Ruddlesden-popper Prn+1NinO3n+1 (n = 1, 2) oxides with in situ exsolved Ni nanoparticles as high-performance anodes for intermediated-temperature solid oxide fuel cells

Abstract

In recent years, the in-situ exsolution of metal nanoparticles from the anodic oxide framework through reduction treatment has emerged as an effective strategy to boost electrochemical performance by increasing active sites and facilitating charge transfer. However, this approach is primarily restricted to simple perovskite structures. The development of novel and more efficient oxide matrices for the controlled desorption of high-density metal catalysts remains a significant challenge. In this study, Ruddlesden-Popper (RP) type layered oxides Pr₂NiO₄ and Pr₃Ni₂O₇ were innovatively employed as new primary matrices with the objective of achieving controllable exsolution of nickel metal nanoparticles by leveraging their unique layered architecture. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses confirmed that following reduction treatment, Ni nanoparticles were successfully exsolved in situ from the oxide surface, with a notably higher density of Ni nanoparticles observed for Pr₃Ni₂O₇. Electrochemical tests show that after 3 h of reduction at 850 °C, the cell with Pr₃Ni₂O₇ anode can achieve a peak power density of 969.7 mW cm⁻². Furthermore, when employed the studied compounds as anode materials, they showed negligible performance degradation after 100-h operation at 700 °C under 300 mA cm⁻² current density. Furthermore, SEM characterization provided additional verification of the experimental results. This research not only underscores the considerable potential of RP phase oxides as high-performance SOFC anode materials but also offers new insights into future developments in SOFC anodes by adjusting RP phase sequences to regulate nanoparticle density effectively.