Transition-metal dichalcogenide NiTe2: an ambient-stable material for catalysis and nanoelectronics

Transition-metal dichalcogenides hosting topological states have potential implications for catalysis and nanoelectronics. The chemical reactivity and ambient stability of NiTe2 has been investigated in order to assess the suitability of technology transfer.

Advanced Functional Materials Volume30, Issue22 2000915 (2020) doi: 10.1002/adfm.202000915 


Recently, transition-metal dichalcogenides hosting topological states have attracted considerable attention for their potential implications for catalysis and nanoelectronics. The investigation of their chemical reactivity and ambient stability of these materials is crucial in order to assess the suitability of technology transfer. With this aim, an international team of researchers from Italy, Russia, China, USA, India, and Taiwan has studied physicochemical properties of NiTe2 by means of several experimental techniques and density functional theory. Surface chemical reactivity and ambient stability were followed by x-ray photoemission spectroscopy (XPS) and x-ray absorption spectroscopy (XAS) experiments at the BACH beamline
High-resolution XPS spectra of Ni-3p and Te-4d core levels for the as-cleaved NiTe2 and the same surface modified by the exposure to 2·104 L of CO, H2O and O2 are reported in Fig. 1. Specifically, the Ni-3p (Fig. 1a) core level was recorded at a binding energy (BE) of 66.8 (J=3/2) and 68.5 (J=1/2) eV. No change was observed upon CO dosage, thus proving the absence of CO poisoning, confirmed by vibrational experiments by high-resolution electron energy loss spectroscopy. Upon O2exposure, the intensity of the Ni-3p level was reduced by 42% with the emergence of a new doublet with a J=3/2 component at 67.6 eV, which is associated with Ni(II) species, evidently related to Ni-O bonds. Correspondingly, the Te-4d (Fig. 1b) core level for as-cleaved NiTe2 showed two doublets with J=5/2 components at 39.9 and 40.1 eV, which arise from surface and bulk contributions, respectively. The NiTe2 surface did not show any reactivity toward H2O and CO, enabling the possibility to fabricate CO-tolerant electrodes for electrocatalysis, which would be stable in an aqueous environment. Conversely, the Te-4d spectrum drastically changed after O2 exposure, which induces oxidation of Te.

Figure 1.    a) Ni-3p and b) Te-4d XPS core-level spectra collected from as-cleaved NiTe2 (black curves) and from the same surface exposed to 2·10L of CO (red curves), H2O (green curves) and O2 (blue curves). Adapted from "S. Nappini et al., Adv. Funct. Mater. 30, 2000915 (2020); DOI: 10.1002/adfm.202000915" with permission from Wiley (Copyright 2020) with license 4873681106527


The as-cleaved NiTe2 was also directly exposed to the atmosphere with the aim to assess its ambient stability. Ni-3p and Te-4d core-level spectra were measured as a function of exposure time to the atmosphere to study the aging of NiTe2. A passivation layer of TeO2 with a thickness ~7 Å was formed after only 5 minutes of air exposure and it saturates after 30 minutes. 

This research was conducted by the following research team:

Silvia Nappini1, Danil W. Boukhvalov2,3, Gianluca D’Olimpio4, Libo Zhang5, Barun Ghosh6, Chia-Nung Kuo7, Haoshan Zhu8, Jia Cheng9, Michele Nardone4, Luca Ottaviano4, Debashis Mondal1, Raju Edla1, Jun Fuji1, Chin Shan Lue7, Ivana Vobornik1, Jory Yarmoff8, Amit Agarwal6, Lin Wang5, Lixue Zhang9, Federica Bondino1, and Antonio Politano4,10

Consiglio Nazionale delle Ricerche (CNR)- Istituto Officina dei Materiali (IOM) , Trieste, Italy

College of Science, Institute of Materials Physics and Chemistry, Nanjing Forestry University, Nanjing, P. R. China
Theoretical Physics and Applied Mathematics Department, Ural Federal University,  Ekaterinburg, Russia 
Department of Physical and Chemical Sciences, University of L’Aquila, L’Aquila , Italy
State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, China
Department of Physics, Indian Institute of Technology Kanpur, India
Department of Physics, National Cheng Kung University, Tainan, Taiwan
Department of Physics and Astronomy, University of California, Riverside, United States
College of Chemistry and Chemical Engineering, Qingdao University, Shandong, China
10 CNR-IMM Istituto per la Microelettronica e Microsistemi, Catania, Italy

Contact persons:

Antonio Politano, e-mail:;
Silvia Nappini, e-mail:
Federica Bondino, e-mail:

Transition-Metal Dichalcogenide NiTe2: An Ambient-Stable Material for Catalysis and Nanoelectronics
Advanced Functional Materials (2020) 
doi: 10.1002/adfm.202000915 (Journal Article)

Last Updated on Friday, 02 October 2020 20:28