Two‐Dimensional Metal Halide Perovskite Nanosheets for Efficient Photocatalytic CO₂ Reduction

Metal halide perovskite (MHP) nanocrystals (NCs) have attained ever‐increasing attention in the field of artificial photosynthesis, due to their desirable strong light‐harvesting capacity and long lifetime of photogenerated carriers. However, the well‐known inherent instability and inferior activity of MHP NCs limit their application foreground in photocatalysis. Herein, a series of 2D MHP nanosheets have been synthesized based on a facile approach at room temperature. These 2D materials are used as photocatalysts for the photocatalysis of CO₂ reduction without any organic sacrificial agents, which display significantly improved stability compared to traditional MHP NCs in water‐contained reaction system. More importantly, benefitting from the large proportion of low‐coordinated metal atoms and short carrier diffusion distance, these MHP nanosheets exhibit a remarkably increased performance for photocatalytic CO₂ reduction. The judicious modulation of halide component endows the MHP nanosheets with a highest electron consumption rate of 87.8 μmol g⁻¹ h⁻¹ among the reported pure MHP catalysts for photocatalytic CO₂ conversion, which is over seven times higher than that of traditional MHP NCs.