Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India.
Department of Chemistry, University of California Irvine, Irvine, California 92617, USA.
J Chem Phys. 2019 Mar 21;150(11):114702. doi: 10.1063/1.5085696.
The influence of alloying on mode-selectivity in HO dissociation on Cu/Ni bimetallic surfaces has been studied using a fully quantum approach based on reaction path Hamiltonian. Both the metal alloy catalyst surface and the normal modes of HO impact the chemical reactivity of HO dissociation. A combination of these two different factors will enhance their influence reasonably. Among all the bimetallic surfaces, one monolayer (Ni4_Cu(111)) and 12 monolayer of Ni on Cu surface (Ni2_Cu(111)) show lowest barrier to the dissociation. Excitation of bending mode and symmetric stretching mode enhances the reactivity remarkably due to a significant decrease in their frequencies near the transition state in the vibrational adiabatic approximation. In the presence of non-adiabatic coupling between the modes, asymmetric stretching also shows similar enhancement in reactivity to that of symmetric stretching for all the systems. Inclusion of lattice motion using a sudden model enhances the dissociation probability at surface temperature 300 K and at lower incident energy, compared to that of the static surface approximation. The mode selective behaviour of HO molecules is almost similar on all the Cu- and Ni-based surfaces. The excitation of symmetric stretching vibration by one quantum is shown to have largest efficacy for promoting reactions for all the systems. Overall, the dissociation probabilities for all the systems are enhanced by vibrational excitation of normal modes and become more significant with the non-adiabatic coupling effect.
采用基于反应路径哈密顿量的全量子方法研究了合金元素对 Cu/Ni 双金属表面 HO 离解模式选择性的影响。HO 冲击金属合金催化剂表面的正常振动模式都会影响 HO 离解的化学反应性。这两个不同因素的结合将合理地增强它们的影响。在所有的双金属表面中，单层（Ni4_Cu(111)）和 12 层的 Ni 在 Cu 表面（Ni2_Cu(111)）对离解具有最低的势垒。在振动绝热近似中，由于在过渡态附近它们的频率显著降低，弯曲模式和对称伸缩模式的激发显著增强了反应性。在各体系中，由于模式之间存在非绝热耦合，不对称伸缩模式也表现出与对称伸缩模式相似的增强反应性。与静态表面近似相比，在表面温度为 300 K 和较低入射能的情况下，使用突变法包括晶格运动，会提高离解概率。HO 分子在所有基于 Cu 和 Ni 的表面上的模式选择性行为几乎相同。对于所有体系，通过一个量子激发对称伸缩振动被证明对促进反应具有最大功效。总的来说，振动模式的激发会增强所有体系的离解概率，并且随着非绝热耦合效应的增强，其影响变得更加显著。
