Dielectric and surface potential study of NiO/La_2Mo_2O_9 composite

The electron gain and loss capability and oxygen diffusion behavior of SOFC anode materials have effects on their catalytic property. In this paper,dielectric behavior and the capability of electron gain and loss for NiO / La2 Mo2O9 composite with 20% and 40% NiO in volume( abbreviated as N / L28 and N / L46,respectively) were studied. According to the order from low to high temperature,the dielectric loss peaks associated with NiO phase and short distance diffusion of oxygen vacancies in La2Mo2O9 phase were observed respectively in both N / L28 and N / L46 samples. The stepwise change of dielectric loss at 833K in both N / L28 and N / L46 samples were attributed to the αLa2Mo2O9-βLa2Mo2O9 phase transition. For N/L46 sample,a broadened dielectric loss peak observed in 500-813K can be fitted by one relaxation peak and two non-relaxation peaks. The results of surface potential measurement using Kelvin probe method indicate that the energy descending order for electron loss was La2Mo2O9,N/L28,N/L46,NiO.