Giant Electron–Hole Interactions in Confined Layered Structures for Molecular Oxygen Activation

Abstract

Numerous efforts have been devoted to understanding the excitation processes of photocatalysts, whereas the potential Coulomb interactions between photogenerated electrons and holes have been long ignored. Once these interactions are considered, excitonic effects will arise that undoubtedly influence the sunlight-driven catalytic processes. Herein, by taking bismuth oxyhalide as examples, we proposed that giant electron-hole interactions would be expected in confined layered structures, and excitons would be the dominating photoexcited species. Photocatalytic molecular oxygen activation tests were performed as a proof of concept, where singlet oxygen generation via energy transfer process was brightened. Further experiments verify that structural confinement is curial to the giant excitonic effects, where the involved catalytic process could be readily regulated via facet-engineering, thus enabling diverse reactive oxygen species generation. This study not only provides an excitonic prospective on photocatalytic processes, but also paves a new approach for pursuing systems with giant electron-hole interactions.

Photoinduced Defect Engineering: Enhanced Photothermal Catalytic Performance of 2D Black In2O3−x Nanosheets with Bifunctional Oxygen Vacancies

“…Second, to investigate another function of oxygen vacancies working as active sites, we carried out temperature programmed desorption (TPD‐CO 2 ) analysis on In 2 O 3− x nanosheets (Figure b) . The peak at 410 °C is attributed to CO 2 adsorption on the photoinduced oxygen vacancy sites .…”

Different Atomic Terminations Affect the Photocatalytic Nitrogen Fixation of Bismuth Oxybromide: A First Principles Study

“…have discovered that a high concentration of excess electrons can greatly improve the charge transportation and suppress the recommendation rate of photogenerated electron‐hole pairs . In addition, Bi‐ter BiOBr {001} facets could be suitable for the photocatalytic molecular oxygen activation due to the enormous excitonic effects . There are OV‐induced defect states localized in the middle of the forbidden band of the O‐ter+H facet with OVs (Figure d), and the defect states are mainly composed of the Bi 6 p orbital (Figure d).…”

“…As displayed in Figure , the (2×2) supercell was employed to simulate the BiOBr {001} facets with different atomic terminations . To test the thickness of the atomic layers of the slabs, the (1×1) surface was applied to all the models, and the thicknesses of slabs adopted in this paper are sufficient to reach the convergence for the cleavage energy (Table S1).…”

“…Xie et al. have reported that Bi‐ter {001} facets could be applied to the photocatalytic molecular oxygen activation and dye degradation . According to the work of Dai et al., there were five possible structures for Bi‐ter {001} facets, of which the Bi−Cl slab was the energetically most favorable structure and the next configuration was the Bi−Bi structure .…”

“…Recently, Xie et al. have verified the enormous excitonic effects that existed in Bi‐ter BiOBr {001} facets could greatly influence the photocatalytic molecular oxygen activation behaviors …”