无铬CO高温变换催化剂的研究Ⅱ.过渡元素对高变催化剂结构与性能的影响

STUDY ON CATALYST FOR CO HIGH TEMPERATURE SHIFT REACTION Ⅱ. Effect of Transition Metals on the Structure and Property of the Catalyst

通过ＸＲＤ，ＢＥＴ和ＸＰＳ表征及反应性能测定表明，铁系高变催化剂中加入的过渡元素能够进入Ｆｅ３Ｏ４晶格形成固溶体，并使催化剂的晶胞参数随着加入元素离子半径的增大而增大，晶粒度明显变小，比表面积增大，起到铬的作用，催化剂的活性和热稳定性提高．发现部分过渡元素具有富集ＯＨ－的特性，使催化剂在较低的汽／气比条件下具有较高的催化活性．研制成功的Ｂ１２１型无铬高变催化剂性能达到铁铬系高变催化剂的技术指标．

The effect of transition metal on the catalyst for CO high temperature shift reaction was investigated by means of XRD, BET, XPS and catalytic activity measurement. The result showed that the transition metal added in the catalyst could enter the lattice of Fe 3O 4 acting as Cr and forming solid solution. The lattice parameter increased with the increasing of radius of the transition metal ion, the crystallite size decreased and the surface area increased obviously. In this case, the catalytic activity and thermostability were improved. It was also found that some of transition metal could increase the density of OH - on the catalyst surface, improve the catalytic activity under low vapor/gas ratio condition. It was proved that the property of B 121 type chromium free catalyst achieved the technical object of iron chromiun catalyst.