NOBLE METAL CATALYST POWDER, GAS SENSOR ELEMENT USING NOBLE METAL CATALYST POWDER, AND GAS SENSOR

摘要

A noble metal catalyst powder produced by using co-precipitation method is made of noble metal alloy particles containing Pa, Pd, and Rh. The noble metal alloy particles have an average particle size within a range of 0.2 μm to 2.0 μm. A standard deviation in content of each of Pa, Pd, and Rh is not more than 20 mass %. This standard deviation in content of each of Pa, Pd, and Rh is detected at not less than ten detection-points of the noble metal catalyst powder by quantitative elemental analysis. A gas sensor element has the noble metal catalyst powder. An A/F sensor is equipped with the gas sensor element using the noble metal catalyst powder.