以原位合成法(De Novo Synthesis)製備胺官能化UiO-66金屬有機骨架孔洞材料搭載鉑奈米粒子之粉粒及薄膜

Abstract

傳統上在製備以金屬有機骨架為基材的擔體型觸媒時，通常是加入金屬粒子或金屬前驅物到已生成的金屬有機骨架中，因此現今在材料合成上，仍存在搭載量低以及金屬粒子聚集的限制。在本研究中，我們以原位合成法( de novo synthesis)，透過在最初同時加入觸媒金屬和金屬有機骨架之前驅物達到更充分地混合，並對後續金屬骨架生成和搭載觸媒金屬還原進行階段溫控，以更有效地藉由金屬有機骨架的形成來限制觸媒金屬粒子的生長。我們成功的合成了具有高度分散性的白金粒子於UiO-66-NH2骨架的粉粒及薄膜，藉由XRD, TEM, BET, ICP/MS等分析確認我們成功合成此材料。隨後，藉調控搭載白金量、生長時間以及苯甲酸加入量，找出此觸媒最佳化生長條件為: 白金與鋯加入莫耳比0.5，反應兩天，以及加入苯甲酸量41.4微莫耳。此產物的白金含量為16.5 wt.%，產物最終白金/鋯莫耳比為0.335，較大部分傳統手法合成的金屬有機骨架觸媒都高。在研究的最後，我們將原位合成法成功地拓展到具催化性薄膜的合成上，將其製備於氧化鋁圓片及氟化氧化錫玻璃板。此薄膜的厚度可達到1微米以下，並依需求製備出不同白金含量的薄膜，可望於未來有更廣泛地應用。

Although MOF-derived heterogeneous catalysts have been widely prepared by adding metal nanoparticles into pre-synthesized MOF or its precursors, there are still some problems such as the loading amount and uniformity of the metal. In this study, we load metal nanoparticles (i.e. Pt) into MOF (i.e. UiO-66-NH2) with controllable loading amount and uniformity through a de novo synthesis where metal and MOF precursors were added together in the very beginning. After careful optimization of temperature program of MOF structuring and metal reduction, we successfully prepare Pt-loaded UiO-66-NH2 (i.e. Pt@UiO-66-NH2) in the morphology of particles and films. The synthesized Pt@UiO-66-NH2 samples are characterized with XRD, TEM, BET, ICP/MS measurements. We optimize the Pt loading ratio, growth time, and amount of benzoic acid to be Pt/Zr=0.5, 48 h, and 41.1 mmol, respectively. The highest loading amount of Pt is 16.5 wt.% (i.e. Pt/Zr ratio is 0.335), which is much higher compared to previous studies. Finally, we expend this de novo synthesis for preparing Pt@UiO-66-NH2 on α-Al2O3 and FTO substrates, and Pt@UiO-66-NH2 with different Pt loadings and film thickness (less than 1 μm) can be prepared. We envision the prepared Pt@UiO-66-NH2 particles and films would have great potential in the catalytic applications.