氧化钨及其复合材料的制备以及光电催化性能的研究
发布时间：2018-10-16 09:08
【摘要】：能源危机和环境恶化是当前人类社会所面临的两个重大问题,采用太阳光进行光催化全分解水产氢产氧是解决上述问题的有效途径之一。由于廉价易得以及稳定无毒,目前大量使用二氧化钛光催化剂,但存在吸收光谱较窄、太阳能利用率低、电子与空穴复合几率高等缺点,同时光催化产氢往往需要添加有机物(如甲醇)作为牺牲剂消耗多余的光生空穴,导致成本增加,而且缺少对光电催化全分解水的探究。WO_3作为一种常见的半导体光催化剂,带隙为2.5-2.8eV,能够捕获近12%的太阳光谱,广泛应用于吸附,催化,储能及敏感器件等领域。围绕着半导体光催化剂WO_3如何有效的增强电子空穴分离,如何构建高质量的异质结界面提高光催化活性等开展了以下几方面的工作。1、WO_3材料作为一个很好的析氧气材料,可与析氢反应相结合,从而形成对水的全分解。本章我们采用气相刻蚀的方法处理W片从而获得WO_3纳米电极材料,并在可见光的照射下探究其光电催化分解水的性能。同时探究了气相刻蚀温度,时间和HF浓度对电极材料表面结构形貌与全分解水活性影响,发现采用4MHF作为刻蚀剂,150℃条件下刻蚀24h获得的WO_3纳米电极材料的光电催化全分解的活性最好,并结合XRD、SEM以及相关电化学表征对WO_3电极材料的表面物理化学性质与光电催化性能的关系进行了探究。2、以上述最佳WO_3电极材料作为基底,通过旋Q肂iVO_4纳米晶体获得BiVO_4/WO_3复合电极材料。从而构建复合型光电催化电极材料,增加载流子的密度和提高了光生电子-空穴利用效率,最终提高光电催化分解水活性。本章采用硝酸铋与偏钒酸铵混合先制备出钒酸铋,然后再用旋转镀膜仪将钒酸铋前驱体旋Q玫絎O_3纳米材料上,经过煅烧形成BiVO_4/WO_3复合材料,并探究了其光电催化分解水性能。3、将已经合成好的WO_3电极材料分别在200℃条件下,不同氛围(真空,氢气,氮气)下煅烧,得到含有氧空位的光电催化电极材料,研究发现在氢气氛围下处理的获得的电极具有最佳的光电催化分解水活性。这是因为在氢气氛围下处理会形成氧空位,产生局部共振效应,从而增加了电子和空穴的分离效率。
[Abstract]:Energy crisis and environmental deterioration are two major problems facing human society at present. One of the effective ways to solve these problems is the photocatalytic decomposition of hydrogen and oxygen in aquatic products by solar light. At present, titanium dioxide photocatalyst is widely used because of its low cost and stability, but it has some disadvantages, such as narrow absorption spectrum, low utilization of solar energy, high probability of recombination of electron and hole, etc. At the same time, the addition of organic compounds (such as methanol) as a sacrificial agent to produce hydrogen in photocatalysis often requires the consumption of excess photogenerated holes, which leads to the increase of cost, and the lack of research on the total decomposition of water in photocatalysis. WO_3 is a common semiconductor photocatalyst. The band gap is 2.5-2.8 EV, which can capture nearly 12% of the solar spectrum. It is widely used in the fields of adsorption, catalysis, energy storage and sensitive devices. The following work has been done on how to effectively enhance the electron hole separation of semiconductor photocatalyst WO_3 and how to construct a high quality heterogeneous boundary surface to improve photocatalytic activity. 1 WO / WO _ 3 material is a good oxygen evolution material. It can be combined with hydrogen evolution reaction to form the total decomposition of water. In this chapter, we use gas phase etching method to treat W wafer to obtain WO_3 nanocrystalline electrode material, and investigate its photocatalytic decomposition of water under visible light irradiation. At the same time, the effects of gas etching temperature, time and HF concentration on the surface morphology and total decomposition water activity of electrode materials were investigated. It was found that the photocatalytic decomposition activity of WO_3 nano-electrode materials obtained by etching at 150 鈩，
本文编号：2273889
[Abstract]:Energy crisis and environmental deterioration are two major problems facing human society at present. One of the effective ways to solve these problems is the photocatalytic decomposition of hydrogen and oxygen in aquatic products by solar light. At present, titanium dioxide photocatalyst is widely used because of its low cost and stability, but it has some disadvantages, such as narrow absorption spectrum, low utilization of solar energy, high probability of recombination of electron and hole, etc. At the same time, the addition of organic compounds (such as methanol) as a sacrificial agent to produce hydrogen in photocatalysis often requires the consumption of excess photogenerated holes, which leads to the increase of cost, and the lack of research on the total decomposition of water in photocatalysis. WO_3 is a common semiconductor photocatalyst. The band gap is 2.5-2.8 EV, which can capture nearly 12% of the solar spectrum. It is widely used in the fields of adsorption, catalysis, energy storage and sensitive devices. The following work has been done on how to effectively enhance the electron hole separation of semiconductor photocatalyst WO_3 and how to construct a high quality heterogeneous boundary surface to improve photocatalytic activity. 1 WO / WO _ 3 material is a good oxygen evolution material. It can be combined with hydrogen evolution reaction to form the total decomposition of water. In this chapter, we use gas phase etching method to treat W wafer to obtain WO_3 nanocrystalline electrode material, and investigate its photocatalytic decomposition of water under visible light irradiation. At the same time, the effects of gas etching temperature, time and HF concentration on the surface morphology and total decomposition water activity of electrode materials were investigated. It was found that the photocatalytic decomposition activity of WO_3 nano-electrode materials obtained by etching at 150 鈩，
本文编号：2273889
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