Lasserus Maximilian, Schnedlitz Martin, Messner Roman, Lackner Florian, Ernst Wolfgang E, Hauser Andreas W
Institute of Experimental Physics , Graz University of Technology , Petersgasse 16 , A-8010 Graz , Austria . Email:
Chem Sci. 2019 Feb 25;10(12):3473-3480. doi: 10.1039/c8sc05699d. eCollection 2019 Mar 28.
Oxide nanoparticles in the size range of a few nanometers are typically synthesized in solution or laser ablation techniques, which open numerous channels for structural change chemical reactions or fragmentation processes. In this work, neutral vanadium oxide nanoparticles are instead synthesized by sublimation from bulk in combination with a pickup by superfluid helium droplets. Mass spectroscopy measurements clearly demonstrate the preservation of the bulk stoichiometric ratio of vanadium to oxygen in He-grown nanoparticles, indicating a tendency towards tetrahedral coordination of the vanadium centers in finite geometries. This unexpected finding opens up new possibilities for a combined on-the-fly synthesis of nanoparticles consisting of metal and metal-oxide layers. In comparison to mass spectra obtained direct ionization of vanadium oxide in an effusive beam, where strong fragmentation occurred, we observe a clear preference for (VO) oligomers with even inside the He nanodroplets, which is further investigated and explained using the electronic structure theory.
尺寸在几纳米范围内的氧化物纳米颗粒通常通过溶液合成或激光烧蚀技术制备，这为结构变化、化学反应或碎片化过程开辟了众多途径。在这项工作中，中性氧化钒纳米颗粒是通过从块状物升华并结合超流氦滴拾取来合成的。质谱测量清楚地表明，在氦气中生长的纳米颗粒中钒与氧的整体化学计量比得以保留，这表明在有限几何结构中钒中心倾向于四面体配位。这一意外发现为同时进行由金属和金属氧化物层组成的纳米颗粒的即时合成开辟了新的可能性。与在逸出束中对氧化钒进行直接电离获得的质谱相比（在逸出束中发生了强烈的碎片化），我们观察到在氦纳米滴内部，偶数的(VO)寡聚物具有明显的偏好，我们使用电子结构理论对此进行了进一步研究和解释。
