三维ATO反蛋白石复合结构的制备及光电化学性能研究
发布时间：2018-09-17 13:07
【摘要】：能源危机和环境污染已经成为制约经济发展的两大严峻问题。光电化学池利用太阳能将水分解制备氢气是一种绿色环保的制氢方法。一些半导体材料,例如Ti O2、Fe_2O_3、Bi VO_4都已经被用作光阳极材料用于光解水制氢。但这些半导体材料存在载流子扩散距离短、导电性差、光吸收率不高等问题,降低了其光电转化效率。基于此,本文制备了Sb掺杂Sn O2的三维ATO反蛋白石结构,并将其作为导电骨架与Fe_2O_3、Ti O2半导体材料复合,研究了这两种复合结构的光电化学性质,以及ATO反蛋白石骨架对于提升材料光电化学性能的作用与机理。主要研究内容如下:(1)采用无皂乳液聚合法制备了不同粒径的聚苯乙烯微球(PS球),并通过垂直沉降法将PS球自组装成三维胶体晶体,再通过溶胶-凝胶法制备了三维ATO反蛋白石结构。结果表明制备的PS球粒径均一、分散性良好;组装的胶体晶体是有序的面心立方结构(fcc),缺陷较少;三维ATO反蛋白石结构是一种大孔阵列结构。(2)以三维ATO反蛋白石为模板,通过水热合成法成功制备了3D ATO/Fe_2O_3复合结构。探究了三维ATO模板中Sb掺杂量、PS球粒径大小、模板厚度对光电化学性质的影响。实验结果表明:(1)三维ATO在体系中起到的作用主要有两个,一是ATO作为导电骨架,有利于电子的快速传递,提高了光电转化效率;二是三维大孔结构有巨大的比表面积提供了更多的活性位点,同时提高了对光的利用率。(2)Sb掺杂量对复合结构的光电流性能有较大影响,当Sb掺杂量为25%时,3D ATO/Fe_2O_3复合结构在E vs.RHE为1.23V时光电流密度值达到1.04 m A/cm~2。(3)以三维ATO反蛋白石为模板,通过化学浴沉积法成功制备了3D ATO/Ti O2复合结构,并探究了前驱体溶液浓度、反应时间对复合结构形貌及光电化学性质的影响。结果显示前驱体溶液浓度与反应时间会影响氧化钛纳米棒的形貌。当纳米棒长度合适时,复合结构的光电化学性质较好,其光电流密度值在E vs.RHE为1.23V时高达到0.78m A/cm~2。
[Abstract]:Energy crisis and environmental pollution have become two serious problems restricting economic development. Photochemical cell is a green method to produce hydrogen by decomposing water into hydrogen by solar energy. Some semiconductor materials, such as Ti O _ 2O _ 2Fe _ 2T _ 2O _ 3H _ 2O _ 3Bi _ VO_4, have been used as photoanode materials for the production of hydrogen by photolysis of water. However, these semiconductor materials have some problems, such as short carrier diffusion distance, poor conductivity and low light absorption rate, which reduce their photoelectric conversion efficiency. Based on this, the three-dimensional ATO opal structure of Sb doped Sn O 2 was prepared and used as a conductive skeleton to composite with Fe_2O_3,Ti O 2 semiconductor material. The photochemical properties of the two structures were studied. And the effect and mechanism of ATO reverse opal skeleton on improving the photoelectric chemical properties of the material. The main contents are as follows: (1) Polystyrene microspheres (PS spheres) with different sizes were prepared by soap-free emulsion polymerization and PS spheres were self-assembled into three-dimensional colloidal crystals by vertical deposition. Three dimensional ATO opal structure was prepared by sol-gel method. The results show that the prepared PS spheres have uniform particle size and good dispersibility, the assembled colloidal crystals have less defects in (fcc), with ordered face-centered cubic structure, and the three-dimensional ATO reverse opal structure is a macroporous array structure. (2) Three-dimensional ATO reverse opal is used as template. The 3D ATO/Fe_2O_3 composite structure was successfully prepared by hydrothermal synthesis. The effects of the Sb doping amount and the thickness of the PS spheres on the photochemical properties of 3D ATO templates were investigated. The experimental results show that: (1) 3D ATO plays two main roles in the system. One is that ATO acts as a conductive skeleton, which is conducive to the rapid transfer of electrons and improves the efficiency of photoelectric conversion; Second, the large specific surface area of the three-dimensional macroporous structure provides more active sites and improves the utilization ratio of light. (2) the doping amount of Sb has a great influence on the photocurrent performance of the composite structure. When the doping amount of Sb is 25, the current density of 3D ATO/Fe_2O_3 composite structure reaches 1.04 Ma / cm ~ (2) at E vs.RHE = 1.23 V. (3) 3D ATO/Ti O _ 2 composite structure was successfully prepared by chemical bath deposition using three-dimensional ATO reverse opal as template, and the concentration of precursor solution was investigated. The influence of reaction time on the morphology and photochemical properties of the composite structure. The results show that the concentration of precursor solution and reaction time will affect the morphology of titanium oxide nanorods. When the length of nanorods is suitable, the photochemical properties of the composite structure are better, and the photocurrent density of the composite structure reaches 0.78 Ma / cm ~ (-2) when E vs.RHE is 1.23 V.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332
