Dual-Phase Structure through Selective Etching of the Double A-Element MAX Phase in Lewis Acidic Molten Salts

Haoshuai Wei; Lu Chen; Haoming Ding; Youbing Li; Zhifang Chai; Qing Huang

doi:10.1021/acs.jpclett.4c00785

Dual-Phase Structure through Selective Etching of the Double A-Element MAX Phase in Lewis Acidic Molten Salts

J Phys Chem Lett. 2024 Apr 25;15(16):4486-4493. doi: 10.1021/acs.jpclett.4c00785. Epub 2024 Apr 18.

Authors

Haoshuai Wei^{1

2

3}, Lu Chen^{1

2}, Haoming Ding^{1

2}, Youbing Li⁴, Zhifang Chai^{1

2}, Qing Huang^{1

2}

Affiliations

¹ Zhejiang Key Laboratory of Data-Driven High-Safety Energy Materials and Applications, Ningbo Key Laboratory of Special Energy Materials and Chemistry, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201, People's Republic of China.
² Qianwan Institute of CNiTECH, Ningbo, Zhejiang 315336, People's Republic of China.
³ University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China.
⁴ State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X) and Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, Jiangsu 215123, People's Republic of China.

PMID: 38634523
DOI: 10.1021/acs.jpclett.4c00785

Abstract

Two-dimensional (2D) MXene materials with innovative properties and versatile applications have gained immense popularity among scientists. The green and environmentally friendly Lewis acid salt etching route has opened up immense possibilities for the advancement of 2D MXene materials. In this study, we precisely etched the Al element from the double A-element MAX phases Ti₂(Sn_yAl_1-y)C by employing Lewis molten salt guided by redox potentials. This approach led to the discovery of a novel Ti₂Sn_yCCl_x dual-phase structure consisting of Ti₂SnC and Ti₂CCl_x. We then established that the etching of the MAX phase via Lewis acid salt is facilitated by the oxidation of M-site elements, with the MX sublayer acting as an electron transmission conduit to enable the oxidation of A-site elements. This work is dedicated to unraveling the underlying mechanisms governing the etching processes using Lewis molten salt, thereby contributing to a more profound comprehension of these innovative etching routes.