Electrochemical generation of H₂O₂ using immobilized carbon nanotubes on graphite electrode fed with air: Investigation of operational parameters

Three cathode materials (i.e. bare graphite, activated carbon immobilized onto graphite surface (AC/graphite) and carbon nanotubes immobilized onto graphite surface (CNTs/graphite)) were investigated for electrochemical generation of hydrogen peroxide. The amount of electrogenerated H ₂O₂ using CNTs/graphite fed with air was nearly three times higher than that of AC/graphite and seven times higher than that of bare graphite. The effect of some operational parameters such as applied current, supporting electrolyte concentration, air flow rate and pH on the generation of H₂O₂ was investigated. Results indicated that the optimal conditions for H₂O₂ generation were applied current of 100 mA (2.5 mA/cm²), air flow rate of 2.5 L/min, and pH = 3. After eight times reuse, electrochemical generated hydrogen peroxide concentration dropped from 118.65 μM to 114.63 μM, indicating a decay of 3.6%. This fact indicates that the present system can be useful for the in situ electrochemical generation of hydrogen peroxide.