, Bellville 7535, South Africa

Scanning Electrochemical Microscopy (SECM) feedback mode and substrate generation-tip collection (SG-TC) mode coupled with chronoamperometric approach were used to investigate H₂ oxidation and hydrogen evolution reaction (HER) at a polyaniline (PAni) coated highly oriented pyrolytic graphite (HOPG) electrode. Using the former mode, the heterogeneous electron transfer (ET) kinetics for H₂ oxidation was studied, while the latter mode allowed mapping of the distribution of local [H₂] at the nanoparticulate/aqueous interface, followed by monitoring the transients at the tip. These preliminary studies demonstrate that SECM is useful in evaluating the activity of nanophase electrocatalysts. Particularly, if one employs nanometer-sized tips or hydrodynamic microjet electrodes where the mass transfer rate is significantly high, it should be possible to investigate the ET kinetics more accurately.

J-STAGE: View this article in J-STAGE