Photochemical Deposition of Highly Dispersed Pt Nanoparticles on Porous CeO₂ Nanofibers for the Water-Gas Shift Reaction

Ceria (CeO₂) nanofibers with high porosity are fabricated using an approach involving sol-gel, electrospinning, and calcination. Specifically, cerium(III) acetylacetonate and polyacrylonitrile (PAN) are dissolved in N,N-dimethylformamide (DMF) and then electrospun into nanofibers. The PAN matrix plays a critical role in stabilizing the porous structure from collapse during calcination in air up to 800 C. CeO₂ porous nanofibers comprising an interconnected network of single crystalline and fully oxidized CeO₂ nanoparticles about 40 nm in size are obtained. The hierarchically porous structure of the CeO₂ nanofibers enables the facile deposition of Pt nanoparticles via heterogeneous nucleation in a photochemical method. When conducted in the presence of poly(vinyl pyrrolidone) (PVP) and 4-benzyolbenzoic acid, uniform Pt nanoparticles with an average diameter of 1.7 nm are obtained, which are evenly dispersed across the entire surface of each CeO₂ nanofiber. The high porosity of CeO₂ nanofibers and the uniform distribution of Pt nanoparticles greatly improve the activity and stability of this catalytic system toward the water-gas shift reaction. It is believed that this method could be extended to produce a variety of catalysts and systems sought for various industrial applications.