LaFe_xCo_(1–x)O₃Thin-Film Oxygen Reduction Catalysts Prepared Using Spray Pyrolysis without Conductive Additives

Abstract

LaFe x Co (1– x ) O 3 thin films were prepared on fluorine-doped tin oxide conducting glass substrates by spray pyrolysis without any conductive additives and evaluated for their ability to catalyze the oxygen reduction reaction. Onset potential and current density were found to be comparable to platinum, and the resulting crystallite size was on the order of 20 nm. Coordination of the precursor metal ions by citrate was found not to be advantageous. Results from multiple scan linear sweep voltammetry suggest lattice oxide saturation during reduction of oxygen and lattice oxide depletion upon water oxidation. The color of the best-performing composition changes dramatically between 1.2 and −1.15 V versus saturated calomel electrode, so X-ray photoelectron spectra of the fully oxidized and reduced films were compared, demonstrating that cobalt in the film changes oxidation state. Performance of the films as a function of iron-to-cobalt ratio is consistent with what others have reported in the literature, indicating that spray pyrolysis is an efficient method to prepare and evaluate new catalytic materials.

Perovskite Oxide Based Electrodes for the Oxygen Reduction and Evolution Reactions: The Underlying Mechanism

“…Indeed, only by using perovskite single-material electrodes can the ORR mechanism occurring on the perovskite surface be studied. To date, a small number of researchers have published the ORR activity of perovskites without carbon and a few examples are given here. − One way that perovskites have been successfully studied without carbon is by using epitaxial thin films. − With physical vapor deposition techniques, the perovskite’s structure and composition can be precisely tailored.…”

LaCoxFe1-XO3 (0≤x≤1) spherical nanostructures prepared via ultrasonic approach as photocatalysts

“…[6] , [58] Further, the XRD patterns of as-synthesized LaCo 0.2 Fe 0.8 O 3 and LaCo 0.4 Fe 0.6 O 3 were well matched with earlier published reference articles and JCPDS card nos. (88–0641 and 40–0224), respectively [59] , [60] .

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Nanoscale Perovskites as Catalysts and Supports for Direct Methanol Fuel Cells

“…Kinetic measurements indicated that the as-prepared LFCO-FTO composite maintained as imilara ctivity to that of unsupported bulk Pt itself. [47] BMethanol oxidation reaction (MOR)…”

“…In particular, a LaFe 0.4 Co 0.6 O 3 (LFCO) thin film was deposited onto FTO by means of spray pyrolysis, and the presence of an optically transparent FTO electrode enabled the observation of a reversible color change upon the application of a potential, thereby suggesting that the perovskite film could repeatedly and reversibly oxidize and reduce. Kinetic measurements indicated that the as‐prepared LFCO‐FTO composite maintained a similar activity to that of unsupported bulk Pt itself …”