Platinum dissolution in nitrogen oxides-containing HClO_4 solution studied by electrochemical quartz crystal microbalance

摘要

Platinum (Pt) dissolution has been elucidated by measuring a mass loss of Pt black-deposited Au quartz resonators in 0.1 mol dm~(-3) HClO_4 containing NaNO_2. A continuous weight loss of ca. 50 ng cm~2 cycle~(-1) was detected at [NaNO_2] = 0.01 mol dm~(-3) under the potential cycling between 0.6 and 1.4 V vs. RHE. The magnitude of Pt dissolution depends on the concentration of NaNO_2 and the range of potential cycling. The average mass loss decreases to 5～10 ng cm~2 cycle~(-1) at [NaNO_2] = 1 mmol dm~(-3). The Pt dissolution occurs when the higher potential limit is more than 1.0 V vs. RHE and the lower potential limit is less than 0.9 V vs. RHE, suggesting that the reduction of Pt oxide in the presence of NaNO_2 in the bulk solution contributes to the dissolution.