Surface defects engineering and reactivity towards methanol decomposition of layered PtTe₂
Jing-Wen Hsueh1*, Lai-Hsiang Kuo1, Wan-Hsin Chen2, Chia-Nung Kuo3, Yu-Ling Lai4, Li-Chung Yu4, Hung-Wei Shiu4, Yao-Jane Hsu4, Chin-Shan Lue3, Chun-Liang Lin2, Meng-Fan Luo1
1Department of Physics, National Central University, Taoyuan, Taiwan
2Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
3Department of Physics, National Cheng-Kung University, Tainan, Taiwan
4National Synchrotron Radiation Research center, Hsinchu, Taiwan
* Presenter:Jing-Wen Hsueh,
Layered transition metal dichalcogenides (TMDs) have attracted considerable interests due to their potential usage as alternative catalysts. However, the limited density of active sites (typically edge sites or surface defects) is a significant challenge to increase surface reactivity. In this study, we show that the reactivity of the PtTe₂ basal plane is enhanced by introducing surface Te-vacancies, corresponding to under-coordinated surface Pt (Ptuc), and the defect density can be controlled with Argon ion (Ar+) bombardment. With the reflection high energy electron diffraction (RHEED) and the photoelectron spectroscopy (PES), we demonstrate the surface structure and the chemical state are both dramatically changed after the Ar+ bombardment whereas the surface structure was restored after the annealing at 720 K for an hour. The PES spectra of Pt 4f indicate the emergence of Ptuc, reflecting the production of Te vacancies and that the number of Ptuc was increased almost in linear proportion with the Ar+ bombardment time. Our results also show a highly positive correlation between the numbers of decomposed methanol and Ptuc and thus indicate that Ptuc is an active site and the surface reactivity can be manipulated by controlling the number of Ptuc through the Ar+ bombardment treatment.

Keywords: PtTe2, Transition metal dichalcogenides, Methanol decomposition, Surface defects engineering , Photoelectron spectroscopy