  Two-dimensional (2D) nanomaterials derived from non-van der Waals solids are
promising due to their fantastic physical and chemical properties, but it
remains challenging to obtain 2D atomic laminates with high stability owing to
the strong intrinsic covalent/metallic bonds and highly exposed active surface.
Here, we report a versatile and scalable protocol to produce 2D atomic
laminates, based on an unexpected topological transformation of MAX phases
under hydrogen chloride gas, and/or subsequent reconstruction under some
programmed gases/vapors. In contrast to the known approaches with liquid or
molten medium, our method involves in a gas-phase reaction with fast
thermodynamics for A layers and positive Gibbs free energies for MX slabs.
Remarkably, through subsequent reconstruction in some active gases/vapors (O2,
H2S, P, CH4, Al and Sn metal vapors), a big family of 2D atomic laminates with
elusive configurations as well as high chemical/thermal stabilities and tunable
electrical properties (from metallic to semiconductor-like behaviors) are
achieved. Moreover, the resultant 2D atomic laminates can be facilely scaled up
to 10 kilograms. We believe that the 2D atomic laminates would have broad
applications in catalysis, energy storage, electromagnetic shielding interface
and microwave absorption.
