分会

第二十分会：固体表界面化学与多相催化

摘要

具有协同效应的PtRu/MCM-41双金属催化剂在无碱条件下的甘油氧化性能研究 闫昊，周鑫，刘熠斌，杨朝合*， 1中国石油大学（华东） 重质油国家重点实验室，山东青岛，266580 *Email: yangch@upc.edu.cn 将廉价的甘油（生物柴油副产物）转化为高附加值的羧酸产物具有重要的意义。在本研究中首次报道了以O2为氧化剂，在无碱介质中用双金属PtRu催化剂氧化甘油制备甘油酸；结合密度泛函理论（DFT）计算和多种表征（如H2-TPR、HAADF-STEM和XPS）发现，Pt和Ru之间的强相互作用可以促进PtRu合金纳米粒子的分散，增强金属表面的电子耦合效应。同时，与单金属铂催化剂相比，Ru的引入有助于分子氧和水直接解离成羟基，从而获得优异的催化活性。系统地建立了Ru/Pt比值、催化性能、结构灵敏度和电子耦合效应之间的“火山型曲线关系”。此外，还详细分析了结构敏感性和电子耦合效应对不同Ru/Pt比PtRu催化剂催化活性的影响。最后，Pt0.8Ru0.8/MCM-41催化剂在优化条件下（80℃、1 MPa O2和12h）表现出良好的催化活性（TOF: 823.9h-1）、甘油酸选择性（80.1%）和稳定性（循环使用5次）。本文所提出的见解和方法可为双金属催化剂在温和条件下高效转化生物衍生底物的合理设计铺平道路。 图1. Pt0.8Ru0.8/MCM-41催化剂上的甘油氧化反应机理 关键词：甘油氧化；PtRu；MCM-41；理论计算 参考文献 [1]Yan H, Yao S, Yin B, et al. Appl. Catal., B 2019, 259: 118070. Synergistic effects of bimetallic PtRu/MCM-41 nanocatalysts for glycerol oxidation in base-free medium Hao Yan, Xin Zhou , Yibin Liu, Chaohe Yang,* State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao 266580, China It is of great significance to transform cheap glycerol (biodiesel by-product) into high value added carboxylic acid. Herein, bimetallic PtRu catalyst was first reported for oxidation of glycerol to glyceric acid in base-free medium using O2 as the oxidant. A combination of density functional theory (DFT) calculations and multi-characterizations (e.g., H2-TPR, HAADF-STEM and XPS) revealed that the strong interaction between Pt and Ru could promote the dispersion of PtRu alloy nanoparticles and enhance the electronic coupling effect on the metal surface. Meanwhile, compared to the monometallic Pt catalyst, the introduction of Ru contributes to the direct dissociation of molecular oxygen and water to hydroxyl group, leading to the excellent catalytic activity. A volcanic-shaped relationship between Ru/Pt ratio, catalytic performance, structure-sensitivity and electronic coupling effect was systematically established. Furthermore, the role of structure-sensitivity and electronic coupling effect for the enhanced catalytic activity of PtRu catalysts with different Ru/Pt ratios are distinguished in detail. Finally, the Pt0.8Ru0.8/MCM-41 catalyst showed excellent catalytic activity (TOF: 823.9 h-1), glyceric acid selectivity (80.1%) and stability (recycling for 5th) under the optimized conditions (80 oC, 1 MPa O2 and 12 h). The insights and methodology reported here may pave the way to the rational design of bimetallic catalysts for efficient conversion of bio-derived substrates under mild conditions Figure 1. Plausible oxidation mechanism on the Pt0.8Ru0.8/MCM-41 catalyst.

关键词

甘油氧化;理论计算

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