Efficient electrochemical CO2 reduction reaction on a robust perovskite type cathode with in-situ exsolved Fe-Ru alloy nanocatalysts

Electrochemical carbon dioxide reduction reaction (CO2RR) via a solid oxide CO2 electrolyzer has been attracting increasing attention because it can effectively convert CO2 into high value-added chemical products and effi-ciently store the excessive electricity. However, the lack of efficient electrodes to catalyze this reaction process severely limits their practical applications. Herein, we report Ru promoted perovskite type Pr0.4Sr0.6Fe0.9-Mo0.1O3-delta with a general formula of Pr0.4Sr0.6Fe0.8Ru0.1Mo0.1O3-delta (Ru-PSFM) cathode to overcome the constraints of low current density, low Faradaic efficiency, and high overpotential of CO2RR. The cathode electrolysis current density of CO2RR at 800 degrees C and 2.0 V is considerably improved from 0.707 to 1.480 A cm-2 with an enhancement rate of 109%, while its corresponding electrode polarization resistance at 1.4 V is significantly lowered from 2.228 to 0.319 omega cm-2. Furthermore, the solid oxide CO2 electrolyzer exhibits superior stability during the operation. Distribution of relaxation times analysis results reveal that the rate-determining process, involving CO2 adsorption, dissociation, and activation on the cathode surface, is significantly activated and dramatically accelerated after Ru doping. Density function theory calculations demonstrate that the in-situ exsolved Fe-Ru alloy nanocatalyst is a more favorable site for the activation of CO2 dissociation. This work provides valuable insights into the rational design of efficient cathodes for CO2RR.