Fast Photoelectron Transfer in (Cring)–C₃N₄ Plane Heterostructural Nanosheets for Overall Water Splitting

Direct and efficient photocatalytic water splitting is critical for sustainable conversion and storage of renewable solar energy. Here, we propose a conceptual design of two-dimensional C₃N₄-based in-plane heterostructure to achieve fast spatial transfer of photoexcited electrons for realizing highly efficient and spontaneous overall water splitting. This unique plane heterostructural carbon ring (Cring)-C₃N₄ nanosheet can synchronously expedite electron-hole pair separation and promote photoelectron transport through the local in-plane π-conjugated electric field, synergistically elongating the photocarrier diffusion length and lifetime by 10 times relative to those achieved with pristine g-C₃N₄. As a result, the in-plane (Cring)-C₃N₄ heterostructure could efficiently split pure water under light irradiation with prominent H₂ production rate up to 371 μmol g⁻¹ h⁻¹ and a notable quantum yield of 5% at 420 nm.