Studies On Preparation And Photocatalytic Properties Of Nanostructured Cuprous Oxide

In this paper, nanostructures cuprous oxide (Cu₂O) with uniform morphology andsmaller particle size are prepared by wet-chemical route. Combining with some modernphysical methods used to characterize the structure and surface chemical-physical propertiesof the prepared samples, such as XRD, SEM, TEM, HRTEM, XPS, and so on. SEM imagesindicate that Cu₂O sample obtained in the absence of PEG shows irregular octahedralnanostructure; however, the uniform size and stable performance of whiskers-like Cu₂Osample is prepared in the appropriate amount of PEG. Their XRD patterns can be indexed to apure cubic phase of Cu₂O, the average size of Cu₂O nano-octahedra and Cu₂O nano-whiskersis about 21 nm and 17 nm. The UV-vis absorption spectras of Cu₂O nano-octahedra andnano-whiskers show a broad absorption peak in the range of 400 nm～600 nm, the band gapenergy is 2.5 eV, which indicate that these samples have perfect activities under visible light.The photocatalytic activities of the as-prepared Cu₂O are investigated through thephotodegradation of p-nitrophenol solution under visible light. It is revealed that thephotocatalytic activities of Cu₂O nano-whiskers are better than Cu₂O nano-octahedra. Underthe optimal conditions: 100mL p-nitrophenol solution, the initial concentration is 20 mg/L,the Cu₂O nano-whiskers catalyst is 0.1g, and the addition of H₂O₂(30%) is 0.4 mL, pH 3, thephotodegradation efficiency could reach 93% in the irradiation time of 3h under visible light.The photodegradation efficiency still reach 79% at the fifth recycle. It is proved that thereaction follows the first-order reaction kinetics.Cu₂O nanosphere films are prepared by a simple liquid reduction approach, and theeffects of preparing Cu₂O film using different precursors are discussed by the characterizationof XRD, SEM, TEM and HRTEM. The photodegradation efficiencies of Cu₂O powder andCu₂O film is compared under visible light. The results indicate that the photocatalyticactivities of Cu₂O powder is superior to Cu₂O films, and the films obtained by differentprecursors have differences in photocatalytic activities. The photodegradation efficiency ofCu₂O film prepared by CuO precursor could reach 87%, the reaction follows the first-orderreaction kinetics, and the film still have a good activities at the fourth recycles for thephotocatalysis.