Porotnikova Natalia, Farlenkov Andrei, Naumov Sergey, Vlasov Maxim, Khodimchuk Anna, Fetisov Andrey, Ananyev Maxim
Institute of High Temperature Electrochemistry, UB RAS, Ekaterinburg, Russia.
Ural Federal University named after the First President of Russia B.N. Yeltsin, Ekaterinburg, Russia.
Phys Chem Chem Phys. 2021 May 19;23(19):11272-11286. doi: 10.1039/d1cp01099a.
The single crystal and polycrystalline specimens of La0.84Sr0.16CoO3-δ oxide were synthesized and characterized by X-ray powder diffraction analysis, energy dispersive X-ray microanalysis, the electron backscatter diffraction technique, and X-ray photoelectron spectroscopy. A thin slab was prepared from the grown single crystal with its surface corresponding to the (110) plane. The kinetics of the oxygen exchange between the gas phase and a single crystal and a polycrystalline specimen was studied by means of 16O/18O oxygen isotope exchange at T = 750-850 °C and PO2 = 5.3 × 10-3-2.2 × 10-2 atm. Temperature dependencies of the oxygen heterogeneous exchange rate, the oxygen dissociative adsorption and incorporation rates, and oxygen diffusion coefficients were obtained. The relationship between the crystallographic orientation of oxides and the kinetic parameters of oxides has been established. Correlations between the surface state and the rates of individual stages of oxygen exchange as well as oxygen diffusion pathways in the single crystal compared with those in the polycrystalline specimen are considered.
合成了La0.84Sr0.16CoO3-δ氧化物的单晶和多晶样品，并通过X射线粉末衍射分析、能量色散X射线微分析、电子背散射衍射技术和X射线光电子能谱对其进行了表征。从生长的单晶制备了一个薄板，其表面对应于(110)平面。通过在T = 750-850°C和PO2 = 5.3×10-3-2.2×10-2 atm下进行16O/18O氧同位素交换，研究了气相与单晶和多晶样品之间的氧交换动力学。获得了氧非均相交换速率、氧解离吸附和掺入速率以及氧扩散系数的温度依赖性。建立了氧化物的晶体取向与氧化物动力学参数之间的关系。考虑了单晶与多晶样品相比，表面状态与氧交换各个阶段的速率以及氧扩散途径之间的相关性。
