Abstract
The primary amine groups on the heptazine-based polymer melon, also known as graphitic carbon nitride (g-C3N4), can be replaced by urea groups using a two-step postsynthetic functionalization. Under simulated sunlight and optimum Pt loading, this urea-functionalized carbon nitride has one of the highest activities among organic and polymeric photocatalysts for hydrogen evolution with methanol as sacrificial donor, reaching an apparent quantum efficiency of 18% and nearly 30 times the hydrogen evolution rate compared to the nonfunctionalized counterpart. In the absence of Pt, the urea-derivatized material evolves hydrogen at a rate over four times that of the nonfunctionalized one. Since defects are conventionally accepted to be the active sites in graphitic carbon nitride for photocatalysis, the work here is a demonstrated example of defect engineering, where the catalytically relevant defect is inserted rationally for improving the intrinsic, rather than extrinsic, photocatalytic performance. Furthermore, the work provides a retrodictive explanation for the general observation that g-C3N4 prepared from urea performs better than those prepared from dicyandiamide and melamine. In-depth analyses of the spent photocatalysts and computational modeling suggest that inserting the urea group causes a metal-support interaction with the Pt cocatalyst, thus facilitating interfacial charge transfer to the hydrogen evolving centers.
Item Type: | Journal article |
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EU Funded Grant Agreement Number: | 639233 |
EU Projects: | Horizon 2020 > ERC Grants > ERC Starting Grant > ERC Grant 639233: Fuel from sunlight: Covalent organic frameworks as integrated platforms for photocatalytic water splitting and CO2 reduction |
Faculties: | Chemistry and Pharmacy > Department of Chemistry |
Research Centers: | Center for NanoScience (CENS) |
Subjects: | 500 Science > 540 Chemistry 500 Science > 500 Science |
URN: | urn:nbn:de:bvb:19-epub-54167-2 |
ISSN: | 1614-6832 |
Language: | English |
Item ID: | 54167 |
Date Deposited: | 14. Jun 2018, 09:55 |
Last Modified: | 25. Nov 2020, 11:46 |