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Free keywords:
barium chloride, nanocomposite, perovskite, strontium chloride, adsorption, Article, chemical structure, crystal structure, crystallization, cyclic voltammetry, drug synthesis, electric conductivity, electrochemical analysis, electron spin resonance, energy dispersive X ray spectroscopy, high resolution transmission electron microscopy, impedance spectroscopy, inductively coupled plasma mass spectrometry, leaching, oxygen evolution, particle size, physical parameters, spectroscopy, structure analysis, X ray photoemission spectroscopy
Abstract:
Ion leaching from pure-phase oxygen-evolving electrocatalysts generally exists, leading to the collapse and loss of catalyst crystalline matrix. Here, different from previous design methodologies of pure-phase perovskites, we introduce soluble BaCl2 and SrCl2 into perovskites through a self-assembly process aimed at simultaneously tuning dual cation/anion leaching effects and optimizing ion match in perovskites to protect the crystalline matrix. As a proof-of-concept, self-assembled hybrid Ba0.35Sr0.65Co0.8Fe0.2O3-δ (BSCF) nanocomposite (with BaCl2 and SrCl2) exhibits the low overpotential of 260 mV at 10 mA cm-2 in 0.1 M KOH. Multiple operando spectroscopic techniques reveal that the pre-leaching of soluble compounds lowers the difference of interfacial ion concentrations and thus endows the host phase in hybrid BSCF with abundant time and space to form stable edge/face-sharing surface structures. These self-optimized crystalline structures show stable lattice oxygen active sites and short reaction pathways between Co–Co/Fe metal active sites to trigger favorable adsorption of OH− species. © 2020, The Author(s).
