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The in situ exsolution technique of nanoparticles has brought new opportunities for the utilization of perovskite‐based catalysts in solid oxide cells. However, the lack of control over the structural evolution of host perovskites during the promotion of exsolution has restricted the architectural exploitation of exsolution‐facilitated perovskites. In this study, we strategically broke the long‐standing trade‐off phenomenon between promoted exsolution and suppressed phase transition via B‐site supplement, thus broadening the scope of exsolution‐facilitated perovskite materials. Using carbon dioxide electrolysis as an illustrative case study, we demonstrate that the catalytic activity and stability of perovskites with exsolved nanoparticles (P‐eNs) can be selectively enhanced by regulating the explicit phase of host perovskites, accentuating the critical role of the architectures of perovskite scaffold in catalytic reactions occurring on P‐eNs. The concept demonstrated could potentially pave the way for designing the advanced exsolution‐facilitated P‐eNs materials and unveiling a wide range of catalytic chemistry taking place on P‐eNs. [ABSTRACT FROM AUTHOR]

Perovskites with exsolved nanoparticles (P-eNs) have immense potentials for carbon dioxide (CO2) reduction in solid oxide electrolysis cell. Despite the recent achievements in promoting the B-site cation exsolution for enhanced catalytic activities, the unsatisfactory stability of P-eNs at high voltages greatly impedes their practical applications and this issue has not been elucidated. In this study, we reveal that the formation of B-site vacancies in perovskite scaffold is the major contributor to the degradation of P-eNs; we then address this issue by fine-regulating the B-site supplement of the reduced Sr2Fe1.3Ni0.2Mo0.5O6-δ using foreign Fe sources, achieving a robust perovskite scaffold and prolonged stability performance. Furthermore, the degradation mechanism from the perspective of structure stability of perovskite has also been proposed to understand the origins of performance deterioration. The B-site supplement endows P-eNs with the capability to become appealing electrocatalysts for CO2 reduction and more broadly, for other energy storage and conversion systems. The instability of perovskites with exsolved nanoparticles for CO2 electrocatalysis impedes their practical applications. Here, the authors show the formation of B-site vacancies in perovskite substrate as a major contributor to the degradation and report a strategy to enhance the stability of the perovskites at high voltages. [ABSTRACT FROM AUTHOR]

The solid oxide electrolysis cell (SOEC) has attracted increased attention in recent years due to its capability to reduce CO 2 emissions in a highly efficient and environmentally sustainable fashion. Previous work in our group has fabricated an A-site Ce doped La 0.7 Sr 0.3 Cr 0.5 Fe 0.5 O 3-δ (LSCrF) with gadolinium doped ceria (GDC) as the cathode material in SOEC by the conventional method. This composite cathode presents a satisfying electrochemical performance and good stability due to the presence of excessive oxygen vacancies and strong CO 2 adsorption ability. However, its electrochemical catalytic activity is still limited by the catalyst specific area. Hence, the optimization of electrode microstructure is considered as a promising way to further improve the SOEC performance by increasing the active reaction area. In this study, highly active (La 0.65 Sr 0.3 Ce 0.05) 0.9 (Cr 0.5 Fe 0.5) 0.85 Ni 0.15 O 3-δ (Ni-LSCeCrF)/GDC nanostructured cathode was successfully fabricated by incorporating infiltration and in situ exsolution processes. The optimized microstructure contains fine and uniformly distributed perovskite particles on GDC backbone with nano-socketed Ni-Fe alloy nanoparticles. The Ni-LSCeCrF/GDC cathode shows significantly improved electrochemical performance, CO production rate, and Faraday efficiency for CO 2 reduction reaction. Furthermore, the density functional theory calculations show that Ni doping could reduce the segregation energy of Fe, revealing a new strategy of multiple elements doping to form active alloy by in situ exsolution. Image 1 [ABSTRACT FROM AUTHOR]