Shape control of ceria catalytic supports for enhanced ethanol reforming in solid oxide fuel cells

Abstract

Matching the catalytic activity of nanostructured materials and processing parameters for high-temperature electrochemical devices is a challenge. Controlling the nanoparticle shape has been proposed as an alternative method to stabilize crystalline surfaces to inhibit particle coarsening and sustain catalytic activity after high-temperature treatment. In this study, nickel-based catalysts supported on shape-controlled (nanorods and nanocubes) gadolinium-doped cerium oxide (GDC) were evaluated for the steam reforming reaction of ethanol, aiming at direct ethanol solid oxide fuel cells (SOFC). The morphology of the support was shown to have an important role in the catalytic activity, particularly when heat treatments for fuel cell fabrication are considered. The Ni catalyst supported on the GDC nanorods sustained the highest catalytic activity after heat treatment despite the morphology change of the support at high temperatures. The excellent properties of the shape-controlled materials were demonstrated in SOFC using the Ni-GDC catalytic layer tailored for the operation on anhydrous ethanol at 700 °C. The fuel cell exhibited a stable performance for more than 100 h of continuous operation without any sign of degradation due to carbon deposition. Such a result is an important step toward the stable operation of direct ethanol intermediate temperature solid oxide fuel cells.