采用密度泛函理论的广义梯度近似(DFT-GGA)方法,研究了双金属改性HZSM-5的ZrOZn、ZrOAl、ZrOMg和ZrOGa等4种双5T构型对甲醇合成二甲醚的影响。4种构型中的合成二甲醚活化能分别为1.09,0.89,0.93,0.90eV,均有利于二甲醚的合成。存在3种可能的反应路径,两甲醇直接反应生成二甲醚反应路径3(CH_3OH+CH_3OH→CH_3O(H)CH_3+OH→CH_3OCH_3+H_2O)为最佳反应路径。实验对寻找改性双金属催化剂具有一定的指导意义。
In the present work,we employed periodic DFT-GGA calculation method and double 5Tcluster model to compare the influence of ZrOZn,ZrOAl,ZrOMg and ZrOGa models on methanol dehydration to dimethyl ether.It was found that:the activation energies on four configurations are 1.09,0.89,0.93,0.90 eV,being helpful for dimethyl ether synthesis;path 3(CH_3OH+CH_3OH→CH_3O(H)CH_3+OH→CH_3OCH_3+H_2O)for direct methanol dehydration to dimethyl ether in three possible paths is the best path.The research has some guidance for searching modified double-metal catalysts.