Breakthrough Synergy in Heterojunction-Ordered Oxide Nanocomposites for Accelerated Oxygen Reduction

"Electrochemical ceramic devices (ECDs) are crucial for advancing the transition to a zero-pollution, sustainable future by converting energy from clean sources like hydrogen and producing green hydrogen through water splitting. A significant challenge lies in the high operating temperature (preferably 700-1000 C), where sluggish cathodic reactions, such as oxygen reduction reaction (ORR), are pivotal obstacles. Cost-effective p-type and n-type mixed electronic and ionic conducting oxides (p-MEIOs and n-MEIOs) suffer from electron depletion and insufficient oxygen vacancies during ORR, respectively. Gathering all desired features in a single oxide conductor has proven impractical. BREATHO pioneers a transformative solution by integrating p-MEIO and n-MEIO into vertically aligned nanocomposites (VANs), which feature densely ordered S-scheme heterojunctions with enriched mobile charge carriers, creating synergistic sites that significantly enhance ORR below 600 C. These VANs will be deposited as thin films onto diverse substrates using Pulsed Laser Deposition (PLD), followed by thorough investigations into their local chemistry, structure, and cathodic kinetics using advanced nanoscale characterization techniques, e.g., Plasma Focused Ion Beam Secondary Ion Mass Spectroscopy (PFIB-SIMS), Isotopic Exchange Depth Profiling (IEDP), low-energy ion scattering spectroscopy (LEISS), and atom probe tomography (APT). The performance of VANs as cathodes will be evaluated in metal-supported fuel cells concerning the resistance to chromium poisoning.BREATHOs bottom-up research methodology, drawing from a convergence of interdisciplinary approaches, aims to overcome the persistent challenges in ECDs. This paradigm is anticipated to set a new benchmark in translating cutting-edge material design concepts into functional, real applications. Additionally, the emergent ""1+1>2"" effect achieved in composites provides valuable scientific insights benefiting a broad spectrum of fields."