New spinel materials for catalytic NO-CO reaction: nonstoichiometric nickel-copper manganites
نویسندگان
چکیده
Nonstoichiometric nickel–copper spinel manganites were found to be highly active for the reduction of nitric oxide by carbon monoxide at low temperature (300C). The activity increases with the level of nonstoichiometry of the oxides and almost linearly with their specific surface area. Moreover, this activity was found to depend strongly on the copper content, nickel manganites being almost inactive. The influence of the surface state of the oxides was also investigated. Cuprous cations are thought to play the determining role in the catalytic cycle.
منابع مشابه
Equilibrium and Kinetics of NO and CO Chemisorptions on Nonstoichiometric Nickel-Copper Manganites.
The equilibrium and kinetics of adsorption of NO and CO on nonstoichiometric nickel-copper manganites have been investigated through volumetric measurements. The adsorption isotherms were satisfactorily fitted to the Freundlich equation. The equilibrium coverages at 298 K were found to depend closely on the chemical composition of the oxide; thus, a decrease in the coverage beyond a maximum cop...
متن کاملX-ray photoelectron spectroscopic study of non-stoichiometric nickel and nickel-copper spinel manganites
The surface of non-stoichiometric nickel and nickel–copper spinel manganites has been investigated by X-ray Photoelectron Spectroscopy (XPS). The oxidation states of the nickel, copper and manganese cations present on the surface of the samples were 21 1 determined from the analysis of the M 2p core levels (M5Ni, Cu, Mn). In particular, both Cu and Cu were evidenced in the 3 / 2 structure where...
متن کاملSynthesis and characterization of non-stoichiometric nickel-copper manganites
Non-stoichiometric nickel–copper manganites Ni Cu Mn h O were synthesized by thermal decomposition of x y 32x2y 3d / 4 41d mixed Ni Cu Mn C O , nH O oxalates in air at low temperature (623–673 K). X-ray diffraction showed that, x / 3 y / 3 (32x2y) / 3 2 4 2 for a nickel content x $ 0.1, the oxalates precipitated presented a mixed crystal structure up to a limit value of copper Ni extent, wherea...
متن کاملA Study of Catalytic Performance of Co3O4 and Cu-Co Nano Metal Oxides in Combustion of Aromatics
Two Cu-Co and Co3O4 oxides were synthesized by the conventional sol-gel auto-combustion and their physical-chemical properties were characterized by XRD, FTIR, SEM, TPR and XPS. The XRD results indicated that copper-cobalt oxide appeared in a mixture form of Cu0.15Co2.85O4 spinel and CuO phases, whereas the cobalt oxide exhibited in the pure form of Co3O4 spinel. The FTIR approved the formation...
متن کاملSpinel ferrites as efficient magnetically reusable nanocatalysts in the solvent-free synthesis of substituted trisphenols
A series of copper and cobalt substituted nanospinel ferrites have been synthesized by the hydrothermal method. These compounds were characterized by FT-IR, XRD, EDX, SEM and VSM techniques. All of the synthesized nanospinel ferrites were found to be highly efficient and magnetically recoverable in the solvent-free synthesis of substituted 2,6-(2-hydroxybenzyl)-phenols (trisphenols). A wide ran...
متن کامل