Effects of H2O2 Accumulation on the Synthesis Performances of the Sulfite Fuel Cell

Abstract

The cathodic destruction reaction severely restricts the ceiling concentration of H2O2 electrosynthesis. The effects of cathodic destruction reaction and H2O2 accumulation on the H2O2 electrosynthesis performances are investigated particularly. The H2O2 electro-reduction reaction mechanism on the Au0.5Pd0.5/C is determined. It indicates that the oxygen reduction reaction will be replaced by the H2O2 electro-reduction reaction after H2O2 accumulates to the ceiling concentration. Two simple methods are tried to enhance the H2O2 electrosynthesis performances. When pure oxygen was supplied, the maximum discharge current density was 47.95 mA cm−2 at 0 V. The maximum power density was 2.57 mW cm−2 at 21.54 mA cm−2. It can self-driven produce 6.75 mmol l−1 H2O2 in H2SO4 medium within 360 min, with a current efficiency of 51.34% and productivity of 0.28 mmol cm−2 h−1. With the external power source, the energy consumption for 1.02 g l−1 H2O2 solution was only 0.87 kWh kg−1, with a remarkable productivity of 0.94 mmol cm−2 h−1.