Effects of Polyvinylpyrrolidone on the Preparation of Supported La2O3 Catalysts by a Modified Impregnation Method for the Oxidative Coupling of Methane
- 化学化工－已发表论文 
The direct transformation of methane, such as oxidative coupling of methane (OCM), is a long-standing challenge in methane utilization. Keeping this objective in mind, we explored the dispersion and acid-base effects of the catalysts on OCM. Herein, we prepared a series of La2O3/MgO catalysts by using a modified impregnation method with polyvinylpyrrolidone added to impregnated solutions. The BET, XRD, SEM, and TEM characterizations of the samples confirm that La2O3 dispersion on MgO increases with the addition of polyvinylpyrrolidone and the particles become smaller in size and more uniform in distribution. High catalytic performances (e.g., the C-2 yield approximate to 16%) of the well-dispersed La2O3/MgO catalysts for OCM are demonstrated at a lower temperature (e.g., 550 degrees C) and a lower loading (e.g., 1.9wt%). In addition, with the modification of acid-base properties of the supports, we find that base properties of the supports are responsible for C-2 formation and acidic properties of the supports are responsible for COx formation. These properties establish a good correlation of the dispersion and basicity of the catalysts with the catalytic performances of the catalysts for OCM.