Facile Synthesis of Ti2AC (A = Zn, Al, In, and Ga) MAX Phases by Hydrogen Incorporation into Crystallographic Voids

Yangfan Lu; Mohammad Khazaei; Xinmeng Hu; Rasoul Khaledialidusti; Masato Sasase; Jiazhen Wu; Hideo Hosono

doi:10.1021/acs.jpclett.1c03149

Facile Synthesis of Ti₂AC (A = Zn, Al, In, and Ga) MAX Phases by Hydrogen Incorporation into Crystallographic Voids

J Phys Chem Lett. 2021 Nov 25;12(46):11245-11251. doi: 10.1021/acs.jpclett.1c03149. Epub 2021 Nov 11.

Authors

Yangfan Lu^{1

2

3}, Mohammad Khazaei^{1

4}, Xinmeng Hu⁵, Rasoul Khaledialidusti⁶, Masato Sasase¹, Jiazhen Wu^{5

7}, Hideo Hosono¹

Affiliations

¹ Materials Research Center for Element Strategy, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
² College of Materials Science and Engineering, Chongqing University, Chongqing 400030, P.R. China.
³ National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400030, P.R. China.
⁴ Department of Physics, University of Tehran, North Kargar Avenue, Tehran 14395-547, Iran.
⁵ Department of Materials Science and Engineering, Southern University of Science and Technology, Guangdong 518055, P.R. China.
⁶ Department of Mechanical and Industrial Engineering, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway.
⁷ Guangdong Provincial Key Laboratory of Functional Oxide Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, Guangdong, P.R. China.

PMID: 34762437
DOI: 10.1021/acs.jpclett.1c03149

Abstract

While using hydride precursors, such as TiH₂, can promote the formation of some MAX phases, the mechanism for this stabilization effect by hydrogen has been unsolved. Herein, we report a facile synthesis method of Ti₂AC (A = Zn, Al, In, and Ga) MAX phases using hydrogen as the phase stabilizer at their crystallographic voids. DFT calculations revealed that hydrogen could be incorporated in the center of the Ti₃A (A = Zn, Al, Ga, and In) cages of Ti₂AC MAX phases. The hydrogen is accommodated as an anion as a result of electron transfer from the surrounding Ti and A to H, leading to the stabilized state through Coulomb interaction between (Ti₃A)^δ+ and H^-. Consequently, high-purity Ti₂AC (A = Zn, Al, Ga, and In) was directly synthesized under pressure-less and milder temperature conditions by simply employing TiH₂ as the precursor. These findings indicate that utilizing hydrogen could be one of the experimental parameters to facilitate the formation of materials having crystallographic voids.