Template-free fabrication of α- and β-Bi2O3 hollow spheres and their visible light photocatalytic activity for water purification
Template-free fabrication of α- and β-Bi2O3 hollow spheres and their visible light photocatalytic activity for water purification
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DOI：
10.1016/j.jallcom.2014.03.111
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发表时间：
2014-08
影响因子：
6.2
通讯作者：
Yunhui Yan;Zhaoxia Zhou;Yun-tao Cheng;Lili Qiu;Cuiping Gao;Jianguo Zhou
中科院分区：
文献类型：
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作者：
Yunhui Yan;Zhaoxia Zhou;Yun-tao Cheng;Lili Qiu;Cuiping Gao;Jianguo Zhou
首次采用无模板溶剂热法合成了均匀的α-和β-Bi 2 O3空心微球。选择甘油（Gly）和乙醇（EtOH）的混合物（Gly-EtOH的体积比= 1：1）作为溶剂，Bi（NO3）3·5 H2O作为铋源。采用热重分析（TG）、傅里叶变换红外光谱（FT-IR）、X射线粉末衍射（XRD）、扫描电镜（SEM）、透射电镜（TEM）、比表面积（BET）和紫外-可见漫反射光谱（DRS）对样品进行了表征。基于电子显微镜的观察，这种空心球结构的形成被认为是一个自组装过程，然后是Ostwald熟化。在270 °C煅烧的样品为β-Bi 2 O3相，而在350 °C煅烧的样品为α相。通过DRS估计所制备的材料的带隙分别为3.50，2.82和2.36 eV的前体，α-和β-Bi 2 O3。在可见光照射下，β-Bi 2 O3对罗丹明B（Rh B）的光催化降解活性明显高于α-Bi 2 O3和前驱体，这可能与其较窄的禁带宽度和对可见光的有效吸收有关。
For the first time, uniform α- and β-Bi2O3hollow microspheres were successfully synthesized through a facile template-free solvothermal method followed by calcination of the precursor. A mixture of glycerol (Gly) and ethanol (EtOH) (volume ratio of Gly–EtOH = 1:1) was selected as the solvent, Bi(NO3)3⋅5H2O as the bismuth source. The resulting samples were characterized by thermogravimetry (TG), Fourier transform infrared spectra (FT-IR), X-ray powder diffraction (XRD), scanning and transmission electron microscopy (SEM, TEM), Brunauer–Emmett–Teller (BET) surface area and UV–Vis diffuse reflectance spectra (DRS). Based on the electron microscope observations, the formation of such hollow spheres structure was proposed as a self-assembly process followed by Ostwald ripening. The sample calcined at 270 °C exhibited β-Bi2O3phase, whereas the sample calcined at 350 °C exhibited α phase. The band gaps of the as-prepared materials were estimated by DRS to be 3.50, 2.82, and 2.36 eV for the precursor, α- and β-Bi2O3, respectively. Upon visible light irradiation, the β-Bi2O3exhibits much higher photocatalytic activities than the α-Bi2O3and precursor for the degradation of rhodamine B (RhB) in aqueous solution, which could be attributed to its narrower band gap and efficient visible light absorption.