Catalytic properties of intermetallic platinum-tin nanoparticles with non-stoichiometric compositions
Catalytic properties of intermetallic platinum-tin nanoparticles with non-stoichiometric compositions
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DOI：
10.1016/j.jcat.2019.04.013
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发表时间：
2019-06
影响因子：
7.3
通讯作者：
Yuchen Pei;Biying Zhang;Raghu V. Maligal-Ganesh;Pranjali J. Naik;T. Goh;Heather L. MacMurdo;Zhiyuan Qi;Minda Chen;R. Behera;Igor I. Slowing;Wenyu Huang
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文献类型：
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作者：
Yuchen Pei;Biying Zhang;Raghu V. Maligal-Ganesh;Pranjali J. Naik;T. Goh;Heather L. MacMurdo;Zhiyuan Qi;Minda Chen;R. Behera;Igor I. Slowing;Wenyu Huang
金属间化合物是一种独特的催化剂平台，用于机理研究和工业应用，因为它们的有序结构相比，随机合金。尽管金属间化合物具有固有的化学计量，但在金属间催化剂中仍可能发生组成偏差。额外金属原子的位置可以使具有非化学计量组成的金属间化合物的催化性质不同，如果那些金属原子最终在表面上/附近的话。在这项研究中，我们合成的PtSn金属间化合物具有准确的化学计量和轻微的Pt-/Sn丰富的组合物。以糠醛加氢和乙炔半加氢为探针反应，研究了不同温度下还原后PtSn金属间化合物催化剂的表面结构。尽管金属间化合物PtSn是非化学计量组成中的主要体相，但金属间化合物PtSn表面只能在富Sn金属间化合物纳米颗粒（iNP）中的高温还原下观察到，而富Pt PtSn iNP显示富Pt表面而不管还原温度如何。基于综合的表面和体积表征，构建了四种结构模型。这项工作扩展了对具有非化学计量组成的金属间化合物催化剂的理解，以定制用于催化的金属间化合物表面结构。
Intermetallic compounds are unique catalyst platforms for mechanistic studies and industrial applications, because of their ordered structures in comparison to random alloys. Despite the intrinsically defined stoichiometry of intermetallic compounds, compositional deviations can still occur in intermetallic catalysts. The location of the extra metal atoms could differ the catalytic properties of intermetallic compounds with non-stoichiometric composition if those metal atoms end up on/near the surface. In this study, we synthesized PtSn intermetallic compounds with accurate stoichiometry and slightly Pt-/Sn-rich compositions. We used furfural hydrogenation and acetylene semi-hydrogenation as probe reactions to investigate the surface structures of PtSn intermetallic catalysts after reduction at different temperatures. Even though the intermetallic PtSn is the major bulk phase among non-stoichiometric compositions, the intermetallic PtSn surface can only be observed under the high-temperature reduction in Sn-rich PtSn intermetallic nanoparticles (iNPs), while the Pt-rich PtSn iNPs show Pt-rich-surfaces regardless of reduction temperatures. Four structural models were constructed based on the comprehensive surface and bulk characterizations. This work extends the understanding of intermetallic catalysts with non-stoichiometric compositions to tailor the intermetallic surface structures for catalysis.