Cost-efficient electrosynthesis of hydrogen peroxide in acidic and neutral solutions

Oxygen reduction reaction is considered a green and low-carbon approach for H₂O₂ production. Low space-time yield and high energy consumption are serious challenges to the implementation of a commercial scale now. A cost-efficient H₂O₂ electrosynthesis using a recycled gold catalyst is developed here. The carbon-supported gold catalyst is synthesized using electroplating gold wastewater, which indicates good catalysis performances for both sulfite oxidation and H₂O₂ production. The sulfite/air fuel cell adopting the bifunctional gold catalyst can directly produce 8.70±0.53 g L⁻¹ H₂O₂ in 0.5 mol L⁻¹ Na₂SO₄ solution, with a good current efficiency of 71.56 %±2.13 % and a remarkable space-time yield of 27.20±1.17 mg cm⁻² h⁻¹. Adopting the desulfurization solution from flue gas as the anodic sacrificial agent, the electricity costs for acidic and neutral H₂O₂ electrosynthesis are only 2.09–3.82 kWh kg⁻¹. The reported H₂O₂ electrosynthesis performances, especially for power consumption, are also summarized and compared.