第一作者：南京理工大学 狄俊
通讯作者：南京理工大学 狄俊, 北京大学周鹏, 南洋理工大学 刘政
DOI：https://doi.org/10.1021/acscatal.4c04407
精确设计催化中心的原子配位结构是降低CO2光还原能垒的迫切需要。本研究表明，将Nb单原子耦合Bi-O空位对（VBi-O）工程引入Bi24O31Br10 （BOB）原子层可以产生优先的局部不对称结构。超快瞬态吸收光谱证明，这种结构可以产生更强的局部极化电场，从而延长载流子寿命。同时，这种独特的Nb SA-VBi-O缔合物有利于键*COOH中间体与催化中心之间形成强的化学相互作用，从而降低了限速步骤的能垒。利用这些特性，在纯水条件下，Nb SA-VBi-O BOB原子层光还原CO2的CO生成速率高达76.4 μmol g-1 h-1，分别是BOB原子层和本体BOB原子层的5.4倍和92.7倍。这项工作揭示了设计单原子耦合缺陷复合物以优化光催化性能的重要范例。
Figure 1. (a) Illustration of the formation process of Nb SA-VBi−O BOB, (b) TEM image of Nb SA-VBi−O BOB, (c,d) HAADF-STEM images of Nb SA-VBi−O BOB, (e) intensity profile corresponding to the dark cyan arrow in (d), and (f) EDS elemental mapping of Nb SA-VBi−O BOB.
Figure 2. (a) Synchrotron radiation Nb K-edge XAFS, (b) EXAFS spectra of Nb K-edge, (c) Bi L1-edge XAFS, and (d) EXAFS spectra of Bi L1-edge. (e) Positron annihilation lifetime spectrum. (f,g) Schematic representations of trapped positrons of Nb SA-VBi−O BOB and BOB, respectively.
Figure 3. (a) Time course for CO evolution over BOB materials in photocatalytic CO2 reduction, (b) cycle performances of Nb SA-VBi−O BOB, and (c) GC−MS analysis of reaction products over Nb SA-VBi−O BOB with 13CO2 as feedstock. Ultrafast transient absorption spectroscopy of (d,e) BOB and (f,g) Nb SA-VBi−O BOB. (h) STEM images of Nb SA-VBi−O BOB after cycles, scale bar 2 nm; (i) intensity profile corresponding to the dark cyan arrow in (h).
Figure 4. (a) In situ FTIR spectra for the CO2 photoreduction process over Nb SA-VBi−O BOB. (b) CO TPD spectra of BOB and Nb SA-VBi−O BOB. (c) PDOS of Bi 6p and Nb 4d states in BOB and Nb SA-VBi−O BOB. Dashed line stands for the Fermi level. (d) Free energy profile ofCO2 reduction on BOB and Nb SA-VBi−O BOB at pH = 7 and U = 0 V vs SHE. Charge density difference mappings between *COOH intermediate and catalyst surface: (e) BOB and (f) Nb SA-VBi−O BOB. Sky blue and yellow isosurfaces stand for the negative and positive charges, respectively. Isosurface charge density is set to 0.002 e Å−3.
Asymmetric Associate Configuration of Nb Single Atoms Coupled Bi−O Vacancy Pairs Boosting CO2 Photoreduction
https://doi.org/10.1021/acscatal.4c04407
