An In Situ XAS Study of the Cobalt Rhenium Catalyst for Ammonia Synthesis.

ABSTRACT: A cobalt rhenium catalyst active for ammonia synthesis at 400 °C and ambient pressure was studied using in situ XAS to elucidate the reducibility and local environment of the two metals during reaction conditions. The ammonia reactivity is greatly affected by the gas mixture used in the pre-treatment step. Following H₂/Ar pre-treatment, a subsequent 20 min induction period is also observed before ammonia production occurs whereas ammonia production commences immediately following comparable H₂/N₂ pre-treatment. In situ XAS at the Co K-edge and Re L_III-edge show that cobalt initiates reduction, undergoing reduction between 225 and 300 °C, whereas reduction of rhenium starts at 300 °C. The reduction of rhenium is near complete below 400 °C, as also

SUBMITTER: Mathisen K 

PROVIDER: S-EPMC6413814 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature