Lee Zachary R, Flores Luis A, Copeland William B, Murphy Julia G, Dixon David A
Department of Chemistry and Biochemistry, The University of Alabama, Shelby Hall, Tuscaloosa, Alabama 35487-0336, United States.
J Phys Chem A. 2020 Nov 5;124(44):9222-9236. doi: 10.1021/acs.jpca.0c06760. Epub 2020 Oct 21.
The addition of NO to Group IV (MO) and Group VI (MO) ( = 1-3) nanoclusters was studied using both density functional theory (DFT) and coupled cluster theory (CCSD(T)). The structures and overall binding energetics were predicted for Lewis acid-base addition without transfer of spin (a physisorption-type process) and the formation of either cluster-ONO (HONO-like or bidentate bonding) or NO formation where for both the spin is transferred to the metal oxide clusters (a chemisorption-type process). Only chemisorption of NO is predicted to be thermodynamically allowed at temperatures ≥298 K for Group IV (MO) clusters with the formation of surface chemisorbed NO being by far the most energetically favorable. The ligand binding energies (LBEs) for physisorption and chemisorption on the TiO nanoclusters are consistent with computational studies of the bulk solids. Chemisorption is only predicted to occur for (CrO) clusters in the form of a terminal nitrate containing species whereas the larger chemisorbed nitrate structures for (MoO) and (WO) were found to be metastable and unlikely to form in any appreciable amount at temperatures of 298 K and higher. NO is predicted to only be capable of physisorbing to (MoO) and (WO) at lower temperatures and therefore unlikely to bind NO at temperatures ≥298 K. Correlations between the (MO)NO ligand bond energies and the chemical properties of the parent (MO) clusters (Lewis acidity, ionization potentials, excitation energies, and M = O/M-O bond strengths) are described.
使用密度泛函理论（DFT）和耦合簇理论（CCSD(T)）研究了向IV族（MO）和VI族（MO）（=1-3）纳米团簇中添加NO的情况。预测了Lewis酸碱加成（无自旋转移，一种物理吸附型过程）以及形成簇-ONO（类HONO或双齿键合）或NO形成（其中自旋转移到金属氧化物簇，一种化学吸附型过程）时的结构和总结合能。对于IV族（MO）簇，仅预测在温度≥298K时NO的化学吸附在热力学上是允许的，形成表面化学吸附的NO在能量上是最有利的。TiO纳米团簇上物理吸附和化学吸附的配体结合能（LBEs）与块状固体的计算研究一致。仅预测（CrO）簇会以末端含硝酸盐物种的形式发生化学吸附，而（MoO）和（WO）更大的化学吸附硝酸盐结构被发现是亚稳态的，在298K及更高温度下不太可能大量形成。预测NO在较低温度下仅能物理吸附到（MoO）和（WO）上，因此在温度≥298K时不太可能结合NO。描述了（MO）NO配体键能与母体（MO）簇的化学性质（Lewis酸性、电离势、激发能以及M = O/M - O键强度）之间的相关性。
