【摘要】：隨著人類社會的發(fā)展,環(huán)境污染已成為制約社會可持續(xù)發(fā)展的難題之一。光催化技術(shù)是利用太陽能,將污染物徹底降解,并且不產(chǎn)生二次污染的環(huán)保型污染處理方法,比傳統(tǒng)的污染處理方式更具優(yōu)勢。BiOCl作為一種新型光催化劑,因其特殊層狀結(jié)構(gòu)而表現(xiàn)出的優(yōu)異光催化性能,而成為近年研究的熱點。然而BiOCl的禁帶寬度較大,導(dǎo)致對太陽能的利用率低,限制了 BiOCl的應(yīng)用。近些年來,有研究發(fā)現(xiàn)g-C3N4和BiOI具有較好的可見光催化性能,但由于制備工藝繁瑣、成本較高以及低效率等原因,使其在生產(chǎn)應(yīng)用中受到了限制。本文在水熱合成優(yōu)異紫外光催化性能的BiOCl基礎(chǔ)上,采用超聲法和水解-水熱法分別合成了 g-C3N4/BiOCl和BiOI/BiOCl復(fù)合光催化劑,并系統(tǒng)研究了利用g-C3N4和BiOI半導(dǎo)體復(fù)合的方式來提升BiOCl光催化活性的機理。論文中首先采用水熱法對BiOCl的合成工藝進(jìn)行探索。結(jié)果表明,在水熱條件為150℃、6h時,BiOCl的形貌為規(guī)則的片層狀,且在紫外條件下對亞甲基藍(lán)的降解率最大,1h內(nèi)為79%。在此基礎(chǔ)上,采用超聲法合成具有不同質(zhì)量比的g-C3N4/BiOCl復(fù)合催化劑。結(jié)果顯示:用g-C3N4雜化BiOCl,可使g-C3N4/BiOCl復(fù)合催化劑具有可見光響應(yīng);當(dāng)g-C3N4的質(zhì)量為BiOCl的60%時,復(fù)合催化劑對亞甲基藍(lán)的降解率最大;反應(yīng)動力學(xué)常數(shù)k為0.0139 min-1,是純g-C3N4的1.9倍。對其催化機理進(jìn)行研究,發(fā)現(xiàn)由于光生電子-空穴對分離率的增加,使得復(fù)合催化劑具有提升的可見光活性。最后采用水解-水熱法合成具有不同摩爾質(zhì)量比BiOI/BiOCl復(fù)合光催化劑。結(jié)果顯示:經(jīng)BiOI的復(fù)合,可使BiOI/BiOCl復(fù)合光催化劑具有可見光響應(yīng);當(dāng)I與C1的物質(zhì)的量比為1:1時,復(fù)合催化劑對亞甲基藍(lán)的降解率最大;反應(yīng)動力學(xué)常數(shù)k為0.037 min-1,是純BiOI的2.3倍。通過機理研究,由于存在BiOI/BiOCl異質(zhì)結(jié),可使光生電子-空穴對復(fù)合率降低,使復(fù)合催化劑具有提升的可見光活性。
[Abstract]:With the development of human society, environmental pollution has become one of the difficult problems restricting the sustainable development of society. Photocatalytic technology is an environmentally friendly pollution treatment method that uses solar energy to completely degrade pollutants and does not produce secondary pollution, which is superior to traditional pollution treatment methods. BiOCl is a new photocatalyst. Because of its special layered structure, its excellent photocatalytic performance has become a hot spot in recent years. However, the wide band gap of BiOCl leads to low utilization of solar energy, which limits the application of BiOCl. In recent years, some studies have found that g-C3N4 and BiOI have better visible light catalytic performance, but because of the tedious preparation process, high cost and low efficiency, they are limited in production and application. In this paper, based on the excellent UV photocatalytic properties of hydrothermal synthesis of BiOCl, g-C3N4/BiOCl and BiOI/BiOCl photocatalysts were synthesized by ultrasonic method and hydrolysis-hydrothermal method, respectively. The mechanism of improving the photocatalytic activity of BiOCl by using g-C3N4 and BiOI semiconductor composite was studied systematically. Firstly, hydrothermal method was used to explore the synthesis process of BiOCl. The results showed that the morphology of BiOCl was regular lamellar at 150 鈩，

本文編號：2299411