Abstract: A system for purifying an exhaust gas includes a plasma unit and a catalyst unit. The plasma unit generates energetic plasma species which react with particulate matters and nitrogen oxides contained in the exhaust gas. The catalyst unit has a catalyst which reacts with the exhaust gas. The plasma unit is disposed upstream relative to the catalyst unit in a direction of flow of the exhaust gas and the system provides sequential purification for the particulate matters and the nitrogen oxides.

Abstract: A system for purifying an exhaust gas includes a plasma unit and a catalyst unit. The plasma unit generates energetic plasma species which react with particulate matters and nitrogen oxides contained in the exhaust gas. The catalyst unit has a catalyst which reacts with the exhaust gas. The plasma unit is disposed upstream relative to the catalyst unit in a direction of flow of the exhaust gas and the system provides sequential purification for the particulate matters and the nitrogen oxides.

Abstract: An active solid polymer electrolyte membrane provides an enhancement in power-generating performance. The active solid polymer electrolyte membrane in a solid polymer electrolyte fuel cell includes a solid polymer electrolyte element, and a plurality of noble metal catalyst grains which are carried by an ion exchange in a surface layer located inside a surface of the solid polymer electrolyte element and which are dispersed uniformly in the entire surface layer. The surface layer has a thickness t2 equal to or smaller than 10 ?m. An amount CA of noble metal catalyst grains carried is in a range of 0.02 mg/cm2?CA<0.14 mg/cm2.

Abstract: To decrease the content of a particulate material contained in an exhaust gas from a diesel engine or the like, the content of the particulate material is continuously decreased by generating plasma in the exhaust gas containing the particulate material to thereby produce a plurality of O(1D) radicals and subsequently produce a plurality of per-hydroxide excited species, and oxidizing the particulate material by the per-hydroxide excited species.

Abstract: A purification catalyst for exhaust gas has high purification performance for the exhaust gas even under a high oxygen concentration atmosphere. The purification catalyst for exhaust gas contains cerium oxide, zeolite carrying Pt, and tin or a tin oxide.

Abstract: A purification catalyst for exhaust gas has high purification performance for the exhaust gas even under a high oxygen concentration atmosphere. The purification catalyst for exhaust gas contains cerium oxide, zeolite carrying Pt, and tin or a tin oxide.

Abstract: An exhaust gas purifying catalyst has an Ir powder. The Ir powder has a two peak particle size distribution, with a peak in a particle size D>25 nm region, and the other peak in a particle size D<25 nm region, respectively.

Abstract: An active solid polymer electrolyte membrane in a solid polymer type fuel cell comprises a solid polymer electrolyte membrane and a plurality of precious metal catalyst particles supported on the surfaces of the aforementioned solid polymer electrolyte membrane by ion exchange and distributed uniformly over the surfaces thereof. In accordance with the use of this active solid polymer electrolyte membrane the ability to generate power can be enhanced.

Abstract: An active solid polymer electrolyte membrane provides an enhancement in power-generating performance. The active solid polymer electrolyte membrane in a solid polymer electrolyte fuel cell includes a solid polymer electrolyte element, and a plurality of noble metal catalyst grains which are carried by an ion exchange in a surface layer located inside a surface of the solid polymer electrolyte element and which are dispersed uniformly in the entire surface layer. The surface layer has a thickness t2 equal to or smaller than 10 &mgr;m. An amount CA of noble metal catalyst grains carried is in a range of 0.02 mg/cm2≦CA<0.14 mg/cm2.

Abstract: A catalyst for purifying exhaust gas is disclosed which can attain a high percentage of NO purification in an oxygen-excess atmosphere even after exposure to a hydrothermal environment. The catalyst for purifying exhaust gas comprises a combination of a carrier having platinum deposited thereon and CeO2 having an average crystallite diameter D satisfying D≧13.0 nm. The carrier is made of a gallosilicate having an SiO2/Ga2O3 molar ratio M satisfying 100≦M≦1,230.

Abstract: An exhaust gas purifying catalyst has an Ir powder. The Ir powder has a two peak particle size distribution, with a peak in a particle size D>25 nm region, and the other peak in a particle size D<25 nm region, respectively.

Abstract: A composite catalyst includes a first catalyst part containing an Ir catalyst and a second catalyst part covering the first catalyst part and containing a perovskite type composite oxide. The perovskite type composite oxide contributes mainly to oxidation reaction such as NO+O2→NO2 in an atmosphere of excess oxygen while the Ir catalyst contributes mainly to reduction reaction with HC (hydrocarbon) as a reducing agent such as NO2+HC+O2→N2+CO2+H2O.

Abstract: An exhaust emission control catalyst having an excellent NOx converting capability includes a modified alumina which has a .theta.-phase and an .alpha.-phase and has an .alpha.-conversion rate R in a range of 0.5 %.ltoreq.R.ltoreq.95 %, and a catalytic metal carried in the modified alumina, e.g., platinum (Pt). In addition, a catalyst including a catalyst material which is the above-described catalyst including the modified alumina and the catalytic metal, and an aluminosilicate or cerium oxide (CeO.sub.2), also has an excellent NOx converting capability.

Abstract: An adsorbent exhibiting an excellent adsorption ability to nitrogen oxides (NO) is made from an oxide-based ceramics having an average crystallite grain size D in a range of D<500 .ANG., e.g., CeO.sub.2. A catalyst is formed from, for example, an cerium oxide (CeO.sub.2) and a zeolite. A content C of CeO.sub.2 in the catalyst is set in a range of 10% by weight .ltoreq.CA.ltoreq.80% by weight. The zeolite adsorbs hydrocarbon (HC). The hydrocarbon (HC) adsorbed is oxidized into active CHO which acts to reduce the nitrogen oxides (NO) adsorbed by the CeO.sub.2.

Abstract: In an exhaust emission control system in an internal combustion engine which includes a spark plug disposed to face a combustion chamber, an intake system having a fuel injection valve disposed therein, an exhaust system having a catalytic converter incorporated therein and filled with a catalyst for reducing nitrogen oxide (NO.sub.x) in the presence of hydrocarbons in an oxidizing atmosphere, and an exhaust gas circulation amount control means capable of measuring and controlling the amount of exhaust gas circulated from the exhaust system to the intake system. The amount of exhaust gas circulated by the exhaust gas circulation amount control means the amount and timing of fuel injected by the fuel injection valve and the timing of ignition of the spark plug are controlled by a control unit, so that the amount of NO.sub.x discharged, is detected by the NO.sub.x detector in the exhaust system at a location downstream from the catalytic converter, is equal to or less than an acceptable amount of NO.sub.