Environmentally Benign pSOFC for Emissions-Free Energy: Assessment of Nickel Network Resistance in Anodic Ni/BCY15 Nanocatalyst

Yttrium-doped barium cerate (BCY15) was used as ceramic matrix to obtain Ni/BCY15 anode cermet for application in proton-conducting solid oxide fuel cells (pSOFC). Ni/BCY15 cermets were prepared in two different types of medium, namely deionized water (W) and anhydrous ethylene glycol (EG) using wet chemical synthesis by hydrazine. An in-depth analysis of anodic nickel catalyst was made aiming to elucidate the effect of anode tablets' preparation by high temperature treatment on the resistance of metallic Ni in Ni/BCY15-W and Ni/BCY15-EG anode catalysts. On purpose reoxidation upon high-temperature treatment (1100 °C for 1 h) in air ambience was accomplished. Detailed characterization of reoxidized Ni/BCY15-W-1100 and Ni/BCY15-EG-1100 anode catalysts by means of surface and bulk analysis was performed. XPS, HRTEM, TPR, and impedance spectroscopy measurements experimentally confirmed the presence of residual metallic Ni in the anode catalyst prepared in ethylene glycol medium. These findings were evidence of strong metal Ni network resistance to oxidation in anodic Ni/BCY15-EG. Enhanced resistance of the metal Ni phase contributed to a new microstructure of the Ni/BCY15-EG-1100 anode cermet getting more stable to changes that cause degradation during operation.