Abstract:

Intercalated layered materials are usually produced by inserting guest species into the van der Waals (vdW) gaps of inherently layered materials such as graphite, hexagonal boron nitride (hBN), and transition metal dichalcogenides. The guest-host interaction alters the electronic structure and enables property tailoring for energy storage, catalysis, electronic, optical, and magnetic properties. Intercalation in non-van der Waals (non-vdW) nanolaminated materials and their two-dimensional (2D) derivatives is, however, rare and lacks understanding of the chemistry and structural tunability involved. Here, we show a structural editing protocol for non-vdW layered ternary carbides and nitrides (known as MAX phases) and their vdW multilayer derivatives (MXenes). Gap-opening and species-intercalating stages are separately mediated by chemical scissors and guest intercalants, respectively. A large family of 3D MAX phases with unconventional components and structures as well as 2D MXenes with versatile termination species, is accomplished. Moreover, a reverse transformation from 2D MXenes to 3D MAX phases is realized through knockout of surface termination species by metal scissors and stitching of ceramic slabs by zero-valence metal atoms. This scissor-mediated structural editing would enable structural and chemical tailoring in a broad class of layered ceramics even non-layered materials. When delicately controlling stoichiometry of metal chlorides, two-dimensional rare-earth metal carbides with chlorin termination can be obtained, showing promising magnetic and semiconductive behaviors.

Qing Huang, Professor, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Science. He pursued degrees in Tianjin University from 1995 to 2002; and obtained bachelor degree in inorganic non-metallics and master degree in materials science. From 2002 to 2005, he studied in Shanghai Institute of Ceramics, CAS; and obtained his PhD in materials physics and chemistry. During 2005 to 2010, he carried out post-doctoral research at National Institute for Materials Science, Japan and University of California Davis, USA. In 2010, he joined Ningbo Institute of Materials Technology and Engineering, and focused on the developments and applications of energy materials under extreme environments including the layered materials (MAX phases and MXenes) and silicon carbide composites for high-safety energy systems.