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Direct electrosynthesis of hydrogen peroxide (H2O2) via two‐electron pathway oxygen reduction reaction (2e− ORR) is crucially essential for a sustainable green economy. However, catalysts inevitably undergo four‐electron pathway oxygen reduction reaction (4e− ORR), resulting in low selectivity and economic benefits. The current challenge is to provide a feasible design strategy for obtaining satisfactory 2e− ORR catalysts with high selectivity. In this work, carbon dots (CDs) act as a cocatalyst to regulate the electron transport kinetics of In2O3/CDs, and the influence of CDs on the ORR pathways of In2O3/CDs is also studied. The electron transfer kinetics on In2O3/CDs composites are studied and analyzed using the transient photo‐induced voltage (TPV) technology. Combining the TPV results and kinetics analysis, it is shown that the electron transport on the In2O3 interface is obviously weakened after the addition of CDs, resulting in a high H2O2 selectivity. It is also demonstrated that CDs can effectively enhance the selectivity of H2O2, and the H2O2 selectivity of In2O3/CDs–10 is in close proximity to 100%, which is much higher than that of pure In2O3 (72%). This work will provide a new understanding and insight into addressing the challenge of low H2O2 selectivity for 2e− ORR catalysts.

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The activation of the C−H bond, a necessary step to get high-value-added compounds, is one of the most important issues in modern catalysis. Combining the advantages of both homogeneous and heterogeneous catalysis, a certain continuous homogeneous process should be one of the ideal routes for the catalytic activation of C−H bonds. Here, through machine learning (ML), we predicted and fabricated metal-free carbon dot (C-Dot) homogeneous catalysts for C−H bond oxidation. These C-Dots have an ascorbic acid unit based polymer-like structure with a polymerization degree in the range of 3−10. With C-Dots as the catalyst, three groups (aliphatic, aromatic, and cycloalkanes) of 10 hydrocarbon molecules were tested, proving its generality for the catalytic oxidation of the C−H bond. A typical example of cyclohexane that was selectively oxidized to adipic acid (AA) by using a circulation and phase-transfer process demonstrates its critical advantages, such as the continuous and large-scaled producing ability of the homogeneous catalysis process. The one-pass conversion efficiency of cyclohexane to AA reaches 77.49% with selectivity up to 84.24% in 4 h. The yield of 16.32% per hour is about 4 times over that of modern technology. Theoretical calculations suggested that the O 2 activation on C-Dots plays a crucial role in determining the reaction rate of the entire catalytic oxidation process of cyclohexane.

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