An efficient electrode for reversible oxygen reduction/evolution and ethylene electro-production on protonic ceramic electrochemical cells

Protonic ceramic electrochemical cells (PCECs) have demonstrated great promise for applications in the generation of electricity, and the synthesis of chemicals (for example, ethylene). However, enhancing the electrochemical reactions kinetics and stability of PCECs electrodes is one grand challenge. Here, we present a novel electrode material via a co-doping of cesium (Cs) and niobium (Nb) on PrBaCo2O6-d with the composition of PrBa0.9Cs0.1Co1.9Nb0.1O6-d (PBCCN), which naturally decomposes into dual phases of a double-perovskite PBCCN (DP-PBCCN, 92.3 wt%) and a single-perovskite Ba0.9Cs0.1Co0.95Nb0.05O3-d (SP-BCCN, 7.7 wt%) under typical powder processing conditions. PBCCN exhibits a low area-specific resistance (ASR) value of 0.107 X cm2, an outstanding performance of 2.04 W cm-2 in fuel cell (FC) mode, a current density of -2.84 A cm-2 at 1.3 V in electrolysis cell (EC) mode, and promising reversible operational durability of 53 cycles in 212 hat +/- 0.5 A cm-2 and 650 C. Cs doping generates more oxygen vacancies and accelerates the oxygen exchange kinetics, while Nb doping effectively enhances the stability, as illustrated by the analyses of X-ray photoelectron spectroscopy, and electrical conductivity relaxations. When applied as the positrode for electrochemical non-oxidative dehydrogenation of ethane (C2H6) to ethylene (C2H4) on PCECs, it displays an encouraging C2H6 conversion of 12.75% and a C2H4 selectivity of 98.4% at 1.2 V. (c) 2024 Science China Press. Published by Elsevier B.V. and Science China Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.