Thermal Unequilibrium of PdSn Intermetallic Nanocatalysts: From In Situ Tailored Synthesis to Unexpected Hydrogenation Selectivity
Thermal Unequilibrium of PdSn Intermetallic Nanocatalysts: From In Situ Tailored Synthesis to Unexpected Hydrogenation Selectivity
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DOI：
10.1002/anie.202106515
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发表时间：
2021-07-16
影响因子：
16.6
通讯作者：
Huang, Wenyu
中科院分区：
文献类型：
--
作者：
Chen, Minda;Yan, Yu;Huang, Wenyu
在催化加氢反应中，由于C=C键在Pd表面的良好吸附，Pd基催化剂很难有效地控制C=O催化加氢对C=C键的化学选择性。在这里，我们报道了一种独特的正交PdSn金属间化合物相，它对C=O氢化具有前所未有的化学选择性。我们在原位观察到了这种PdSn相的形成和亚稳性。在自然冷却过程中，PdSn2纳米粒子很容易恢复为Pd3Sn2相。取而代之的是，我们用热淬灭的方法制备了纯相的PdSn型纳米催化剂。PdSn对各种α、β-不饱和醛的C=O键加氢选择性为96%，在已报道的Pd基催化剂中最高。进一步的研究表明，有效的猝灭防止了从PdSn2结构到Pd3Sn2结构的回复，这是获得预期催化性能的关键。密度泛函理论计算和反应动力学分析为观察到的高选择性提供了解释。
Effective control on chemoselectivity in the catalytic hydrogenation of C=O over C=C bonds is uncommon with Pd-based catalysts because of the favored adsorption of C=C bonds on Pd surface. Here we report a unique orthorhombic PdSn intermetallic phase with unprecedented chemoselectivity toward C=O hydrogenation. We observed the formation and metastability of this PdSn phase in situ. During a natural cooling process, the PdSn nanoparticles readily revert to the favored Pd3Sn2 phase. Instead, using a thermal quenching method, we prepared a pure-phase PdSn nanocatalyst. PdSn shows an >96 % selectivity toward hydrogenating C=O bonds of various alpha,beta-unsaturated aldehydes, highest in reported Pd-based catalysts. Further study suggests that efficient quenching prevents the reversion from PdSn- to Pd3Sn2-structured surface, the key to the desired catalytic performance. Density functional theory calculations and analysis of reaction kinetics provide an explanation for the observed high selectivity.