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

Shahid, Malik Zeeshan; Zhang, Xinlei; Su, Qiwen; Xu, Minghua; Ruan, Xiaowen; Zhang, Wei; Leng, Jing; Zhang, Lei et al. · Nano Lett · 2026

basic_science · Level V

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Abstract

The inefficient dynamics of photogenerated charge carriers and the limited accessibility of active sites remain concurrent challenges for achieving efficient solar-driven CO<sub>2</sub> photoreduction. Herein, a distinct nano-on-micro (NOM) BiOCl<sub>0.6</sub>Br<sub>0.4</sub>/Zn<sub>3</sub>In<sub>2</sub>S<sub>6</sub> heterostructure (<i>NOM-BZ</i>) is rationally constructed by precisely anchoring nano-BiOCl<sub>0.6</sub>Br<sub>0.4</sub> onto micro-Zn<sub>3</sub>In<sub>2</sub>S<sub>6</sub> via an <i>in situ</i> seed-growth route. This architecture simultaneously optimizes charge kinetics and surface redox sites, thereby significantly enhancing the CO<sub>2</sub>-to-CO conversion performance. In particular, NOM-BZ exhibits a prolonged average charge lifetime of 3102 ps (<i>5-fold higher than pristine</i>) and abundant electron-rich Bi active sites, especially Bi<sup>(3-<i>x</i>)+</sup> species, which efficiently drive CO<sub>2</sub> reduction. In addition, NOM-BZ facilitates CO<sub>2</sub> 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<sub>2</sub> conversion.