SÜmer Aslıhan
Faculty of Pharmacy, University of Health Sciences Turkey, İstanbul Turkey.
Turk J Chem. 2020 Aug 18;44(4):1016-1030. doi: 10.3906/kim-2001-63. eCollection 2020.
The physical and chemical properties of bimetallic nanoparticles can be optimized by tuning the particle composition. In this study, we identified CO adsorption and dissociation energetics on five Pt-Mo nanoparticles at different concentrations, the lowest energy Pt, PtMo, PtMo, PtMo, and Mo clusters. We have shown that the CO adsorption and dissociation energies and preferred CO adsorption sites are largely dependent on the composition of the nanoparticles. As the Mo concentration increases, the strength of the C-O internal bond in the adsorption complex decreases, as indicated by a decrease in the C-O stretching frequency. Also, more Mo sites in the nanoparticle become available for CO adsorption, and the preferred CO adsorption site switches from Pt to Mo. For these reasons, dissociation of CO is energetically favorable on PtMo and Mo. On both compositions, we have shown that the dissociation paths begin with CO adsorbed on a Mo site in a multifold configuration, in particular in a tilted configuration. These findings provide insight on the effects of the composition on the chemical and catalytical properties of Pt-Mo nanoparticles, thereby guiding future experiments on the synthesis of nanoparticles, especially those that may be suitable for various desired applications containing CO.
双金属纳米颗粒的物理和化学性质可通过调整颗粒组成来优化。在本研究中，我们确定了不同浓度下五个铂 - 钼纳米颗粒（最低能量的铂、铂钼、铂钼、铂钼和钼团簇）上一氧化碳的吸附和解离能量学。我们已经表明，一氧化碳的吸附和解离能量以及优选的一氧化碳吸附位点在很大程度上取决于纳米颗粒的组成。随着钼浓度的增加，吸附络合物中碳 - 氧内键的强度降低，这由碳 - 氧伸缩频率的降低表明。此外，纳米颗粒中更多的钼位点可用于一氧化碳吸附，并且优选的一氧化碳吸附位点从铂切换到钼。由于这些原因，一氧化碳在铂钼和钼上的解离在能量上是有利的。在这两种组成上，我们已经表明解离路径始于一氧化碳以多重构型吸附在钼位点上，特别是倾斜构型。这些发现为组成对铂 - 钼纳米颗粒的化学和催化性质的影响提供了见解，从而指导未来纳米颗粒合成的实验，尤其是那些可能适用于包含一氧化碳的各种期望应用的实验。
