Achieving remarkable charge transfer through the depolarization field in the 2D/2D S-scheme heterojunction consisted of C3N5 nanosheets and layered ferroelectric Bi3TiNbO9 for photocatalytic hydrogen production

One appealing approach to achieving high photocatalytic activity in the hydrogen evolution process is the logical design of step-scheme (S-scheme) heterojunctions in hybrid semiconductors by creating the predicted routes. In this work, a 2D/2D S-scheme heterojunction was constructed by a 2D nanosheet-like C₃N₅ and layered ferroelectric Bi₃TiNbO₉ (BTNO), which exhibits improved photocatalytic performance under simulated sunlight. Notably, the engineered 50 %-C₃N₅/BTNO catalyst exhibits superior performance than that of the pure C₃N₅ and BTNO with an H₂ evolution rate of up to 3607μmol g⁻¹h⁻¹ and an apparent quantum efficiency of 6.42 % at 420 nm. The remarkable activity in photocatalytic H₂ evolution of C₃N₅/BTNO could be attributed to the efficient intralayer separation of photogenerated carriers motivated by a depolarization field and the strong internal electric field motivated by the construction of S-scheme heterojunction. The coupling effect of the built-in electric field at the S-scheme C₃N₅/BTNO heterojunction interface and the depolarization field across BTNO promote the desired spatial separation of carriers by facilitating the anisotropic migration of photogenerated electrons and holes to the lateral {110} facet and basal {001} facet of the 2D BTNO nanosheets (NSs) based on the results of simulation calculation, respectively. Therefore, ferroelectric S-scheme heterojunction photocatalysts were achieved with great efficiency by utilizing the C₃N₅ in conjunction with BTNO ferroelectric photocatalyst to obtain an effective and long-lasting photocatalytic activity.