研究报道一种单原子催化吸附机制
哈尔滨工业大学李哲团队报道了选择性轨道耦合——一种单原子催化吸附机制。相关研究成果于2024年4月29日发表在国际知名学术期刊《美国化学会杂志》。
通过单原子催化剂的电子性质定量了解其化学吸附对催化剂设计至关重要。然而，物理机制仍在争论之中。
该文中，使用单一过渡金属（即Sc、Ti、V、Cr、Mn、Fe、CO、Ni）掺杂剂上的CO催化氧化作为理论模型，来探索电子结构特征与SACs上的化学吸附之间的相关性。对于这些金属掺杂剂，它们的原子d轨道形成几个非退化和局域电子态，发现这些电子态与吸附的O2的π*轨道选择性耦合，研究人员将其定义为选择性轨道耦合。
基于选择性轨道耦合，研究人员发现所选d态和π*态之间的排列决定了键强度，而与所选d状态的电子占有数无关，形成M–O键的电子转移可以由载体提供。这种电子转移可能与电子-金属-载体的相互作用有关。
研究人员将化学吸附机制的起源归因于，单个过渡金属的局域轨道和Au载体的连续能带的共存。最后，研究人员说明了这种机制是如何主导反应屏障的变化趋势的。研究结果揭示了SAC系统的基本吸附机制。
附：英文原文
Title: Selective Orbital Coupling: An Adsorption Mechanism in Single-Atom Catalysis
Author: Chen He, Chih-Heng Lee, Lei Meng, Hsin-Yi Tiffany Chen, Zhe Li
Issue&Volume: April 29, 2024
Abstract: Quantitative understanding of the chemisorption on single-atom catalysts (SACs) by their electronic properties is crucial for the catalyst design. However, the physical mechanism is still under debate. Here, the CO catalytic oxidation on single transition metal (i.e., Sc, Ti, V, Cr, Mn, Fe, Co, Ni) dopants is used as a theoretical model to explore the correlations between the characteristics of electronic structures and the chemisorption on SACs. For these metal dopants, their atomic d orbitals form several nondegenerate and localized electronic states that are found to be selectively coupled with the π* orbital of the adsorbed O2, which we defined as selective orbital coupling. Based on the selective orbital coupling, we find that the alignment between the selected d state and the π* state determines the bond strength, regardless of the electron occupation number of the selected d states; the electron transfer to form M–O bonding can be provided by the support. Such electron transfer can be related with the electronic metal–support interaction. We attribute the origin of the chemisorption mechanism to the coexistence of the localized orbital of the single transition metal and the continuous energy band of the Au support. Finally, we illustrate how this mechanism dominates the variation trend of the reaction barriers. Our results unravel a fundamental adsorption mechanism in SAC systems.
DOI: 10.1021/jacs.3c13119
Source: https://pubs.acs.org/doi/abs/10.1021/jacs.3c13119
来源：科学网 小柯机器人
