The oxygen reduction reaction (ORR) is a key component of biological processes and energy technologies. This Review provides a comprehensive report of soluble molecular catalysts and electrocatalysts for the ORR. The precise synthetic control and relative ease of mechanistic study for homogeneous molecular catalysts, as compared to heterogeneous materials or surface-adsorbed species, enables a detailed understanding of the individual steps of ORR catalysis. Thus, the Review places particular emphasis on ORR mechanism and thermodynamics. First, the thermochemistry of oxygen reduction and the factors influencing ORR efficiency are described to contextualize the discussion of catalytic studies that follows. Reports of ORR catalysis are presented in terms of their mechanism, with separate sections for catalysis proceeding via initial outer- and inner-sphere electron transfer to O₂. The rates and selectivities (for production of H₂O₂ vs H₂O) of these catalysts are provided, along with suggested methods for accurately comparing catalysts of different metals and ligand scaffolds that were examined under different experimental conditions.

中文翻译：

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均相分子催化剂和电催化剂的氧还原

氧还原反应（ORR）是生物过程和能源技术的关键组成部分。这篇综述提供了ORR的可溶性分子催化剂和电催化剂的综合报告。与异质材料或表面吸附的物质相比，均相分子催化剂的精确合成控制和相对容易的机理研究，使您能够对ORR催化的各个步骤进行详细的了解。因此，本综述特别强调了ORR机理和热力学。首先，描述了氧还原的热化学法和影响ORR效率的因素，以使随后的催化研究的讨论更趋于情境化。ORR催化的报告按其机理进行了介绍，₂。提供了这些催化剂的速率和选择性（用于生产H ₂ O ₂与H ₂ O），以及建议的方法，该方法可准确比较在不同实验条件下检查的不同金属和配体支架的催化剂。