The infrared spectral performance of the N x O y species observed on oxide surfaces [N2O, NO−, NO, (NO)2, N2O3, NO+, NO2 − (different nitro and nitrito anions), NO2, N2O4, N2O5, NO2, and NO3 − (bridged, bidentate, and monodentate nitrates)] is considered. The spectra of related compounds (N2, H-, and C-containing nitrogen oxo species, C─N species, NH x species) are also briefly discussed. Some guidelines for spectral identification of N x O y adspecies are proposed and the transformation of the nitrogen oxo species on catalyst surfaces are regarded.

Identification of Neutral and Charged N x O y Surface Species by IR Spectroscopy

Automotive catalytic converters: current status and some perspectives

Catalytic removal of NO

This review covers the literature through 1991 on nitric oxide catalysis as applied to automobile exhaust systems. Attention is given to the threeway catalyst system which simultaneously promotes the reduction of nitrogen oxides and the oxidation of carbon monoxide and hydrocarbons. These systems have been used on most passenger cars in the United States since 1982. Prior to 1980, emission control catalysts were oxidation catalysts, and reduction in exhaust nitric oxide was achieved using engine modifications (i.e., exhaust gas recirculation). This review focuses on catalytic control of NO, for gasoline-fueled vehicles (not diesels and alternate fuels) and primarily on developments reported since 1982. The term NO, refers to both NO and NOz. The reader is referred to an earlier publication by the author for a general review of automobile catalytic converters [1] and to a review by Egelhoff [2] on the nitric oxide literature through 1980. The recent literature on NO, reduction in lean exhaust is c...

Nitric oxide catalysis in automotive exhaust systems

Catalysis for NOx abatement

PURPOSE:To effectively remove NOx without lowering the activity of a catalyst in use and to make it possible to remove incomlete combustion products that may be discharged by the removal of the NOx CONSTITUTION:In an oxidizing atmosphere where the exists excess oxygen and in the presence of hydrocarbons or their oxygen contg compounds (thereafter called hydrocarbons) that exists in waste gas or are introduced from the outside, the waste gas is brought into contact with a catalyst which metal oxide given transition metal ion exchange treatment is contained to form The catalyst accelerates in an oxidizing atmosphere the reaction of NOx and hydrocarbons taking priority over that of oxygen and hydrocarbons to remove NOx in the waste gas with high efficiency And the waste gas after coming into contact with the catalyst is brought into contact with an oxidizing catalyst to remove incomplete combustion products

Purification treatment of nitrogen oxide containing waste gas

PURPOSE:To remove efficiently NOx in an exhaust gas containing SOx without deterioration of catalyst activity in an oxidizing atomosphere containing excessive oxygen and to remove the products of incomplete combustion possibly discharged through the removal of the NOx. CONSTITUTION:In the presence of hydrocarbons or oxygen-containing compounds (hereafter called hydrocarbons) contained in exhaust gas or introduced from outside, the exhaust gas is brought into contact with a catalyst of a multivalent metal sulfate. The catalyst, in an oxidizing atomosphere, promotes preferably the reaction of NOx with the hydrocarbons over the reaction of oxygen with the hydrocarbons so that the NOx in the exhaust gas can be removed with a high efficiency. The exhaust gas after being contacted with the catalyst is brought into contact with an oxidation catalyst to remove the products of incomplete combustion.

Method for removing nitrogen oxide in exhaust gas

PURPOSE:To provide a method to reduce and remove NOx in exhaust gas produced from gasoline engine, diesel engine, or various facilities in an atmosphere containing excess oxygen or in the presence of water vapor and sulfur oxide as well as oxygen CONSTITUTION:Exhaust gas containing NOx is brought into contact with an alumina catalyst containing tin in an atmosphere containing excess oxygen and in the presence of hydrocarbons or oxygen-contg compd In this case, by using methanol as the oxygen-contg compd, NOx can effectively be, removed even at low temp Instead of the alumina catalyst, such an alumina catalyst containing tin satisfying the following conditions can be used (1) The amt of either alkali metal or alkaline-earth metal or both of these is =026cm g pore volume for such pores having =048cm g pore volume

Purifying method of exhaust gas containing nitrogen oxide

PURPOSE:To obtain a method to reduce and remove nitrogen oxides in exhaust gas produced from a gasoline engine, diesel engine or various kinds of facilities. CONSTITUTION:Exhaust gas containing nitrogen oxides is brought into contact with a catalyst comprising at least silica or zirconia containing at least one kind of alumina, silver or silver compd. in the presence of at least one of hydrocarbons or oxygen-contg. compd. in an oxidative atmosphere containing an excess amt. of oxygen. The alumina contains (a) =0.26cm .g pore volume of pores having =0.48cm .g total pore volume. The oxygen-contg. compd. is preferably either ethanol or acetone or both of these.

Method for contact-reduction-removal of nitrogen oxide

PURPOSE:To make it possible to remove NOx in a highly efficient manner, if vapor or a sulfur oxide coexists in an excess oxygen atmosphere CONSTITUTION:An exhaust gas containing NOx is allowed to come into contact with an alumina catalyst which contains tin, and (1) 05wt% or less of alkali metals or alkaline earth metals, with (2) at least, 006cm /g of the pore volume formed by pores having a diameter of 60Angstrom or less and at least, 01cm /g of the pore volume formed by pores having a diameter of 80Angstrom or less, in an oxidation atmosphere where an excess oxygen is present and in the presence of hydrocarbons or an organic compound containing oxygen IN this case, the preferable organic compound containing oxygen is methanol

Hamada Hideaki

Papers

Purification treatment of nitrogen oxide containing waste gas

Method for removing nitrogen oxide in exhaust gas

Purifying method of exhaust gas containing nitrogen oxide

Method for contact-reduction-removal of nitrogen oxide

Reduction purification of exhaust gas containing nitrogen oxide