Mechanism of tribo-chemical reactions of ionic liquids on titanium alloys

In this paper, the tribological, the tribo-chemical reaction mechanisms and desorption properties of three ionic liquids (ILs), [Bu3MeP][ Tf2N], [Bu3MeN][ Tf2N] and [Bu3MeP][ (MeO)2PO2], in contact with titanium and under vacuum conditions are studied with the CATRI © UHV Tribometer developed by IK4-TEKNIKER [1]. The two ILs containing the bis(trifluoromethanesulfonyl)amide anion presented lower coefficient of friction compared to that having the dimethyl phosphate anion. The tribodesorption study revealed that it is required an induction period to decrease the friction coefficient. The end of this period is accelerated in the case of trifluoromethane ionic liquids by the CF3+ release. Hence, the CF3+ reacts with the titanium surface generating a titanium fluoride tribolayer that could act like a catalyst to generate the tribodesorption of ionic liquid cation fragments (CH3+, C2H5+, C3H7+, C4H9+). The XPS analysis confirmed the generation of a boundary film, comprising of sulfide and inorganic fluoride, and being possibly the responsible of decreasing the friction coefficient. The [Bu3MeP][MeO)2PO2] ionic liquid required a long induction period, it did not form any tribolayer and no reduction of friction coefficient, yielding instead a high abrasion and adhesion mechanism. Thus, it can be concluded that bis(trifluoromethanesulfonyl)amide anion is more effective than dimethylphosphate in generating a surface protective film on the titanium surface under the selected test conditions and the testing methodology seems to be useful to understand the tribodesorption mechanism.The partners would like to acknowledge the financing to the Austrian Government financing of COMET K2 Excellence Centre of Tribology called X-Tribology to carry out this research collaborative activity. The authors also would like to acknowledge the financing of the EMAITEK Programme by the Basque Country

Pt monometallic and bimetallic catalysts prepared by acid sol–gel method for liquid phase reforming of bioglycerol

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Deactivation study of the Pt and/or Ni-based γ-Al2O3 catalysts used in the aqueous phase reforming of glycerol for H2 production

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The effect of sulfidation on the Ni distribution in Ni/USY zeolites

NI/USY zeolite catalysts have been prepared by either an ion- exchange or an impregnation procedure. The modification of support and the effect of sulfidation on the Ni distribution were examined by various techniques (water adsorption, FT i.r. spectroscopy of chemisorbed NO, XPS, Xe-129 n.m.r. and Xe adsorption). in all catalysts the sulfidation of Ni is incomplete and the method of Ni introduction influenced the Ni distribution in Ni/USY zeolites. In unsulfided samples ion- exchange technique led to Ni located essentially in hexagonal prisms, whereas in the other samples prepared by impregnation procedure the Ni concentrates were located at or near the outer zeolite surface. Some nickel redistribution has been observed during catalyst sulfidation. (C) Elsevier Science Inc. 199

The effect of sulfidation on the Ni distribution in Ni/USY zeolites

NI/USY zeolite catalysts have been prepared by either an ion- exchange or an impregnation procedure. The modification of support and the effect of sulfidation on the Ni distribution were examined by various techniques (water adsorption, FT i.r. spectroscopy of chemisorbed NO, XPS, Xe-129 n.m.r. and Xe adsorption). in all catalysts the sulfidation of Ni is incomplete and the method of Ni introduction influenced the Ni distribution in Ni/USY zeolites. In unsulfided samples ion- exchange technique led to Ni located essentially in hexagonal prisms, whereas in the other samples prepared by impregnation procedure the Ni concentrates were located at or near the outer zeolite surface. Some nickel redistribution has been observed during catalyst sulfidation. (C) Elsevier Science Inc. 199

Health impact assessment of ozone on mortality in 30 European cities

ISEE/ISEA 2006 conference abstracts suppl.info:eu-repo/semantics/publishe