Role of topological surface states and mirror symmetry in topological crystalline insulator SnTe as an efficient electrocatalyst

Qing Qu; Bin Liu; Hongtao Liu; Jing Liang; Jiannong Wang; Ding Pan; Iam Keong Sou

doi:10.1039/d1nr05089c

Role of topological surface states and mirror symmetry in topological crystalline insulator SnTe as an efficient electrocatalyst

Nanoscale. 2021 Nov 11;13(43):18160-18172. doi: 10.1039/d1nr05089c.

Authors

Qing Qu^{1

2}, Bin Liu³, Hongtao Liu³, Jing Liang^{3

2}, Jiannong Wang^{3

2}, Ding Pan^{3

4}, Iam Keong Sou^{1

3

2}

Affiliations

¹ Nano Science and Technology Program, The Hong Kong University of Science and Technology, Hong Kong, China. phiksou@ust.hk.
² William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Hong Kong, China.
³ Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China. dingpan@ust.hk.
⁴ Department of Chemistry, The Hong Kong University of Science and Technology, Hong Kong, China.

PMID: 34704582
DOI: 10.1039/d1nr05089c

Abstract

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.