• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>RSC Advances >Magnetically separable and reusable rGO/Fe3O4 nanocomposites for the selective liquid phase oxidation of cyclohexene to 1,2-cyclohexane diol
【24h】

Magnetically separable and reusable rGO/Fe3O4 nanocomposites for the selective liquid phase oxidation of cyclohexene to 1,2-cyclohexane diol

机译：用于选择性液相氧化环己烯至1,2-环己烷二醇的磁性可分离和可重复使用的RGO / Fe3O4纳米复合材料

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

A series of magnetically separable rGO/Fe3O4 nanocomposites with various amounts of graphene oxide were successfully prepared by a simple ultrasonication assisted precipitation combined with a solvothermal method and their catalytic activity was evaluated for the selective liquid phase oxidation of cyclohexene using hydrogen peroxide as a green oxidant. The prepared materials were characterized using XRD, FTIR, FESEM, TEM, HRTEM, BET/BJH, XPS and VSM analysis. The presence of well crystallized Fe3O4 as the active iron species was seen in the crystal studies of the nanocomposites. The electron microscopy analysis indicated the fine surface dispersion of spherical Fe3O4 nanoparticles on the thin surface layers of partially-reduced graphene oxide (rGO) nanosheets. The decoration of Fe3O4 nanospheres on thin rGO layers was clearly observable in all of the nanocomposites. The XPS analysis was performed to evaluate the chemical states of the elements present in the samples. The surface area of the nanocomposites was increased significantly by increasing the amount of GO and the pore structures were effectively tuned by the amount of rGO in the nanocomposites. The magnetic saturation values of the nanocomposites were found to be sufficient for their efficient magnetic separation. The catalytic activity results show that the cyclohexene conversion reached 75.3% with a highest 1,2-cyclohexane diol selectivity of 81% over 5% rGO incorporated nanocomposite using H2O2 as the oxidant and acetonitrile as the solvent at 70 degrees C for 6 h. The reaction conditions were further optimized by changing the variables and a possible reaction mechanism was proposed. The enhanced catalytic activity of the nanocomposites for cyclohexene oxidation could be attributed to the fast accomplishment of the Fe2+/Fe3+ redox cycle in the composites due the sacrificial role of rGO and its synergistic effect with Fe3O4, originating from the conjugated network of pi-electrons in its surface structure. The rapid and easy separation of the magnetic nanocomposites from the reaction mixture using an external magnet makes the present catalysts highly efficient for the reaction. Moreover, the catalyst retained its activity for five repeated runs without any drastic drop in the reactant conversion and product selectivity.
机译：成功地被一个简单的超声辅助的沉淀用溶剂热方法组合制备一系列磁可分离RGO /磁性纳米复合物与不同量的氧化石墨烯和它们的催化活性使用过氧化氢作为绿色氧化剂对环己烯的选择性液相氧化评价。使用XRD，FTIR，FESEM，TEM，HRTEM，BET / BJH，XPS和VSM分析所制备的材料进行了表征。结晶良好的Fe3O4作为活性铁物质的存在被认为在纳米复合材料的晶体的研究。电子显微镜分析表明对部分还原的石墨烯氧化物（RGO）纳米片的薄表面层的球形纳米Fe3O4的精细的表面分散。上薄RGO层的Fe3O4纳米球的装饰是在所有的纳米复合材料的清楚地观察。进行XPS分析，以评估样品中存在的元素的化学状态。纳米复合材料的表面积通过增加GO的量显著增加和孔结构进行有效地RGO在纳米复合材料的量调整。发现纳米复合材料的磁饱和度值足够用于其有效磁分离。催化活性结果表明，环己烯转化率81％最高1,2-环己烷二醇的选择性超过5％RGO掺入纳米复合材料使用H 2 O 2作为氧化剂和乙腈作为在70℃下将溶剂6小时达到75.3％。的反应条件，通过改变变量和一个可能的反应机理，提出了进一步优化。纳米复合材料为环己烯的氧化的增强的催化活性可能归因于所述的Fe2 + / Fe3 +的氧化还原中，由于RGO从π电子的共轭网络牺牲作用及其与Fe3O4的协同效应，始发的复合周期的快速完成其表面结构。使用外部磁体从所述反应混合物中的磁性纳米复合材料的快速和容易的分离使得本发明的催化剂用于反应高效。此外，催化剂保留其活性五个重复运行而不会在反应物转化率和产物选择性的任何急剧下降。

著录项

  • 来源
    《RSC Advances》 |2019年第56期|共18页
  • 作者

  • 作者单位
  • 收录信息
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号