Bimetallic Exsolved Heterostructures of Controlled Composition with Tunable Catalytic Properties

摘要

In this paper, we show how the composition of bimetallic Fe-Ni exsolution can be controlled by the nature and concentration of oxygen vacancies in the parental matrix and how this is used to modify the performance of CO2-assisted ethane conversion. Mesoporous A-sitedeficient La0.4Sr0.6-alpha Ti0.6Fe0.35Ni0.05O3 +/-delta (0 40 m2/g) enabled fast exsolution kinetics (T < 500 degrees C, t < 1 h) of bimetallic Fe-Ni nanoparticles of increasing size (3-10 nm). Through the application of a multitechnique concentration of oxygen vacancies associated with iron, which controlled the Fe reduction. Instead of homogeneous bimetallic nanoparticles, the increasing Fe fraction from 37 to 57 led to the emergence of bimodal Fe/Ni3Fe systems. Catalytic tests showed superior stability of our catalysts with respect to commercial Ni/Al2O3. Ethane reforming was found to be the favored pathway, but an increase in selectivity toward ethane dehydrogenation occurred for the systems with a low metallic Fe fraction. The chance to control the reduction and growth processes of bimetallic exsolution offers interesting prospects for the design of advanced catalysts based on bimodal nanoparticle heterostructures.