Materials Science Division, Poornaprajna Institute of Scientific Research, Devanahalli, Bangalore Rural-, 562164, India.
Graduate studies, Manipal Academy of Higher Education, Manipal, 576104, India.
Chemistry. 2018 Oct 26;24(60):15978-15982. doi: 10.1002/chem.201803200. Epub 2018 Oct 5.
Metal-organic frameworks (MOFs) have emerged as a new class of supports for metal nanoparticles(NPs) in heterogeneous catalysis because of possible synergetic effects between the two components. In addition, MOFs also can be coated over metal NPs to influence the entire nanoparticle's surface. Herein, NPs were hybridized with UiO-66(Hf) MOF possessing Brønsted acidic sites (on secondary building units) and fabricated Pd@UiO-66 (Hf) core-shell and Pd/UiO-66(Hf) supported catalysts. These hybrid materials exhibited enhanced catalytic properties (TOF increased up to 2.5 times) compared to individual counterparts or their physical mixture for dehydrogenation of ammonia borane(AB) in non-aqueous medium(1,4-dioxane). Further, nanostructure of the hybrid material had pronounced influence on the catalytic properties. The core-shell catalyst exhibited highest activity towards H generation from AB owing to greater contact interface between Pd and MOF. Further, phenylacetylene semi-hydrogenation with AB over Pd@UiO-66 (Hf) furnished styrene selectivity as high as 93.2 % at ∼100 % conversion mostly due to the regulated phenylacetylene diffusion through UiO-66(Hf) shell.
金属-有机骨架（MOFs）作为一种新型的多相催化金属纳米粒子（NPs）载体，由于两种组分之间可能存在协同作用而受到关注。此外，MOFs 还可以包覆在金属 NPs 上，从而影响整个纳米粒子的表面。本文将具有 Brønsted 酸性位（在次级构筑单元上）的 UiO-66（Hf）MOF 与 NPs 进行复合，制备了 Pd@UiO-66（Hf）核壳和 Pd/UiO-66（Hf）负载型催化剂。与单独的对应物或其物理混合物相比，这些复合材料在非水介质（1,4-二恶烷）中用于氨硼烷（AB）脱氢反应时表现出增强的催化性能（TOF 提高了 2.5 倍）。此外，复合材料的纳米结构对催化性能有显著影响。核壳催化剂在 AB 放氢反应中表现出最高的活性，这是由于 Pd 和 MOF 之间具有更大的接触界面。此外，AB 对苯乙炔的半氢化反应在 Pd@UiO-66（Hf）上进行时，苯乙烯的选择性高达 93.2%，在接近 100%的转化率下，这主要是由于苯基乙炔通过 UiO-66（Hf）壳的扩散受到调控。
