The richly functionalized basal plane bonded to polar organic moieties makes graphene oxide (GO) innately hydrophilic. Here, a methodology to synthesize fluorinated graphene oxide by oxidizing the basal plane of fluorinated graphite, allowing for tunable hydrophobicity of GO, is reported. Fluorine exists as tertiary alkyl fluorides covalently bonded to graphitic carbons, and using magic‐angle spinning (MAS) 13C NMR as a primary tool chemical structures for the two types of synthesized fluorinated graphene oxides (FGOs) with significantly different fluorine contents are proposed. The low surface energy of the C–F bond drastically affects GO's wetting behavior, leading to amphiphobicity in its highly fluorinated form. Ease of solution processing enables the fabrication of inks that are spray‐painted on various porous/non‐porous substrates. These coatings maintain amphiphobicity for solvents with surface tensions down to 59 dyn/cm, thus bypassing existing lithographic means to create similar surfaces. The approach towards fluorinating GO and fabricating graphene‐based surfaces with tunable wettability opens the path towards unique, accessible, carbon‐based amphiphobic coatings.
The metal–support interactions of titanium dioxide
decorated
silicon carbide (β-SiC)-supported cobalt catalyst for Fischer–Tropsch
synthesis (FTS) were explored by a combination of energy-filtered
transmission electron microscopy (EFTEM), 59Co zero-field
nuclear magnetic resonance (59Co NMR), and other conventional
characterization techniques. From the 2D elemental maps deduced by
2D EFTEM and 59Co NMR analyses, it can be concluded that
the nanoscale introduction of the TiO2 into the β-SiC
matrix significantly enhances the formation of small and medium-sized
cobalt particles. The results revealed that the proper metal–support
interaction between cobalt nanoparticles and TiO2 led to
the formation of smaller cobalt particles (<15 nm), which possess
a large fraction of surface atoms and, thus, significantly contribute
to the great enhancement of conversion and the reaction rate. The
cobalt time yield of the catalyst after modification increased to
7.5 × 10–5 molCO gCo
–1 s–1 at 230 °C, whereas the
C5+ selectivity maintained a high level (>90%). In addition,
the adequate meso- and macro-pores of the SiC-based support facilitated
intimate contact between the reactants and active sites and also accelerated
the evacuation of the intermediate products. It was also worth noting
that a superior and stable FTS specific rate of 0.56 gC5+
gcatalyst
–1 h–1 together with high C5+ selectivity of 91% were obtained
at common industrial content of 30 wt % cobalt.
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