Amorphous 2D materials containing a conjugated-polymer network

Abstract

Two-dimensional materials, such as layered compounds and nanosheets, have attracted interest for their characteristic structures and properties. If layered materials containing functional organic molecules are synthesized, designed nanosheets can be obtained by exfoliation. Here we show the design and synthesis of an amorphous organic layered material containing a conjugated-polymer network, its exfoliation into nanosheets, and their applications. Copolymerization of benzoquinone and pyrrole generates random stacks of the conjugated polymer layers through successive CC bond formation and pericyclic reaction under mild conditions at 60°C. The amorphous organic layered materials are efficiently exfoliated into nanosheets in 44.6% after 1 h. The nanosheets are used as a metal-free electrocatalyst for hydrogen evolution reaction with the overpotential 0.28 V (vs. RHE). The present approach may be applied to the design of functional nanosheets with graphenelike structures under mild conditions.

Amorphous flexible covalent organic networks containing redox-active moieties: a noncrystalline approach to the assembly of functional molecules

“…A similar broadened peak was observed for commercial glassy carbon (GC) and a BQ-Py network polymer (Fig. 4a), 28 whereas GO had a sharpened peak. The lattice spacing around d ¼ 0.356 nm (2q ¼ 25 ) corresponds to the weak periodicities of the stacked graphitic domains.…”

“…Our previous studies indicated that DLS peak appeared with formation of nanostructures after the exfoliation in dispersion media. 28 , 44 The lattice fringes were not observed on the high-resolution TEM (HRTEM) images (Fig. S7 in the ESI † ).…”

“…2a). 28 In contrast, the weight loss was observed below 300 C for the monomers except DAT (Fig. S2 in the ESI †).…”

“…[7][8][9][10][11] Our previous work suggested that low-crystalline stacking states with more exibility have an advantage for smooth exfoliation into nanostructures, such as twodimensional (2D) amorphous network polymers. 28 In the present work, the pristine low-crystalline stackings of new three-dimensional (3D) amorphous network polymers were exfoliated into nanostructures for their applications.…”

Formation processes, size changes, and properties of nanosheets derived from exfoliation of soft layered inorganic–organic composites

“…This exfoliation method has potential for synthesis of nanosheets with controlled yield, size, and surface chemistry. [29][30][31][32][33][34][35][36][37] The exfoliation behavior can be changed with different combinations of interlayer guests and dispersion media. However, the exfoliation processes and stability of the resultant nanosheets have not been fully studied in previous work.…”