【摘要】 采用XAFS方法对Fe₂/ZrO₂气凝胶超细粒子催化剂中Fe的近邻结构进行研究.随着催化剂颗粒减小,Fe/ZrO₂远程结构逐渐无序,Fe最近邻Fe-O配位数不变,Fe-O键长略有下降,次近邻Fe-O配位数和键长均减小,对于高配位层,配位数下降更快,Fe的配位环境的影响与催化剂活性和选择性的规律有较好的关联.更多还原

【Abstract】 A series of Fe / ZrO2 catalysts with different particle size has been prepared by the supercritical fluid drying and conventional impregnation methods. The neighboring coordinative environment of iron in these catalysts was investigated by XAFS. The results show that as the particle size of Fe/ ZrO2 catalysts is decreased, their structure is disorder gradually, the coordination number of the first Fe-O shell does not change and their Fe-O bond length has a litter shrink, The coordination number and bond length of the second Fe-O shell are decreased, and coordination number of higher coordination shell decreases very quickly. The correlation between the XAFS results and the activity and selectivity of these catalysts was obtained.更多还原