Fe-Based MOFs can serve as low cost, stable, eco-friendly and visible light-driven photocatalysts, exhibiting promising applications in a broad range of fields. However, the present modification or semiconductor-coupling routes are still unable to extend their light response to the NIR region. Herein we present a microwave-assisted method to prepare MIL-53(Fe) octahedra with uniform concave facets. This unique structural geometry enables MIL-53(Fe) to trap upconversion nanocrystals (UCNPs) on their concave surface with a stable morphology. The developed MIL-53(Fe)/UCNP composites exhibit remarkable photocatalytic activity under NIR light and enhanced performance under Vis-NIR light. Through modifying the organic linkers with amino groups, both light absorption and utilization of upconverted emission of the composites can be enhanced, showing an improved activity. The formation and working mechanisms of the MOF/UCNP composite photocatalysts are also explored.

中文翻译：

---

在凹面MIL-53（Fe）八面体上锚定NaYF ₄：Yb，Tm上转换纳米晶体，用于近红外光增强光催化

铁基MOF可以用作低成本，稳定，环保和可见光驱动的光催化剂，在广泛的领域中显示出广阔的应用前景。但是，当前的修改或半导体耦合路线仍然不能将其光响应扩展到NIR区域。本文中，我们提出了一种微波辅助方法来制备具有均匀凹面的MIL-53（Fe）八面体。这种独特的结构几何形状使MIL-53（Fe）可以在凹形表面上捕获具有稳定形态的上转换纳米晶体（UCNP）。开发的MIL-53（Fe）/ UCNP复合材料在近红外光下表现出显着的光催化活性，并在可见-近红外光下表现出增强的性能。通过用氨基改性有机连接基，可以增强复合材料的光吸收和上转换发射的利用，显示出改善的活动。还探讨了MOF / UCNP复合光催化剂的形成和作用机理。