A sulfite/air fuel cell using cost-effective carbon-supported silver for hydrogen peroxide electrosynthesis

The development of highly selective, stable, and cost-effective electrocatalysts is a key step toward H2O2 electrosynthesis commercialization. Ag/C catalysts are developed for H2O2 production in the sulfite/air fuel cell here. An ammonia method desulfurization wastewater is applied as the fuel, which is a "waste to treasure" process. For low-cost catalysts and waste recycling, the Ag/C catalysts are also synthesized using an electroplating effluent. The rotating ring disc electrode tests and fuel cell tests exhibit high 2e(-)-ORR activity and durable stability of the Ag/C catalysts. RRDE results indicate a maximum H2O2 selectivity in the H2SO4 medium of >85 %. Adopting the Ag/C catalysts, the sulfite/air fuel cell can achieve the highest open cell voltage of 0.44 V. It sheds light on the self-driven ability of the cell, attributed to the depolarized effects of both the sulfite oxidation anode and oxygen reduction cathode. At 20 mA cm(-2), the initial current efficiencies are similar to 96 %, related to a product concentration of similar to 0.1 g L-1.