Abstract: The anodic oxidation reaction of sulfur dioxide in 0.5mol/L H₂SO₄ with different elec-trode material (as catalyst) have been compared through cyclovoltametry.All the catalystsstudied can be divided into three groups.For the first group, such as Pt, Au, Pd, thereare two anodic current peaks on the cyclovoltamograph.The sulfur dioxide is oxidized firstby direct discharging at the potential below 1.0V and further by the surface oxide of thecataly st atmore positive potential.For the second group of the catalysts, such as Ir, Ru,and Rh,there is only one anodic current peak and the sulfur dioxide is oxidized by thesurface oxide of the catalyst.For the third group,as porphyrin, there also exists one anodiccurrent peak on the cyclovoltamograph,but the sulfur dioxide is oxidized by direct dischargeof the SO₂ molecules.

Key words: sulfur dioxide, anodic oxidation, electrode