Role of Iron on the Structure and Stability of Ni_3.2Fe/Al₂O₃ during Dynamic CO₂ Methanation for P2X Applications

Abstract

Abstract An energy scenario, mainly based on renewables, requires efficient and flexible Power‐to‐X (P2X) storage technologies, including the methanation of CO 2 . As active Ni 0 surface sites of monometallic nickel‐based catalysts are prone to surface oxidation under hydrogen‐deficient conditions, we investigated iron as “protective” dopant. A combined operando X‐ray absorption spectroscopy and X‐ray diffraction setup with quantitative on‐line product analysis was used to unravel the structure of Ni and Fe in an alloyed Ni−Fe/Al 2 O 3 catalyst during dynamically driven methanation of CO 2 . We observed that Fe protects Ni from oxidation and is itself more dynamic in the oxidation and reduction process. Hence, such “sacrificial” or “protective” dopants added in order to preserve the catalytic activity under dynamic reaction conditions may not only be of high relevance with respect to fine‐tuning of catalysts for future industrial P2X applications but certainly also of general interest.