▎ 摘　　要

NOVELTY - A catalyst layer additive comprises a heteroatom-doped carbon carrier. USE - Catalyst layer additive for electrochemical catalyst used in oxygen electrode for membrane electrode assembly for use in water electrolysis device and fuel cell (all claimed) e.g. acid-based polymer electrolyte membrane fuel cell (PEMFC). Uses include but are not limited to portable, backup, transportation and stationary power applications. ADVANTAGE - The catalyst layer additive provides oxygen electrode having excellent durability. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) electrochemical catalyst, which comprises the catalyst layer additive and platinum; and (2) oxygen electrode.