Tuning 2D perovskite–graphene layered composite for photocatalysis

The augmentation of photocatalytic activity in layered perovskite oxides via the integration of graphene-like materials presents a promising pathway for the optimization of solar energy conversion. The electron-rich nature of graphene, coupled with its high electron conductivity, functions as an effective photosensitizer, thereby enhancing visible light harvesting. In this investigation, we have, for the first time, assembled ultrathin exfoliated Dion–Jacobson perovskite layers with reduced graphene oxide (rGO) layers, resulting in a high surface area layered nanocomposite, achieved through a tailored electrostatic approach. To further refine the electron properties of the layered perovskite–reduced graphene oxide composites, we have explored the use of various lanthanides as A-site cations in the Dion–Jacobson perovskites, including LaNb₂O₇ (LNO), PrNb₂O₇ (PNO), and NdNb₂O₇ (NNO). The synthesized composites demonstrate exceptional performance in photocatalytic H₂ production, with rGO/NNO exhibiting the highest activity, achieving a hydrogen evolution rate (HER) of 835 μmol g⁻¹ under light illumination, attributable to optimal interfacial effects. Our experimental and theoretical analyses indicate that hydrogen production is predominantly influenced by the A-site cation charge density at the materials' interface, as dictated by the charge transfer dynamics. This research potentially contributes to the comprehension and enhancement of photocatalytic processes for applications in solar energy conversion.