Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-4-37 Takeda, Kofu 400-8510, Japan.
Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan.
Sci Adv. 2017 Jul 26;3(7):e1700101. doi: 10.1126/sciadv.1700101. eCollection 2017 Jul.
The catalytic activity of alloy nanoparticles depends on the particle size and composition ratio of different metals. Alloy nanoparticles composed of Pd, Pt, and Au are widely used as catalysts for oxidation reactions. The catalytic activities of Pt and Au nanoparticles in oxidation reactions are known to increase as the particle size decreases and to increase on the metal-metal interface of alloy nanoparticles. Therefore, multimetallic nanoclusters (MNCs) around 1 nm in diameter have potential as catalysts for oxidation reactions. However, there have been few reports describing the preparation of uniform alloy nanoclusters. We report the synthesis of finely controlled MNCs (around 1 nm) using a macromolecular template with coordination sites arranged in a gradient of basicity. We reveal that Cu-Pt-Au MNCs supported on graphitized mesoporous carbon show catalytic activity that is 24 times greater than that of a commercially available Pt catalyst for aerobic oxidation of hydrocarbons. In addition, solvent-free aerobic oxidation of hydrocarbons to ketones at room temperature, using small amounts of a radical initiator, was achieved as a heterogeneous catalytic reaction for the first time.
合金纳米粒子的催化活性取决于粒子尺寸和不同金属的组成比例。由 Pd、Pt 和 Au 组成的合金纳米粒子被广泛用作氧化反应的催化剂。已知 Pt 和 Au 纳米粒子在氧化反应中的催化活性随着粒子尺寸的减小而增加，并在合金纳米粒子的金属-金属界面上增加。因此，直径约为 1nm 的多金属纳米团簇（MNCs）有望成为氧化反应的催化剂。然而，关于制备均匀合金纳米团簇的报道很少。我们报告了使用具有在碱性梯度中排列的配位位点的高分子模板来合成精细控制的 MNCs（约 1nm）。我们揭示了负载在石墨化介孔碳上的 Cu-Pt-Au MNC 对烃类的有氧氧化具有比市售 Pt 催化剂高 24 倍的催化活性。此外，首次以非均相催化反应的形式，在室温下使用少量自由基引发剂，实现了无溶剂烃类到酮类的有氧氧化。
