Electrochemical Oxidation of Sulfur Dioxide on Nitrogen-Doped Graphite in Acidic Media

• Nitrogen-doped graphite was fabricated via one-step pyrolysis of sugar and urea.
• Nitrogen-doped graphite exhibited activity for electrooxidation of sulfur dioxide.
• The electrocatalytic activity positively related to the pyrolysis temperature.
• The electrooxidation reaction was irreversible and diffusion controlled.

This work reports on the electrochemical oxidation of sulfur dioxide on nitrogen-doped graphite (NG) in acidic media. The NG samples were prepared via one-step pyrolysis of the mixtures of sugar and urea at 700–1000 °C in argon atmosphere. Mechanism analysis indicated that the electrochemical oxidation reaction of sulfur dioxide on NG was irreversible and diffusion controlled. Moreover, the influence of pyrolysis temperature on the electrocatalytic activity of NG was also investigated. The electrochemical measurement and physical characterization results revealed that elevating the pyrolysis temperature could enhance the electrocatalytic activity of NG, which might ascribe to the improved surface area, graphitization degree and electrical conductivity.