Catalytic methane activation over La1−xSrxScO3−α proton-conducting oxide surface: A comprehensive study

Photo-assisted synthesis of protonated oxides for fuel cells

The absence of intrinsic protons in proton-conducting oxides (PCO) is a significant challenge that limits the proton conductivity of proton-conducting perovskites, such as Y-doped BaMO3 (M = Zr, Ce), in proton ceramic fuel cells exhibit low conductivity (10-3 to 10-2 S cm-1 at 600 °C). Herein, we introduce a photo-assisted synthesis method for incorporating protons into Al-doped ceria (AlxCe1-xO2-δ, x = 0.2; M-ACO), leveraging the open cubic fluorite structure and photo-activated radical reactions. Specifically, photon-generated hydroxyl reactiveOH ∙ and superoxide (O 2 ∙ - ) Radicals are generated and interact with the ACO crystal lattice, facilitating proton incorporation and resulting in the synthesis of native-proton-type PCO. This process results in a protonated (H-ACO) with a high proton conductivity of 0.14 S cm-1 and exceptional power density of 922 mW cm-2 at 500 °C. This versatile synthesis methodology offers broader development of advanced PCO for energy-related applications.

Design of Mixed Ionic-Electronic Materials for Permselective Membranes and Solid Oxide Fuel Cells Based on Their Oxygen and Hydrogen Mobility

Oxygen and hydrogen mobility are among the important characteristics for the operation of solid oxide fuel cells, permselective membranes and many other electrochemical devices. This, along with other characteristics, enables a high-power density in solid oxide fuel cells due to reducing the electrolyte resistance and enabling the electrode processes to not be limited by the electrode-electrolyte-gas phase triple-phase boundary, as well as providing high oxygen or hydrogen permeation fluxes for membranes due to a high ambipolar conductivity. This work focuses on the oxygen and hydrogen diffusion of mixed ionic (oxide ionic or/and protonic)-electronic conducting materials for these devices, and its role in their performance. The main laws of bulk diffusion and surface exchange are highlighted. Isotope exchange techniques allow us to study these processes in detail. Ionic transport properties of conventional and state-of-the-art materials including perovskites, Ruddlesden-Popper phases, fluorites, pyrochlores, composites, etc., are reviewed.