Au/LaPO4 nanowires: Synthesis, characterization, and catalytic CO oxidation

Abstract

Au/M-P-O (M=Mg, Al, Ca, Fe, Co, Zn, La) catalysts were prepared by loading ca. 1wt.% gold onto commercial metal phosphate supports by deposition-precipitation with urea (DPU), and tested in CO oxidation. Au/La-P-O showed the highest activity, achieving complete CO conversion at 70°C. Au/Ca-P-O was the second most active, achieving complete CO conversion at 155°C. The remaining catalysts were not active below 200°C. In view of the results, we additionally prepared Au/LaPO4 nanowires by loading ca. 1wt.% gold onto LaPO4 nanowires via DPU. The Au/LaPO4 nanowires catalyst was even more active, achieving complete CO conversion at 15°C. The catalysts were characterized by N2 adsorption-desorption, inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption of O2 or CO2 (O2-TPD, CO2-TPD). Reasons for the higher activity of Au/LaPO4 nanowires were discussed.