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The thermal stability and the structural evolution of graphene grown on Fe(110) has been studied upon annealing in ultra-high vacuum conditions (UHV, P ≤ 10−9 mbar) and in the presence of gaseous ethylene at a pressure of ∼10−6 mbar by grazing incidence X-ray diffraction. It was observed that upon annealing at temperatures below 630 °C, graphene on Fe is thermally stable. Exposure to ethylene at these temperatures promotes the formation of graphene while inhibiting its deterioration. Annealing graphene/Fe(110) at temperatures above 630 °C results in a fast degradation of graphene followed by carburization of the sample, that is the irreversible formation of various iron carbides, with the most common phases being Fe3C (cementite) and Fe7C3 (Eckstrom-Adcock carbide). Annealing of the carburized sample does not result in the formation of a detectable graphitic structure.

In order to achieve the selective detection of NO2 in the environment, a chemical filter is added to a semiconductor gas sensor that is very sensitive to oxidizing gases in the gas flow. The aim is to remove ozone (O3), the main interfering oxidizing gas for NO2 detection before its measurement by a phthalocyanine sensor. The first parameter for the carbon material as a filter is the specific surface area (SSA), which should be high enough to ensure interaction with O3 and low enough to avoid interaction with NO2. The key role of surface oxygenated groups and dangling bonds was underlined by NEXAFS and EPR, respectively. A mixture of nanocones/nanodiscs (20/70% w/w) with SSA of 30 m2 g−1 with both structural and electronic defects is found to be the most efficient filter and was used upstream of a phthalocyanine sensor. The lifetime of the chemical filter was investigated and a strategy to increase it is described. Raman spectroscopy, EPR and NEXAFS allow the reactivity of the carbon with NO2 and O3 in the 10–1000 ppb concentration range to be studied.

CuX@SWCNT (X = Cl, Br, I) nanostructures were prepared by capillary filling of 1.4‐1.6 nm single-walled carbon nanotubes (SWCNT) with copper halides. The structure of CuX@SWCNT (X = Cl, Br, I) represents a distorted two-layer hcp of halogen atoms arranged along the SWCNT. The EXAFS and the high angle angular dark field (HAADF) HRTEM data indicate that Cu is partially coordinated by C. According to the optical absorption, valence band photoemission spectroscopy and work function measurements, a Fermi level (FL) downshift as compared with the initial value for the nanotubes and a corresponding charge transfer from the nanotubes to the 1D crystals is observed for CuX@SWCNT nanostructures. The FL shift increases in the sequence CuI < CuBr < CuCl due to an increase of the electron affinity for the halogen atoms. The XPS data confirm the acceptor effect of copper halides and indicate that metallic and semiconducting nanotubes behave differently. Raman spectroscopy performed under electrochemical charging allowed estimation of the value of charge transfer between the nanotube walls and the intercalated 1D crystal. The X-ray absorption and emission spectra for carbon and copper thresholds revealed a new energy level composed of the carbon 2pz and copper 3d-orbitals. This indicates the

One-dimensional silver halide crystals were grown within single-walled nanotube (SWCNT) channels from the melt using a “molten media method”. Atomic structures of the AgX@SWCNT hybrids were proposed based on high-resolution transmission electron microscopy images. It was found that AgCl intercalation results in amorphous filling of the SWCNT channels. 1D AgBr and AgI crystals intercalated into 1.34 nm SWCNTs possess the structure of a two-layer hcp of halogen atoms arranged laterally with respect to the SWCNT axis. Electronic properties and chemical bonding in AgX@SWСNTs have been investigated by high-resolution X-ray photoelectron and near edge X-ray absorption fine structure spectroscopy (BESSY, Germany), optical absorption and Raman spectroscopy. Optical absorption spectroscopy indicates disappearance of E 11 S transitions between van-Hove singularities, which is caused by an effective electron exchange between AgX and the SWCNT. C 1s X-ray absorption spectra indicate a new empty level (S1) induced by charge transfer. Multi-component structure of photoemission spectra can be explained both by the variation of the work function of AgX@SWCNT hybrids and local interactions between halogen ions and carbon atoms. Raman spectroscopy performed under electrochemical charging clearly and directly demonstrated the acceptor behavior of AgX with respect to SWCNTs. Based on a whole dataset, a self-consistent picture of the AgX-SWCNT interactions is derived.