Compared to the current commercial three-step production process involving low phenol yield, low atomic efficiency, and the formation of explosive intermediates, the direct oxidation of aromatic hydrocarbon to more desirable and important chemical industry intermediate such as phenol offers a more attractive and challenging pathway. Here, we report the selective photocatalytic hydroxylation of benzene to phenol using NH₂-MIL-88/PMo₁₀V₂-3 as the catalyst and H₂O₂ as a mild oxidant. Heteropoly acid (PMo₁₀V₂) was immobilized to metal–organic frameworks (NH₂-MIL-88), where PA anions play an essential role in anchoring NH³⁺ cations to form stable heterogeneous photocatalysts. The reaction offered a high selectivity of 99% with a yield of 24% for phenol under optimum reaction conditions. Comprehensive characterizations and experiments disclosed a multistep reaction mechanism in which high dispersion of PMo₁₀V₂, the production of hydroxyl radical(˙OH) and the formation of V⁵⁺/V⁴⁺ redox pairs are responsible for the activity of the reaction in the presence of electrons (e⁻). The recycling experiments were essential in confirming the reusability of the catalyst, and FT-IR characterization analysis also proved the integrity of NH₂-MIL-88/PMo₁₀V₂-3 after three cycles. This work provides potential applications in the green and highly efficient photocatalytic synthesis of other organic compounds and other environmental applications.

中文翻译：

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一种用于苯羟基化光催化活性增强的新型多相催化剂NH2-MIL-88/PMo10V2

与目前涉及苯酚产率低、原子效率低和易爆中间体形成的商业三步法生产工艺相比，将芳烃直接氧化为更理想和更重要的化工中间体（如苯酚）提供了更具吸引力和挑战性的途径. 在这里，我们报告了使用 NH ₂ -MIL-88/PMo ₁₀ V ₂ -3 作为催化剂和 H ₂ O ₂作为温和氧化剂将苯选择性光催化羟基化为苯酚。杂多酸 (PMo ₁₀ V ₂ ) 被固定在金属有机骨架 (NH ₂ -MIL-88) 上，其中 PA 阴离子在锚定 NH ^{3+ 中}起重要作用阳离子形成稳定的多相光催化剂。在最佳反应条件下，该反应提供了 99% 的高选择性和 24% 的苯酚收率。综合表征和实验揭示了多步反应机制，其中PMo ₁₀ V _{2 的}高分散、羟基自由基(·OH)的产生和V ⁵⁺ /V ⁴⁺氧化还原对的形成是反应活性的原因。电子的存在 (e ^- )。回收实验对于确认催化剂的可重复使用性至关重要，FT-IR 表征分析也证明了 NH ₂ -MIL-88/PMo ₁₀ V ₂的完整性-3 个循环后。这项工作为其他有机化合物的绿色高效光催化合成和其他环境应用提供了潜在的应用。