尖晶石型LiMn_2O_4亚微米粉体的制备与结构性能表征

Synthesis and performance of submicron spinel compound LiMn_2O_4

采用无机盐溶胶凝胶法制备了LiMn2O4尖晶石亚微米粉体，探讨了工艺参数对LiMn2O4化合物形成的影响。采用XRD、SEM、TEM研究了样品的晶体结构及其表面形貌，以其作为光催化剂对水溶性染料（活性艳红K-2G）进行了光催化性能研究，通过吸光度法表征了样品的光催化活性，采用重铬酸钾法研究了降解后染料溶液的化学需氧量，并根据配位场理论探讨了光催化反应的机理。结果表明，800℃热处理的LiMn2O4样品已完全形成尖晶石型晶体结构，晶粒呈长约300-400nm，宽约1.0-200nm，厚约100nm的短柱状，在可见光辐射下对染料溶液的降解脱色率和总有机碳去除率分别为76．5％和53．3％，是一种新型具有可见光活性的催化材料。

The spinel style LiMn2O4 sub-micron powders were prepared by inorganic salts sol-gel method. The crystal structure of the sample was examined by XRD, SEM and TEM. The photodegradation of dye （Reactive brilliant red K-2G） were carried out in the suspension systems of LiMn2O4 acting as photocatalyst. The results showed that LiMn2O4 powders sintered at 800 ℃ have the ideal configuration of spinel and the well photocatalytic property. The particles of crystal are short rod shape with 300-400 nm in length, 100-200 nm in width and about 100 nm in thickness. The decolori- zing rate and the COD removal yield of dye is 76.5% and 53.3% respectively. The spinel LiMn2O4 compound is a novel catalyst with visible light activity.