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Page 8 of 16 Feng et al. Chem Synth 2023;3:37 https://dx.doi.org/10.20517/cs.2023.26

MULTI-TEMPLATES METHOD
The multi-templates method refers to the simultaneous use of polymer micelles as mesoporous growth
templates and 2D materials as substrate templates during the 2DMMs synthesis process [42,55] . This method is
suitable for the preparation of planar mesoporous nanosheets or sandwich-like mesoporous
heterostructures, which typically depend on the fabrication of mesoporous inorganic/organic layers on 2D
directional substrates [56-58] . Under the force of hydrogen bonding, electrostatic attraction, or coordination
interaction between 2D substrates and inorganic/organic precursors, sandwich-shaped precursor template
composites were first assembled. Subsequently, after specific post processing, a target sandwich-shaped
mesoporous nanosheet is revealed, and a planar mesoporous nanosheet can be observed after clearing away
the 2D template. Remarkably, the mesoporous structures arise from growth vacancies, accumulation of
nanoparticles, and chemical reactions. To date, graphene oxides (GO), hexagonal boron nitride, graphitic
carbon nitride, transitional metal dichalcogenides, layered double hydroxides, and MXene have been proven
to be ideal sacrificial 2D templates for the preparation of in-plane mesoporous nanosheets.

As an example, the synthesis scheme of mesoporous polydopamine/MXene (mPDA/MXene) is described in
Figure 6A . The thickness of the MXene (Ti C T ) nanosheet is about 1.5 nm. The obtained MXene layer
[59]
2 x
3
has polar terminal groups of F, O, and OH, which can be surface-modified. Firstly, the P123 copolymer is
dissolved directly in water to form a cylindrical micellar under 40 C. MXene nanosheets and DA
o
hydrochloride were stirred in the micellar solution. The cylindrical micelles were adsorbed on the surface of
MXene by hydrogen bonds and electrostatic attraction, while the DA monomers were adsorbed on the PEO
crown, resulting in the P123/DA composite micelles being tightly packed on the MXene nanosheets. Then,
by adding ammonia water to initiate the polymerization of DA monomers, a continuous polydopamine
(PDA) network around the P123 template is generated. Finally, the micellar template was removed, and
mPDA/MXene nanosheets with good planar columnar mesoporous can be prepared.

Constructing 2D ordered heterogeneous structures via 2D template methods is an effective way to improve
the application performance of materials [60,61] . Recently, our group synthesized 2D ordered mesoporous
carbon/titanium carbide heterostructures (OMCTs) in an aqueous system using a triblock copolymer
(Pluronic F127) as a template, a low molecular weight phenolic resin as a carbon source, and a Ti C T
2 x
3
nanosheet as an interface [Figure 6B]. The presence of ordered mesoporous carbon can not only inhibit
[62]
the stacking of Ti C T nanosheets but also prevent the oxidation of Ti C T nanosheets at high
x
2
3
3
x
2
temperatures (up to 600 C). The synthesized OMCTs have high specific surface areas, high thermal and
o
mechanical stability, and ordered mesoporous structures. The obtained 2D ordered mesoporous carbon/
MXene heterostructure effectively inhibited the aggregation and oxidation of MXene and improved its
electrochemical performance.
Graphene is an excellent conductive material widely used as a substrate for synthesizing 2DMMs [48,63,64] .
Wang et al. prepared mesoporous nanosheets of polyaniline decorated on graphene (PANI/G) using a 2D
template method. Specifically, PS -PEO micelles were adsorbed on the surface of GO nanosheets by
100
115
[65]
electrostatic adsorption and hydrogen bond force to obtain PS-PEO@GO . Then, ammonium persulfate
was used as an initiator to initiate the polymerization of aniline on the PS-PEO@GO surface to obtain
PANI/PS-PEO@GO. Subsequently, the PS-PEO template was removed by washing with THF. Finally,
ordered mesoporous PANI/G nanosheets were obtained by hydrothermal heat treatment. In particular, the
obtained nanosheets have flat 2D structures, uniform pore structures, transverse sizes of 1-3 μm, and surface
mesoporous about 18 nm.