کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1445949 1509611 2014 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Correlation between defect structure and electrochemical properties of mixed conducting La0.1Sr0.9Co0.8Fe0.2O3−δ
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Correlation between defect structure and electrochemical properties of mixed conducting La0.1Sr0.9Co0.8Fe0.2O3−δ
چکیده انگلیسی

The high catalytic properties of LSCF1982 arise from its defect structure. In this work, the oxygen nonstoichiometry (δ  ) of LSCF1982 was analyzed as a function of oxygen partial pressure (PO2)(PO2) and temperature for the -6⩽log(PO2/atm)⩽0-6⩽log(PO2/atm)⩽0 and 800 ⩽ T/°C ⩽ 1000 ranges. A defect structure model for LSCF1982 was presented, which fitted well with the experimental data for δ. The equilibrium constants of appropriate defect reactions were determined. Analysis of the defect structure of LSCF1982 suggested that the conduction mechanism of LSCF1982 is governed by hopping conduction and band conduction of p-type carriers, which was determined by the analysis of thermoelectric power. The characteristic membrane thickness (Lc), indicating the transition from predominantly bulk-diffusion controlled reaction to surface-exchange controlled reaction, had a value of 3.5 ± 0.9 × 10−2 cm. The oxygen vacancy diffusivity was calculated from the relationship between oxygen flux and oxygen chemical potential gradient. The chemical expansion was measured as a function of PO2PO2 and temperature in the 10-3⩽PO2/atm⩽0.2110-3⩽PO2/atm⩽0.21 and 800 ⩽ T/°C ⩽ 1000 ranges. The chemical expansion model based on the relative change in mean ionic radius was employed to compute the chemical expansion vs. δ, which indicated that the spin states of B-site transition metal ions are a mixture of high-spin and low-spin states, and made the transition from the low-spin to the high-spin state with an increase in δ and temperature.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Acta Materialia - Volume 65, 15 February 2014, Pages 373–382
نویسندگان
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