CuO decorated vacancy-rich CeO nanopencils for highly efficient catalytic NO reduction by CO at low temperature.

With the rapid development of transportation and vehicles, the elimination of NO and CO has highly attracted public attention. In this work, vacancy-rich CeO nanopencil supported CuO catalysts (CuO/CeO-NPC) were successfully prepared for NO reduction by CO. Importantly, CeO with nanopencil-like shape (CeO-NPC) have been synthesis by solvothermal method for the first time. The physicochemical properties of all samples were studied in detail by combining the means of X-ray diffraction (XRD), Raman spectroscopy, electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), H-temperature-programmed reduction (H-TPR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N physisorption (Brunauer-Emmett-Teller), and NO and CO temperature-programmed desorption (NO-TPD and CO-TPD) techniques. Compared with CeO nanorods and nanoparticles supported CuO catalysts (CuO/CeO-NR and CuO/CeO-NP), the CuO/CeO-NPC catalysts showed the highest catalytic activity, affording more than 90% NO conversion at 69 °C as well as excellent HO tolerance at 150 °C, which is superior to catalysts previously reported. Characterization results indicated that the synergistic effect between the well-dispersed CuO and the CeO nanopencil support enables a favorable electron transfer between these components and enhances the density of surface oxygen vacancies and Cu species, which consequently accelerating the redox cycle. The results indicated that the morphology control of CeO support could be an efficient way to evidently enhance the catalytic performance for NO + CO reaction.