Analysis of the propylene epoxidation mechanism on supported gold nanoparticles
Analysis of the propylene epoxidation mechanism on supported gold nanoparticles
复制标题
负载金纳米粒子丙烯环氧化机理分析
DOI：
10.1016/j.ces.2017.09.018
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发表时间：
2017
影响因子：
4.7
通讯作者：
Lei, Yu
中科院分区：
文献类型：
--
作者：
Turner, C. Heath;Ji, Jingjing;Lu, Zheng;Lei, Yu
过去已有几个不同的研究组对丙烯直接环氧化反应进行了实验研究，金基催化剂对环氧丙烷的选择性较高，但转化率相对较低。为了确定新的催化剂结构和配方，需要能够将原子催化细节与观察到的实验数据联系起来的模型。虽然电子结构计算已被用于量化丙烯直接环氧化反应中的一些关键反应步骤，但需要原子模型将这些信息转化为更多与实验相关的数据。在这里，动力学蒙特卡罗（KMC）模拟被用来弥补建模层次结构中的这一差距。利用以往实验的相关数据和电子结构计算，参数化了预测Au/TiO2/ sio2催化剂生成环氧丙烷的KMC模型。该模型将发生在Au位点上的H2/ o2相关反应与孤立的Ti表面位点上的环氧化步骤联系起来。此外，本体气相的组成与表面发生的动态反应事件是同步的。KMC模型能够充分地再现有关温度和不同反应物分压的实验趋势。然而，这只能通过考虑从气相中重新吸附微量氧化剂（H2O2）来实现，而不仅仅是假设解吸的物质立即在气流中被冲走。
The direct propylene epoxidation reaction has been investigated experimentally in the past by several different groups, and gold-based catalysts tend to provide high selectivity for propylene oxide, but the conversion is relatively low. Models that can connect the atomistic catalytic details to the observed experimental data are desired, in order to identify new catalyst structures and formulations. While electronic structure calculations have been used to quantify some of the key reaction steps in the direct propylene epoxidation reaction, atomistic models for translating this information into more experimentally-relevant data are needed. Here, kinetic Monte Carlo (KMC) simulations are used to bridge this gap in the modeling hierarchy. Relevant data from previous experiments and electronic structure calculations are used to parameterize a KMC model for predicting propylene oxide production from an Au/TiO2/SiO2catalyst. The model connects the H2/O2-related reactions occurring on the Au sites with the epoxidation step on the isolated Ti surface sites. In addition, the composition in the bulk gas phase is synchronized with the dynamic reaction events occurring on the surface. The KMC model is able to adequately reproduce the experimental trends with respect to temperature and different reactant partial pressures. However, this is only achieved by considering the re-adsorption of trace amounts of the oxidant (H2O2) from the gas phase, versus merely assuming that desorbed species are immediately swept away in the gas stream.
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作者：
C. Qi;M. Okumura;T. Akita;M. Haruta
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DOI：
--
发表时间：
2008
期刊：
Physical review. E, Statistical, nonlinear, and soft matter physics
影响因子：
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DOI：
10.1063/1.4974261
发表时间：
2016
期刊：
The Journal of chemical physics
影响因子：
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作者：
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