Metal-Support Synergy of Supported Gold Nanoclusters in Selective Oxidation of Alcohols
Metal-Support Synergy of Supported Gold Nanoclusters in Selective Oxidation of Alcohols
复制标题
负载金纳米团簇在醇选择性氧化中的金属负载协同作用
DOI：
10.3390/catal10010107
复制
发表时间：
2020-01-01
期刊：
影响因子：
3.9
通讯作者：
Ding, Yunjie
中科院分区：
文献类型：
--
作者：
Liu, Lu;Li, Huayin;Ding, Yunjie
金催化剂在醇的有氧氧化反应中表现出良好的性能，但其催化活性的内在来源仍然是令人迷惑的。催化剂的制备方法、金颗粒的形貌、甚至载体都可能是决定催化剂活性的关键因素。在这里，我们制备了一系列具有不同载体的金催化剂，即，水滑石（HT）、ZnO、MgO、Al 2 O3和SiO2，通过使用原子控制的Au 25纳米团簇（NC）作为金前体。X射线衍射（XRD）、紫外-可见光谱（UV-vis）和透射电镜（TEM）表征结果表明，金粒子在载体上分布均匀，平均粒径在3 nm以内。在苯甲醇的有氧氧化中，MgAl-HT-和Al 2 O3-负载的Au 25 NC表现出良好的性能，周转频率（TOF）值分别为~2927和2892 h-1，而SiO2-、MgO-和ZnO-负载的类似物表现出低得多的活性。高分辨透射电镜和X射线光电子能谱（XPS）结果表明，不同样品中金与载体之间的相互作用不同，从而影响了金的形貌和性质。我们的研究结果进一步指出，在实现高性能的选择性醇氧化的重要性，酸碱性的支持和金属支持的协同作用，而不是单独的金颗粒大小。此外，该工作提供了一个很好的方法来设计具有可控尺寸的金催化剂，这是至关重要的，了解在有氧氧化醇的反应过程。
Gold catalysts have been reported to exhibit good performance in aerobic oxidation of alcohols, but the intrinsic origin of the catalytic reactivity is still illusive. The catalyst preparation method, the morphology of the gold particles, and even the support might be key factors that determine the activity. Here, we prepared a series of gold catalysts with different supports, i.e., the hydrotalcite (HT), ZnO, MgO, Al2O3, and SiO2, by using the atomically controlled Au25 nanoclusters (NCs) as the gold precursor. The characterization results of the X-ray diffraction (XRD), UV-vis and transmission electron microscopy (TEM) show that the gold particles were mostly uniformly distributed on the supports, with a mean particle size within 3 nm. In aerobic oxidation of benzyl alcohol, the MgAl-HT- and Al2O3-supported Au25 NCs display good performances, with turnover frequency (TOF) values of ~2927 and 2892 h−1, respectively, whereas the SiO2-, MgO-, and ZnO-supported analogues show much inferior activity. The high resolution TEM and X-ray photoelectron spectra (XPS) results suggest that the interactions between gold and the supports in different samples are differing, which influences the morphology and the nature of gold. Our results further point to the importance of acid-base property of the support and the metal-support synergy rather than the gold particle size alone in achieving high-performance in selective alcohol oxidation. Moreover, this work provided a good way to design gold catalysts with controllable sizes that is crucial for understanding the reaction process in aerobic oxidation of alcohol.