In-situ dual-exsolved nanometal anchoring on heterogeneous composite nanofiber using as SOEC cathode for direct and highly efficient CO2 electrolysis

Abstract

An effective strategy for CO₂ electrolysis by solid oxide electrolysis cells (SOECs) is to design high-performance cathode material by interface engineering. In this work, a Ni-doped Sr_0.95Ti_0.3Fe_0.7O_3-δ/Ce_0.9Gd_0.1O_2-δ (denoted as STFN/GDCN) nanofiber composite is directly obtained via electrospinning. Then, Ni nanoparticles are dual-exsolved by 10%H₂/Ar reduction to in-situ anchor on the surface of STFN and GDCN (denoted as Ni@STFN/GDCN), which is used as SOECs cathode. This developed composite cathode not only facilitates CO₂ reduction reaction (CO₂RR) rate but also resists thermal aggregation and carbon deposition. The Ni@STFN/GDCN cathode operating in pure CO₂ with an applied voltage of 1.6 V achieves a current density of 1.85 A cm⁻², surpassing most of the advanced electrodes reports by other works. Furthermore, the CO₂RR testing at a current density of 1.5 A cm⁻² shows no significant voltage fluctuations during 180 h, demonstrating excellent long-term stability. Our testing results show that the in-situ dual-exsolved nanometal anchoring on heterogeneous composite nanofiber is a reliable and stable SOEC cathode for direct and highly efficient CO₂ electrolysis.