Highly efficient electrosynthesis of hydrogen peroxide on a superhydrophobic three-phase interface by natural air diffusion

Qizhan Zhang,Xuedong Du,Yawei Li,Minghua Zhou,Yanchun Li,Gengbo Ren

doi:10.1038/s41467-020-15597-y

Qizhan Zhang, Xuedong Du + Show 4 more

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https://doi.org/10.1038/s41467-020-15597-y

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Journal: Nature Communications	Publication Date: Apr 7, 2020
Citations: 383	License type: open-access

Affiliation: Nankai University

Abstract

Hydrogen peroxide (H2O2) synthesis by electrochemical oxygen reduction reaction has attracted great attention as a green substitute for anthraquinone process. However, low oxygen utilization efficiency (<1%) and high energy consumption remain obstacles. Herein we propose a superhydrophobic natural air diffusion electrode (NADE) to greatly improve the oxygen diffusion coefficient at the cathode about 5.7 times as compared to the normal gas diffusion electrode (GDE) system. NADE allows the oxygen to be naturally diffused to the reaction interface, eliminating the need to pump oxygen/air to overcome the resistance of the gas diffusion layer, resulting in fast H2O2 production (101.67 mg h-1 cm-2) with a high oxygen utilization efficiency (44.5%–64.9%). Long-term operation stability of NADE and its high current efficiency under high current density indicate great potential to replace normal GDE for H2O2 electrosynthesis and environmental remediation on an industrial scale.

Highlights

Hydrogen peroxide (H2O2) synthesis by electrochemical oxygen reduction reaction has attracted great attention as a green substitute for anthraquinone process
Moreira et al prepared gas diffusion electrode (GDE) modified with 0.5% Sudan Red 7B, obtaining 8.9 mg h−1 cm−2 of H2O2 with a current efficiency of 17.87% when 0.3-bar O2 was supplied at a current density of 75 mA cm−2 23
The carbon felt (CF) consisted of 10-μm-diameter fibers forming an interconnected network with an interfiber distance of ~50 μm (Supplementary Fig. 1a) and the porosity was more than 90%; thereby, the oxygen mass transfer hindrance in the diffusion layer became extremely low, which rendered oxygen in the atmosphere actively diffuse to the reaction interface without air pumps[34]

Summary

Introduction

Hydrogen peroxide (H2O2) synthesis by electrochemical oxygen reduction reaction has attracted great attention as a green substitute for anthraquinone process. The oxygen reduction reaction (ORR), as an important green, cathodic process, can proceed by a direct twoelectron reduction to produce H2O2, which has garnered great attention ascribed to its advantages, such as environmental friendliness and cost-effectiveness[6,7]. For those H2O2-based electrochemical advanced oxidation processes (EAOPs), e.g., electro-Fenton (EF) and photoelectroFenton (PEF), efficient H2O2 production is important, which can promote the formation of hydroxyl radicals to degrade organic pollutants[8,9]. When scaling up the H2O2-based EAOPs with GDEs, a significant energy loss occurs unavoidably[13]

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