Unraveling the Enhanced Kinetics of Sr₂Fe_1+xMo_1‐xO_6‐δ Electrocatalysts for High‐Performance Solid Oxide Cells (Adv. Energy Mater. 48/2021)

Abstract

Perovskites In article number 2102845, Xian‐Zhu Fu and co‐workers report that partial substitution of Mo by Fe in a perovskite of Sr2Fe1+xMo1−xO6−δ shifts up the O p band energy closer to the Fermi level, which lowers O vacancy formation as well as the O migration barrier energy, significantly accelerating the catalytic reaction kinetics in H2 oxidation and CO2 reduction reactions.

Shifting Oxygen Evolution Reaction Pathway via Activating Lattice Oxygen in Layered Perovskite Oxide

“…Layered perovskite oxides, such as Ruddlesden‐Popper (RP) phase (SrGdNi 0.2 Mn 0.8 O 4± δ , [ 11 ] La 0.6 Sr 1.4 MnO 4+ δ , [ 12 ] etc.) and double perovskite oxides (Sr 2 FeMo 2/3 Mg 1/3 O 6‐ δ , [ 13 ] Sr 2 Fe 1+ x Mo 1‐ x O 6‐ δ , [ 14 ] etc. ), have been widely used as electrode materials for solid oxide fuel cells owing to their mixed electronic and ionic conductivity.…”

Phase Transition Engineering of Host Perovskite toward Optimal Exsolution‐facilitated Catalysts for Carbon Dioxide Electrolysis

“…As listed in Figure 3d and Table S4, the electronic conductivities of all P‐eNs follow an order of DP‐NPs>DLP‐NPs>LP‐NPs in the atmospheres of 1 : 1 CO−CO 2 and 2 : 1 CO−CO 2 , substantiating that CO 2 activation on DLP‐NPs is easier to proceed than that on LP‐NPs [36, 38] . XPS analysis of Fe 2 p and Mo 3 d with redox charge couples reveals that the higher electron conductivity of DLP‐NPs than that of LP‐NPs can be attributed to the more concentrated Fe 2+ −Fe 3+ charge couples, which acts as the primary electronic pathways bridging the surface‐adsorbed CO 2 and SFN 3 M perovskite substrate (Figures 3d, S17 and Table S5) [39, 40] . The highest electronic conductivities of DP‐NPs can thus be assigned to both the most concentrated Fe and Mo‐related redox charge couples and B‐site supplement in the perovskite substrate.…”

Atomistic Insights into Medium-Entropy Perovskites for Efficient and Robust CO2 Electrolysis

“…shifts negatively by 0.2 eV from SFM to SFTCMM, contributing to the formation and diffusion of oxygen vacancies. 9 Electron paramagnetic resonance (EPR) presents that the peak single intensity of SFTCMM is higher than that of SFM (Figure 3c), further suggesting the increased oxygen vacancies in the SFTCMM perovskite. 37−39 As depicted in thermogravimetric (TG) curves (Figure 3d), the SFTCMM exhibits more weight loss, implying that the oxygen vacancies are more readily generated in the SFTCMM at elevated temperatures.…”

“…A similar relationship between the metal−O hybridization and the O 2p band center is also verified in the literature. 9,58 Compared with SFM (−2.17 eV), the reduced O 2p band center of −2.02 eV for SFTCMM favors the formation and diffusion of oxygen vacancies. In addition, the PDOS in Figure S14 shows that Fe and Mo in SFTCMM possess a more prominent state (light-orange block highlights) around the Fermi level and more overlap with O compared to SFM, suggesting the strengthened metal 3d−O 2p hybridization of SFTCMM.…”

“…8 Partial substitution of Mo by the Fe cation in the Sr 2 Fe 1+x Mo 1−x O 6−δ perovskite enhanced the metal−oxygen hybridization and improved the oxygen 2p band energy, which reduced the formation and migration energies of oxygen vacancies and thereby contributed to CO 2 RR electrolysis. 9 Consequently, manipulating the electronic configuration of perovskite oxides has great potential in boosting the CO 2 RR activity.…”