METHOD FOR IMPROVING START/STOP DURABILITY OF OXYGEN REDUCTION CATALYST, AND METHOD FOR INSPECTING OXYGEN REDUCTION CATALYST

摘要

PROBLEM TO BE SOLVED: To provide a method for improving start/stop durability of an oxygen reduction catalyst when a fuel cell is started and stopped repeatedly.SOLUTION: The oxygen reduction catalyst contains a composite particle having a portion comprising an inorganic metal compound and a carbon-containing portion. The composite particle contains a metal element M1, carbon and oxygen as constituent elements. When the total amount of atoms of the metal element M1 is 1 mole, the amount of carbon atoms is 1-10 moles and that of oxygen atoms is 1-3 moles. The method for improving start/stop durability of the oxygen reduction catalyst comprises a step of preparing the oxygen reduction catalyst so that a G band and a D band exist in a Raman spectrum of the oxygen reduction catalyst and the V/G ratio defined by the following expression is 0.10-0.35. The expression: the V/G ratio=(the minimum value of the spectral intensity in a region V being the region between the G band and the D band)/(the peak intensity of the G band).