Effect of modified CeO on the performance of PdCu/CeTiO catalyst for methanol purification.

In this paper, we prepared a series of CeTiO (x = 0-0.20) nanorods by hydrothermal method, which were used to construct the PdCu/CeTiO catalysts. The CeTiO and PdCu/CeTiO samples were characterized by transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), N adsorption-desorption, X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometer (ICP-OES), etc. Catalytic activity, stability, and repeatability of the catalysts for methanol oxidation were investigated. The results show that doping a proper amount of titanium could strengthen the interaction between CeTiO support and PdCu nanoalloy, thus increasing the oxygen vacancy concentration and promoting Pd species with a higher oxidation state. These modified properties are beneficial for the deep oxidation of methanol. The light-off temperature (T) and full-conversion temperature (T) of methanol over the PdCu/CeO catalyst are 108 °C and 159 °C, respectively. The greatest activity improvement is found for PdCu/CeTiO, which shows the lowest T of 88 °C and T of 138 °C. Furthermore, neither PdCu/CeO nor the modified PdCu/CeO catalyst produces by-products and exhibit excellent stability and repeatability throughout the whole test period. This study provides a reference for in-depth understanding and designing of efficient and stable CeO-based oxidation catalysts.