Enhanced Electrocatalytic Activity of SrFe0.9Nb0.1O3-δ through In-situ Synthesis of Sr3Fe1.8Nb0.2O7-δ Coating

The influence of the heterogeneous interface is critical for the catalytic activity of the oxygen reduction reaction (ORR). This study demonstrates an enhancement of the electrocatalytic activity of the SrFe0.9Nb0.1O3-δ (SFN113) electrode through the construction of a SrFe0.9Nb0.1O3-δ-Sr3Fe1.8Nb0.2O7-δ (SFN113-SFN327) heterogeneous interface. By coating varying amounts of Sr(NO3)2 (0.1g, 0.2g and 0.3g) on SFN113 (1g), SFN113/327 composite electrodes with different amounts of triple conducting oxide SFN327 are in-situ synthesized by high temperature calcination. Electrical Conductivity Relaxation (ECR) tests show that SFN327 has superior oxygen surface exchange performance compared to SFN113, especially at lower temperatures. At 550 °C, the oxygen surface exchange parameter of SFN327 is 4.23 times higher than that of SFN113. Symmetric cell tests with SFN113/327||BaCe0.7Zr0.1Y0.1Yb0.1O3-δ (BCZYYb)||SFN113/327 configuration and single cell tests with Ni-BCZYYb||BCZYYb||SFN113/327 configuration indicate that the SFN113/327 composite electrode with a mass ratio of 1:0.2 displays the best electrocatalytic performance, achieving a power output of 502 mW cm-2 at 700 °C. The work not only in-situ synthesizes the SFN113/327 triple conducting composite electrode, but also introduces a novel method for developing proton conducting electrode materials.