Bottom-up wet-chemical synthesis of a two-dimensional porous carbon material with high supercapacitance using a cascade coupling/cyclization route

Wet-chemical bottom-up synthesis methods for two-dimensional (2D) layered materials are less explored than the top-down exfoliation of bulk materials. Here, we set out to synthesize a graphyne-type material by a wet-chemical synthesis method using Sonogashira-Hagihara cross-coupling polycondensation of a multifunctional monomer,2, bearing alkyne and vinyl bromide functionalities. Spectroscopic and chemical analysis revealed that upon C-C bond formation, an unanticipated Bergman cyclization occurred to give an aromatic 2D porous carbon material (2D-PCM).2D-PCMis a black material with graphene-like layers and a bulk structure that is similar to irregular graphite. It is porous with a hierarchical pore structure and an apparent Brunauer-Emmett-Teller surface area of 575 m²g⁻¹. The material has excellent electrochemical performance as an electrode in supercapacitors with a specific capacitance of 378 F g⁻¹at the current density of 0.1 A g⁻¹, which surpasses state-of-the-art carbon materials, suggesting that wet-chemical methods might give functional benefits over top-down processing routes.