Egg-shaped core/shell α-Mn2O3@α-MnO2 as heterogeneous catalysts for decomposition of phenolics in aqueous solutions.
Egg-shaped core/shell α-Mn2O3@α-MnO2 as heterogeneous catalysts for decomposition of phenolics in aqueous solutions.
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DOI：
10.1016/j.chemosphere.2016.06.021
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发表时间：
2016-09
期刊：
影响因子：
8.8
通讯作者：
E. Saputra;Huayang Zhang;Qiaoran Liu;Hongqi Sun;Shaobin Wang
中科院分区：
文献类型：
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作者：
E. Saputra;Huayang Zhang;Qiaoran Liu;Hongqi Sun;Shaobin Wang
采用水热法制备了均匀的椭球形α-Mn2O3@α-MnO 2核/壳（McMs）纳米复合材料。采用热重分析（TGA）、X射线衍射（XRD）、N2吸附、扫描电镜（SEM）等技术对复合材料的性能进行了表征。核/壳材料在非均相oxone®活化中非常有效，以产生硫酸根和羟基自由基用于降解苯酚水溶液。在20 ~ 120 min的短时间内，复合材料对苯酚的催化降解率为100%，远高于均相Mn ~（2+）体系在120 min内苯酚降解率为95%的催化活性。它们的活性也比单相α-Mn_2O_3或α-MnO_2高。苯酚降解的催化活性取决于温度、oxone®浓度、苯酚浓度和催化剂负载。催化剂在几个循环中也显示出稳定的活性。动力学研究表明，在MCMs催化剂上苯酚的降解符合一级反应，反应活化能为32.1- 68.8kJ/mol。通过电子顺磁共振（EPR）对自由基的检测，提出了自由基的产生机理。
Novel uniform ellipsoid α-Mn2O3@α-MnO2core/shell (McMs) nanocomposites were prepared via a hydrothermal process with a shape-control protocol followed by calcination at different temperatures. The properties of the composites were characterized by a number of techniques such as thermogravimetric analysis (TGA), X-ray diffraction (XRD), N2adsorption, and scanning electron microscopy (SEM). The core/shell materials were much effective in heterogeneous oxone®activation to generate sulfate and hydroxyl radicals for degradation of aqueous phenol. The McMs composites demonstrated catalytic activity for 100% phenol decomposition in short duration varying between 20 and 120 min, much higher than that of homogeneous Mn2+system with 95% phenol degradation in 120 min. They also showed a higher activity than single-phase α-Mn2O3or α-MnO2. The catalytic activity of phenol degradation depends on temperature, oxone®concentration, phenol concentration, and catalyst loading. The catalysts also showed a stable activity in several cycles. Kinetic study demonstrated that phenol degradation reactions follow a first order reaction on McMs catalysts giving activation energies at 32.1–68.8 kJ/mol. With the detection of radicals by electron paramagnetic resonance (EPR), the generation mechanism was proposed.