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The Diels–Alder (DA) reaction, a classic cycloaddition reaction involving a diene and a dienophile to form a cyclohexene, is among the most versatile organic reactions. Theories have predicted thermodynamically unfavorable DA reactions on pristine graphene owing to its low chemical reactivity. We hypothesized that metals like Ni could enhance the reactivity of graphene towards DA reactions through charge transfer. The results indeed showed that metal substrates enhanced the reactivity of graphene in the DA reactions with a diene, 2,3-dimethoxy butadiene (DMBD), and a dienophile, maleic anhydride (MAH), with the activity enhancement in the order of Ni > Cu, and both are more reactive than graphene supported on silicon wafer. The rate constants were estimated to be two times higher for graphene supported on Ni than on silicon wafer. The computational results support the experimentally obtained rate trend of Ni > Cu, both predicted to be greater than unsupported graphene, which is explained by the enhanced graphene–substrate interaction reflected in charge transfer effects with the strongly interacting Ni. This study opens up a new avenue for enhancing the chemical reactivity of pristine graphene through substrate selection.
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Enhancing the Chemical Reactivity of Graphene through Substrate Engineering
Abstract Covalent functionalization of pristine graphene can modify its properties, enabling applications in optoelectronics, biomedical fields, environmental science, and energy. However, the chemical reactivity of pristine graphene is relatively low, and as such, methods have been developed to increase the reactivity of graphene. This review focuses on substrate engineering as an effective strategy to enhance the reactivity of graphene through strain and charge doping. Nanoparticles, metals with different crystal orientations, and stretchable polymers are employed to introduce strains in graphene, leading to enhanced chemical reactivity and increased degree of functionalization. Charge doping through orbital hybridization with metals and charge puddles induced by oxide substrates generally enhance the reactivity of graphene, while alkyl‐modified surfaces and 2D materials often reduce graphene reactivity via charge screening and van der Waals interactions that increase the stability of the graphene layer, respectively. This review summarizes methods for creating and characterizing strains and charge doping in graphene and discusses their effects on the chemical functionalization of graphene in various reactions.
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- Award ID(s):
- 2305006
- PAR ID:
- 10561293
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Small
- ISSN:
- 1613-6810
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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