Mechanistic insights into hydrodeoxygenation of phenol on bimetallic phosphide catalysts
Mechanistic insights into hydrodeoxygenation of phenol on bimetallic phosphide catalysts
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DOI：
10.1039/c8cy00977e
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发表时间：
2018-08
影响因子：
5
通讯作者：
Varsha Jain;Y. Bonita;A. Brown;Anna Taconi;J. Hicks;N. Rai
中科院分区：
文献类型：
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作者：
Varsha Jain;Y. Bonita;A. Brown;Anna Taconi;J. Hicks;N. Rai
酚类物质的催化加氢脱氧（HDO）是将生物油升级为运输燃料的必要步骤。双金属催化剂具有提高所需产品的活性和选择性的潜力。添加非金属元素，例如磷，可以实现金属和非金属原子之间的电荷分布，从而改善催化表面的路易斯酸特性。这项工作利用基于实验和密度泛函理论 (DFT) 的计算来确定 FeMoP、RuMoP 和 NiMoP 催化剂上 HDO 反应的潜在 C-O 键裂解途径和产物选择性。我们的工作表明，FeMoP 催化剂由于 C-O 键断裂的活化能垒较低，有利于直接脱氧途径，而 RuMoP 和 NiMoP 催化剂首先促进环氢化，然后是 C-O 键断裂。 Bader 电荷分析表明，对于这些催化系统，Moδ+ 位点带有大量正电荷，充当 HDO 反应的路易斯酸位点。总体而言，我们发现实验产物选择性的趋势与 DFT 计算预测的趋势非常一致。
Catalytic hydrodeoxygenation (HDO) of phenolics is a necessary step for upgrading bio-oils to transportation fuels. Bimetallic catalysts offer the potential of increased activities and selectivities for desired products. Adding non-metallic elements, such as phosphorous, allows for charge distribution between the metal and nonmetal atoms, which improves Lewis acid character of catalytic surfaces. This work utilizes experimental and density functional theory (DFT) based calculations to identify potential C–O bond cleavage pathways and product selectivities for HDO reactions on FeMoP, RuMoP, and NiMoP catalysts. Our work demonstrates that FeMoP catalyst favors direct deoxygenation pathway due to a lower activation energy barrier for C–O bond cleavage whereas RuMoP and NiMoP catalysts promote ring hydrogenation first, followed by the cleavage of C–O bond. The Bader charge analysis indicates that for these catalytic systems Moδ+ site bears a large positive charge which acts as a Lewis acid site for HDO reactions. Overall, we find that trends in the experimental product selectivities are in good agreement with that predicted with DFT calculations.