Electrogeneration of hydrogen peroxide in gas diffusion electrodes modified with tert-butyl-anthraquinone on carbon black support

Abstract Hydrogen peroxide (H 2 O 2 ) is a versatile oxidizing agent that is synthesized commercially by the reduction of oxygen in organic medium. Electrochemical technology employing a modified gas diffusion electrode (MGDE) offers a viable alternative for the industrial-scale synthesis of the oxidant. Addition of 1% (w/w) of tert -butyl-anthraquinone (TBAQ) to carbon black deposited in the form of a microporous layer onto the disk of a rotating ring-disk electrode produced an increase in the ring current, which is directly related to H 2 O 2 formation, and presented an efficiency of H 2 O 2 generation of 89.6% compared with 76.6% for carbon black alone. No significant changes were detected in the number of electrons transferred in the presence of the catalyst suggesting an electrochemical/chemical mechanism for H 2 O 2 formation. Analogous improvements in the generation of H 2 O 2 were obtained with MGDEs comprising TBAQ on carbon black. The highest concentrations of H 2 O 2 (301 mg L −1 ) were produced at the fastest rate (5.9 mg L −1  min −1 ) with the lowest energy consumption (6.0 kWh kg −1 ) when a potential of −1.0 V vs SCE was applied to a MGDE containing 1.0% of TBAQ on carbon black. It is concluded that the application of MGDEs comprising TBAQ on carbon black support offers considerable advantages in the electrogeneration of H 2 O 2 .