Developing a multistep surface reaction mechanism to model the impact of H2 and CO on the performance and defect chemistry ofLa0.9Ca0.1

Hydrogen‐assisted Carbon Dioxide Thermochemical Reduction on La0.9Ca0.1FeO3−δ Membranes: A Kinetics Study

“…This oxygen incorporation reaction is similar to those for O 2 or H 2 O incorporation in LCF‐91 materials.…”

“…The species concentrations very close to the membrane surface are calculated using Equations , and the kinetic parameters k and k̃ are fitted using experimental data. Although more elaborate models that consider diffusion of differently charged species and multi‐step reactions have been developed recently, Equation is sufficient to examine the role of the different resistances in the oxygen‐transport processes and surface chemistry, which will be discussed below.…”

“…The fitted parameters are summarized in Table . The activation energy values are in the same order of magnitude as those obtained using a more elaborate model (considering four‐step surface reaction mechanisms and the Poisson–Nernst–Planck diffusion) . We show that the resistance‐network model developed herein can describe the dependence of oxygen flux resulting from CO 2 thermochemical reduction on various factors.…”

“…The activation energy is higher to overcome the transition state. [b] Activation energies for the reactions with holes ( ) …”

“…H 2 oxidation was found to be faster than CO oxidation on many oxide surfaces, such as BaCo 0.7 Fe 0.2 Nb 0.1 O 3− δ , La 0.9 Ca 0.1 FeO 3− δ , and Ni/YSZ . As the sweep side surface kinetics are rate limiting at 990 °C with a CO 2 concentration >50 mol%, adding more reactive fuel on the sweep side is expected to improve the reduction of CO 2 .…”