硫掺杂石墨相氮化碳的独特光电子结构[外文翻译].rar

中文字数：4088
概略内容：
摘要：电子结构本质上控制着吸光率，氧化还原电位，载流子迁移率，因此控制了半导体光催化剂的光反应性。为获得更广的吸收范围，传统的改变半导体催化剂电子结构的方法是掺杂阴离子来降低氧化还原电位和/或载流子迁移率，所以其光反应性通常是有限的，并且一些重要的反应可能根本不会发生。在本文中，具有独特电子结构的硫掺杂石墨相氮化碳(C3N4-xSx)，会将提高导带的最小值，并与轻微的吸光率降低相结合，增加价带带宽。在λ>300和400nm时C3N4-xSx存在的光反应中氢气的生成分别7.2倍和8倍于C3N4。更显著的是，在λ>400时对于C3N4-xSx可以发生完成的苯酚的氧化过程，而这对于C3N4来说，即使是λ>300也是不可能的。同一种族的硫代替了晶格氮，随之而来的量子限制效应被认为是特殊的电子结构引起的，因此表明C3N4-xSx具有良好的光反应性。这一结果提供了设计潜在的有效的光催化剂的一种基本的掺杂方法。
英文字数（字符数不计空格）：32018
概略内容：
Graphitic carbon nitride (g-C3N4) and boron-doped g-C3N4 were prepared by heating melamine and the mixture of
melamine and boron oxide, respectively. X-ray diffraction, X-ray photoelectron spectroscopy, andUV-vis spectra were
used to describe the properties of as-prepared samples. The electron paramagnetic resonance was used to detect the
active species for the photodegradation reaction over g-C3N4. The photodegradation mechanisms for two typical dyes,
rhodamine B (Rh B) and methyl orange (MO), are proposed based on our comparison experiments. In the g-C3N4
photocatalysis system, the photodegradation of Rh B and MO is attributed to the direct hole oxidation and overall
reaction, respectively; however, for the MO photodegradation the reduction process initiated by photogenerated
electrons is a major photocatalytic process compared with the oxidation process induced by photogenerated holes.
Boron doping for g-C3N4 can promote photodegradation of Rh B because the boron doping improves the dye adsorption
and light absorption of catalyst.