Palladium-based catalysts have been widely employed in the electro-Fenton process for in situ generation of H₂O₂. However, the process is still far from being practical on a large scale. In this work, a series of Cl_xFePd/γ-Al₂O₃/Al catalysts were prepared by a three-step-impregnation method. They exhibited excellent activity in H₂O₂ in situ synthesis and high efficiency in phenol degradation. The characterization results showed that Cl could assist in increasing the content of Pd⁰ and reducing the isoelectric point of catalysts, which led to the drastic promotion in the synthesis of H₂O₂. Theoretical calculations further demonstrated that Cl doping could facilitate the main reaction in H₂O₂ synthesis, as well as inhibit side reactions such as dissociation of the OO bond. Furthermore, kinetic models were proposed and fitted. A plausible reaction mechanism as well as degradation pathways were elaborated based on electron spin resonance and gas chromatography–mass spectrometry results. These findings illustrate the value of palladium-based Cl_xFePd/γ-Al₂O₃/Al catalysts for their application in the electro-Fenton process.

中文翻译：

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电-Fenton体系中氯增强Pd催化剂原位合成H2O2的机理

钯基催化剂已广泛用于电芬顿法原位生成 H ₂ O ₂。然而，该过程仍远未大规模实用。本工作采用三步浸渍法制备了一系列Cl _x FePd/γ-Al ₂ O _{3 /Al催化剂。它们在H 2} O ₂ 原位合成中表现出优异的活性和对苯酚的高效降解。表征结果表明，Cl有助于提高Pd ⁰的含量，降低催化剂的等电点，从而大大促进H的合成。₂ O ₂。理论计算进一步表明，Cl掺杂可以促进H ₂ O ₂合成中的主要反应，并抑制OO键解离等副反应。此外，还提出并拟合了动力学模型。基于电子自旋共振和气相色谱-质谱分析结果，阐述了一种合理的反应机理和降解途径。这些发现说明了钯基 Cl _x FePd/γ-Al ₂ O ₃ /Al 催化剂在电芬顿工艺中的应用价值。