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

Abstract

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 ∼96 %, related to a product concentration of ∼0.1 g L−1.