Thermally Stable RuO_x–CeO₂ Nanofiber Catalysts for Low-Temperature CO Oxidation

With the ever-growing concerns for sustainable energy production and clean air, developing highly efficient catalysts to eliminate exhaust emission pollutants is of vital importance. In this work, we report a class of thermally stable RuOx–CeO2 nanofiber catalysts derived from a facile one-pot electrospinning method. Ru–CeO2 nanofiber catalysts exhibit outstanding low-temperature activity (∼90% conversion of CO below 150 °C) and long-term durability. The as-prepared Ru–CeO2 nanofiber catalysts show a high Brunauer–Emmett–Teller (BET) surface area (>110 m2/g), demonstrating the effectiveness of electrospinning for fabricating high-surface-area catalysts. The Ru–CeO2 nanofiber catalysts have a hollow interior and porous exterior structure, particularly at the Ru–CeO2 nanofiber interfaces, providing plentiful accessible CO and oxygen adsorption sites, which are beneficial for CO catalytic oxidation. H2 temperature-programmed reduction (H2-TPR) was applied to probe the reducibility of the as-synthesized catalysts. The reduced Ru–CeO2 nanofiber catalysts exhibited hydrogen consumption near room temperature. The catalysts were further characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) to explore the relationship between the microstructure and extraordinary low-temperature reducibility, as well as the CO oxidation activity. In addition, X-ray photoelectron spectroscopy (XPS), in situ CO-diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and density functional theory (DFT) calculation were employed to investigate the chemical states of the active surface species and identify the gas adsorption and reaction sites.