Mc Manus John B, Horvath Dominik V, Browne Michelle P, Cullen Conor P, Cunningham Graeme, Hallam Toby, Zhussupbekov Kuanysh, Mullarkey Daragh, Coileáin Cormac Ó, Shvets Igor V, Pumera Martin, Duesberg Georg S, McEvoy Niall
School of Chemistry, Trinity College Dublin, Dublin 2 D02 PN40, Ireland. AMBER Centre, CRANN Institute, Trinity College Dublin, Dublin 2 D02 PN40, Ireland.
Nanotechnology. 2020 Sep 11;31(37):375601. doi: 10.1088/1361-6528/ab9973. Epub 2020 Jun 4.
The synthesis of transition metal dichalcogenides (TMDs) has been a primary focus for 2D nanomaterial research over the last 10 years, however, only a small fraction of this research has been concentrated on transition metal ditellurides. In particular, nanoscale platinum ditelluride (PtTe) has rarely been investigated, despite its potential applications in catalysis, photonics and spintronics. Of the reports published, the majority examine mechanically-exfoliated flakes from chemical vapor transport (CVT) grown crystals. This method produces high quality-crystals, ideal for fundamental studies. However, it is very resource intensive and difficult to scale up meaning there are significant obstacles to implementation in large-scale applications. In this report, the synthesis of thin films of PtTe through the reaction of solid-phase precursor films is described. This offers a production method for large-area, thickness-controlled PtTe, potentially suitable for a number of applications. These polycrystalline PtTe films were grown at temperatures as low as 450 °C, significantly below the typical temperatures used in the CVT synthesis methods. Adjusting the growth parameters allowed the surface coverage and morphology of the films to be controlled. Analysis with scanning electron- and scanning tunneling microscopy indicated grain sizes of above 1 µm could be achieved, comparing favorably with typical values of ∼50 nm for polycrystalline films. To investigate their potential applicability, these films were examined as electrocatalysts for the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). The films showed promising catalytic behavior, however, the PtTe was found to undergo chemical transformation to a substoichiometric chalcogenide compound under ORR conditions. This study shows while PtTe is stable and highly useful for in HER, this property does not apply to ORR, which undergoes a fundamentally different mechanism. This study broadens our knowledge on the electrocatalysis of TMDs.
在过去十年中，过渡金属二硫属化物（TMDs）的合成一直是二维纳米材料研究的主要焦点，然而，这项研究中只有一小部分集中在过渡金属二碲化物上。特别是，纳米级铂二碲化物（PtTe₂）尽管在催化、光子学和自旋电子学方面有潜在应用，但很少有人对其进行研究。在已发表的报告中，大多数研究的是通过化学气相传输（CVT）生长的晶体经机械剥离得到的薄片。这种方法能产生高质量的晶体，非常适合基础研究。然而，它资源消耗极大且难以扩大规模，这意味着在大规模应用中存在重大障碍。在本报告中，描述了通过固相前驱体薄膜反应合成PtTe₂薄膜的方法。这提供了一种用于大面积、厚度可控的PtTe₂的制备方法，可能适用于多种应用。这些多晶PtTe₂薄膜在低至450℃的温度下生长，显著低于CVT合成方法中使用的典型温度。调整生长参数可以控制薄膜的表面覆盖率和形态。扫描电子显微镜和扫描隧道显微镜分析表明，可以实现大于1μm的晶粒尺寸，与多晶薄膜约50nm的典型值相比具有优势。为了研究它们的潜在适用性，将这些薄膜作为析氢反应（HER）和氧还原反应（ORR）的电催化剂进行了研究。这些薄膜表现出了有前景的催化行为，然而，发现PtTe₂在ORR条件下会化学转化为亚化学计量的硫属化物化合物。这项研究表明，虽然PtTe₂在HER中稳定且非常有用，但这种性质不适用于ORR，ORR经历的是一种根本不同的机制。这项研究拓宽了我们对TMDs电催化的认识。
