Ag/AgBr/MWCNT复合纳米材料可见光催化还原CO2的机理研究
首发时间:2011-12-23
摘要:采用液相沉淀-沉积法,在十三烷基三甲基溴化铵(CTAB)辅助下制备不同长度的Ag/AgBr/MWCNT催化剂,通过X射线衍射(XRD)、场发射扫描电镜(FESEM)、透射电镜(TEM)、等手段对催化剂进行表征,并考察其在可见光下催化还原CO2制备碳氢化合物的可行性及催化性能。结果表明:Ag/AgBr/MWCNT中AgBr纳米颗粒均匀地分散到MWCNT表面,有利于光诱导下产生的电荷在Ag/AgBr与MWCNT界面间的有效传递,载体MWCNT的长度对光催化活性的提高起到重要的作用。Ag/AgBr/MWCNT光催化还原CO2效率的提高是因为载体MWCNT具有储存电子和传递电子的作用,有利于实现界面间的电子转移,使AgBr在光诱导下产生的光生电子能够迅速转移至MWCNT,从而提高了其光催化还原CO2的活性和稳定性。
关键词: Ag/AgBr/MWCNT 光催化还原CO2 可见光
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High-efficiency Photocatalytic Reducttion of CO2 over Ag/AgBr/MWCNT to Hydrocarbons under Visible Light
Abstract: In this investigation, a novel approach for effective photocatalytic reduction of CO2 using different length of MWCNT coupled with Ag/AgBr nanocomposites under visible light (λ > 420 nm) was studied. Ag/AgBr/MWCNT nanocomposite was prepared by the deposition-precipitation method in the presence of cetyltrimethylammonium bromide (CTAB), and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) method. Their photocatalytic activities were evaluated by the reduction yield in the presence of CO2 and water. The experiment results showed that Ag/AgBr/MWCNT nanocomposites with longer MWCNT had relatively higher reduction yields under visible-light irradiation for 5 h. The higher efficiency of Ag/AgBr/MWCNT with a longer MWCNT in the reduction process of CO2 was attributed to MWCNT charge transfer impedance, which is lower in Ag/AgBr/MWCNT with a longer MWCNT. In addition, this investigation on using MWCNT in Ag/AgBr/MWCNT catalyst to reduce the carbon dioxide under visible light will provide new insights into the fundamental theory not only for efficient CO2 conversion and fixation, storage of solar energy, but also for optimizing the real factor which it may due the high yield of carbon dioxide reduction.
Keywords: Ag/AgBr/MWCNT Photocatalytic Reduction of CO2 Visible Light
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