Qu Qing, Liu Bin, Liu Hongtao, Liang Jing, Wang Jiannong, Pan Ding, Sou Iam Keong
Nano Science and Technology Program, The Hong Kong University of Science and Technology, Hong Kong, China.
William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Hong Kong, China.
Nanoscale. 2021 Nov 11;13(43):18160-18172. doi: 10.1039/d1nr05089c.
The surface orientation dependence on the hydrogen evolution reaction (HER) performance of topological crystalline insulator (TCI) SnTe thin films is studied. Their intrinsic activities are determined by linear sweep voltammetry and cyclic voltammetry measurements. It is found that SnTe (001) and (111) surfaces exhibit intrinsic activities significantly larger than the (211) surface. Density functional theory calculations reveal that pure (001) and (111) surfaces are not good electrocatalysts, while those with Sn vacancies or partially oxidized surfaces, with the latter as evidenced by X-ray photoelectron spectroscopy, have high activity. The calculated overall performance of the (001) and (111) surfaces with robust topological surface states (TSSs) is better than that of the lowly symmetric (211) surface with fragile or without TSSs, which is further supported by their measured weak antilocalization strength. The high HER activity of SnTe (001) and (111) is attributed to the enhanced charge transfer between H atoms and TSSs. We also address the effect of possible surface facets and the contrast of the HER activity of the available active sites among the three samples. Our study demonstrates that the TSSs and mirror symmetry of TCIs expedite their HER activity.
研究了拓扑晶体绝缘体（TCI）SnTe薄膜析氢反应（HER）性能对表面取向的依赖性。通过线性扫描伏安法和循环伏安法测量确定了它们的本征活性。发现SnTe（001）和（111）表面的本征活性明显大于（211）表面。密度泛函理论计算表明，纯（001）和（111）表面不是良好的电催化剂，而具有Sn空位或部分氧化表面的则具有高活性，后者由X射线光电子能谱证实。计算得出，具有稳健拓扑表面态（TSSs）的（001）和（111）表面的整体性能优于具有脆弱或没有TSSs的低对称（211）表面，这进一步得到了它们测得的弱反局域化强度的支持。SnTe（001）和（111）的高HER活性归因于H原子与TSSs之间增强的电荷转移。我们还讨论了可能的表面小面的影响以及三个样品中可用活性位点的HER活性对比。我们的研究表明，TCI的TSSs和镜面对称性加快了它们的HER活性。
