Cu–Fe–Ni nano alloy particles obtained by exsolution from Cu(Ni)Fe2O4 as active anode for SOFCs

Abstract

The metal exsolution of anodes was studied using spinel oxides of CuFe₂O₄ for enhancing the anodic activity of electrodes for solid oxide fuel cells (SOFCs) at lower temperatures. Moreover, Ni-doped Cu_1−xNi_xFe₂O₄ (x = 0.1, 0.2, 0.3, and 0.5; CNFO) spinel oxides were investigated. Although CNFO spinel oxides were decomposed by a reduction atmosphere, decomposed CNFO became a metallic phase with the exsolved nanosized alloy particles, which are composites of Cu-rich Cu–Fe–Ni and Fe-rich Fe–Ni–Cu metals on anodes, investigated using SEM-EDX, TEM-EDX and XRD. According to power generation properties, the exsolved alloy formed from CNFO 0.1 showed the highest MPD of 670 mW cm⁻² at 1073 K and 120 mW cm⁻² at 873 K. Compared with the Ni–Fe (9 : 1 wt%) alloy anode, CNFO 0.1 showed significantly decreased anodic polarization resistance, and hence, high power density was attributed to nano alloy particles. Therefore, the metal particles on the metallic matrix exsolved from the CNFO spinel oxide are highly effective for active anode catalysts for intermediate temperature operations.