Electrochemical Activation Applied to Perovskite Titanate Fibers to Yield Supported Alloy Nanoparticles for Electrocatalytic Application
Min Xu, Chencheng Liu, Aaron B. Naden, Herbert Früchtl, Michæl Bühl, John T. S. Irvine
Abstract
Abstract Active bi‐metallic nanoparticles are of key importance in catalysis and renewable energy. Here, the in situ formation of bi‐metallic nanoparticles is investigated by exsolution on 200 nm diameter perovskite fibers. The B‐site co‐doped perovskite fibers display a high degree of exsolution, decorated with NiCo or Ni 3 Fe bi‐metallic nanoparticles with average diameter about 29 and 35 nm, respectively. The perovskite fibers are utilized as cathode materials in pure CO 2 electrolysis cells due to their redox stability in the CO/CO 2 atmosphere. After in situ electrochemical switching, the nanoparticles exsolved from the perovskite fiber demonstrate an enhanced performance in pure CO 2 electrolysis. At 900 °C, the current density of solid oxide electrolysis cell (SOEC) with 200 µm YSZ electrolyte supported NiFe doped perovskite fiber anode reaches 0.75 Acm −2 at 1.6 V superior to the NiCo doped perovskite fiber anode (about 1.5 times) in pure CO 2 . According to DFT calculations (PBE‐D3 level) the superior CO 2 conversion on NiFe compared to NiCo bi‐metallic species is related to an enhanced driving force for C‐O cleavage under formation of CO chemisorbed on the nanoparticle and a reduced binding energy of CO required to release this product.