Ultrathin Hf-MOF with Dinitrogen Chelating Sites Stabilizing and Inducing Generation of Single-Rod Cs 3 Bi 2 Br 9 Nanocrystals for Efficient Photocatalytic CO 2 Reduction

作者：Ren Ma, Tianyu Wang, Baoyin Qian, Zhengqiang Xia, Sirong Chen, Sirong Chen, Weiliang Shi, Qibin Yang, Gang Xie, Sanping Chen, Sanping Chen · 发表于：Journal of the American Chemical Society · 年份：2025 · DOI：10.1021/jacs.5c08000 · 被引用次数：14 · 研究领域：Perovskite Materials and Applications、Advanced Photocatalysis Techniques、Metal-Organic Frameworks: Synthesis and Applications

The ordered growth of semiconductor quantum dots (QDs) in confined environments remains a critical challenge in photocatalysis. Herein, Cs 3 Bi 2 Br 9 (CBB) QDs were covalently anchored as single-rod nanocrystals (SRNCs) within Hf-based metal–organic framework (MOF) nanosheets (Hf 12 -bpy, H 2 bpy = 2,2′-bipyridine-5,5′-dicarboxylic acid), forming a series of host–guest photocatalysts CBB@Hf 12 -bpy. By modulation of the thickness of MOF nanosheets, the length of CBB SRNCs was effectively shortened to 18 nm, exhibiting strong quantum confinement effects. Mechanistic studies reveal that the bpy-CBB dual-nitrogen chelation effect induces a discrete distribution of CBB within Hf 12 -bpy pores, and the well-matched interlayer spacing of H 2 bpy (7.95 Å ≈ d Bi···Bi ) guides the anisotropic growth of CBB along the [001] direction into SRNCs. Such a long-range-ordered SRNC architecture significantly improves the bulk-to-surface charge separation efficiency, enabling ultrafast electron supply (average charge excitation rate: 5.320 mV). Additionally, the chelated N–Bi–N moieties work as covalent electron-transfer bridges to markedly reduce charge-transfer resistance (7.75 Ω) and interfacial charge-transfer barriers (100.5 meV), accelerating interfacial charge migration kinetics. These synergistic advantages endow CBB@Hf 12 -bpy(18 nm) with an exceptional electron accumulation rate (1.54 g –1 ·min –1 ) and record-breaking CO 2 -to-CO conversion efficiency (15,982.1 μmol·g –1 ·h –1 ) wi...