On-site catalytic wastewater remediation by sustainably produced H2O2 via scalable single-atomic Fe-incorporated Janus membrane

Electrosynthesis of hydrogen peroxide (H2O2) from oxygen is a green and sustainable route toward on-site wastewater treatment. Nevertheless, the performance mismatch of the catalyst species and gas-diffusion com-ponents gives rise to low O2 utilization efficiency and limited H2O2 production rate in a practical cell. Herein, we propose a flexible and scalable Janus electrode comprising hydrophilic single-atomic Fe-incorporated catalytic layer and hydrophobic gas-attraction layer. The hydrophobic layer enables efficient oxygen diffusion, and the hollow-structured catalysts allow oxygen gas trapping with a high local oxygen concentration, resulting in a high Faradaic efficiency and fast H2O2 production rate. Accordingly, an 80 h electrocatalytic H2O2 synthesis could be gained at 80 mA cm-2. The Janus electrode delivers a H2O2 selectivity of 92% and a yield of 592 mmol g-1 h-1 in a flow cell. The thus-produced H2O2 allows for an in situ antibiotic removal, with the potential for on-site eco-restoration.

Automated summary

In this study, a flexible and scalable Janus electrode was proposed to achieve high H2O2 production rate and selectivity by optimizing the design of the catalytic layer and the hydrophobic layer. The electrode can be used for on-site wastewater treatment and eco-restoration, and has high application potential.