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 (PtTe2) 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 PtTe2 through the reaction of solid-phase precursor films is described. This offers a production method for large-area, thickness-controlled PtTe2, potentially suitable for a number of applications. These polycrystalline PtTe2 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 PtTe2 was found to undergo chemical transformation to a substoichiometric chalcogenide compound under ORR conditions. This study shows while PtTe2 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.

中文翻译：

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大面积PtTe2薄膜的低温合成及电催化应用

在过去的 10 年中，过渡金属二硫化物 (TMD) 的合成一直是二维纳米材料研究的主要焦点，然而，只有一小部分研究集中在过渡金属二碲化物上。特别是，尽管纳米级二碲化铂 (PtTe2) 在催化、光子学和自旋电子学中有潜在的应用，但它很少被研究。在已发表的报告中，大多数研究从化学蒸汽传输 (CVT) 生长的晶体中机械剥离的薄片。这种方法产生高质量的晶体，非常适合基础研究。然而，它非常占用资源并且难以扩展，这意味着在大规模应用中实施存在重大障碍。在这份报告中，描述了通过固相前驱体薄膜的反应合成 PtTe2 薄膜。这为大面积、厚度受控的 PtTe2 提供了一种生产方法，可能适用于许多应用。这些多晶 PtTe2 薄膜在低至 450 ˚C 的温度下生长，明显低于 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。使用扫描电子显微镜和扫描隧道显微镜进行分析表明，可以实现大于 1 µm 的晶粒尺寸，与多晶薄膜的典型值 ~50 nm 相比具有优势。为了研究它们的潜在适用性，这些薄膜被用作析氢反应 (HER) 和氧还原反应 (ORR) 的电催化剂。薄膜显示出有希望的催化行为，然而，发现 PtTe2 在 ORR 条件下发生化学转化为亚化学计量的硫属化物化合物。该研究表明，虽然 PtTe2 在 HER 中稳定且非常有用，但这种特性不适用于 ORR，ORR 具有根本不同的机制。这项研究拓宽了我们对 TMD 电催化的认识。它经历了一个根本不同的机制。这项研究拓宽了我们对 TMD 电催化的认识。它经历了一个根本不同的机制。这项研究拓宽了我们对 TMD 电催化的认识。