铁镍复合氧化物的制备及光催化性能研究

发布时间：2018-05-26 03:59

  本文选题：模板法 + NiFe_2O_4　； 参考：《河南师范大学》2017年硕士论文

【摘要】：光催化是处理废水最理想的反应,不仅利用了太阳能,并且无有害副产物生成。自从发现TiO_2光催化分解水以来,人们对于半导体材料在光催化技术领域进行了广泛的研究。磁性铁氧体材料的磁性有利于催化剂的回收,所以磁性铁氧体材料被应用到光催化技术领域。其中NiFe_2O_4是非常重要的尖晶石铁氧体材料。NiFe_2O_4的带隙能为1.7eV,作为光催化剂,吸收太阳光中的可见光部分,提高了太阳光利用率;同时NiFe_2O_4的磁性解决了光催化剂回收的难题。到目前为止,关于NiFe_2O_4光催化降解污染物的研究发现,NiFe_2O_4直接用于光催化降解污染物时,光催化降解率普遍较低。本论文中,使用模板法制备了NiO,Fe_2O_3,并进行光催化性能研究;在不同的温度下以棉纤维为模板制备了多孔NiFe_2O_4,研究了温度对于NiFe_2O_4光催化性能的影响;研究了模板法,水热法,溶胶-凝胶法对于NiFe_2O_4样品光催化性能的影响;通过负载Bi_2O_3,尝试优化多孔NiFe_2O_4光催化性能;主要实验内容和结果如下:1.以棉纤维为模板制备了NiO,Fe_2O_3,并进行光催化性能研究。NiO样品,Fe_2O_3样品的光催化降解率分别为28%,63%。NiO样品,Fe_2O_3样品和吸附率分别是24%,46%。由实验数据知,Fe_2O_3样品光催化效果较好。2.以棉纤维为模板制备多孔NiFe_2O_4,在不同的温度下(400℃,500℃,600℃)煅烧得到不同样品的光催化性能,由实验数据知:400℃,500℃,600℃下样品的吸附率分别为41%,33%,29%,光催化降解率分别为63%,92%,90%,比表面积分别为9.38 m~2/g,12.61 m~2/g,7.21 m~2/g。500℃下样品的光催化降解率较好,说明适中的结晶度、吸附率以及比表面积可以提高光催化降解率。3.模板法制备多孔NiFe_2O_4样品,与水热法,溶胶-凝胶法制备的NiFe_2O_4样品的催化性能进行对比,由实验数据知,水热法样品,溶胶-凝胶法样品,模板法样品的光催化降解率分别为23%,69%,92%,吸附率分别为23%,29%,33%,比表面积分别为55.6 m~2/g,12.61 m~2/g,3.59 m~2/g;溶胶-凝胶法和模板法的到的样品是多孔材料,而水热法样品的平均孔径是12.4nm,属于介孔材料。说明适中的比表面积、孔径、吸附率可以提高光催化降解率。4.直接煅烧法制备α-Bi_2O_3与多孔NiFe_2O_4复合,由实验数据知,并没有将α-Bi_2O_3负载到多孔NiFe_2O_4上,纯多孔NiFe_2O_4的光催化降解率(92%)较负载α-Bi_2O_3的光催化降解率(41%)高出51%;说明较大粒径的α-Bi_2O_3与多孔NiFe_2O_4没有形成有效的异质结构,导致光催化降解率的降低;水热法制备较小粒径的β-Bi_2O_3与多孔NiFe_2O_4负载,形成β-Bi_2O_3/NiFe_2O_4异质结构。由实验数据知,纯多孔NiFe_2O_4的光催化降解率(92%)较负载β-Bi_2O_3的光催化降解率(42%)高出50%,;说明较小粒径的β-Bi_2O_3负载到多孔NiFe_2O_4的表面,使得多孔NiFe_2O_4的吸附率降低,导致光催化降解率降低。
[Abstract]:Photocatalysis is the most ideal reaction for wastewater treatment, which not only uses solar energy, but also produces no harmful byproducts. Since the discovery of TiO_2 photocatalytic decomposition of water, semiconductor materials have been widely studied in the field of photocatalytic technology. Magnetic ferrite materials are favorable to the recovery of catalysts, so magnetic ferrite materials have been applied to photocatalytic technology. Among them, NiFe_2O_4 is a very important spinel ferrite material. NiFeS _ 2O _ 4 has a band gap energy of 1.7 EV. As a photocatalyst, it absorbs the visible light in the solar light and improves the utilization ratio of the sunlight. Meanwhile, the magnetic properties of NiFe_2O_4 solve the problem of photocatalyst recovery. Up to now, studies on photocatalytic degradation of pollutants by NiFe_2O_4 have shown that the photocatalytic degradation rate is generally low when NiFeS _ 2O _ 4 is directly used for photocatalytic degradation of pollutants. In this thesis, we have prepared NiO- Fe _ 2O _ 3 by template method and studied its photocatalytic properties; we have prepared porous NiFeS _ 2O _ 4 with cotton fiber as template at different temperatures to study the effect of temperature on the photocatalytic performance of NiFe_2O_4; we have studied template method, hydrothermal method, The effect of sol-gel method on the photocatalytic properties of NiFe_2O_4 samples was studied. The photocatalytic properties of porous NiFe_2O_4 were optimized by loading Bikes _ 2O _ 3. The main experimental contents and results were as follows: 1. NiOG Fe2O3 was prepared by using cotton fiber as template, and the photocatalytic performance of NiO sample was studied. The photocatalytic degradation rate of Fe2O3 sample was 280.63% and NiO sample / Fe2O3 sample was 240.46%, respectively. According to the experimental data, the photocatalytic effect of FeS _ 2O _ 3 sample is better than that of Fe _ S _ 2O _ 3 sample. The porous NiFeS _ 2O _ 4 was prepared by using cotton fiber as template, and calcined at different temperatures (400 鈩，

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