A Three-dimensional Floating Air Cathode with Dual Oxygen Supplies for Energy-efficient Production of Hydrogen Peroxide

Haichuan Zhang,Hao Zhang,Yingjie Li,Guanghe Li,Fang Zhang

doi:10.1038/s41598-018-37919-3

Abstract

The in situ and cleaner electrochemical production of hydrogen peroxide (H2O2) through two-electron oxygen reduction reaction has drawn increasing attentions in environmental applications as an alterantive to traditional anthraquinone process. Air cathodes avoid the need of aeration, but face the challenges of declined performance during scale-up due to non-uniform water infiltration or even water leakage, which is resulted from changing water pressures and immature cathode fabrication at a large scale. To address these challenges, a three-dimensional (3-D) floating air cathode (FAC) was built around the commercial sponge, by coating with carbon black/poly(tetrafluoroethylene) using a simple dipping-drying method. The FAC floated on the water-air interface without extensive water-proof measures, and could utilize oxygen both from passive diffusion and anodic oxygen evolution to produce H2O2. The FAC with six times of dipping treatment produced a maximum H2O2 concentration of 177.9 ± 26.1 mg L−1 at 90 min, with low energy consumption of 7.1 ± 0.003 Wh g−1 and stable performance during 10 cycles of operation. Our results showed that this 3-D FAC is a promising approach for in situ H2O2 production for both environmental remediation and industrial applications.

Highlights

At present, H2O2 is commercially produced using the anthraquinone process in large-scale facilities, involving the sequential hydrogenation and oxidation of anthraquinone molecules[7,8]
In order to address the uneven water infiltration issues and enhance the O2 mass transfer to air cathodes for scale up applications, we developed a floating air cathode (FAC) using the commercially available poly(urethane) (PU) sponge that floats at the solution/air interface for effective H2O2 production without the needs of extensive water-proof measures
We examined the H2O2 production with different relative positions of the cathode in the electrolyte, to characterize the influence of O2 supply sources to the ORR system

Summary

Introduction

H2O2 is commercially produced using the anthraquinone process in large-scale facilities, involving the sequential hydrogenation and oxidation of anthraquinone molecules[7,8]. The electrochemical ORR systems often rely on single external O2 supply methods such as passive oxygen diffusion or active aeration, but neglect the produced O2 from the anodic oxygen evolution reaction (OER)[10,19,27]. In order to address the uneven water infiltration issues and enhance the O2 mass transfer to air cathodes for scale up applications, we developed a floating air cathode (FAC) using the commercially available poly(urethane) (PU) sponge that floats at the solution/air interface for effective H2O2 production without the needs of extensive water-proof measures. We examined the H2O2 production with different relative positions of the cathode in the electrolyte, to characterize the influence of O2 supply sources (passive diffusion from air, and O2 produced from the OER anode) to the ORR system

Methods

Results

Conclusion