Electrocatalytic Properties of Lanthanum-based Perovskites for Water Splitting and Energy Storage Applications

Abstract

Recent changes in global weather patterns have punctuated the need for mollification through a cleaner energy option. As part of the plan, hydrogen production for fuel cells offers substantial power without carbon emissions. Overall water splitting, with the aid of a low cost electrocatalyst could prove to be an abundant green fuel source. Utilizing readily available transition metals, three perovskite nanostructures were studied as a multifunctional material for hydrogen production as well as energy storage. LaCoO₃ (LCO), LaFeO₃ (LFO), and LaMnO₃ (LMO) were synthesized and characterized by X-ray diffraction and then dip coated onto nickel foam as electrodes in a standard three electrode system. The electrochemical properties were analyzed with electrochemical impedance spectroscopy (EIS), line scan voltammetry (LSV), and cyclic voltammetry (CV) for its electro-catalytic activity towards both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) as well as its effectiveness as a supercapacitor. It was shown that electrocatalytic activity toward OER was highly dependent on the material composition. Accordingly, LFO had the lowest overpotential voltage of 316 mV at 10 mA/cm2 compared with 376 mV (LCO) and 419 mV (LMO). Toward HER, LMO showed overpotential voltage of 176 mV at 10 mA/cm2, while LCO and LFO showed 221 mV and 230 mV, respectively. Measured at a common current density of 0.5 A/g, the specific capacitance of LMO was 105 F/g over LCO (45 F/g) and LFO (35 F/g). Further investigation for fabrication of devices for energy storage and water splitting electrolyzer application has been considered

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