Enhanced oxygen reduction reaction with nano-scale pyrochlore bismuth ruthenate via cost-effective wet-chemical synthesis

Abstract

Pyrochlore ruthenate oxides are promising electrocatalytic materials for lower temperature solid oxide fuel cell (LT-SOFC) cathodes due to their high catalytic activity toward oxygen reduction reaction (ORR) which is the major rate-limiting step at reduced temperatures (below 750 degrees C). Here we report for the first time highly pure pyrochlore bismuth ruthenate (Bi2Ru2O7, BRO7) synthesized via a practical and cost-effective glycine-nitrate (GNC) combustion method. The synthesis parameters including glycine to nitrate ratio and calcination conditions were systematically optimized, resulting in nanoparticles with crystallite size of similar to 30 nm and significant reduction in synthesis steps. Incorporating the synthesized BRO7 nanoparticles with highly conductive bismuth oxide as an SOFC cathode results in significant enhancement of ORR, showing 9 times lower SOFC cathode area specific resistance, compared to that of BRO7 via conventional solid-state reaction. Thus, this result demonstrates the feasibility of BRO7 nanoparticles via GNC to enhance the ORR for lower temperature SOFC applications.