Ultra‐Low Loading Pt/CeO 2 Catalysts: Ceria Facet Effect Affords Improved Pairwise Selectivity for Parahydrogen Enhanced NMR Spectroscopy
Ultra‐Low Loading Pt/CeO 2 Catalysts: Ceria Facet Effect Affords Improved Pairwise Selectivity for Parahydrogen Enhanced NMR Spectroscopy
复制标题
超低负载量 Pt/CeO 2 催化剂：二氧化铈刻面效应为仲氢增强核磁共振波谱提供了改进的成对选择性
DOI：
10.1002/anie.202012469
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Hagelin‐Weaver, Helena
中科院分区：
文献类型：
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作者：
Song, Bochuan;Choi, Diana;Xin, Yan;Bowers, Clifford R.;Hagelin‐Weaver, Helena
具有明确形状的氧化物载体能够研究表面结构对金属-载体相互作用的影响以及与催化活性和选择性的相关性。在此，开发了改进的原子层沉积技术以在成形的二氧化铈纳米晶体上实现超低负载量（8-16 ppm）的Pt。 使用八面体和立方体，分别暴露（111）和（100）表面，CeO 2表面小面对还原条件下Pt-CeO 2相互作用的影响被揭示。强的电子相互作用导致还原后CeO 2（111）上的缺电子Pt物种，这增加了原子分散的Pt的稳定性。与CeO 2上的富电子铂（100）相比，这在仲氢诱导的极化实验中提供了显著更高的NMR信号增强，并且在丙烯氢化中比任何先前报道的单组分非均相Pt催化剂高两倍的成对选择性（6.1%）。
Oxide supports with well‐defined shapes enable investigations on the effects of surface structure on metal–support interactions and correlations to catalytic activity and selectivity. Here, a modified atomic layer deposition technique was developed to achieve ultra‐low loadings (8–16 ppm) of Pt on shaped ceria nanocrystals. Using octahedra and cubes, which expose exclusively (111) and (100) surfaces, respectively, the effect of CeO2surface facet on Pt‐CeO2interactions under reducing conditions was revealed. Strong electronic interactions result in electron‐deficient Pt species on CeO2(111) after reduction, which increased the stability of the atomically dispersed Pt. This afforded significantly higher NMR signal enhancement in parahydrogen‐induced polarization experiments compared with the electron‐rich platinum on CeO2(100), and a factor of two higher pairwise selectivity (6.1 %) in the hydrogenation of propene than any previously reported monometallic heterogeneous Pt catalyst.