不同制备方式的铜基甲醇合成催化剂的性质和结构研究

采用3种不同的沉淀方式(正加、反加和并流)制备出3个具有相同组成的甲醇合成催化剂样品CuO/ZnO/Al2O3,它们的活性顺序为:并流法样品>反加法样品>正加法样品;还原温度由低到高的顺序为:反加法样品<并流法样品<正加法样品。通过对催化剂前驱物进行DTA分析,证实了3种沉淀过程中相应的Cu2+和Zn2+的沉淀行为,即在并流和反加沉淀过程中,Cu2+和Zn2+同时均匀地沉淀,而在正加沉淀过程中,Cu2+和Zn2+发生分步沉淀。催化剂氧化态的IR结果表明了由3种沉淀方式所获得的样品中CuO和ZnO组分间相互作用的强弱。

Structure and properties of copper-based catalysts for methanol synthesis prepared by different precipitation methods

Three copper based catalysts(CuO/ZnO/Al2O3 )for methanol synthesis with the same Cu/Zn/Al atomic ratio (5∶4∶1) were prepared by normal precipitation (that is addition of a solution of Na2CO3 to a mixed solution of Cu2+, Zn2+ and Al3+) , reverse precipitation (addition of a mixed solution of Cu2+, Zn2+ and Al3+ to a solution of Na2CO3) and parallel flow precipitation, respectively The activities of the catalysts indicate that the parallel flow precipitation method is the best, and the reverse precipitation method is also much better than the normal precipitation method The order of reduction temperature from low to high obtained by TPR is as follows: reverse precipitation catalysts