Unraveling Double-Exchange Effect Coupling Spin Modulation of SrFeMoO Electrocatalyst for Solid Oxide Cells.

Perovskites are promising electrocatalysts for solid oxide cells (SOCs) due to their tunable structures. The reactivity/stability can be effectively enhanced by tuning the spin, whereas few studies have been able to elucidate the correlation between spin and reactivity/stability. Herein, the double-exchange effect coupling spin modulation is studied for SrFeNiMoO, which exhibits a current density of 2.48 A cm with high stability at 800 °C and 1.5 V as the cathode in CO reduction. Based on Mössbauer spectroscopy, X-ray absorption spectroscopy, and density functional theory calculations, it is revealed that the doped Ni induces an additional double-exchange effect with enhanced conductivity coupling spin modulation. It produces high-spin Fe () with vacant orbitals which can accommodate additional electrons from the lone pairs of oxygen, thus facilitating CO reduction by enhancing CO adsorption and weakening CO adsorption. This work provides a general strategy for the design of SOC electrocatalysts.