Preparation And Photocatalytic Properties Of Ce Modified ZnO Ultrafine Powders

In recent years,ZnO inorganic nanomaterial has been widely used in photocatalytic degradation of organic pollutants.In order to improve and enhance the photocatalytic performance of ZnO,making the sample element by doping or compositing is the most common method.Ce is a rare earth element with a unique outermost electron structure,which is not fully filled by electrons in 4f shell.It can effectively regulate the properties and applications of ZnO ultrafine powders.In this paper,ZnO,Ce/ZnO and CeO₂/ZnO materisls were prepared by a one-step hydrothermal method using various zinc salts and sodium hydroxide.The photocatalytic activity of the samples was studied by using methylene blue and rhodamine B as the target pollutants.The main contents are summarized as follows:?1?Three-dimensional flower-like,micro-sheet spherical,wool-like ZnO photocatalysts were prepared by using ZnCl₂ and NaOH as raw materials in a high basicity hydrothermal solution([Zn²⁺]:[OH-]=1:7).The photocatalytic activities of the as-prepared ZnO samples were evaluated by degradation of methylene blue and rhodamine B.The result indicate that the micro-sheet sphericalZnO possess the most excellent photocatalytic activity.The degradation efficiencytoward methylene blue?with 180 min irradiation?and rhodamine B?with 400 min irradiation?are more than 90%.?2?Grainy,tubular and slice-like ZnO samples were prepared by using Zn?CH₃COO?₂ and NaOH as raw materials in a the low alkalinity hydrothermal condition?pH=7¹0?.The photocatalytic degradation efficiency of the as-prepared ZnO samples was evaluated by decomosing methylene blue and rhodamine B.The results show that the grainyZnO possess the most excellent photocatalytic performance.The degradation efficiencytoward methylene blue?with 120 min irradiation?and rhodamine B?with 200 min irradiation?are more than 90%.The second is the photocatalytic activity of tubular ZnO samples with hollow structure and the worst is slice-like ZnO samples.?3?Ce/ZnO photocatalysts with different doping content were prepared by using Zn?NO₃?₂,Ce?NO₃?₃ and NaOH as raw materials.The photocatalytic degradation efficiency of as-prepared samples was evaluated by decomosing methylene blue and rhodamine B.The results illuminate that all the Ce/ZnO samples exhibit high photocatalytic activity,compared to the undoped ZnO sample.The sample of 1 % Ce/ZnO possesses excellent photocatalytic activity.The degradation efficiency toward methylene blue?with 140 min irradiation?and rhodamine B?with 180 min irradiation?were 96.11% and 63.79%,respectively.?4?CeO₂/ZnO photocatalysts with different Ce levels were prepared by using Zn?NO₃?₂,Ce?NO₃?₃ and NaOH as raw materials.The photocatalytic degradation efficiency of the as-prepared ZnO samples was evaluated by decomosing methylene blue and rhodamine B.Results show that the photocatalytic performance of CeO₂/ZnO compositesare better than that of pure ZnO.Among them,the CeO₂/ZnO?0.6:1?samplesexhibite superior photocatalytic activity.The degradation efficiency of methylene blue?with 120 min irradiation?and rhodamine B?with 180 min irradiation?were 93.11% and 67.59%,respectively.