Ali Sajjad, Xie Zijuan, Xu Hu
Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China.
Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.
Chemphyschem. 2021 Nov 18;22(22):2352-2361. doi: 10.1002/cphc.202100436. Epub 2021 Sep 27.
Based on first-principles calculations, the potential of Ti CO monolayer (MXene) as a single-atom catalyst (SAC) support for 3d transition metal (TM) atoms (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) is studied for CO oxidation. We first screen the support effect according to the stability of a single metal atom and find that Sc and Ti supported on Ti CO have stronger adsorption energy than the cohesive energy of their bulk counterparts and therefore, we selected Sc and Ti supported on Ti CO for further catalytic reactions. The stability and the potential catalytic reactivity are verified by electronic structure and charge transfer analysis. Both Eley-Rideal (ER) and Langmuir-Hinshelwood (LH) mechanisms are considered in this study, and lower energy barriers of 0.002 and 0.37 eV were found in the ER mechanism compared to the LH mechanism, which are 0.25 and 0.34 eV for Sc and Ti catalysts, respectively. Moreover, kinetic ER and LH mechanisms are favorable for both Sc- and Ti/Ti CO because of the comparable energy barrier to other metals and SAC supported on 2D materials. However, Ti/Ti CO catalyst is thermodynamically unfavorable. Based on these calculations, we propose that Sc supported on Ti CO is the best catalyst for CO-oxidation. The current study not only broadens the scope of the single-atom Sc catalyst but also extends the consideration of MXene support for catalyst optimization.
基于第一性原理计算，研究了Ti CO单层（MXene）作为3d过渡金属（TM）原子（Sc、Ti、V、Cr、Mn、Fe、Co、Ni、Cu和Zn）的单原子催化剂（SAC）载体用于CO氧化的潜力。我们首先根据单个金属原子的稳定性筛选载体效应，发现负载在Ti CO上的Sc和Ti具有比其块状对应物的内聚能更强的吸附能，因此，我们选择负载在Ti CO上的Sc和Ti进行进一步的催化反应。通过电子结构和电荷转移分析验证了稳定性和潜在的催化反应活性。本研究考虑了Eley-Rideal（ER）和Langmuir-Hinshelwood（LH）两种机制，发现与LH机制相比，ER机制中的能垒更低，分别为0.002和0.37 eV，对于Sc和Ti催化剂，LH机制的能垒分别为0.25和0.34 eV。此外，由于与二维材料上负载的其他金属和SAC的能垒相当，动力学ER和LH机制对Sc和Ti/Ti CO都有利。然而，Ti/Ti CO催化剂在热力学上是不利的。基于这些计算，我们提出负载在Ti CO上的Sc是CO氧化的最佳催化剂。当前的研究不仅拓宽了单原子Sc催化剂的范围，还扩展了对MXene载体用于催化剂优化的考虑。
