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

Removal of nitrogen monoxide from exhaust gases through novel catalytic processes

A process for reducing nitrogen oxides to nitrogen from exhaust gases is disclosed, which involves bringing an exhaust gas containing nitrogen oxides into contact with at least one catalyst from proton-type zeolites, zeolites of an alkali metal exchanged form and acidic metal oxides, by reaction with a hydrocarbon or an oxygen-containing organic compound in an oxidizing atmosphere containing excess oxygen. A process which further involves bringing the exhaust gas into contact with an oxidizing catalyst subsequent to the above process.

Process for removing nitrogen oxides in exhaust gases to nitrogen

A process for removing nitrogen oxide from exhaust is disclosed, comprising contacting exhaust containing nitrogen oxide with an alumina catalyst which contains not more than 0.5% by weight of an alkali metal and/or an alkaline earth metal and has a total pore volume of from 0.48 to 1.2 cm 3 ·g -1 with 0.26 to 0.6 cm 3 ·g -1 of the total pore volume being formed of pores of not greater than 80 Å or has a volume of pores formed of pores of not greater than 60 Å of from 0.06 to 0.2 cm 3 ·g -l and which may have supported thereon tin in an oxidative atmosphere containing excess oxygen in the presence of a hydrocarbon or an oxygen-containing organic compound.

Removal of nitrogen oxide from exhaust gas

PURPOSE: To efficiently and catalytically reduce NOx in exhaust gas by using alcohol as a reducing agent when NOx in exhaust gas is selectively and catalytically reduced with a reducing agent in the presence of a catalyst. CONSTITUTION: When harmful NOx contained in exhaust gas discharged from an automobile, etc., is selectively and catalytically reduced with a reducing agent, alcohol is added as the reducing agent to the exhaust gas and this reducing agent is brought into contact with a catalyst to reduce and remove the NOx. By this method, NOx in exhaust gas is efficiently removed under coexistence of nitrogen. The alcohol is lower alcohol which is liq. at ordinary temp. and becomes gas at a reaction temp. and it is preferably ethanol, propanol or isopropanol. The amt. of the alcohol added is preferably 0.1-10 times (mol) that of NOx contained in exhaust gas.

Method for catalytically reducing nitrogen oxide

PURPOSE:To remove NOx in an exhaust gas efficiently. CONSTITUTION:From a viewpoint that in the reduction reaction between NOx and hydrocarbons on a reduction catalyst in an oxidative atmosphere, NO2, is reduced more easily than NO, an exhaust gas is previously contacted with an oxidation catalyst to oxidize NO in the exhaust gas into NO2. The treated exhaust gas, in an oxidative atmosphere containing excessive oxygen and in the presence of hydrocarbons, is contacted with a reduction catalyst selected from zeolite of a proton type, zeolite of an alkali metal type, and acid metal oxide (metal oxide treated with a compound having sulfate group to reduce NO2, in the exhaust gas into nitrogen.

Hamada Hideaki

Papers

Removal of nitrogen monoxide from exhaust gases through novel catalytic processes

Process for removing nitrogen oxides in exhaust gases to nitrogen

Removal of nitrogen oxide from exhaust gas

Method for catalytically reducing nitrogen oxide

Treatment method for removing nitrogen oxide