Single-Molecule Kinetics of Styrene Hydrogenation on Silica-Supported Vanadium: The Role of Disorder for Single-Atom Catalysts
Single-Molecule Kinetics of Styrene Hydrogenation on Silica-Supported Vanadium: The Role of Disorder for Single-Atom Catalysts
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DOI：
10.1021/acs.jpcc.1c04759
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发表时间：
2021-09
期刊：
影响因子：
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通讯作者：
R. H. Wells;S. An;Prajay Patel;Cong Liu;R. T. Skodje
中科院分区：
文献类型：
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作者：
R. H. Wells;S. An;Prajay Patel;Cong Liu;R. T. Skodje
基于单分子动力学研究的最新进展，发展了一种研究负载原子催化的理论方法。这一观点特别适用于展示无定形载体上的单原子和单位点催化剂中无序的作用。通过源自一组耦合活性位点的复杂催化网络的通过时间（或等待时间）的分布由概率分布函数（PDF）f（t）描述，其反映反应中心的局部环境。基于产生f（t）或其矩的马尔可夫转移矩阵的线性代数，开发了一种有效的算法。研究了苯乙烯在以无定形二氧化硅为载体的有机钒催化剂上的加氢反应动力学。一个动力学模型，由三个相互交织的催化循环从三个化学不同的活性位点提出来描述的化学。采用密度泛函理论（DFT）计算来确定反应的自由能垒，用于构建速率系数矩阵。由无定形支撑材料引起的无序被分成反映反应中心附近的共价结构的低维短程分量和模拟体随机性的较弱的长程分量。结果进行了计算和分析的浓度值和混乱的情况下，范围很广。发现f（t）PDF中的不寻常结构在某些情况下发生，这些情况揭示了多个催化途径协同作用的贡献。
A theoretical approach for the study of supported atom catalysis is developed based on recent advances in the study of single-molecule kinetics. This view is particularly useful in exhibiting the role of disorder in single-atom and single-site catalysts on amorphous supports. The distribution of passage times (or waiting times) through a complex catalytic network originating from a set of coupled active sites is described by a probability distribution function (PDF),f(t), that reflects the local environment of the reaction center. An efficient algorithm is developed based on the linear algebra of the Markov transition matrix that producesf(t) or its moments. The kinetics of the hydrogenation reaction of styrene on an organovanadium(III) catalyst supported on amorphous silica is studied. A kinetic model consisting of three intertwined catalytic cycles emanating from three chemically distinct active sites is proposed to describe the chemistry. Density functional theory (DFT) calculations are employed to determine the free energy barriers of the reactions, which are used to construct the rate coefficient matrix. The disorder induced by the amorphous support material is divided into a low-dimensional short-range component reflecting the covalent structures near the reaction center and a weaker long-range component modeling the bulk randomness. The results are computed and analyzed for a wide range of concentration values and disorder scenarios. The unusual structure in thef(t) PDF is found to occur for certain cases that reveal the contribution of multiple catalytic pathways acting in concert.