Nano-on-Micro BiOCl 0.6 Br 0.4 /Zn 3 In 2 S 6 Heterostructure with Prolonged Charge Separation and Exposed Bi Active Sites for Efficient CO 2 Photoreduction

The inefficient dynamics of photogenerated charge carriers and the limited accessibility of active sites remain concurrent challenges for achieving efficient solar-driven CO 2 photoreduction. Herein, a distinct nano-on-micro (NOM) BiOCl 0.6 Br 0.4 /Zn 3 In 2 S 6 heterostructure ( NOM-BZ ) is rationally constructed by precisely anchoring nano-BiOCl 0.6 Br 0.4 onto micro-Zn 3 In 2 S 6 via an in situ seed-growth route. This architecture simultaneously optimizes charge kinetics and surface redox sites, thereby significantly enhancing the CO 2 -to-CO conversion performance. In particular, NOM-BZ exhibits a prolonged average charge lifetime of 3102 ps ( 5-fold higher than pristine ) and abundant electron-rich Bi active sites, especially Bi (3– x )+ species, which efficiently drive CO 2 reduction. In addition, NOM-BZ facilitates CO 2 adsorption and activation and promotes *COOH intermediate formation by lowering the energy barriers, leading to noteworthy activity and long-term stability. This work highlights a robust NOM-engineered heterostructure capable of concurrently modulating charge dynamics and active-site chemistry, offering a promising paradigm for the rational design of next-generation photocatalysts for CO 2 conversion.