Constructing fibril-in-tube structures in ultrathin CeO2-based nanofibers as the ideal support for stabilizing Pt nanoparticles

Abstract

The intriguing one-dimensional (1D) nanofibers with secondary structures (e.g., hollow, core-sheath, fiber-in-tube) have attracted much attention for their unique open structure, high surface area, and hierarchical pore structure. This work utilized single-spinneret electrospinning to construct mesoporous CeO2-based ultrathin nanofibers with a new fibril-in-tube morphology. The intriguing fibril-in-tube structure within Al2O3/CeO2 nanofibers was achieved by carefully selecting two different metal precursors with different decomposition rates upon calcination. The use of Al(acac)3 as Al2O3 precursor, which rapidly releases gaseous pieces and leads to the growth kinetics varied along the radial direction of nanofibers, is critical to the formation of fibril-in-tube structure. The new CeO2 nanofibers with different amount of Al2O3 endowed with homogenous elemental distribution and were explored as reliable metal supports toward stabilizing Pt nanoparticles under harsh aging. This inspiring result was ascribed to an energy barrier established by reducible (CeO2) and non-reducible oxide (Al2O3), strong metal-support interaction between Pt and CeO2, as well as the physical confinement caused by the fibril-in-tube structure. The resultant new catalytic system (referred to Pt@Al2O3/CeO2) displayed good sinter-resistant performance and exhibited 13-times great catalytic activity than that of Pt@Al2O3 catalyst after harsh aging at 700 °C toward the hydrogenation of p-nitrophenol.