Meso-Microporous Nanosheet-Constructed 3DOM Perovskites for Remarkable Photocatalytic Hydrogen Production

Three-dimensionally ordered macroporous (3DOM) structures have been widely utilized to largely enhance a photocatalytic activity. However, the common nanoparticles-constructed 3DOM photocatalysts possess numerous grain boundaries, unavoidably leading to a fast recombination of photogenerated electrons and holes. Herein, for the first time, a hierarchically two-dimensional (2D) meso-microporous perovskite nanosheet-constructed 3DOM CaTiO₃ to significantly reduce the grain boundaries is designed and fabricated. Using carbon quantum dots (CQDs) as a metal-free co-catalyst, the 3DOM CQDs-CaTiO₃ exhibits an outstanding photocatalytic activity for hydrogen generation of 0.13 mmol h⁻¹ (20 mg photocatalyst) with remarkable apparent quantum efficiency (QAY) of 14.55% at 365 nm monochromatic light. This unprecedented performance is endowed by the synergy of a macro-meso-microporosity architecture, a large surface area, enhanced light harvesting, and improved charge carriers separation and transport. Density functional theory calculations and finite difference time-domain simulations further reveal the mechanism behind the enhanced separation of photogenerated electrons and holes. The present work demonstrates a trial on rationally designing meso-microporous nanosheet-constructed 3DOM perovskites for solar driven hydrogen production.