Nanoscopic Ni Interfaced with Oxygen Conductive Supports: Link between Electrochemical and Catalytic Studies

Abstract

© The Electrochemical Society. Nickel nanoparticles (NPs) of ∼70 nm diameter were tested for their catalytic and electrochemical performance when free-standing or supported at 1 wt.% on CeO2 or YSZ conductive supports. Ni/CeO2 showed a high complete ethylene conversion (43%) followed by Ni/YSZ (38%) and then free-standing Ni (5%) at 350 °C. The Tafel plots allowed us to find the exchange current density, io, of the catalysts. Using i0, the self-induced Faradaic efficiency, AMsu was calculated for the two supported catalysts and was found to be almost the double for Ni/CeO2 compared to Ni/YSZ. The inverse relationship between i0 and the catalytic rate of Ni. Ni/YSZ and Ni/CeO2 is similar to the one for the noble Pt, Ru and Ir catalysts reported previously. This correlation suggests that for nanoscopic Ni catalysts interfaced with oxygen conducting ceramics, the mechanism of metal-support interaction (MSI) is functionally identical to that of electrochemical promotion of catalysis (EPOC).