Au/γ-MnO2催化剂催化无溶剂条件下甲苯氧化反应

采用氧化还原法制备了α, δ, γ-MnO₂载体, 采用原位还原法制备了Au负载量为0.5%-3.0%的Au/γ-MnO₂催化剂, 并采用X射线衍射、扫描电镜、透射电镜和N₂物理吸附等手段对其进行了表征. 透射电镜照片表明Au/γ-MnO₂催化剂中Au颗粒的大小约为10 nm. 采用无溶剂存在下的甲苯氧化反应测试所制备样品的催化活性. 结果表明, 甲苯转化率随着Au负载量的增加而增大. 这是由于Au颗粒数量增多, 尺寸减小的缘故. 同时, 负载Au颗粒对苯甲醛具有较高的选择性. Au/γ-MnO₂催化剂具有良好的重复使用性.

Au/γ-MnO2 catalyst for solvent-free toluene oxidation with oxygen

α-, δ-, and γ-MnO₂ were synthesized by a redox method and Au/γ-MnO₂ catalysts with different Au loadings (0.5%-3.0%) were synthesized by an in situ reduction method. The supports and catalysts were characterized by X-ray diffraction, scanning electron microscope, transmission electron microscopy (TEM), and N₂ adsorption. TEM images showed that the Au particles were about 10 nm. The catalysts were used in solvent-free toluene oxidation with oxygen. The results showed that toluene conversion increased with increasing Au loading, which was ascribed to the increasing amount of Au particles and also the smaller Au particles. The Au loading gave a uniquely high selectivity to benzaldehyde. The Au/γ-MnO₂ catalysts exhibited good reusability in liquid phase toluene oxidation.