Division of Chemistry & Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University , Singapore 637371, Singapore.
Department of Inorganic Chemistry, University of Chemistry and Technology Prague , Technická 5, 166 28 Prague 6, Czech Republic.
ACS Appl Mater Interfaces. 2017 Aug 2;9(30):25587-25599. doi: 10.1021/acsami.7b05083. Epub 2017 Jul 19.
Owing to the anisotropic nature, layered transition metal dichalcogenides (TMDs) have captured tremendous attention for their promising uses in a plethora of applications. Currently, bulk of the research is centered on Group 6 TMDs. Layered noble metal dichalcogenides, in particular the noble metal tellurides, belong to a subset of Group 10 TMDs, wherein the transition metal is a noble metal of either palladium or platinum. We address here a lack of contemporary knowledge on these compounds by providing a comprehensive study on the electrochemistry of layered noble metal tellurides, PdTe and PtTe, and their efficiency as electrocatalysts toward the hydrogen evolution reaction (HER). Observed parallels in the electrochemical peaks of the noble metal tellurides are traced to the tellurium electrochemistry. PdTe and PtTe can be discriminated by their distinct reduction peaks in the first cathodic scans. Considering the influence of the metal component, PtTe outperforms PdTe in aspects of charge transfer and electrocatalysis. The heterogeneous electron transfer (HET) rate of PtTe is an order of magnitude faster than PdTe, and a lower HER overpotential of 0.54 V versus reversible hydrogen electrode (RHE) at a current density of -10 mA cm is evident in PtTe. On PdTe and PtTe surfaces, adsorption via the Volmer process has been identified as the limiting step for HER. A general phenomenon for the noble metal tellurides is that faster HET rates are observed upon electrochemical reductive pretreatment, whereas slower HET rates occur when the noble metal tellurides are oxidized during pretreatment. PtTe becomes successfully activated for HER when subject to oxidative treatment, whereas oxidized or reduced PdTe shows a deactivated HER performance. These findings provide fundamental insights that are pivotal to advancing the field of the underemphasized TMDs. Furthermore, electrochemical tuning as a means to tailor specific properties of the TMDs is advantageous for the development of their future applications.
由于各向异性，层状过渡金属二卤化物（TMDs）在众多应用中具有广阔的应用前景，因此引起了极大的关注。目前，大部分研究集中在第 6 族 TMDs 上。层状贵金属二卤化物，特别是贵金属碲化物，属于第 10 族 TMDs 的一个子集，其中过渡金属是钯或铂的贵金属。我们在这里通过对层状贵金属碲化物（PdTe 和 PtTe）的电化学性质及其作为析氢反应（HER）电催化剂的效率进行全面研究，解决了对这些化合物缺乏当代认识的问题。贵金属碲化物电化学峰的相似之处可追溯到碲的电化学。PdTe 和 PtTe 可以通过它们在第一次阴极扫描中的独特还原峰来区分。考虑到金属成分的影响，PtTe 在电荷转移和电催化方面优于 PdTe。PtTe 的非均相电子转移（HET）速率比 PdTe 快一个数量级，在电流密度为-10 mA cm 时，PtTe 的 HER 过电位明显更低，为 0.54 V 相对于可逆氢电极（RHE）。在 PdTe 和 PtTe 表面，通过 Volmer 过程的吸附已被确定为 HER 的限制步骤。贵金属碲化物的一个普遍现象是，电化学还原预处理后观察到更快的 HET 速率，而预处理过程中贵金属碲化物氧化时则观察到较慢的 HET 速率。当经受氧化处理时，PtTe 成功地被激活用于 HER，而氧化或还原的 PdTe 则表现出失活的 HER 性能。这些发现为推进被低估的 TMDs 领域提供了重要的见解。此外，电化学调谐作为一种调整 TMDs 特定性质的方法，有利于其未来应用的发展。
