Low solubility and slow oxygen transport in the electrolyte lead to poor hydrogen peroxide (H2O2) generation performance through oxygen reduction reactions (ORR) at traditional submerged cathodes. Herein, we fabricated a Janus-gas diffusion electrode with asymmetric wettability, high gas permeability, and abundant catalytic active sites using HNO3-modified graphite felt as the substrate, polytetrafluoroethylene (PTFE) as a hydrophobic gas diffusion layer (GDL), and polyvinylidene fluoride (PVDF)/acetylene black(AB) composite as a hydrophilic and aerophilic catalyst layer (CL). Using air as an oxygen supply and a working current density of 10.0 mA∙cm−2, the constructed Janus-gas diffusion electrode achieves an H2O2 yield of 39.0 mg∙L−1∙cm−2, a current efficiency of 97.8 %, and an oxygen utilization ratio of 3.5 % at 60 min, indicating excellent two-electron ORR performance. The enhanced performance is attributed to the superaerophilicity of the PTFE-based hydrophobic GDL, which provides sufficient oxygen mass transfer and supply. The hydrophilic PVDF-based CL remains good aerophilicity and contains abundant active functional groups due to the AB and graphite felt modified with nitric acid. AB increases the electrode’s specific surface area and gas permeability, allowing for more effective oxygen collection and transport. The electrode is stable for continuous use and indicates a promising application in in-situ H2O2 production.

中文翻译：

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一种具有合适亲水性和亲气性的 Janus 气体扩散电极，用于高效 H2O2 电合成


电解质中的低溶解度和缓慢的氧传输导致传统浸没式阴极的氧还原反应 （ORR） 生成过氧化氢 （H2O2） 性能不佳。在此，我们以 HNO3 改性石墨毡为基材，聚四氟乙烯 （PTFE） 作为疏水性气体扩散层 （GDL），聚偏二氟乙烯 （PVDF）/乙炔黑 （AB） 复合材料作为亲水和亲氧催化剂层 （CL），制造了一种具有不对称润湿性、高透气性和丰富的催化活性位点的 Janus 气体扩散电极。使用空气作为氧气供应，工作电流密度为 10.0 mA∙cm-2，构建的 Janus 气体扩散电极实现了 39.0 mg∙L-1∙cm-2 的 H2O2 产率，电流效率为 97.8 %，氧利用率为 3.5 %，在 60 min 时表现出优异的双电子 ORR 性能。性能的增强归功于基于 PTFE 的疏水性 GDL 的超亲氧性，它提供了足够的氧气传质和供应。亲水性 PVDF 基 CL 保持良好的亲氧性，并且由于 AB 和石墨毡经硝酸改性而含有丰富的活性官能团。AB 增加了电极的比表面积和透气性，从而可以更有效地收集和运输氧气。该电极可稳定地连续使用，在原位 H2O2 生产中具有广阔的应用前景。