A fundamental study of infiltrated CeO2 and (Gd,Ce)O2 nanoparticles on the electrocatalytic activity of Pt cathodes of solid oxide fuel cells

A thin Pt skeleton with a well-defined porous structure prepared on Y 2 O 3 –ZrO 2 (YSZ) substrate is used as template to study the effect of impregnated pure CeO 2 and Gd-doped CeO 2 (GDC) nanoparticles on the electrochemical activity of Pt electrodes and to minimize possible interactions between the infiltrated phase/solution and the porous skeleton structure. The results show that the activity of Pt cathodes is enhanced by the infiltration of 0.2 mg cm − 2 (6.2 wt.%) CeO 2 and GDC nanoparticles. For the O 2 reduction reaction under open circuit and at low current region the promotion effect of infiltrated CeO 2 and GDC nanoparticles is close, but under higher currents the infiltrated GDC exhibits a much higher electrocatalytic activity as compared to the infiltrated CeO 2 for the O 2 reduction reaction on the Pt electrodes. The high electronic conductivity and high oxygen vacancies of GDC nanoparticles under polarization or dc bias, as compared to that of pure CeO 2 are most likely responsible for the high catalytic effect of GDC nanoparticles for the O 2 reduction reaction on the Pt. This study demonstrates that the electrochemical performance of infiltrated nano-structured electrodes is fundamentally affected by the catalytic properties of infiltrated nanoparticles.