Pr and Mo Co‐Doped SrFeO_3–δ as an Efficient Cathode for Pure CO₂ Reduction Reaction in a Solid Oxide Electrolysis Cell

Abstract

Carbon dioxide (CO 2) electrolysis via a solid oxide electrolysis cell (SOEC), simplified as CO 2 RR, is a significantly promising energy conversion technology, which can effectively convert greenhouse gas CO 2 to value-added chemical agent carbon monoxide (CO) by using renewable electricity with high efficiency. [1] A SOEC is usually consisted of an ion conducting electrolyte, an anode for O 2 generation, and a cathode for CO 2 electroreduction. [1a,1b] To make the technology available for commercial application, it is necessary to simultaneously enhance the electrocatalytic activity and stability of the cathode during the operation. The state-of-the-art Ni-based cathodes exhibit excellent electrochemical performance, [2] but suffer from performance degradation due to the aggregation and oxidation of Ni particles as well as carbon deposition at the elevated temperature. [3] Therefore, it is highly in need to develop alternative cathode materials with high electrocatalytic activity and good long-term stability for CO 2 RR application. In recent years, mixed ionic-electronic conducting (MIEC) perovskite oxides, such as strontium titanate (SrTiO 3)-based oxides and lanthanum chromate (LaCrO 3)-based oxides, have been explored as the potential cathode materials because these cathode materials have demonstrated excellent stability at the elevated temperature for directly electrolyzing CO 2 to CO without the addition of any safe gas (usually H 2 , CO, or H 2-CO mixture). [4] However, their performance is still insufficient for practical CO 2 RR application. Therefore, further modification still needs to be done to efficiently enhance the cathode performance to enable direct CO 2 electrolysis. It is well known that CO 2 is difficult to be directly reduced to CO because of its extremely high energy barrier for directly breaking C═O bond (%1.9 eV), and sufficient CO 2 adsorption and activation is an important prerequisite for direct CO 2 electroreduction via a SOEC. [5] Previous studies have revealed that the introduction of oxygen vacancies at the cathode surface could not only effectively accelerate the CO 2 chemical adsorption, but also significantly reduce the energy barrier of CO 2 dissociation, possibly facilitating the direct CO 2 RR. [6] Metallic nanoparticles have been commonly introduced into the perovskite oxide cathodes to effectively alter the electrocatalytic properties of the cathodes, and to significantly increase the concentration of oxygen vacancies, resulting in a remarkable improvement of CO 2 adsorption and activation. [4d,5b,7] Therefore, it is highly expected to construct metallic nanoparticles-decorated perovskite oxide cathodes for efficient CO 2 RR. Recently, metallic nanoparticles-structured perovskite oxide cathodes have been effectively generated in one step by the in situ exsolution method. [8] It is demonstrated that these in situ exsolved metallic nanoparticles can strongly facilitate CO 2 adsorption and C═O bond activation, reasonably

In Situ Exsolution of Core‐Shell Structured NiFe/FeOx Nanoparticles on Pr0.4Sr1.6(NiFe)1.5Mo0.5O6‐δ for CO2 Electrolysis

“…[43] The P3 is mainly related to the charge transfer process, P4 is mainly related to the CO 2 dissociation and adsorption. [12,14,39] It is noted that the total R P of the single cells are dominated by P3 and P 4 , confirming that electrochemical reaction process is the rate-limiting step for CO 2 electrolysis. Notably, comparing the DRT curves as indicated in Figure S7 (Supporting Information), P3 and P4 of the single cell with PSNFM-NFA@FeO cathode is much smaller than that of the single cell with PSNFM cathode.…”

Characterization of Pr0.5A0.5Fe0.9W0.1O3−δ (A = Ca, Sr and Ba) as symmetric electrodes for solid oxide fuel cells

“…28 Up to now, the electrochemical performance of praseodymium ferrite single perovskite oxides as symmetric electrodes for SSOFCs/SSOECs has been extensively investigated. 19,21,29,30 However, there are a few references reporting the effects of different alkaline-earth metal dopants on the A-site on the structure, thermal behavior, and electrochemical performance of perovskite oxides as symmetric electrodes. Therefore, it would be interesting to investigate the effect of alkaline-earth metal doping at the A-site on the electrochemical performance of ferrite-based perovskite oxides.…”