A High‐Entropy Layered Perovskite Coated with In Situ Exsolved Core‐Shell CuFe@FeO_x Nanoparticles for Efficient CO₂ Electrolysis

Abstract

Solid oxide electrolysis cells (SOECs) are promising energy conversion devices capable of efficiently transforming CO2 into CO, reducing CO2 emissions, and alleviating the greenhouse effect. However, the development of a suitable cathode material remains a critical challenge. Here a new SOEC cathode is reported for CO2 electrolysis consisting of high‐entropy Pr0.8Sr1.2(CuFe)0.4Mo0.2Mn0.2Nb0.2O4‐δ (HE‐PSCFMMN) layered perovskite uniformly coated with in situ exsolved core‐shell structured CuFe alloy@FeOx (CFA@FeO) nanoparticles. Single cells with the HE‐PSCFMMN‐CFA@FeO cathode exhibit a consistently high current density of 1.95 A cm−2 for CO2 reduction at 1.5 V while maintaining excellent stability for up to 200 h under 0.75 A cm−2 at 800 °C in pure CO2. In situ X‐ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations confirm that the exsolution of CFA@FeO nanoparticles introduces additional oxygen vacancies within HE‐PSCFMMN substrate, acting as active reaction sites. More importantly, the abundant oxygen vacancies in FeOx shell, in contrast to conventional in situ exsolved nanoparticles, enable the extension of the triple‐phase boundary (TPB), thereby enhancing the kinetics of CO2 adsorption, dissociation, and reduction.

Realizing Efficient Activity and High Conductivity of Perovskite Symmetrical Electrode by Vanadium Doping for CO2 Electrolysis

“…The Faraday efficiency reaches 95.85% at 1.5 V, indicating excellent selectivity for CO production . These results suggest that SFMV 0.1 electrode exhibits high resistance to carbon deposition …”

Robust Cathode for Efficient CO2 Electrolysis Driven by Entropy Engineering in Solid Oxide Electrolysis Cells

“…Applied potentials have minimal impact on the peaks in the HF region, as the cell shares the same LSGM electrolyte and PBSCoF anode. 34 However, processes in LF and IF regions have dominant contributions to R p , indicating their substantial influences on the overall CO 2 RR rate. Figure 4b and Figures S11e and S12a−d (Supporting Information) show the EIS spectra of single cells with various cathodes over a temperature range of 700−850 °C at an applied potential of 1.5 V. The R p values of PLSBSCF are 0.06, 0.10, 0.18, and 0.37 Ω cm 2 at 850, 800, 750, and 700 °C, respectively, demonstrating that the PLSBSCF has the lowest R p at all temperature points.…”

“…For instance, under reducing atmosphere, in situ exsolved CuFe@ FeO x decorated Pr 0.8 Sr 1.2 (CuFe) 0.4 Mo 0.2 Mn 0.2 Nb 0.2 O 4−δ (PSCFMMN) displayed enhanced CO 2 RR kinetics compared with bare PSCFMMN, achieving a high current density of 1.95 A cm −2 (850 °C, 1.5 V). 34 Despite the vital potential of B-site high entropy perovskites in material design and optimization, it remains unclear whether the improvements in catalytic activity are solely due to increased entropy, as catalytic activity is closely related to the species and concentrations of B-site active metals. To address these issues, A-site high-entropy perovskites, such as Pr Herein, we propose an entropy engineering strategy to design a novel A-site high-entropy perovskite, Pr 1/6 La 1/6 Sm 1/6 Ba 1/6 Sr 1/6 Ca 1/6 FeO 3−δ (PLSBSCF), derived from the tunable Pr 1/2 Ba 1/2 FeO 3−δ (PBF) parent, as a highly active and durable cathode for CO 2 reduction in SOECs.…”

“…Adopting high-entropy perovskites as SOEC cathodes can efficiently combine excellent structural stability with superior catalytic activity under harsh operational conditions. For instance, under reducing atmosphere, in situ exsolved CuFe@FeO x decorated Pr 0.8 Sr 1.2 (CuFe) 0.4 Mo 0.2 Mn 0.2 Nb 0.2 O 4−δ (PSCFMMN) displayed enhanced CO 2 RR kinetics compared with bare PSCFMMN, achieving a high current density of 1.95 A cm –2 (850 °C, 1.5 V) . Despite the vital potential of B-site high entropy perovskites in material design and optimization, it remains unclear whether the improvements in catalytic activity are solely due to increased entropy, as catalytic activity is closely related to the species and concentrations of B-site active metals.…”

“…To gain deeper insights into the CO 2 RR reaction steps, DRT analysis is performed (Figure S12f, Supporting Information). Applied potentials have minimal impact on the peaks in the HF region, as the cell shares the same LSGM electrolyte and PBSCoF anode . However, processes in LF and IF regions have dominant contributions to R p , indicating their substantial influences on the overall CO 2 RR rate.…”