Au-CeO2 Janus-like nanoparticles fabricated by block copolymer templates and their catalytic activity in the degradation of methyl orange

Abstract A simple approach towards the fabrication of Au-CeO 2 Janus-like nanoparticles is presented. Composite micelles of polystyrene- block -poly (ethylene oxide) (PS- b -PEO)/Ce(NO 3 ) 3 /HAuCl 4 with HAuCl 4 and Ce(NO 3 ) 3 precursors incorporated in the PEO domains are prepared first. By manipulating the pH value of the composite micelles solution, a redox reaction between Au(III) with Ce(III) in the PEO domains occurs and Au-CeO 2 Janus-like nanoparticles composed of a porous CeO 2 and an Au nanoparticle are generated. X-ray diffraction (XRD), UV–vis spectrum (UV), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) measurements are employed to characterize the Janus-like nanoparticles. The catalytic degradation of methyl orange dye (MO) under ultrasonic irradiation is chosen as the test reaction to examine the catalytic activity of the Au-CeO 2 Janus-like nanoparticles. It is found that Au-CeO 2 Janus-like nanoparticles show higher activity than that of CeO 2 nanoparticles or Au-CeO 2 composite nanoparticles. The increased catalytic activity of Au-CeO 2 Janus-like nanoparticles is attributed to the exposed Au core on one side of the Janus nanoparticles and the Au-CeO 2 heterointerfaces.