Thermo-enhanced photocatalysis combines the advantages of thermocatalysis and photocatalysis and provides a very promising approach for the selective oxidation of organic compounds to value-added chemicals. In this work, the amino group in MIL-125-NH₂ first reacts with formaldehyde to form the reducing group (–NH–CH₂OH), which can in situ auto reduce the introduced Ag⁺ ions to Ag clusters/nanoparticles in the cavities. Then the formed MIL-125-NH–CH₂OH@Ag was further coated with a covalent organic framework (COF) through imine bonds to form a series of MIL-125-NH–CH₂OH@Ag@COF hybrids. Oxidative coupling of amines was selected to evaluate the photocatalytic performance of these materials under visible light at set temperatures (20–60 °C). With an optimized composition, MIL-125-NH–CH₂OH@Ag-0.5@COF-2 not only improves the optical properties, but also exhibits the highest conversion (almost 100%) of benzylamine under visible light at 60 °C and good stability for at least three cycles. Free radical capture experiments and electron spin resonance detection demonstrated that holes (h⁺), hydroxyl (˙OH) and superoxide radicals (O₂˙⁻) were the active species. The results prove that the MIL-125-NH–CH₂OH@Ag@COF hybrid possessed higher photocatalytic performance than individual MIL-125-NH₂, Ag and COF on account of the efficient separation and transfer of photoinduced electrons and holes. Moreover, the promotion of the reaction temperature on the photocatalytic oxidation of amines has been reported, revealing that the conversion of benzylamine over MIL-125-NH–CH₂OH@Ag-0.5@COF-2 at 60 °C is nearly twice as high as that at 20 °C under visible light irradiation. Therefore, the thermo-enhanced photocatalytic oxidation performance of the MOF@Ag@COF hybrid demonstrates the great potential of thermal energy for further improving the photocatalytic selective oxidation performance.

中文翻译：

---

MIL-125-NH2@Ag@COF杂化物在可见光下热增强光催化氧化胺为亚胺

热增强光催化结合了热催化和光催化的优点，为将有机化合物选择性氧化为增值化学品提供了一种非常有前景的方法。在这项工作中，MIL-125-NH _{2 中}的氨基首先与甲醛反应形成还原基团 (–NH–CH ₂ OH)，它可以原位自动将引入的 Ag ⁺离子还原为银团簇/纳米颗粒。空洞。然后将形成的 MIL-125-NH-CH ₂ OH@Ag 通过亚胺键进一步包覆共价有机骨架（COF），形成一系列 MIL-125-NH-CH ₂OH@Ag@COF 杂化物。选择胺的氧化偶联来评估这些材料在可见光下在设定温度（20-60°C）下的光催化性能。MIL-125-NH-CH ₂ OH@Ag-0.5@COF-2具有优化的组成，不仅提高了光学性能，而且在 60 °C 的可见光下表现出最高的苄胺转化率（几乎 100%）和至少三个循环的良好稳定性。自由基捕获实验和电子自旋共振检测表明空穴（h ⁺）、羟基（˙OH）和超氧自由基（O ₂ ˙ ^-）是活性物质。结果证明 MIL-125-NH-CH ₂由于光生电子和空穴的有效分离和转移，OH@Ag@COF 杂化物比单独的 MIL-125-NH ₂、Ag 和 COF具有更高的光催化性能。此外，据报道，提高反应温度对胺光催化氧化的影响表明，在 60°C 下，苄胺在 MIL-125-NH-CH ₂ OH@Ag-0.5@COF-2 上的转化率几乎是其两倍。在可见光照射下高达 20°C。因此，MOF@Ag@COF 杂化物的热增强光催化氧化性能证明了热能在进一步提高光催化选择性氧化性能方面的巨大潜力。