铁酸铋的合成及其可见光催化性能的研究
发布时间：2018-10-25 09:22
【摘要】：半导体光催化材料用于光催化降解有机污染物和光解水制氢气是当前研究的热点。与二氧化钛(～3.1 eV)相比,铁酸铋材料具有较小的禁带宽度(2.1-2.5eV),能够有效的吸收见光,从而受到越来越多的人的关注。但是,合成单相的铁酸铋材料比较困难,因此,本论文主要研究单相铁酸铋的合成,探讨不同制备工艺条件对合成铁酸铋的物相、形貌和可见光催化性能的影响,并分析提出了其光催化机理。主要结论如下：1.水热合成：首次在反应过程中加入分散剂PVP合成了分散性良好的立方形单相的钙钛矿结构的铁酸铋(-2 um)。研究发现：PVP作为分散剂不仅改变合成的铁酸铋的分散度和形貌,还可以促进合成的铁酸铋的结晶。研究这些不同尺寸和形状的BiFe03样品的光吸收和光催化性能可知：PVP作为分散剂合成的立方形的分散性良好的铁酸铋具有较好的可见光催化效果；对于颗粒尺寸相当的铁酸铋而言,颗粒的形貌对铁酸铋光催化性能的影响比颗粒尺寸对光催化性能的影响更明显。2.溶胶-凝胶合成：在较低的煅烧温度(500℃)不加入任何螯合剂和分散剂的条件下,合成了～50 nm的单相的铁酸铋纳米颗粒。研究发现：前驱体溶胶的浓度过低或过高都不利于合成单相的BiFeO3颗粒；在相同煅烧温度下,前驱体溶胶的浓度越低合成的单相BiFe03颗粒的尺寸越小；对于纳米尺寸的BiFeO3颗粒而言,尺寸越大光吸收性能越好,但是可见光催化性能却越差。因此,比较光吸收性能和颗粒尺寸对光催化性能的影响,BiFeO3颗粒的尺寸是影响光催化性能的主要的因素。3.微波水热合成：同样实验条件下,微波水热法合成单相铁酸铋的反应时间远比水热法快,并且合成的铁酸铋颗粒的分散性更好。研究不同反应时间合成的铁酸铋发现：微波水热反应过程中BiFeO3和Bi25FeO40两相会相互转化；单相的铁酸铋的颗粒尺寸会随着反应时间的增加而增大。对于颗粒尺寸相当的铁酸铋而言,铁酸铋的光吸收性能随着颗粒增大而减小。
[Abstract]:Semiconductor photocatalytic materials used in photocatalytic degradation of organic pollutants and photolysis of water to produce hydrogen are the current research hotspot. Compared with titanium dioxide (~ 3.1 eV), bismuth ferrate material has a smaller band gap (2.1-2.5eV), which can effectively absorb light, which has attracted more and more attention. However, it is difficult to synthesize single phase bismuth ferrate material. Therefore, the synthesis of single phase bismuth ferrate is studied in this paper, and the effects of different preparation conditions on the phase, morphology and visible light catalytic performance of bismuth ferrate are discussed. The photocatalytic mechanism is also analyzed. The main conclusions are as follows: 1. Hydrothermal synthesis: bismuth ferrate (-2 um).) with good dispersion of square single phase perovskite structure was synthesized by adding dispersant PVP in the reaction process for the first time. It is found that PVP can not only change the dispersity and morphology of bismuth ferrate, but also promote the crystallization of bismuth ferrate. The photoabsorption and photocatalytic properties of these BiFe03 samples with different sizes and shapes were studied. The results showed that bismuth ferrate with good dispersion of square synthesized by PVP as dispersant had better visible light catalytic effect. For bismuth ferrate whose particle size is the same, the effect of particle morphology on the photocatalytic performance of bismuth ferrate is more obvious than that of particle size. 2. Sol-gel synthesis: single phase bismuth ferrate nanoparticles with ~ 50 nm were synthesized without any chelating agent and dispersant at lower calcination temperature (500 鈩，
本文编号：2293284
[Abstract]:Semiconductor photocatalytic materials used in photocatalytic degradation of organic pollutants and photolysis of water to produce hydrogen are the current research hotspot. Compared with titanium dioxide (~ 3.1 eV), bismuth ferrate material has a smaller band gap (2.1-2.5eV), which can effectively absorb light, which has attracted more and more attention. However, it is difficult to synthesize single phase bismuth ferrate material. Therefore, the synthesis of single phase bismuth ferrate is studied in this paper, and the effects of different preparation conditions on the phase, morphology and visible light catalytic performance of bismuth ferrate are discussed. The photocatalytic mechanism is also analyzed. The main conclusions are as follows: 1. Hydrothermal synthesis: bismuth ferrate (-2 um).) with good dispersion of square single phase perovskite structure was synthesized by adding dispersant PVP in the reaction process for the first time. It is found that PVP can not only change the dispersity and morphology of bismuth ferrate, but also promote the crystallization of bismuth ferrate. The photoabsorption and photocatalytic properties of these BiFe03 samples with different sizes and shapes were studied. The results showed that bismuth ferrate with good dispersion of square synthesized by PVP as dispersant had better visible light catalytic effect. For bismuth ferrate whose particle size is the same, the effect of particle morphology on the photocatalytic performance of bismuth ferrate is more obvious than that of particle size. 2. Sol-gel synthesis: single phase bismuth ferrate nanoparticles with ~ 50 nm were synthesized without any chelating agent and dispersant at lower calcination temperature (500 鈩，
本文编号：2293284
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