氢气及壬基蒽在铂团簇上吸附活化的电子作用机制初探

Orbital Interaction Mechanism of Hydrogen and 9-Nonylanthracene Adsorption and Dissociation on Platinum Clusters

多环芳烃在石油的高沸点馏分中占据一定比重且较难转化,通过加氢裂化使稠环芳烃轻质化是目前较为有效的转化途径。作为催化反应的第一步,多环芳烃在催化材料表面的吸附对后续的反应历程具有重要意义。采用分子动力学与密度泛函理论(DFT)作为研究手段,选取纳米尺寸的Pt团簇作为吸附模型,首先从前线轨道角度分析了H_2在Pt团簇上吸附的作用方式,比较了H_2在Pt团簇上从物理吸附到化学吸附转化过程中电子分布的变化,考察了9-壬基蒽在加氢团簇表面吸附加氢的内在电子作用机制,并基于该共吸附体系内电子传递的环路机制构建了带取代侧链的三环芳烃与加氢中心相互作用的电子传递模型。

Nowadays,the refining of polycyclic aromatic hydrocarbons in the heavy distillations of petroleum is still a great challenge for refiners in global,due to the strict environmental regulations and the rapid catalyst deactivation in the downstream secondary processing,such as fluid catalytic cracking and hydrocracking. Thus,the adsorption of polycyclic aromatic hydrocarbons on transitional metal surfaces is regarded as one of the key factors to affect their subsequent hydrogenation and heterogeneously catalytic transformation processes.Theoretical researches are helpful to direct the development of both catalysts and processing.In this paper,periodic density function theory（DFT）and molecular dynamic method are combined for the mechanism investigation of the adsorption 9-nonyl anthracene on nano-sized Pt5 clusters.The physisorption and chemisorption of 9-nonyl anthracene on Pt5 clusters is compared by using frontier molecular orbitals and electronic analysis methods.According to these results,a clear interaction mechanism of the adsorption of PAHs on Pt5 clusters is proposed from orbital interaction aspect.