Liu Tianhui, Peng Tianze, Fu Bina, Zhang Dong H
School of Sciences, Great Bay University, Songshan Lake International Innovation Entrepreneurship Community A5, Dongguan 523000, China.
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
J Chem Phys. 2024 Jan 7;160(1). doi: 10.1063/5.0187233.
The 6D time-dependent wave packet calculations were performed to explore H2 dissociation on Ag, Au, and two AgAu alloy surfaces, using four newly fitted potential energy surfaces based on the neural network fitting to density functional theory energy points. The ligand effect resulting from the Ag-Au interaction causes a reduction in the barrier height for H2+Ag/Au(111) compared to H2+Ag(111). However, the scenario is reversed for H2+Au/Ag(111) and H2+Au(111). The 6D dissociation probabilities of H2 on Ag/Au(111) surfaces are significantly higher than those on the pure Ag(111) surface, but the corresponding results for H2 on Au/Ag(111) surfaces are substantially lower than those on the pure Au(111) surface. The reactivity of H2 on Au(111) is larger than that on Ag(111), despite Ag(111) having a slightly lower static barrier height. This can be attributed to the exceptionally small dissociation probabilities at the hcp and fcc regions, which are at least 100 times smaller compared to those at the bridge or top site for H2+Ag(111). Due to the late barrier being more pronounced, the vibrational excitation of H2 on Ag(111) is more effective in promoting the reaction than on Au(111). Moreover, a high degree of alignment dependence is detected for the four reactions, where the H2 dissociation has the highest probability at the helicopter alignment, as opposed to the cartwheel alignment.
进行了含时间的六维波包计算，以探究氢气在银、金以及两种银金合金表面上的解离情况，计算使用了基于神经网络拟合密度泛函理论能量点的四个新拟合势能面。与氢气 + 银（111）相比，银 - 金相互作用产生的配体效应导致氢气 + 银/金（111）的势垒高度降低。然而，对于氢气 + 金/银（111）和氢气 + 金（111），情况则相反。氢气在银/金（111）表面上的六维解离概率显著高于在纯银（111）表面上的解离概率，但氢气在金/银（111）表面上的相应结果则远低于在纯金（111）表面上的结果。尽管银（111）的静态势垒高度略低，但氢气在金（111）上的反应活性大于在银（111）上的反应活性。这可归因于在六方密堆积（hcp）和面心立方（fcc）区域的解离概率异常小，与氢气 + 银（111）在桥位或顶位的解离概率相比至少小100倍。由于后期势垒更为显著，氢气在银（111）上的振动激发比在金（111）上更有效地促进反应。此外，检测到这四个反应具有高度的取向依赖性，其中氢气解离在直升机取向时概率最高，与车轮取向相反。
