Carbon monoxide doped

Diazoimidazoles were reported to be light sensitive (CHEC-II(1996)). Stepwise controlled fragmentation photolysis in carbon monoxide-doped argon matrices of 4-diazo-4/7-imidazole was reported, and FT-IR characterization of each fragmentation step in Scheme 44 was in accord with theoretical calculations [B3LYP/6-3111G(d,p)] <2000EJ02535>. 

Photolysis experiments involving HaCO, D2CO, and HFCO have been carried out. U.v. and vacuum-u.v. photolysis of HjCO and DgCO in argon, carbon monoxide, and carbon-monoxide-doped argon matrices have been performed between 8 and 10 The major products of the photolysis, CO, H2, HCO, and H, presumably arise from the two primary processes (24) and (25) (c/. the photochemical decomposition of HgCO ). 

Fig. 25. Differential heats of adsorption of carbon monoxide at 30°C on fresh (A) or oxygenated (B) samples of a gallium-doped nickel oxide. Reprinted from (63) with permission J. Chim. Phys.

Thermochemical Cycles Testing the Formation of Gaseous (Cycle 1) or Adsorbed (Cycle 2) Carbon Dioxide by the Interaction of Carbon Monoxide with Oxygen Preadsorbed on Gallium-Doped Nickel Oxide ... 

Fig. 26. Differential heats of interaction of carbon monoxide at 30°C with a sample of gallium-doped nickel oxide, containing a limited amount (0.4 cm3 02 gm l) of preadsorbed oxygen.

One of the conclusions deduced from the thermochemical cycle 2 in Table V, for instance, is that in the course of the catalytic combustion of carbon monoxide at 30°C, the most reactive surface sites of gallium-doped nickel oxide are inhibited by the reaction product, carbon dioxide. This conclusion ought to be verified directly by the calorimetric study of the reaction. Small doses of the stoichiometric reaction mixture (CO + IO2) were therefore introduced successively in the calorimetric cell of a Calvet microcalorimeter containing a freshly prepared sample of gallium-doped... 

Fig. 33. Reaction yield as a function of time for carbon monoxide oxidation at room temperature on pure and doped nickel oxides. NiO (200), A NiO(Li) (250), O NiO (250) X NiO(Ga) (250). Reprinted from (8) with permission. Copyright 1969 by Academic Press, Inc., New York.

Ar (42), in both cases within a factor of four of the theoretical prediction. Also, a similar decay rate was obtained in sc CH4 (6.2 + 0.6 x 106s 1), and in heptane (8.1 + 0.7 x 107s 1) (42). The observed decay rate constant in sc Ar doped with H2, 3.3( + 0.1) x 106s 1, mentioned above, is also close to these values. Finally, in sc Ar doped with carbon monoxide, the rate of decay is 5.3 x 106 s-1 (42). All of these values are in reasonable agreement with the computed rate constant k31 considering the many uncertainties involved in predicting the latter, associated with errors in the computed energy of MECP noL and in the NA-TST itself. 

The model sensitive layer, which will be used for gas sensor performance tests throughout this book, was Sn02 that has been doped with 0.2 wt % Pd. The minute Pd-content leads to a better sensitivity to carbon monoxide. The larger response is a consequence of the increased reaction rate. For the sensor arrays in Chap. 6, two additional materials have been prepared. Pure tin oxide shows a good sensor response... 

By in situ MAS NMR spectroscopy, the Koch reaction was also observed upon co-adsorption of butyl alcohols (tert-butyl, isobutyl, and -butyl) and carbon monoxide or of olefins (Ao-butylene and 1-octene), carbon monoxide, and water on HZSM-5 (Ksi/ Ai — 49) under mild conditions (87,88). Under the same conditions, but in the absence of water (89), it was shown that ethylene, isobutylene, and 1-octene undergo the Friedel-Crafts acylation (90) to form unsaturated ketones and stable cyclic five-membered ring carboxonium ions instead of carboxylic acids. Carbonylation of benzene by the direct reaction of benzene and carbon monoxide on solid catalysts was reported by Clingenpeel et al. (91,92). By C MAS NMR spectroscopy, the formation of benzoic acid (178 ppm) and benzaldehyde (206 ppm) was observed on zeolite HY (91), AlC -doped HY (91), and sulfated zirconia (SZA) (92). 

This type of N-doped soot catalyst is of particular interest for the development of advanced fuel cells. As this type of catalyst is not poisoned by carbon monoxide, it is a promising candidate for O2 cathodes in methanolconsuming fuel cells (132). In methanol-combusting cells, diffusive transport of methanol from the anode to the cathode cannot be avoided, with the consequence that the activity of Pt-activated cathodes becomes severely impaired by CO poisoning of the Pt catalyst therefore, a CO-insensitive cathodic electrocatalyst seems to be indispensible. Yet the longevity of this type of catalyst is still in dispute (133). 

B. The Oxidation of Carbon Monoxide over Doped Nickel Oxide Catalysts.. 36... 

Fig. 9. Apparent activation energies for the oxidation of carbon monoxide on doped nickel oxide. O G. M. Schwab and J. Block [Z. physik. Chem. Frankfurt) [N.S.] 1, 42 (1954)] M. E. Dry and F. S. Stone [Discussions Faraday Soc. 28, 192 (1959)].

VI. Room-Temperature Oxidation of Carbon Monoxide on Doped... 

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