Strong Activity Changes Observable during the First Pretreatment Cycles of Trimetallic PtNiMo/C Catalysts

Abstract Pt‐based alloy catalysts supported on carbon are commonly characterized for oxygen reduction reaction (ORR) activity using the rotating disk electrode technique (RDE). Within this study, we show exemplarily PtNiMo/C that applied pretreatment influences strongly determined activity. The classically employed descriptor of unchanged cyclic voltammetry response is insufficient to portrait completed surface restructuring, and gives an incorrect impression stable can be determined. This might one reasons deviating activities reported in literature. Following changes during also with in‐situ FTIR online dissolution measurements insights up now largely overseen high trimetallic catalysts. A maximum 0.57 mA cm Pt −2 at 0.95 V RHE reached quickly first six cycles decreases slowly subsequently. change over cycle number affected by scan rate electrolyte refreshing, while gas atmosphere plays only a minor role. exemplary study important general.