The properties of graphene, including a high intrinsic mobility [1, 2], a large theoretical specific surface area, and a high chemical stability, are potentially useful in
applications ranging from chemical sensors to transistors [3–8]. Toward exploiting GDC 0032 these unique properties of graphene, several research groups have attempted to fabricate large-scaled graphene oxide sheets [9–12]. Graphene oxide (GO) is a layered material consisting of hydrophilic oxygenated graphene oxide sheets bearing oxygen functional groups on their basal planes and edges . It is a useful platform for fabricating functionalized graphene that can potentially confer improved mechanical, thermal, or electronic properties. The numerous chemical functionalities on a GO surface are expected to readily lend themselves to further chemical click here functionalization. Graphene-based materials, therefore, show promise in a variety of technological applications. The use of GO surfaces as catalysts of synthetic transformations is a relatively new research area
with outstanding potential. Current efforts are directed toward harnessing the oxygen carriers present on GO surfaces as heterogeneous catalysts [14–16]. In this study, we systematically compared and investigated the oxidation of aniline to form azobenzene on monolayer graphene (EG) or graphene-oxide-like (GOx) surfaces fabricated with benzoic acid. Moreover, we focus on examining the difference between EG and GOx surfaces in one substrate, simultaneously.
Raman spectroscopy and high-resolution photoemission spectroscopy (HRPES) were used to characterize the surface-bound products. The carboxyl groups introduced onto the graphene surface upon oxidation Y-27632 2HCl by benzoic acid to GOx allowed aniline to react with the oxygen carriers. The oxidation of aniline proceed via a reaction between the aniline amine groups and the oxygen groups on the GOx surface under ultra-high vacuum (UHV) conditions maintaining a 365-nm UV light Captisol exposure. Generally, it is hard to distinguish the difference between EG and GOx surfaces in one substrate due to the large size of the HRPES beam. Hence, no previous systematic experimental studies have examined the oxidation of aniline on a GOx surface. However, this study is meaningful with regards to indicating this distinctive difference using the feature of micro Raman spectroscopy. Methods A Si-terminated 6H-SiC(0001) substrate (Cree Research, Durham, NC, USA) was used to fabricate EG. The substrate was degassed, annealed at 1,200 K under a Si flux (1 Å/min), and graphitized at temperatures up to 1,500 K (for 2 min) to produce a monolayer of graphene (EG). The annealing temperature was monitored using an infrared pyrometer (with an emissivity of 0.9). A GOx surface was fabricated by exposing the EG surface to benzoic acid (Sigma Aldrich, purity, 97%, St. Louis, MO, USA).