Pr and Mo Co‐Doped SrFeO 3– δ as an Efficient Cathode for Pure CO 2 Reduction Reaction in a Solid Oxide Electrolysis Cell

Electroreduction of carbon dioxide (CO 2 ) to carbon monoxide (CO) via a solid oxide electrolysis cell, simplified as CO 2 RR, is now attracting more and more attention because it can effectively utilize greenhouse gas and efficiently convert surplus electrical energy into chemical energy. In this work, a stable cathode material Pr 0.4 Sr 0.6 Fe 0.875 Mo 0.125 O 3– δ (PSFM), which can be transferred to metallic Fe nanoparticles–structured PSFM (Fe@PSFM) cathode through the in situ exsolution method, has been successfully prepared for CO 2 RR application, and exhibits a considerable electrolysis current density of 0.71 A cm −2 with good stability when operated at 800 °C and 1.5 V. It is demonstrated that a critical applied voltage is needed for initiating the in situ exsolution of metallic Fe nanoparticles, which can effectively accelerate the CO 2 adsorption, dissociation ionization, and surface diffusion to three phase boundaries (TPBs) processes. These results indicate that PSFM is a promising cathode candidate for CO 2 RR application because of its good electrochemical performance and stability. The findings can guide the development of other ceramic nanostructured electrode decorated with in situ exsolved metallic nanoparticles for energy conversion and storage devices.