合金催化剂的制备及CO_2加氢性能研究

Preparation and performance of alloy catalysts for CO_2 hydrogenation

采用熔融法制备了掺杂Mn的Cu/Zn/Al_2O_3催化剂,用于CO_2加氢合成甲醇。考察了元素组成对催化剂结构和性能的影响。通过扫描电子显微镜(SEM)、X射线能谱仪(1EDS)、X射线衍射仪(XRD)、比表面积分析仪(BET)等对制备的催化剂进行了表征。结果表明:熔融法制备的催化剂为合金固溶体(ss),合金化程度较高;随着Mn含量的增加,Cu在合金中的分布更加分散;晶格常数随着Mn含量的增加而增大;当Cu占合金总质量的40%时,催化剂的晶格常数最大,甲醇选择性最高,约为35.8%。催化剂合金化后,甲醇的选择性明显提高,这可能归因于合金催化剂表面的缺陷较多。合金通常具有优良的耐腐蚀和耐高温性能,其在CO_2加氢合成低碳醇方面具有潜在的应用价值。

Melting method is used in the preparation of catalysts for methanol synthesis,and the effects of composing element on the structure of catalysts and the performance for CO_2 hydrogenation are investigated.The samples are characterized by scanning electron microscope（SEM）,X-ray energy-dispersive spectrometer（EDS）,X-ray diffraction（XRD） and specific surface area analyzer（BET）.The results show that the catalysts prepared by melting method are alloy solid solution（ss） with higher alloying degree.With the increase of Mn content,the distribution of Cu in the alloy is more dispersive.The lattice constant increases with the increase of Mn content.For the catalyst with Cu accounted for 40% of the total mass of the alloy,the lattice constant is the largest,and the selectivity for methanol is the highest,about 35.8%.On the alloyed catalyst,the selectivity for methanol increases significantly.The higher methanol selectivity of the catalyst may be attributed to more defects on its surface.Alloy generally has excellent corrosion resistance and high temperature resistance,and it has potential application value in the synthesis of low carbon alcohols from CO_2 hydrogenation.