Enhancing Electrochemical CO₂ Reduction using Ce(Mn,Fe)O₂ with La(Sr)Cr(Mn)O₃ Cathode for High‐Temperature Solid Oxide Electrolysis Cells

Abstract

is mostly dominated by the cathode reaction related to the CO/CO 2 redox couple on the electrode surface. SOECs mostly utilize materials and techniques relevant to solid oxide fuel cells (SOFCs), as they operate in the reverse mode of SOFCs. However, some materials have not been specifically tailored for CO 2 electrolysis conditions. Thus, several research groups have extensively searched for durable fuel electrodes that are suitable for both SOFC and SOEC conditions and provide high catalytic reactivity compared to the Ni-based blending electrodes for SOFCs. [15][16][17][18][19][20][21] The Ni-based cathode (fuel electrode) is easily deactivated by re-oxidation or carbon formation when directly exposed to the CO/CO 2 redox reaction and hydrocarbon atmosphere. [22,23] Therefore, the alternative cathode should have catalytic activity and electrical conductivity, and durability in terms of CO/CO 2 redox reaction. Consequently, redox stability and carbon coking tolerance have been considered as main factors when developing robust ceramic cathode (fuel electrode) candidates for CO 2 electrolysis in SOECs. Several conductive perovskite oxides have been reported to display re-oxidation resistance and coke tolerance as perovskite-type fuel electrode materials for the anode in SOFCs as well as the cathode in SOECs. [13][14][15][16][17][18][19][20] Among them, La(Sr)Cr(Mn)O 3-δ (LSCM) is one of the promising cathode materials for hydrocarbon-typed SOFCs because of its high redox stability and acceptable conductivity under the reducing conditions. [24] Irvine and Yue reported (La 0.75 Sr 0.25 ) 0.97 Cr 0.5 Mn 0.5 O 3-δ /Gd 0.1 Ge 0.9 O 1.95 (LSCM/GDC) as a composite ceramic cathode for CO 2 electrolysis. However the

Electrochemical Performance of Pr0.4Sr0.5CoxFe0.9–xMo0.1O3−δ Oxides in a Reversible SOFC/SOEC System

“…To further explore the factors affecting the catalytic activity of R-PSCFM, the distribution of relaxation time (DRT) method was used, and the results are shown in Figure S3. Four peaks are obtained, representing P 1 , P 2 , P 3 , and P 4 , respectively, corresponding to the low-frequency region (LF), medium-frequency region (IF), and high-frequency region (HF) . Based on the Adler–Lane–Steele model, the LF region corresponding to the P 1 peak reflects the gas diffusion process, the IF region corresponding to P 2 and P 3 peaks reflects the ion surface exchange process, and the HF region corresponding to the P 4 peak reflects the interface charge transfer process .…”

Ti/Ni co-doped perovskite cathode with excellent catalytic activity and CO2 chemisorption ability via nanocatalysts exsolution for solid oxide electrolysis cell

“…The positions of the characteristic peaks related to IF and LF shift to higher frequencies, suggesting that the electrochemical reaction kinetics should be accelerated. In contrast, after the reduction treatment, the exsolved Ni metal and the increased oxygen vacancies supply more active reaction sites for CO 2 adsorption and activation, while the formed metal-oxide heterostructure with strong interaction enhances the surface exchange reactions (Lee et al, 2021;Zhang L. H. et al, 2022). This occurrence indicates that the CO 2 -RR performance of the Ni@SFNTM Frontiers in Chemistry frontiersin.org cathode is enhanced.…”

“…However, certain inevitable issues hinder its further application, including Ni oxidation during the CO 2 /CO redox reaction process in the absence of a safe gas (H 2 /CO), carbon deposition at high CO concentrations, and Ni particle growth during long-term operation ( Dong et al, 2017 ; Sciazko et al, 2021 ; Yang et al, 2022 ). Materials comprising perovskite oxide with mixed ionic-electronic conductivity, such as Sr 2 Fe 1.5 Mo 0.5 O 6-δ (SFM), show promise for SOEC, and exhibit excellent redox stability, coke resistance, and long-term stability ( Li et al, 2017a ; Zhang et al, 2021 ). Nevertheless, compared with the Ni-YSZ cathode material, SFM oxide exhibits weak chemical CO 2 adsorption and inadequate catalytic activity for CO 2 -RR, which limits the performance of CO 2 electrolysis.…”

Unravelling the role of dopants in the electrocatalytic activity of ceria towards CO2 reduction in solid oxide electrolysis cells

“…For SOECs conditions specifically, DFT calculations showed that both the tetravalent Rh, Ir and Pt 52 and the trivalent Gd 53 are expected to reduce the energy of oxygen vacancy formation at the surface of ceria. Promising results on the beneficial effect of doping ceria for the electrochemical reduction of CO 2 are also reported in a number of experimental studies employing technological electrodes, 54–60 even though a clear correlation between the presence of dopants and the electrochemical performance is hindered by the absence of well-controlled experimental conditions.…”