中文字?jǐn)?shù)：4088
概略內(nèi)容：
摘要：電子結(jié)構(gòu)本質(zhì)上控制著吸光率，氧化還原電位，載流子遷移率，因此控制了半導(dǎo)體光催化劑的光反應(yīng)性。為獲得更廣的吸收范圍，傳統(tǒng)的改變半導(dǎo)體催化劑電子結(jié)構(gòu)的方法是摻雜陰離子來降低氧化還原電位和/或載流子遷移率，所以其光反應(yīng)性通常是有限的，并且一些重要的反應(yīng)可能根本不會(huì)發(fā)生。在本文中，具有獨(dú)特電子結(jié)構(gòu)的硫摻雜石墨相氮化碳(C3N4-xSx)，會(huì)將提高導(dǎo)帶的最小值，并與輕微的吸光率降低相結(jié)合，增加價(jià)帶帶寬。在λ>300和400nm時(shí)C3N4-xSx存在的光反應(yīng)中氫氣的生成分別7.2倍和8倍于C3N4。更顯著的是，在λ>400時(shí)對(duì)于C3N4-xSx可以發(fā)生完成的苯酚的氧化過程，而這對(duì)于C3N4來說，即使是λ>300也是不可能的。同一種族的硫代替了晶格氮，隨之而來的量子限制效應(yīng)被認(rèn)為是特殊的電子結(jié)構(gòu)引起的，因此表明C3N4-xSx具有良好的光反應(yīng)性。這一結(jié)果提供了設(shè)計(jì)潛在的有效的光催化劑的一種基本的摻雜方法。
英文字?jǐn)?shù)（字符數(shù)不計(jì)空格）：32018
概略內(nèi)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.