考察了X射线光电子能谱(XPS)测试过程中金属Cu改性钒基脱硝催化剂在X射线照射下Cu元素的价态变化及影响因素.结果表明,催化剂中Cu元素以CuO(Cu2+)和Cu2O(Cu+)两种形式存在,X射线照射会引起CuO的还原;且初始测得的Cu2O主要为样品焙烧后本征存在的物质.样品中Cu元素还原(CuO转化为Cu2O)受X射线照射时间与功率、Cu负载量以及样品制备方法等因素的影响:随着照射时间的增加或X射线功率的提高,CuO还原率均逐渐升高;随着Cu负载量的升高,CuO还原率整体呈下降趋势,但当负载量达3％后,CuO的绝对变化量与Cu负载量几乎无关(维持在～1.2％);制备方法中活性组分V元素的存在提高了CuO的还原活性,而草酸的添加降低了其还原活性.该研究为Cu改性钒基脱硝催化剂的表征分析提供了重要参考,也为其它类似敏感样品的XPS分析提出了测试条件及方法上的建议.%The chemical state variation of Cu element and its influencing factors on Cu modified vanadium-based de-NOx catalyst were investigated by X-ray photoelectron spectrometry(XPS).The results showed that Cu element in catalyst existed in the forms of CuO and Cu2O,and CuO could be reduced under X-ray irradiation.However,the initially observed Cu2O was mainly derived from the prepared samples other than generated by X-ray.The influencing factors for the reduction from CuO to Cu2O included the irradiation time and power of X-ray,copper load and sample preparation methods,etc.The results indicated that the reduction percentage for CuO increased gradually with the increase of irradiation time or power of X-ray.In general,the reduction percentage for CuO decreased with the increase of Cu load.The reduction percentage for CuO keeped at the level about 1.2％ when the Cu load reached to 3％.The existence of the active component vanadium increased the reduction activity of CuO,while the addition of oxalic acid reduced the reduction activity.This study provided an important reference for the characterization and analysis of Cu modified vanadium denitrification catalyst,and also gave some suggestions for parameter settings and analysis method for other similar X-ray sensitive samples.
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