Engineering dual-exsolution on self-assembled cathode to achieve efficient electrocatalytic CO2 reduction

Solid oxide electrolysis cells (SOEC) hold great promise for efficiently converting CO2 into valuable products. However, their commercial viability is impeded by the sluggish kinetics of CO2 reduction reaction (CO2RR). Herein, we propose a novel approach of dual-exsolution on self-assembled cathode for SOEC to achieve efficient CO2RR. Induced by in-situ exsolution, metallic Ni nanoparticles are created on both Ni doped Sr2Fe1.5Mo0.5O6-δ (Ni-SFM) and Ni doped Gd0.1Ce0.9O2-δ (Ni-GDC) surfaces. As a demonstration, a SOEC with the Ni@Ni-SFM/Ni-GDC cathode delivers a high current density of 1.72 A cm−2 at 800 °C and 1.5 V and exhibits favorable durability for 100 h, rivaling most the state-of-the-art cathode materials of SOEC for CO2RR. Theoretical calculations reveal that not only exsolved Ni@Ni-SFM heterointerface but also exsolved Ni@Ni-GDC heterointerface are intrinsically active for CO2RR. This protocol offers new insights into designing dual-exsolved self-assembled cathode materials for high-temperature CO2 electrolysis.