Study of a modiFied low pressure copperbased catalyst XC502 For methanol synthesis

Abstract

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

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