The synergy of active sites induced by surface pits in BiOCl nanoplates for efficient CO2 photoreduction

Abstract

Two-dimensional semiconductors are extensively discussed materials for photocatalytic reactions; however, their active sites originate from in-plane surface pits (SPs), and understanding their underlying mechanism remains challenging. Herein, unique BiOCl nanoplates with SP (BiOCl-SP) are developed via a non-rapid synthetic route for CO2 photoreduction. Unlike conventional photocatalysts, owing to SP, BiOCl-SP features multiple active sites, including spatially separated and coordinatively unsaturated sites disclosed by kinks and atomic steps, super-exposed sublayer lattices with order/disorder symmetry, and Bi-oxygen defects associates. The synergy of active sites in BiOCl-SP enables accelerated charge separation/transfer to the surface with hampered recombination. Consequently, BiOCl-SP exhibits a remarkable CO production rate of 89.72 μmol·g−1·h−1 with excellent stability/reproducibility in a period of 30 h CO2 photoreduction, in pure water without introducing any sacrificial agents or co-catalysts. Notably, the activity of BiOCl-SP outperforms a series of pit-free state-of-the-art photocatalysts, and promisingly, our synthetic approach is scalable and applicable to BiOBr and BiOI photocatalysts. This work highlights cost-effective pit engineering in bismuth-based materials to achieve efficient photocatalysis and motivates exploring other pits-confined materials for practical applications.