In situ XPS Observation of Selective NO_x Adsorption on the Oxygenated Graphene Films

Abstract

Graphene derivatives are promising sensor materials due to their high surface area available for molecule adsorption and conductivity changes under the adsorbate impact. The selectivity of such materials can be tuned through the attaching of certain functional groups preferably interacting with the defined gases. In the present work, we compare the reactivity of graphene oxide, oxyfluorinated graphene, and fluorinated graphene toward gaseous NO x molecules. The interaction of the molecules with the graphenebased films was monitored by in situ X-ray photoelectron and near-edge X-ray absorption fine structure spectroscopy measurements. The spectra before and after exposure of the films to a gaseous NO x mixture detected equal concentrations of adsorbed NO 2 and NO species on graphene oxide, the preferable interaction of oxyfluorinated graphene with NO 2 and the absence of the adsorbed molecules on the fluorinated graphene surface. These results are useful for the development of selective graphene-based gas sensors.

Welding Metallophthalocyanines into Bimetallic Molecular Meshes for Ultrasensitive, Low-Power Chemiresistive Detection of Gases

“…To gain insight into the sensing mechanism, we chose two spectroscopic techniques, XPS and EPR, capable of providing information regarding changes in chemical composition and associated redox events. Because of the dosimetric nature of the interaction of NiPc-M MOFs with H 2 S and NO, we reasoned that these analytes may serve as permanent spectroscopic probes of the sensing mechanism without the assistance of in situ techniques. − EPR analysis was carried out at 77 K under N 2 atmosphere after the bulk MOF sample (∼2 mg) was exposed to 40 ppm of H 2 S or 1 ppm of NO for 30 min (Section 13.3 in Supporting Information). XPS analysis was carried out on MOF samples using similar procedures of analyte exposure, which were subsequently mounted on copper tape and analyzed under reduced pressure (<10 –9 psi).…”

Investigating the Effect of NO on the Capture of CO2 Using Superbase Ionic Liquids for Flue Gas Applications

“…15,16 This shift was not observed in the co-feed treated sample due to the small amount of NO absorbed. The chemisorbed species gave a new contribution in the N 1s region at 402.4 eV in the XPS spectrum of the IL, post-absorption (Figure S4 in SI), which was likely due to the absorption of a small amount of NO to yield either an NO or N 2 O 2 species, reported to have photoelectron peaks at 401.2 and 403.0 eV respectively, in the literature 34,35. All the co-feed post-absorption characterisation corroborate was used to identify the species formed during the absorption of NO alone and for CO2 in the presence of NO.…”

Preparation of a sunlight-driven TiO2 film with excellent material characterizations and photoelectrocatalytic properties by an eco-friendly manner

“…The peak at 399.22 eV was ascribed to interstitial N in Ti-O-N bond [26,27] (Fig. 2b), and the peak at 401.14 eV usually attributed to NO [28,29] . It was possible that the NO molecules produced by Eq.…”