Electrocatalytic reduction of hydrogen peroxide on a palladium‐modified carbon paste electrode

A palladium‐dispersed carbon paste electrode was used for the electrocatalytic reduction of hydrogen peroxide. After cycling the potential between 0.4 and −0.8V (vs. SCE) in pure dilute alkaline solution (10 −3 M NaOH), the resulting electrode surface exhibited stable and sensitive electrocatalytic response for hydrogen peroxide. The involved catalytic mechanism was thoroughly investigated. The electrocatalytic effect was attributed to electrogenerated elemental palladium at the electrode surface. The catalytic reduction of hydrogen peroxide proceeds via the hydroxyl radical, OH·. Dissolved oxygen can also be catalytically reduced in a similar way to hydrogen peroxide. The height of the cathodic catalytic current peak, as obtained by linear sweep voltammetry (LSV) was directly proportional to the hydrogen peroxide concentration over a very wide concentration range (0.1–600mgL −1 ). The detection limit (3σ) was calculated as 50 μgL −1 H 2 O 2 .