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Heterogenized molecular catalysts have shown interesting activities in different chemical transformations. In our previous studies, a molecular catalyst, Re(bpy)(CO)3Cl where bpy is 2,2’-bipyridine, was covalently attached to silica surfaces via an amide linkage for use in photocatalytic CO2 reduction. Derivatizing the bpy ligand with electron-withdrawing amide groups led to detrimental effects on the catalytic activity of Re(bpy)(CO)3Cl. In this study, an alkyl amine linkage is utilized to attach Re(bpy)(CO)3Cl onto SiO2 in order to eliminate the detrimental effects of the amide linkage by breaking the conjugation between the bpy ligand and the amide group. However, the heterogenized Re(I) catalyst containing the alkyl amine linkage demonstrates even lower activity than the one containing the amide linkage in photocatalytic CO2 reduction. Infrared studies suggest that the presence of the basic amine group led to the formation of a photocatalytically inactive Re(I)-OH species on SiO2. Furthermore, the amine group likely contributes to the stabilization of a surface Re(I)-carboxylato species formed upon light irradiation, resulting in the low activity of the heterogenized Re(I) catalyst containing the alkyl amine linkage.
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Breaking the short-range proximity requirement in quantum dot/molecular catalyst hybrids for CO 2 reduction via long-range hot electron sensitization
The efficient light-driven fuel production from homogeneous photocatalytic systems is one promising avenue towards an alternative energy economy. However, electron transfer from a conventional photosensitizer to a catalyst is short-range and necessitates spatial proximity between them. Here we show that energetic hot electrons generated by Mn-doped semiconductor quantum dots (QDs) allow for long-range sensitization of Ni(cyclam)-based molecular catalysts, enabling photocatalytic reduction of CO 2 to CO without requiring chemical linkages between the QDs and catalyst molecules. Our results demonstrate the potential of hot electron sensitization in simplifying the design of hybrid catalyst systems while improving photocatalytic activity.
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- Award ID(s):
- 1804412
- PAR ID:
- 10173587
- Date Published:
- Journal Name:
- Journal of Materials Chemistry A
- Volume:
- 8
- Issue:
- 26
- ISSN:
- 2050-7488
- Page Range / eLocation ID:
- 12984 to 12989
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1039/d0ta05258b
