Core-Sheath Pt-CeO₂/Mesoporous SiO₂ Electrospun Nanofibers as Catalysts for the Reverse Water Gas Shift Reaction

One-dimensional (1D) core-sheath nanofibers, platinum (Pt)-loaded ceria (CeO₂) sheath on mesoporous silica (SiO₂) core were fabricated, characterized, and used as catalysts for the reverse water gas shift reaction (RWGS). CeO₂ nanofibers (NFs) were first prepared by electrospinning (ES), and then Pt nanoparticles were loaded on the CeO₂ NFs using two different deposition methods: wet impregnation and solvothermal. A mesoporous SiO₂ sheath layer was then deposited by sol-gel process. The phase composition, structural, and morphological properties of synthesized materials were investigated by scanning electron microscope (SEM), scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), nitrogen adsorption/desorption method, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis, and CO₂ temperature programmed desorption (CO₂-TPD). The results of these characterization techniques revealed that the core-sheath NFs with a core diameter between 100 and 300 nm and a sheath thickness of about 40-100 nm with a Pt loading of around 0.5 wt.% were successfully obtained. The impregnated catalyst, Pt-CeO₂ NF@mesoporous SiO₂, showed the best catalytic performance with a CO₂ conversion of 8.9% at 350 °C, as compared to the sample prepared by the Solvothermal method. More than 99% selectivity of CO was achieved for all core-sheath NF-catalysts.