Synthesis of Fe-doped CeO2 nanorods by a widely applicable coprecipitation route

Fe-doped CeO2 solid solution nanorods were successfully prepared via a simple coprecipitation method without templates/surfactants at ambient temperature and pressure. The single crystalline nanorod structure was preserved after calcination at higher temperatures. The formation of the nanorod morphology strongly depends on Fe contents. Beyond the solid solution limit, only nanoparticles were observed. The morphology was also affected by precipitation agents, temperatures and aging times. The formation of the nanorods originates from the intrinsic anisotropy of Ce hydroxide. The dissolution/recrystallization mechanism was thus proposed, in which the coexistent ammonia and/or Fe act as the capping agents for the formation of nanorods. Simultaneously, the enrichment of Fe on the surface results in the nanorods with round shape and sharp tips. The element-capped concept for the formation of the nanorod morphology can be extended to Cr-doped CeO2.

► Coprecipitation is used to prepare Fe-doped CeO2 nanorods.
► Doping elements can control the morphology of CeO2 from nanoparticles to nanorods.
► The coexistent ammonia and/or doping elements act as capping agents.
► Cr-doped CeO2 nanorods were obtained using the same strategy.