Photo-enhanced Zn–air batteries with simultaneous highly efficient in situ H2O2 generation for wastewater treatment

Abstract

The energy crisis and environmental pollution currently represent a substantial impediment. For the first time, we constructed an electricity and H₂O₂ cogeneration-pollutant degradation integrated system based on a Zn–air battery with polyterthiophene (pTTh) as photo-enhanced electrocatalysts for the highly efficient catalysis of the 2e oxygen reduction reaction (ORR). This integrated system manifested a high peak power density of 253.5 μW cm⁻² at 195.0 μA cm⁻² as well as a high H₂O₂ production rate of 34.8 mg L⁻¹ h⁻¹. Simultaneously, the superoxide (O₂˙) and hydroxyl radicals (˙OH) resulting from the decomposition of the in situ generated H₂O₂ could be used as oxidants to degrade the pollutant, as demonstrated in the succeeding sections as appropriate. The removal rate of RhB increased to almost 100% in the discharging process of this integrated system for 1 h. This work provides a proof-of-concept for applications combining energy conversion with wastewater treatment technologies.