本文编号：2246014
[Abstract]:Energy crisis and environmental pollution have become two serious problems restricting economic development. Photochemical cell is a green method to produce hydrogen by decomposing water into hydrogen by solar energy. Some semiconductor materials, such as Ti O _ 2O _ 2Fe _ 2T _ 2O _ 3H _ 2O _ 3Bi _ VO_4, have been used as photoanode materials for the production of hydrogen by photolysis of water. However, these semiconductor materials have some problems, such as short carrier diffusion distance, poor conductivity and low light absorption rate, which reduce their photoelectric conversion efficiency. Based on this, the three-dimensional ATO opal structure of Sb doped Sn O 2 was prepared and used as a conductive skeleton to composite with Fe_2O_3,Ti O 2 semiconductor material. The photochemical properties of the two structures were studied. And the effect and mechanism of ATO reverse opal skeleton on improving the photoelectric chemical properties of the material. The main contents are as follows: (1) Polystyrene microspheres (PS spheres) with different sizes were prepared by soap-free emulsion polymerization and PS spheres were self-assembled into three-dimensional colloidal crystals by vertical deposition. Three dimensional ATO opal structure was prepared by sol-gel method. The results show that the prepared PS spheres have uniform particle size and good dispersibility, the assembled colloidal crystals have less defects in (fcc), with ordered face-centered cubic structure, and the three-dimensional ATO reverse opal structure is a macroporous array structure. (2) Three-dimensional ATO reverse opal is used as template. The 3D ATO/Fe_2O_3 composite structure was successfully prepared by hydrothermal synthesis. The effects of the Sb doping amount and the thickness of the PS spheres on the photochemical properties of 3D ATO templates were investigated. The experimental results show that: (1) 3D ATO plays two main roles in the system. One is that ATO acts as a conductive skeleton, which is conducive to the rapid transfer of electrons and improves the efficiency of photoelectric conversion; Second, the large specific surface area of the three-dimensional macroporous structure provides more active sites and improves the utilization ratio of light. (2) the doping amount of Sb has a great influence on the photocurrent performance of the composite structure. When the doping amount of Sb is 25, the current density of 3D ATO/Fe_2O_3 composite structure reaches 1.04 Ma / cm ~ (2) at E vs.RHE = 1.23 V. (3) 3D ATO/Ti O _ 2 composite structure was successfully prepared by chemical bath deposition using three-dimensional ATO reverse opal as template, and the concentration of precursor solution was investigated. The influence of reaction time on the morphology and photochemical properties of the composite structure. The results show that the concentration of precursor solution and reaction time will affect the morphology of titanium oxide nanorods. When the length of nanorods is suitable, the photochemical properties of the composite structure are better, and the photocurrent density of the composite structure reaches 0.78 Ma / cm ~ (-2) when E vs.RHE is 1.23 V.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332
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