Fluorination of Cu(001) Surface by C₆₀F₄₈ Molecule Adsorption

Abstract

Copper surface functionalization by defluorination of C60F48 molecules with submonolayer and monolayer coverages on the Cu(001) crystal is studied by X-ray photoelectron spectroscopy. At room temperature, fluorinated fullerene molecules on the copper surface start to lose fluorine atoms immediately after adsorption. C 1s level spectra indicate a significant decrease of C-F bonds in the fullerene frame for submonolayer coverage and a gradual fluorine loss with time for monolayer coverage. The energy position of the C-F peak in the C 1s spectrum is a function of the current fluorine content in the molecule during decomposition. The fluorine 1s spectrum on the copper surface has two peaks characterizing F-C bonds with a fullerene cage and F-Cu bonds at lower binding energy. The energy positions of both peaks depend on the fluorine content on the fullerene cage and the copper surface. The Cu 2p spectra for submonolayer coverage show only minor changes. In the meantime, the Cu 2p line after monolayer adsorption has additional features of copper difluoride. The combined F 1s, C 1s, and Cu 2p spectra analysis elucidates a process of fluorine loss with subsequent fluorination of the copper surface from the fluorine surface superstructure to thin copper fluoride film depending on the molecule coverage.

Visible Light-Driven D–A Conjugated Linear Polymer and Its Coating for Dual Highly Efficient Photocatalytic Degradation and Disinfection

“…Similarly, the F 1s core-level XPS spectra of PBDT–F–COOH and PBDT–F–COOH–PU also show the same main peak at 687.12 eV classified as F–C bonds (Figure S3b). These results prove that the PBDT–F–COOH and PBDT–F–COOH–PU featuring chemical bonding between PBDT–F–COOH and PU are successfully synthetized.…”

“…The two dominant peaks centered at 284.5 and 285 eV for PBDT–F–COOH show a lower band energy than those for PBDT–F–COOH–PU (284.49 and 285 eV), all of which are attributed to the CC and C–C in the skeleton of CPs . The other three peaks for PBDT–F–COOH at around 285.49, 288.2, and 288.29 eV are assigned to C –S, O– C O, and C –F species, respectively. , Correspondingly, the other peaks for PBDT–F–COOH–PU at around 285.5, 286.25, and 288.29 eV are classified as C –S, O C –N, and C –F species, respectively. − In the C 1s spectrum of pre-PU, the peaks located at 284.73, 286.25, and 288.8 eV are attributed to C–C, O C –N, and O C N, respectively. − As expected, the O C N of pre-PU and carboxylic O– C O of PBDT–F–COOH disappear in the PBDT–F–COO–PU, while the content of O C –N species increases from 18.1 to 23.7%, indicating that the PBDT–F–COOH–PU was successfully synthesized through the polymerization between pre-PU and PBDT–F–COOH. The characteristic peak of 531.75 eV (NC O ) in pre-PU for the O 1s XPS spectra (Figure c) also disappears compared with the two dominant peaks of 532.0 eV ( O C) and 533.0 eV ( O –C) in PBDT–F–COOH–PU due to the formation of OC–N groups.…”

“…42 Similarly, the F 1s corelevel XPS spectra of PBDT−F−COOH and PBDT−F− COOH−PU also show the same main peak at 687.12 eV classified as F−C bonds (Figure S3b). 41 3a). The band gaps of BDT-tin, 2,5-dibromothiophene-3-carboxylic acid, and PBDT−F−COOH by the Tauc plot according to DRS spectra are calculated to be 2.79, 3.66, and 2.12 eV, respectively (Figure 3b).…”

Dehydrofluorination as a Residue-Free Selective Route to C–C Bond Formation at Metal Surfaces

“…At room temperature, excess fluorine at the surface of a metal usually leads to surface metal fluoride formation. For example, it was observed that highly fluorinated fullerenes C 60 F 48 spontaneously deposit fluorine at the surface of Cu(100) at room temperature and readily form stable surface CuF 2 . Similarly, exposing a metal surface to a fluorinated species such as XeF 2 also leads to metal fluoride production through the self-terminated Mott–Cabrera mechanism, in which F – is stabilized and attracted by its image charge in the metal surface .…”

“…For example, it was observed that highly fluorinated fullerenes C 60 F 48 spontaneously deposit fluorine at the surface of Cu(100) at room temperature and readily form stable surface CuF 2 . 42 Similarly, exposing a metal surface to a fluorinated species such as XeF 2 also leads to metal fluoride production through the self-terminated Mott−Cabrera mechanism, in which F − is stabilized and attracted by its image charge in the metal surface. 43 In the work presented here, no metal fluoride is observed in XPS at any stage of the reaction.…”