Enhancing CO₂ Catalytic Adsorption on an Fe Nanoparticle-Decorated LaSrFeO_4 + δ Cathode for CO₂ Electrolysis

Abstract

The development of cathode materials with high catalytic activity and low cost is a challenge for CO2 electrolysis based on solid oxide electrolysis cells. Herein, we report a low-cost and highly active metallic Fe nanoparticle-decorated Ruddlesden-Popper (La, Sr)­FeO4+δ cathode catalyst (Fe-RPLSF), which shows a high oxygen vacancy concentration and robust CO2 reduction rate. At 850 °C, the current density of the electrolysis cell with the Fe-RPLSF cathode reaches −1920 mA cm–2 at a voltage of 1.5 V, and the Faraday efficiency is as high as 100%. The polarization resistance at low frequency (0.1–10 Hz), which is the rate-limit step for CO2 electrolysis, significantly decreases with the exsolved Fe nanoparticles because of improved CO2 dissociative adsorption. Moreover, our electrolysis cell demonstrates acceptable short-term stability for direct CO2 electrolysis.

The facilitated cathodic elementary reactions of solid oxide electrolysis cells for CO2 conversion over a Ce decorated La0.43Ca0.37Ti0.94Ni0.06O3−δ electrocatalyst

“…9(a) and (b), there exist three peaks, corresponding to three kinds of oxygen species, i.e., lattice oxygen (O L at $529.1 eV), surface adsorption oxygen (O A at $531.4 eV) and hydroxyl oxygen (O H at $533.0 eV). 52,53 The calculated relative proportions of different oxygen species are presented in the inset of Fig. 9(a) and (b).…”

Exsolved metallic iron nanoparticles in perovskite cathode to enhance CO2 electrolysis

“…Of course, it demonstrates limited activity even though it has relatively good electrical conductivity [25][26][27][28]. To achieve high activity and stability, we exsolve metallic Fe nanoparticles from La 0.75 Sr 0.25 Cr 0.5 Fe 0.5+x O 3−δ to obtain metal-oxide interfaces that function as three-phase boundary [29][30][31]. The metallic Fe nanoparticles may be stably present through directly exsolving excess Fe ions in B site from perovskite lattice to form tightly contacted interface which exhibits long-term thermal stability.…”

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.…”

“…The electrochemical reaction process in SOEC cathode is regarded as the rate‐limiting step during the CO 2 electrolysis process due to its poor chemical adsorption of nonpolar CO 2 at high temperature. [ 1,4,12–13 ] Therefore, the development of a cathode material with high catalytic active and durability for CO 2 adsorption, dissociation, and reduction is vital to the development of high‐performance SOEC for CO 2 electrolysis.…”

“…In situ exsolution of metal or alloy (metal/alloy) nanocatalysts (e.g., Ni, Fe, Co, NiFe, FeNi 3 , and CoFe) on perovskite oxides surface has been considered as another promising strategy to enhance the CO 2 electrolysis performance of these perovskite‐based SOEC cathode materials. [ 1,4,12,21–24 ] During in situ exsolution process, highly active metal/alloy nanocatalysts and oxygen vacancies are simultaneously generated, and plentiful metal/alloy‐oxide interfaces are formed for highly efficient CO 2 electrolysis. The SOEC single cell with in situ exsolved FeNi 3 alloy nanoparticles decorated SFMN‐GDC cathode exhibits an enhanced current density of 0.62 A cm −2 at 1.4 V at 800 °C for CO 2 electrolysis, which is 1.55 times that of the SOEC with pure SFMN‐GDC cathode.…”