Ligand-engineered hydrothermal synthesis of {100}-terminated ceria nanocrystals and their role as supports in OER

Facet-dependent oxide nanocrystals (NCs) are promising electrocatalyst supports due to their strong metal–support interactions, yet synthesizing facet-defined NCs with robust structures remains a challenge. We report a ligand-engineered hydrothermal strategy for synthesizing cerium oxide (CeO2) NCs with controlled surface features, alongside counterpart CeO2 NCs prepared through alternative methods. By tuning the type and ratio of capping ligands, two distinct morphologies, nanocubes and truncated nano-octahedra, were obtained, with facet selectivity consistent with ligand binding preferences and CeO2 surface energy trends. When employed as supports for NiOx catalysts prepared via alkaline precipitation, the CeO2 NCs significantly reduced the oxygen evolution reaction overpotential, indicating strong support–catalyst interactions. Overall, this study delivers a versatile strategy for investigating facet-engineered oxide supports, advancing the rational design of oxide-supported electrocatalysts.