Synergistic design of an exsolved nano-nickel catalyst layer and fuel electrode architecture toward efficient CO2 hydrogenation in protonic ceramic electrolysis cells

Protonic ceramic electrolysis cells (PCECs) emerge as a promising technology for CO 2 conversion. However, their CO 2 conversion efficiency and stability are limited by conventional fuel electrodes. In this work, highly dispersed Ni nanocatalysts supported on Sm doped CeO 2 are fabricated via in situ exsolution of Ce 0.8 Sm 0.2-x Ni x O 2-δ precursors (x = 0, 0.1, 0.2; denoted as SDC, SDC@Ni10, and SDC@Ni20). Furthermore, a coking-resistant Cu-BaCe 0.4 Zr 0·4 Y 0.1 Yb 0.1 O 3- σ (BCZYYb4411)/SDC@Ni10 double-layer fuel electrode is designed for air electrode supported PCECs. The introduction of the SDC@Ni10 catalytic layer reduces the ohmic resistance and polarization resistance of the PCEC by 49.9% and 84.2%, respectively, and boosts the CO 2 conversion rate by 4.5 times. Characterization and DFT calculations reveal that strong CO 2 adsorption on the catalytic layer and fast proton transport within the active layer work synergistically to promote CO 2 conversion. Moreover, the catalytic layer improves the CO 2 resistance of electrolytes, enabling stable operation for 120 h at 650 °C.