A comparative study is presented of the hydrolytic and thermal stability of 24 different kinds of monolayers on Si(111), Si(100), SiC, SiN, SiO2, CrN, ITO, PAO, Au, and stainless steel surfaces. These surfaces were modified utilizing appropriate organic compounds having a constant alkyl chain length (C18), but with different surface-reactive groups, such as 1-octadecene, 1-octadecyne, 1-octadecyltrichlorosilane, 1-octadecanethiol, 1-octadecylamine and 1-octadecylphosphonic acid. The hydrolytic stability of obtained monolayers was systematically investigated in triplicate in constantly flowing aqueous media at room temperature in acidic (pH 3), basic (pH 11), phosphate buffer saline (PBS) and deionized water (neutral conditions), for a period of 1 day, 7 days, and 30 days, yielding 1152 data points for the hydrolytic stability. The hydrolytic stability was monitored by static contact angle measurements and X-ray photoelectron spectroscopy (XPS). The covalently bound alkyne monolayers on Si(111), Si(100), and SiC were shown to be among the most stable monolayers under acidic and neutral conditions. Additionally, the thermal stability of 14 different monolayers was studied in vacuum using XPS at elevated temperatures (25-600 °C). Similar to the hydrolytic stability, the covalently bound both alkyne and alkene monolayers on Si(111), Si(100) and SiC started to degrade from temperatures above 260 °C, whereas on oxide surfaces (e.g., PAO) phosphonate monolayers even displayed thermal stability up to ∼500 °C.

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High surface area, bulk molybdenum nitride catalysts were synthesized via temperature programmed ammonalysis of ammonium hepta molybdate and citric acid (CA) composite. The sythesized materials were tested for COx free H 2 production via ammonia decomposition for fuel cell application. Cobalt was added in different loadings (1, 3, 5wt %) as a promoter for the bulk molybdenum nitrides. The chemical composition and surface morphology of nitride catalysts were studied by XRD, XPS, SEM-EDAX and TEM techniques. Addition of cobalt increased the formation of γ-Mo 2 N phase and cobalt existed as Co 3 Mo 3 N phase, which was uniformly distributed over Mo 2 N evidenced by TEM and SEM analysis.A drastic increase in Mo 2 N crystal size was observed when the Co loading exceeded 3 wt%, which in turn decreased the catalyst activity for ammonia decomposition reaction. All catalysts are exhibiting high activity than reported nitride catalysts at low temperatures. All catalysts showed stable activity for 30 hours. Activation energy calculated for ammonia decomposition was decreased drastically from 131.2 to 99kJ/mol by the addition of cobalt (1 wt%) in Mo 2 N prepartion.