Perovskites have been shown to be high-performance oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts, easily outperforming noble metals like platinum. Some of the most promising are Ba0.5Sr0.5Co0.8Fe0.2O3-∂ (BSCF-5582) and La0.5Sr0.5Co0.8Fe0.2O3-∂ (LSCF-5582), however the literature synthesis procedures for these catalysts is time- and energy-intensive. Prior research with La1.0Fe0.4Co0.6O3-∂ has shown that spray pyrolysis can produce thin films of similar quality to the literature perovskites, and this research sought to extend that success to BSCF-5582 and LSCF-5582. Perovskite thin films of varying La:Sr:Co:Fe and Ba:Sr:Co:Fe ratios were synthesized by spray pyrolysis, which entailed deposition of the aqueous nitrate or acetate precursors and annealing at 500 degrees C for 5 hours, after which the films are ready for testing. Performance of each composition was measured by linear sweep voltammetry (LSV) in a 4-electrode cell, with each composition directly compared to a platinum reference or another perovskite electrode. BSCF-5582 did not exhibit the performance indicated by the literature, though LSCF-5582 met literature ORR values in 0.1 M NaOH and exhibited an earlier current onset potential for both OER and ORR activity. Compared to the other perovskites synthesized, LSCF-5582 exhibited the greatest bifunctional activity, and exhibited remarkable stability at catalyzing the OER. While diminishing performance of the film was observed during ORR, recovery of the film occurred after cycling the films through the OER.

Synthesis of leading perovskite oxygen reaction catalysts by spray pyrolysis: A simpler and successful technique

253rd National Meeting (2017)

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