Electrocatalytic performance of Pb−Ru pyrochlore prepared by the amorphous citrate precursor method for bifunctional air electrodes

Abstract

Pb-Ru pyrochlore has been of interest as bifunctional electrocatalyst for an air electrode. An amorphous citrate precursor (ACP) process has been optimized to prepare Pb-Ru pyrochlore powders with high surface areas with consequent improvement of its electrocatalytic performance in an air electrode. The surface area of the final powder is 30 m 2 /g, which is larger than the value obtained by the conventional hydroxide method. A PTFE-bonded gas diffusion electrode loaded with pyrochlore catalysts prepared by the ACP method showed good bifunctional performance. The electrode loaded with only 10 mg/cm 2 of pyrochlore powder prepared by ACP showed good bifunctional performance, i.e. 100 mA/cm 2 for oxygen reduction and 100 mA/cm 2 for oxygen evolution, at 0.6 and 1.6 V vs. RHE, respectively. This performance compares well to the results from lower-area pyrochlore at much higher loading.

Flux growth and physical properties of pyrochlore Pb2Ru2O6.5 single crystals

“…The polycrystalline PRO shows metallic behavior with an electronic conductivity as high as 2 -5 Â 10 3 S cm À1 at 300 K [3,4]. Furthermore, solid solutions of Pb 2 (Ru 2Àx Pb x )O 6.5 (0pxp1) [5], have also been of interest as bifunctional electrocatalysts for both oxygen gas reduction and evolution [6][7][8][9]. The high conductivity of these solid solutions is essential to their high electrocatalystic activity.…”

Synthesis and Application of La[sub 0.59]Ca[sub 0.41]CoO[sub 3] Nanotubes

“…6 Compared to various other electrocatalysts such as noble metals, 7 spinels, 8 pyrochlores, 9 and metallorganic compound, 10 the La 0.6 Ca 0.4 CoO 3 compound has advantages of low cost, high electrochemical activity, good alkaline stability, and excellent conductivity, and has been successfully applied in zinc-air and metal hydride ͑MH͒-air batteries. [11][12][13][14][15] To date, La 0.6 Ca 0.4 CoO 3 nanostructures with two morphologies of nanoparticles 5,16-20 by sol-gel and film 21 by pulsed laser deposition have been prepared.…”

“…Over the past decades, calcium-doped perovskite-type lanthanum cobaltate La 0.6 Ca 0.4 CoO 3 has been established to be the best candidate 5 as electrocatalyst in alkaline electrolytes for air electrodes since the initial application by Meadowcroft. 6 Compared to various other electrocatalysts such as noble metals, 7 spinels, 8 pyrochlores, 9 and metallorganic compound, 10 the La 0.6 Ca 0.4 CoO 3 compound has advantages of low cost, high electrochemical activity, good alkaline stability, and excellent conductivity, and has been successfully applied in zinc-air and metal hydride ͑MH͒-air batteries. [11][12][13][14][15] To date, La 0.6 Ca 0.4 CoO 3 nanostructures with two morphologies of nanoparticles 5,[16][17][18][19][20] by sol-gel and film 21 by pulsed laser deposition have been prepared.…”