Abstract
Two well-defined iron catalysts, Fe(II)/Al2O3 (4.5 wt %) and Fe2O3/Al2O3 (1.5 wt %), have been studied using Fe K-edge X-ray absorption fine structure (XAFS). The total coordination number of the nearest oxygen neighbors is found to be 4.9 for the former and 5.7 for the latter, but the average Fe−O bond length remains the same, 1.98 Å. The nearest iron neighbors at 2.95−2.97 Å are observed for both the catalysts, but for the Fe2O3/Al2O3, further two iron neighbors at 3.42 and 3.86 Å are also present. The fact that the shell radius of 3.42 Å is times longer than that of the first nearest irons is consistent with what is expected from the para- and the meta-positions surrounding the same oxygen on the γ-Al2O3 (111) plane but is at variance with the estimation made for the (110) plane. Two geometrical models proposed for the catalysts stoichiometrically explain why the higher metal loading only leads to one type of the iron neighbors but the lower metal loading unexpectedly leads to three types of iron neighbors.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
