Effect of modified CeO2 on the performance of PdCu/Ce1−xTixO2 catalyst for methanol purification

In this paper, we prepared a series of Ce 1- x Ti x O 2 ( x  = 0–0.20) nanorods by hydrothermal method, which were used to construct the PdCu/Ce 1− x Ti x O 2 catalysts. The Ce 1− x Ti x O 2 and PdCu/Ce 1− x Ti x O 2 samples were characterized by transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), N 2  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 Ce 1− x Ti x O 2 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 50 ) and full-conversion temperature ( T 90 ) of methanol over the PdCu/CeO 2 catalyst are 108 °C and 159 °C, respectively. The greatest activity improvement is found for PdCu/Ce 0.9 Ti 0.1 O 2 , which shows the lowest T 50 of 88 °C and T 90 of 138 °C. Furthermore, neither PdCu/CeO 2 nor the modified PdCu/CeO 2 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 2 -based oxidation catalysts. Graphical abstract