Anion Fluorine-Doped La_0.6Sr_0.4Fe_0.8Ni_0.2O_3−δ Perovskite Cathodes with Enhanced Electrocatalytic Activity for Solid Oxide Electrolysis Cell Direct CO₂ Electrolysis

Abstract

As a promising and profound device for energy conversion, a solid oxide electrolysis cell (SOEC) can efficiently convert CO2 to CO, realizing chemical storage of renewable energy. However, developing active and stable cathode catalysts for the CO2 reduction reaction (CO2-RR) is critical for SOECs. Herein, to enhance the electrocatalytic performance of a La0.6Sr0.4Fe0.8Ni0.2O3−δ (LSFN) cathode catalyst for CO2-RR, fluorine doping is investigated as anion doping for O-site in the LSFN perovskite lattice. The results confirm that F-doped La0.6Sr0.4Fe0.8Ni0.2O3−δ (LSFNF0.1) has more oxygen vacancies and better CO2 adsorption ability (approaching 4 times than LSFN). The cell with LSFNF0.1 can achieve a maximum electrolysis current density of 1.93 A·cm–2 at 1.8 V at 850 °C, with a R p of 0.275 Ω·cm2 at OCV. Meanwhile, the cell possesses good durability for more than 60 h at an electrolysis current density of 0.6 A·cm–2 without apparent degradation. Mechanistic analysis indicates that F-doping can accelerate the formation of intermediates during electrolysis, indirectly promoting the reaction of the bidentate carbonate (rate-determining step). This work shows that anion-doped LSFNF0.1 is a promising cathode for SOEC direct CO2 electrolysis and provides a potential route for the cathode catalyst development of SOECs.

Self-assembled cathode induced by polarization for high-performance solid oxide fuel cell

“…Generally, P1-P3 are closely related to the adsorption/dissociation of oxygen molecules on the electrode surface, the diffusion and exchange of oxygen species at the gas/solid interface, and charge transfer in the porous layer, respectively; P4 and P5 reect the transmission of oxygen This journal is © The Royal Society of Chemistry 2023 ions in the bulk. [35][36][37][38][39] Thus, the variation of the electrode processes with polarization time can be revealed by the areas of the deconvoluted peaks, namely, the sub-process resistances. As quantitatively summarized in Fig.…”

Metal nanoparticles at grain boundaries of titanate toward efficient carbon dioxide electrolysis

“…8 However, solid oxide electrolysis cells still face many challenges in CO 2 electrolysis. Therefore, researchers have taken different measures to optimize the performance in CO 2 electrolysis, such as doping with different metallic or non-metallic elements, 9,10 taking different pretreatments in order to enrich the noble metal elements doped on the electrode and so on. 11 The development of tailored materials consisting of catalytic nanoparticles dispersed on composite surfaces or grain boundaries is important in many elds like catalysis, photocatalysis and energy conversion and storage (including fuel cells, electrolytic cells and batteries).…”

“…8 However, solid oxide electrolysis cells still face many challenges in CO 2 electrolysis. Therefore, researchers have taken different measures to optimize the performance in CO 2 electrolysis, such as doping with different metallic or non-metallic elements, 9,10 taking different pretreatments in order to enrich the noble metal elements doped on the electrode and so on. 11…”

Non-perovskite Structural CaFe2O4 with Matched Thermal Expansion Coefficients Exhibiting High Performance for CO2 Electroreduction

“…Therefore, it is essential to improve the catalytic activity of the cathode to enhance the cell performance. Ni-based cermets, such as Ni-GDC (Gd 2 O 3 -doped CeO 2 ) and Ni-YSZ (Y 2 O 3 -stabilized ZrO 2 ), widely used as cathodes of SOECs, have the advantages of low costs and high electrochemical activities. − However, Ni-based cathodes face various problems, such as Ni oxidation, Ni coarsening, and carbon deposition, thus threatening their long-time operation. − LaCrO 3 - and SrTiO 3 -based perovskite oxides with matching thermal expansion coefficients (TECs) to other components of SOECs were considered as potential cathodes for CO 2 electroreduction in SOECs, − while their electrochemical activity still needs to be significantly improved. − Therefore, Fe-, Co-, and Ni-based perovskite oxides were developed, such as La 0.6 Sr 0.4 Fe 0.8 Ni 0.2 O 3−δ F 0.1 , La 0.6 Sr 0.4 Co 0.5 Ni 0.2 Mn 0.3 O 3−δ , La 0.66 Ti 0.8 Fe 0.2 O 3−δ , and Sr 2 Fe 1.35 Mo 0.45 Co 0.2 O 6−δ . − In these perovskite oxides, the easily reducible metal elements (Fe, Co, and Ni) are exsolved from perovskite bulk under a H 2 -containing atmosphere or a reducing potential to form metal nanoparticles on perovskite surfaces. − The interfaces of metal nanoparticles/perovskite have been identified to be highly active toward CO 2 electroreduction because the metal nanoparticles can strengthen the adsorption of intermediates and lower the CO 2 dissociation barriers. Meanwhile, the perovskite substrate with high oxygen ionic conductivity facilitates the diffusion of oxygen ions from the metal nanoparticles/perovskite interfaces to electrolyte. − …”