Cerium phosphate-supported Au catalysts for CO oxidation

LaPO 4 and hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ) are typical metal phosphates recently found to be useful for making supported metal or metal oxide catalysts, but CePO 4 (also belonging to the metal phosphate family) has been rarely used to make supported catalysts. It would be interesting to develop CePO 4 -supported catalysts and explore their catalytic applications. Herein, hexagonal CePO 4 nanorods (denoted as CePO 4 -H), hexagonal CePO 4 nanowires (CePO 4 -HNW), monoclinic CePO 4 nanoparticles (CePO 4 -M), and monoclinic CePO 4 nanowires (CePO 4 -MNW) prepared by different methods were used to support gold via deposition-precipitation with urea (DPU). The gold contents of these catalysts were all around 1   wt%. The catalytic activities of these Au/CePO 4 catalysts in CO oxidation were found to follow the sequence of Au/CePO 4 -MNW   >   Au/CePO 4 -HNW   >   Au/CePO 4 -M   >   Au/CePO 4 -H. These catalysts were characterized by inductively coupled plasma-optical emission spectroscopy (ICP-OES), N 2 adsorption–desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), oxygen temperature-programmed desorption (O 2 -TPD), and CO 2 temperature-programmed desorption (CO 2 -TPD) to find possible correlations between the physicochemical properties and catalytic activities of these catalysts.