Carbon monoxide oxidation effect

Whittle DM, et al. Co-precipitated copper zinc oxide catalysts for ambient temperature carbon monoxide oxidation effect of precipitate ageing on catalyst activity. Phys Chem Chem Phys. 2002 4(23) 5915-20. 

Oxidation. Carbon monoxide can be oxidized without a catalyst or at a controlled rate with a catalyst (eq. 4) (26). Carbon monoxide oxidation proceeds explosively if the gases are mixed stoichiometticaHy and then ignited. Surface burning will continue at temperatures above 1173 K, but the reaction is slow below 923 K without a catalyst. HopcaUte, a mixture of manganese and copper oxides, catalyzes carbon monoxide oxidation at room temperature it was used in gas masks during World War I to destroy low levels of carbon monoxide. Catalysts prepared from platinum and palladium are particularly effective for carbon monoxide oxidation at 323 K and at space velocities of 50 to 10, 000 h . Such catalysts are used in catalytic converters on automobiles (27) (see Exhaust CONTHOL, automotive). 

Lithium, promotion of carbon monoxide oxidation, 74, 293 Long range effects, 189... 

Lintz and co-workers have investigated the effect of a bismuth additive in metal electrodes for carbon monoxide oxidation56 and have also used SEP to study carbon monoxide oxidation.57... 

The evidence that phosphorus in fuel is detrimental to the oxidation activity of noble metal catalysts is quite convincing. Data from engine dynamometer runs with pelleted catalysts (28) show that raising the level of phosphorus from 60 to 130 mg/gal (added as cresyl diphenylphosphate, CDP) at a low concentration of lead, markedly suppresses the oxidation of hydrocarbons and of carbon monoxide. The effect on the oxidation of... 

Carbon Monoxide Oxidation. Analysis of the carbon monoxide oxidation in the boundary layer of a char particle shows the possibility for the existence of multiple steady states (54-58). The importance of these at AFBC conditions is uncertain. From the theory one can also calculate that CO will bum near the surface of a particle for large particles but will react outside the boundary layer for small particles, in qualitative agreement with experimental observations. Quantitative agreement with theory would not be expected, since the theoretical calculations, are based on the use of global kinetics for CO oxidation. Hydroxyl radicals are the principal oxidant for carbon monoxide and it can be shown (73) that their concentration is lowered by radical recombination on surfaces within a fluidized bed. It is therefore expected that the CO oxidation rates in the dense phase of fluidized beds will be suppressed to levels considerably below those in the bubble phase. This expectation is supported by studies of combustion of propane in fluidized beds, where it was observed that ignition and combustion took place primarily in the bubble phase (74). More attention needs to be given to the effect of bed solids on gas phase reactions occuring in fluidized reactors. 

Holgate HR, Webley PA, Tester JW. Carbon monoxide oxidation in supercritical water the effects of heat transfer and the water-gas shift reaction on observed kinetics. Energy Fuels 1992 6 586-597. 

There is little information of the chemisorption of water on gold surfaces, although its presence has a marked acceleratory effect on the rate of carbon monoxide oxidation over Au/Si02 132 since the support is not expected to be involved in the reaction, it was considered that it might help the adsorption of oxygen on gold panicles. Water occupies oxygen vacancies on... 

After heating to 623 K in helium, which also effected reduction according to XAFS, treatment with sodium cyanide solution removed the Au°, and left 10% of gold as cationic Au111.54 The specific rate of carbon monoxide oxidation was constant, irrespective of the treatment with sodium cyanide, as were activation energy and orders of reaction. It appeared that the Au111 was reduced under reaction conditions, and was not an active species. 

The practical motivation for understanding the microscopic details of char reaction stem from questions such as How does the variability in reactivity from particle to particle and with extent of reaction affect overall carbon conversion What is the interdependence of mineral matter evolution and char reactivity, which arises from the catalytic effect of mineral matter on carbon gasification and the effects of carbon surface recession, pitting, and fragmentation on ash distribution How are sulfur capture by alkaline earth additives, nitric oxide formation from organically bound nitrogen, vaporization of mineral constituents, and carbon monoxide oxidation influenced by the localized surface and gas chemistry within pores ... 

Examples of catalysts in combustion reaction include the effect of H2O on the carbon monoxide oxidation reaction CO H- 2 C02- Nitric oxide also catalyzes CO oxidation through the mechanism 2 NO 4-O2 2NO2 (overall) and NO2 -f CO NO H- CO2. In both of these examples, an intermediate compound (for example, NO2) is formed and then destroyed. The addition of a small amount of NO2 to an H2 — O2 mixture leads to a branched-chain explosion by introducing the relatively rapid initiation step NO2 H- X NO H- O H- X, with the O atoms so produced generating the usual H2 — O2 chain. The NO2 also participates in the efficient termination step NO2 H- O NO H- O2, which is sufficiently important at large concentrations of NO2 to cause a slow reaction to be... 

Nehasil V, Stara I, Matolm V (1996) Size effect study of carbon monoxide oxidation by Rh surfaces. Surf Sci 352 305... 

H. R. Holgate, P. A. Webley, J. W. Tester and R. K. Helling, Carbon Monoxide Oxidation in Supercritical Water The Effects of Heat Transfer and the Water-Gas Shift Reaction on Observed Kinetics, Energy Fuels, 6, 586-597 (1992). 

Evidence for health effects associated with exposure to smoke from combustion of biomass fuels was provided initially by studies on outdoor air pollution as well as by studies dealing with exposure to environmental tobacco smoke. Criteria documents for outdoor air pollutants published by the USEPA [ 13], for example, detail the effects of many components, including particulate matter, carbon monoxide, oxides of sulfur and nitrogen and polycyclic aromatic hydrocarbons. 

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