钒酸铋二维纳米材料及光催化性能研究
摘要:近年来,伴随着经济的发展,环境污染和能源短缺成为了两大主要问题。光催化技术因其能转化太阳能和光催化氧化有机污染物,是一项理想的绿色技术,并且由于该技术可以直接利用太阳能并且没有二次污染的现象,所以得到了相当高的重视。因此需要寻找具有充足光吸收、有效的电荷分离和表面活性高的材料。自20世纪70年代,纳米半导体材料TiO2的发现,但是由于其宽禁带、光生电子-空穴对易复合等缺点限制了对太阳能的利用。铋系光催化剂的带隙较窄,明显的吸收可见光,具有良好的催化活性,成为了研究重点。本文是对纳米材料的定义和性质以及光催化的原理进行介绍;并进一步的对钒酸铋二维纳米材料结构、性能、合成方法以及其光催化性能研究,以及不同形貌的钒酸铋和稀土掺杂的钒酸铋以及钒酸盐的光催化性能研究。
关键词:钒酸铋 二维纳米材料 光催化 性能研究
Abstract: In recent years, with the development of economy, environmental pollution and energy shortage have become two major problems. Photocatalytic technology is an ideal green technology because it can transform solar energy and photocatalytic oxidation of organic pollutants, and because it can directly utilize solar energy without secondary pollution, it has received considerable attention. Therefore, it is necessary to find materials with sufficient light absorption, effective charge separation and high surface activity. Since the 1970s, the discovery of nano-semiconductor material titanium dioxide has limited the use of solar energy due to its wide band gap, photogenerated electron-hole recombination and other shortcomings. Bismuth photocatalyst has narrow band gap, visible light absorption and good catalytic activity, which has become the focus of research. In this paper, the definition and properties of nano-materials and the principle of photocatalysis are introduced, and the structure, properties, synthesis methods and photocatalytic properties of bismuth vanadate two-dimensional nano-materials, as well as the photocatalytic properties of bismuth vanadate and rare earth doped bismuth vanadate and vanadate with different morphologies are further studied.
Key words: photocatalytic properties of bismuth vanadate two-dimensional nanomaterials
1 BiVO4的晶体结构、制备、改性方法及其光催化原理
BiVO4是一种廉价、无毒稳定的,禁带宽度约为2.4cV的可见光半导体光催化材料,被人们应用于光催化降解有机污染物、光解水、光催化合成等领域【1】。此外,他在铁电、太阳能电池、离子导体以及气体传感器等领域有着广阔的应用前景。
1.1 BiVO4的晶体结构
一般说来,BiVO4具有单斜白钨矿型(m-s)、四方硅酸型(t-z)、四方白钨矿型(t-s)和正交钒铋矿型这四种不同的晶型结构。其中正交钒铋矿型大多天然存在,很难通过实验条件制备得到。因此,目前主要研究的是前三种晶型。单体白钨矿型和四方白钨矿型的晶体结构相似。三种晶型中,第一种具有相对较高的光催化活性,所以,第一种的研究最为关注。
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