摘要
采用XPS-Auger、XRD和FTIR等方法,对5组分Cu-Zn-Al-M1-M2改进XC502铜基低压甲醇合成催化剂进行了表征。XPS-Auger结果表明,XC502催化剂出现主峰为336.4eV(Cu+),而Cu-Zn-Al催化剂主峰为334.9eV(Cu0);XRD结果表明,两种工作态催化剂比氧化态新增峰的2θ分别为36.5°(Cu+)和43.3°(Cu0),XC502催化剂这两峰的强度比I36.5/I43.3是Cu-Zn-Al催化剂的2.1倍,说明工作态XC502催化剂单位Cu0中的Cu+含量比Cu-Zn-Al催化剂多;FTIR谱显示,XC502和Cu-Zn-Al两种工作态催化剂新增波数分别为622cm-1和627cm-1的振动峰,此新增峰可能是Cu+-O或Cu+-O-Zn2+的振动峰。改进型铜基甲醇合成催化剂的活性位可能是Cu0-Cu+-O-Zn2+/Al2O3-MOx。
pectroscopic characterization of the active site of a modified low pressure copperbased catalyst XC502, prepared by adding a small amount of metal oxides of the VI B and VB groups to a CuZnAl catalyst for methanol synthesis, is carried out by XPSAuger, XRD and FTIR. The main peaks are detected by XPSAuger to be 336.4eV(Cu+) and 334.9eV(Cu0) on the surfaces of XC502 and the CuZnAl catalyst, respectively. The XRD result shows that two new peaks appear at 2θ=36.5°(Cu+) and 43.3°(Cu0) for those functioning catalysts, but I36.5/I43.3 of XC502 is twice as large as that of the CuZnAl catalyst, showing that the surface of the functioning XC502 catalyst has higher Cu+/Cu0 ratio and valence stability than those of the CuZnAl catalyst. By applying FTIR spectroscopy, bands at 622 cm-1 and 627cm-1 are observed on the functioning XC502 and CuZnAl catalysts, respectively, and the band may be assigned to Cu+OZn2+ bond vibration. In light of the above results, it is suggested that the active site on the functioning XC502 copperbased catalyst for methanol synthesis at low pressure is probably Cu0Cu+OZn2+/Al2O3MOx.
出处
《天然气化工—C1化学与化工》
CAS
CSCD
北大核心
1998年第3期16-19,共4页
Natural Gas Chemical Industry
关键词
甲醇
合成
低压
铜基
催化剂
改进
methanol synthesis, copperbased catalyst, XPSAuger, XRD, FTIR, active site