电合成
电解质
催化作用
阳极
化学工程
法拉第效率
碳纤维
化学
无机化学
膜
水溶液
阴极
过氧化氢
材料科学
电化学
电极
有机化学
工程类
复合数
物理化学
复合材料
生物化学
作者
Basil Sabri Rawah,Mohammad Albloushi,Wenzhen Li
标识
DOI:10.1016/j.cej.2023.143282
摘要
The two-electron oxygen reduction reaction (2e-ORR) generates on-site hydrogen peroxide (H2O2) more sustainably than the industrial anthraquinone process. Pure aqueous H2O2 electrosynthesis is the most desirable approach, as it is ready-to-use and pH-adjustable. Recently an innovative dual membrane-based solid-electrolyte flow cell (SE-FCAEM/CEM) was reported [Science, 2019, 366, 226-231], in which the anode and cathode “sandwiched” the cation-exchange-membrane (CEM) and anion-exchange-membrane (AEM), separated by a solid-electrolyte, thus allowing H+ and HO2– ions to recombine to form pure H2O2 in deionized (DI)-water stream. One key research needs to effectively deploy this flow cell is to address the stability and engineering difficulties of using an AEM, creating significant drawbacks in cell performance and lifespan. Here, we report a modified SE-FC without involving AEM (SE-FCAEM-FREE) to achieve better performance of H2O2 electrosynthesis. To validate SE-FCAEM-FREE for industrial-relevant production rates, we first developed a nitrogen-doped-carbon catalyst (N-C) with varied nitrogen-to-carbon ratios. Among all samples, the catalyst N-C(2:3) contains high carbon and a proper nitrogen precursor that boosted its activity, resulting in excellent half-cell performance with faradaic efficiency (FE) above 90% at different pH-electrolytes. Secondly, we optimized the catalyst microenvironment by applying a PTFE layer. The Layered-PTFE (5 wt.%) arrangement suppresses hydrogen evolution reaction (HER) and exhibits a high 2e-ORR activity with high current density of 389 mA cm−2 (about 6.53 mmol cm-2h−1) at 90% FEH2O2 without degradation for a 50-hour durability test.
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