(198r) Encapsulation of Dye in NH2-Uio-66 Metal-Organic Framework for Photosensitized Oxidation of Benzyl Alcohol

Encapsulation of Dye in NH₂-UiO-66 Metal-organic
Framework for Photosensitized Oxidation of Benzyl Alcohol

Xiyi Li, Qingqing Hou,
Neng Liao, Jing Xiao*

Dye-sensitization
has become a relatively mature technology for visible-light harvesting for the
photocatalysts. However, it always suffers from desorption problem during the
photocatalytic reaction which impedes it acts as a sustained and stable photocatalyst.
Our work makes good use of the characteristic during the self-assembly process
of metal-organic framework, synthetizing the RhB@NH₂-UiO-66 to
prevent the leaching of RhB without losing the crystalline lattice, as shown in
Figure 1. The introduction of RhB significantly enhanced the light-absorption
properties, which exhibits a large visible light absorption peak at around 553
nm, as shown in Figure 2. Therefore, in the visible-light-induced aerobic
oxidation of benzyl alcohol, RhB@NH₂-UiO-66 exhibits 3.5 times
higher conversion than the pristine NH₂-UiO-66 without losing the
high selective, as shown in Figure 3. Moreover, the solution after the
photocatalytic oxidation is measured by UV-Vis spectrophotometer to rule out
the leaching of RhB. The mechanism of photocatalytic oxidation is analyzed by
capture experiment and electron paramagnetic resonance, as shown in Figure 4.
This work demonstrates the first example of the encapsulation of dye during the
nucleation of metal-organic framework, which provides a facile and promising
way to the consolidate dye-sensitized photocatalytic system.

Keywords:
RhB@NH₂-UiO-66; photosensitization; photocatalytic oxidation

Figure 1 The XRD pattern of RhB@NH2-UiO-66 and NH2-UiO-66.

Figure 2 The UV-Vis spectra of RhB@NH2-UiO-66 and NH2-UiO-66.

Figure 3 Photocatalytic oxidation of benzyl alcohol in different system. Reaction condition: 15 mg photocatalyst, 3 ml solvent, 0.03 mmol benzyl alcohol, 1 atm O2, and 300 W Xenon lamp >420 nm

Figure 4 The mechanism of photocatalytic oxidation of benzyl alcohol over RhB@NH2-UiO-66