g-C3N4-BiOBr复合材料制备及可见光催化性能
g-C3N4-BiOBr Composites: Synthesis and High Photocatalytic Performance under Visible-Light Irradiation
作者单位E-mail
李娜 桂林理工大学材料科学与工程学院, 广西有色金属及特色材料加工国家重点实验室培育基地, 桂林 541004  
王茗 桂林理工大学材料科学与工程学院, 广西有色金属及特色材料加工国家重点实验室培育基地, 桂林 541004 2007034@glut.edu.cn 
赵北平 桂林理工大学材料科学与工程学院, 广西有色金属及特色材料加工国家重点实验室培育基地, 桂林 541004  
曹雪丽 桂林理工大学理学院, 桂林 541004  
摘要: 利用原位沉积法将BiOBr纳米片生长到g-C3N4表面,制得g-C3N4-BiOBrp-n型异质结复合光催化剂。采用X射线衍射(XRD)、红外光谱(FTIR)、场发射扫描电子显微镜(FE-SEM)、透射电子显微镜(TEM)、紫外可见漫反射(UV-Vis-DRS)和荧光光谱(PL)等测试对光催化剂结构和性能进行表征。通过可见光辐照降解甲基橙水溶液检测评估复合光催化剂光催化活性。研究结果表明:复合光催化剂由BiOBr和g-C3N4两相组成,BiOBr纳米片在片状g-C3N4表面快速形核生长形成面-面复合结构。相比于纯相g-C3N4和BiOBr,g-C3N4-BiOBr复合材料具有更强可见光吸收能力,吸收带边红移。在可见光辐照100min后,性能最佳的2:8g-C3N4-BiOBr复合光催化剂光催化活性分别是纯相g-C3N4和BiOBr的1.8和1.2倍,经过4次循环实验后,其降解率仍达84%,说明复合结构光催化剂催化性能和稳定性增强。复合光催化剂的荧光强度显著降低,说明光生载流子复合得到了有效抑制。复合光催化剂催化性能的提高归因于p-n型异质结促进电荷有效分离、抑制电子-空穴复合和吸收光波长范围的扩展,相比单一成分材料具有更好的催化活性和稳定性。自由基捕获实验证明,可见光降解甲基橙光催化过程中的主要活性成分为空穴,并据此提出了可能的光催化机理。
关键词: g-C3N4  BiOBr  复合材料  可见光催化
基金项目: 广西自然科学基金(No.2015GXNSFAA139278,2013GXNSFBA019013)资助项目。
Abstract: Anovel p-n heterojunction composite photocatalyst of graphitic carbon nitride-BiOBr (g-C3N4-BiOBr) fabricated by deposition of BiOBr nanoflakes on g-C3N4 surface were presented. The structures and properties of as-synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflection spectroscopy (DRS) and photoluminescence (PL). The photocatalytic activity was evaluated by degradation of methyl orange (MO) aqueous solution under visible-light irradiation. The study results show that the composite photocatalysts were consisted of two components of g-C3N4 and BiOBr, and the BiOBr nanoflakes can be rapidly deposited on g-C3N4 sheet surface. In comparison with pure BiOBr and g-C3N4, the g-C3N4-BiOBr composite photocatalysts shows more absorption intensity within the visible light range and the sorption edge shifts to lower energy direction. The optimum photocatalytic activity of the 2:8 g-C3N4-BiOBr composite sample was 1.8 and 1.2 times as high as those of individual g-C3N4 and BiOBr after 100 minutes irradiation with visible light. After reusing4 cycles, the photodecomposition rate of MOstill remains 84%, which proves the enhancement of photocatalytic activity and stability of the composite photocatalyst. The PLemission intensity of the composite photocatalyst decreased remarkably due to the suppression of photogenerated charges recombination. The enhancement in both photocatalytic performance and stability was induced by a synergistic effect, including the improved charge separation efficiency of the photoinduced electron-hole pair at the interface of g-C3N4 and BiOBr, the inhibition of photoinduced charge recombination and the extension of the absorption bands comparing with the sole component. Aseries of radical trapping experiments demonstrate that the holes should be the main active species in MOphotodegradation and a possible photocatalytic mechanism is proposed.
Keywords: g-C3N4  BiOBr  composite materials  visible light responded photocatalysts
投稿时间:2015-11-26 修订日期:2016-03-23
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李娜,王茗,赵北平,曹雪丽.g-C3N4-BiOBr复合材料制备及可见光催化性能[J].无机化学学报,2016,32(6):1033-1040.
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