▎ 摘　　要

NOVELTY - Evaluation of oxygen reduction activity of carbon-based catalyst involves locally arranging (i) a to-be-evaluated carbon-based catalyst on a surface of a semiconductor, immersing (ii) the semiconductor comprising the carbon-based catalyst on the surface in an etching solution to form local etching traces on the semiconductor surface, and evaluating (iii) the oxygen reduction activity from the depth of the local etching traces. USE - Evaluation of oxygen reduction activity of carbon-based catalyst used as platinum alternate in electrode catalyst for forming electrode e.g. negative electrode used for polymer electrolyte fuel cell for clean next-generation energy source including domestic power source and mobile power source such as motor vehicle, dye-sensitized solar cell and metal-air secondary battery. ADVANTAGE - The method enables simple and quantitative evaluation of oxygen reduction activity of carbon-based catalyst by easily visualizing catalytic activity (oxygen reduction activity). DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view explaining the evaluation of oxygen reduction activity of carbon-based catalyst. (Drawing includes non-English language text) Carbon nanomaterials (1,2,3)