Abstract: A catalyst system to be used in an automobile exhaust gas purification apparatus which exerts excellent purification capability to a nitrogen oxide, even when hydrocarbon concentration varies, by subjecting exhaust gas discharged from an automotive internal engine to contacting with a catalyst, an exhaust gas purification apparatus using the same, and an exhaust gas purification method. A catalyst system etc.

Abstract: A catalyst system to be used in an automobile exhaust gas purification apparatus which exerts excellent purification capability to a nitrogen oxide, even when hydrocarbon concentration varies, by subjecting exhaust gas discharged from an automotive internal engine to contacting with a catalyst, an exhaust gas purification apparatus using the same, and an exhaust gas purification method. A catalyst system etc.

Abstract: An electrocatalyst comprising an alloy of platinum with a base metal selected from the group consisting of gallium, vanadium, chromium, manganese, iron, cobalt, nickel and copper, having a structure of vacant lattice site type lattice defects; the alloy being supported on a conductive carbon powder. The electrocatalyst is useful as a platinum-supported catalyst for an electrode, and has a superior electrochemical oxygen reduction activity and has platinum alloy particles having less base metal component.

Abstract: A platinum alloy electrocatalyst comprising an electrically conductive carrier and a platinum-cobalt-nickel-copper quaternary solid solution alloy dispersed in and deposited on the carrier, composed of 40-70 atomic % of platinum, 9-27 atomic % of cobalt, 9-27 atomic % of nickel and 9-27 atomic % of copper; and an electrode for acid electrolyte fuel cell, comprising said platinum alloy electrocatalyst, a water-repellent binder and an electrically conductive and acid-resistant supporting member to which the electrocatalyst and the binder are bonded.

Abstract: Disclosed are a platinum alloy electrocatalyst having high activity and a long life comprising an electrically conductive carrier and dispersed in, and deposited on it, a platinum-iron-cobalt-copper quaternary ordered alloy composed of 40 to 70 atomic % of platinum, 9 to 27 atomic % of iron, 9 to 27 atomic % of cobalt and 9 to 27 atomic % of copper, and an electrode for an acid electrolyte fuel cell which electrode comprises the platinum alloy electrocatalyst, a water-repellent binder and a conductive and acid-resistant supporting member, the electrocatalyst and the water-repellent binder being bonded to.