Precise Regulation of In Situ Exsolution Components of Nanoparticles for Constructing Active Interfaces toward Carbon Dioxide Reduction

Metal nanocatalysts supported on oxide scaffolds have been widely used in energy storage and conversion reactions. So far, the main research is still focused on the growth, density, size, and activity enhancement of exsolved nanoparticles (NPs). However, the lack of precise regulation of the type and composition of NPs elements under reduction conditions has restricted the architectural development of in situ exsolution systems. Herein, we propose a strategy to attain a regulated distribution of exsolved transition metals (Cu, Ni, and Fe) on Sr₂Fe_1.2Ni_0.2Cu_0.2Mo_0.4O_6-δ medium-entropy perovskite oxides by varying the oxygen partial pressure (pO₂) gradient in the mixture. At 800 °C, the unitary Cu, binary Cu-Ni, and ternary Cu-Ni-Fe NPs are exsolved as pO₂ decreases from high to low. Combining experimental and theoretical simulations, we further corroborate that solid oxide electrolysis cells with ternary alloy clusters at the CNF@SFO interface exhibit superior CO₂ electrolytic performance. Our results provide tailored strategies for nanostructures and nanointerfaces for studying metal oxide exsolution systems, including fuel electrode materials.