Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585 (Singapore).
Angew Chem Int Ed Engl. 2015 Jul 6;54(28):8271-4. doi: 10.1002/anie.201503148. Epub 2015 May 27.
Metallic nanocrystals (NCs) with well-defined sizes and shapes represent a new family of model systems for establishing structure-function relationships in heterogeneous catalysis. Here in this study, we show that catalyst poisoning can be utilized as an efficient strategy for nanocrystals shape and composition control, as well as a way to tune the catalytic activity of catalysts. Lead species, a well-known poison for noble-metal catalysts, was investigated in the growth of Pd NCs. We discovered that Pb atoms can be incorporated into the lattice of Pd NCs and form Pd-Pb alloy NCs with tunable composition and crystal facets. As model catalysts, the alloy NCs with different compositions showed different selectivity in the semihydrogenation of phenylacetylene. Pd-Pb alloy NCs with better selectivity than that of the commercial Lindlar catalyst were discovered. This study exemplified that the poisoning effect in catalysis can be explored as efficient shape-directing reagents in NC growth, and more importantly, as a strategy to tailor the performance of catalysts with high selectivity.
具有明确尺寸和形状的金属纳米晶体 (NCs) 代表了一类用于在多相催化中建立结构-功能关系的新型模型系统。在本研究中，我们表明催化剂中毒可用作控制纳米晶体形状和组成的有效策略，以及调节催化剂催化活性的一种方式。铅物种是贵金属催化剂的一种众所周知的毒物，我们研究了其在 Pd NCs 生长过程中的作用。我们发现 Pb 原子可以掺入 Pd NCs 的晶格中，并形成具有可调组成和晶面的 Pd-Pb 合金 NCs。作为模型催化剂，具有不同组成的合金 NCs 在苯乙炔的半氢化反应中表现出不同的选择性。我们发现 Pd-Pb 合金 NCs 的选择性优于商业 Lindlar 催化剂。该研究例证了在催化中的中毒效应可用作 NC 生长中有效的定向试剂，更重要的是，可用作具有高选择性的催化剂的性能调整策略。
