Dy/WO_3光催化降解罗丹明B的反应机理

Photocatalytic Degradation Mechanism of RB over Dy-Doped WO_3 Photocatalysts

在稀土Dy掺杂的WO3光催化降解罗丹明B（RB）体系中，采用紫外-可见吸收光谱、高效液相色谱和电喷雾质谱等技术测定了不同辐照时间下RB的降解中间产物，发现RB的降解过程以苯环的开环氧化反应为主，脱乙基反应为辅．同时发现降解中间产物有脱去1～4个乙基的RB分子碎片；质谱分析发现降解中间产物除了存在上述脱乙基RB的分子碎片外，还存在RB、脱乙基RB的羟基化产物以及结构难以确定的小分子．通过上述分析方法的综合，推出了Dy／WO3光催化降解RB的初步机理．

The UV-Vis absorption spectra, high performance liquid chromatograph （HPLC） and electric spray interface mass spectra （ESI-MS） of RB（rhodamine B） were measured under different irradiation time during the photocatalytic procedures of Dy-doped WO3 nanoparticles suspension system. The experimental results indicated that the photodegradation mechanism of the RB mainly involved the broken of benzene ring in RB combined with de-ethylation and hydroxylation process. Some intermediates can be attributed to RB molecular fragments which resulted from severing one, two, three and/or four ethyl from RB, respectively. Moreover, hydroxylation intermediates of RB and its de-ethylation products have also been determined by mass spectra. According to the above-mentioned experimental facts, the primary photocatalytic degradation mechanism of RB over Dy-doped WO3 photocatalysts was proposed.