Electrocatalytic oxidation of C‐H bonds in hydrocarbons represents an efficient and sustainable strategy for the synthesis of value‐added chemicals. Herein, a highly selective and continuous‐flow electrochemical oxidation process of toluene to various oxygenated products (benzyl alcohol, benzaldehyde, and benzyl acetate) is developed with the electrocatalytic membrane electrodes (ECMEs). The selectivity of target products can be manipulated via surface and interface engineering of Co3O4‐based electrocatalysts. We achieved a high benzaldehyde selectivity of 90% at a toluene conversion of 47.6% using 1D‐Co3O4 nanoneedles (NNs) loaded on a microfiltration (MF) titanium (Ti) membrane, i.e, Co3O4 NNs/Ti. In contrast, the main product shifted to benzyl alcohol with a selectivity of 90.1% at conversion of 32.1% after modifying MnO2 nanosheets (NSs) on Co3O4 NNs/Ti (Co3O4@MnO2/Ti) catalyst. Moreover, benzyl acetate product can be obtained with selectivity of 92% at a conversion of 58.5% at high current density (> 1.5mA cm‐2), demonstrating that the pathway of toluene oxidation is readily maneuvered. DFT results reveal that modifying MnO2 on Co3O4 optimizes the electron structure of Co3O4@MnO2/Ti and modulates the adsorption behavior of intermediate species. This work demonstrates a sustainable, and continuous‐flow process for precise control over production selectivity of value‐added oxygenated derivatives in electrochemical oxidation of aromatic hydrocarbons.

中文翻译：

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一维 Co3O4 纳米阵列上芳烃中 C-H 键高选择性氧化的绿色高效电催化路线


碳氢化合物中 C-H 键的电催化氧化代表了一种高效且可持续的增值化学品合成策略。在此，利用电催化膜电极（ECME）开发了一种高选择性、连续流的甲苯电化学氧化工艺，生成各种含氧产品（苯甲醇、苯甲醛和乙酸苄酯）。目标产物的选择性可以通过 Co3O4 基电催化剂的表面和界面工程来控制。我们使用负载在微滤（MF）钛（Ti）膜上的1D-Co3O4纳米针（NNs）（即Co3O4 NNs/Ti）实现了90%的高苯甲醛选择性，甲苯转化率为47.6%。相比之下，在 Co3O4 NNs/Ti (Co3O4@MnO2/Ti) 催化剂上修饰 MnO2 纳米片 (NSs) 后，主要产物转向苯甲醇，选择性为 90.1%，转化率为 32.1%。此外，在高电流密度（> 1.5mA cm-2）下，可以以 92% 的选择性、58.5% 的转化率获得乙酸苄酯产物，这表明甲苯氧化途径很容易操纵。 DFT结果表明，在Co3O4上修饰MnO2可以优化Co3O4@MnO2/Ti的电子结构并调节中间物质的吸附行为。这项工作展示了一种可持续的、连续流动的工艺，用于精确控制芳烃电化学氧化中增值含氧衍生物的生产选择性。