Tailoring CeO2 Nanomorphologies in Cathodes: A Strategy for Simultaneously Boosting Performance and Stability in PEM Fuel Cells

In the present work, the effect of cerium oxide (CeO2) additives with different morphologies: cubic (c-CeO2), rod-shaped (r-CeO2), and octahedron (o-CeO2); overall performance; and long-term stability of PEM fuel cell electrodes were investigated. CeO2 nanostructures were synthesized via a hydrothermal method, and physicochemical characteristics are performed, aiming to approve the desired morphologies with distinct surface facets. Fuel cell cathodes were subsequently fabricated using fixed low Pt loading (0.15 mgPt cm–2), and Nafion, while the CeO2 to Pt/C ratio was varied to investigate its influence on performance and durability. The results reveal that CeO2 morphologies significantly affect the performance and durability of PEMFCs. Among the tested morphologies, the cubic CeO2 showed the highest improvement after Pt-dissolution accelerated stress tests (ASTs), with up to a 31.8% increase in maximum power density with a loading of only 0.075 mg cm–2 of CeO2 (20 wt % of Pt). Furthermore, all CeO2 morphologies showed enhanced performance compared to the electrode with only Pt/C, highlighting the potential of morphology-controlled CeO2 additives in advancing PEM fuel cell technology.