Uptake ofn-Hexane, 1-Butene, and Toluene by Au/Pt Bimetallic Surfaces:  A Tool for Selective Sensing of Hydrocarbons under High-Vacuum Conditions

Abstract

The dissociative adsorption and decomposition on a range of metal surfaces of an alkane, an alkene, and an aromatic, all representative of species present in an important technological application, has been studied under conditions relevant to selective gas sensing based on solid electrolyte potentiometry. At 870 K, pure polycrystalline Pt surfaces do not discriminate between n-hexane, toluene, and 1-butene: graphitic carbon accumulation occurs at almost the same rate. However, by varying the composition of polycrystalline bimetallic Pt/Au surfaces, good discrimination between these species can be achieved. Thus at a nominal surface composition of approximately 75% Au (XPS), good selectivity toward 1-butene and toluene uptake is achieved, with essentially no response to n-hexane. At approximately 80% Au the system is selective to 1-butene alone. Particular merits of these systems include good high-temperature stability and good tunability of their chemical selectivity. This makes possible the development of array devices in which the elements have overlapping but different selectivity profiles.

Nitrogen‐Enriched Fe3O4@Carbon Nanospheres Derived from Fe3O4@3‐Aminophenol/Formaldehyde Resin Nanospheres Based on a Facile Hydrothermal Strategy: Towards a Robust Catalyst Scaffold for Platinum Nanocrystals

“…Figure a exhibits the Pt 4f spectra of Fe 3 O 4 @N‐Carbon@Pt composite nanocatalysts. The characteristic peaks of Pt 0 at 71.5 (Pt 4f 7/2 ) and 74.9 eV (Pt 4f 5/2 ) were observed clearly, which suggests that the Pt nanoparticles immobilized on the Fe 3 O 4 @N‐Carbon nanospheres are in the metallic state (Pt 0 ). The N 1s XPS spectra of Fe 3 O 4 @N‐Carbon@Pt nanocomposites (Figure b) further clarified the existence of the nitrogen species in the composites.…”

Antibody-Directed Synthesis of Catalytic Nanoclusters for Bioanalytical Assays

“…XPS measurements were performed to study the valence state of the metal cores of NCs-IgG (Figure 2C). The Pt4f spectra exhibit a doublet containing the Pt4f7/ 2 energy band at 71.1 eV and the Pt4f5/ 2 at 74.3 eV which indicates the presence of metallic state Pt 26 . In the Pt 4f7/ 2 spectrum, a broad peak was found.…”

Gold oxide films grown in the confined aqueous layer between gold and organic solvents

“…Therefore, we can assume that the aromatic adsorption in our case is stronger than that with aliphatic compounds. However, the presence of water hinders the adsorption of organics, such as hexane and xylene, which are scantly adsorbed [24][25][26][27].…”