Effects of Silver Nanoparticles on the Electrochemical Response of La_0.1Sr_0.9TiO₃ Solid Oxide Fuel Cell Anode

The effect of the incorporation of silver nanoparticles (Ag-NPs) on the electrochemical behavior of symmetrical La0.1Sr0.9TiO3 (LST)/ La0.4Ce0.6O2 (LDC)/ La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) cells is presented. Ag-NPs were infiltrated into LST anodes by using a wet chemical reduction technique. The cells with different concentrations of Ag-NPs were prepared by modifying the immersion time in a reducing solution. The Ag-NPs infiltrated were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The analysis of the fraction of AgNPs incorporated into the cells was performed by X-ray diffraction (XRD) and particle-induced X-ray emission (PIXE). The effect of the Ag-NPs on the electrochemical behavior of the obtained electrodes was studied by electrochemical impedance spectroscopy (EIS), varying the hydrogen partial pressure. The EIS spectra obtained were analyzed by the distribution of relaxation times (DRT). The results of this study indicated that the infiltration of Ag-NPs improved the electrochemical response of the LST anodes by reducing their ohmic losses due to the increase in electronic conductivity. In this regard, incorporating 16 wt % of silver nanoparticles led to a 70% decrease in the area-specific resistance (ASR) of the LST. Furthermore, it was observed that the Ag-NPs infiltrated acted as catalysts of the hydrogen oxidation reaction (HOR), decreasing the overpotential and affecting the mechanisms that limit the HOR.