溶胶-凝胶法合成La_(2)Ce_(2)O_(7)粉体及其紫外吸收性能  

Synthesis and UV Absorption of La_(2)Ce_(2)O_(7) Powders by Sol-gel Method

作　　者：夏小洁 孙玥 金星 冉松林[1,2] XIA Xiao-Jie;SUN Yue;JIN Xing;RAN Song-Lin(Key Laboratory of Metallurgical Emission Reduction&Resources Recycling(Anhui University of Technology),Ministry of Education,Maanshan 243002,China;Advanced Ceramics Research Center,School of Materials Science and Engineering,Anhui University of Technology,Maanshan 243032,China)

机构地区：[1]安徽工业大学冶金减排与资源综合利用教育部重点实验室,安徽马鞍山243002 [2]安徽工业大学材料科学与工程学院先进陶瓷研究中心,安徽马鞍山243032

出　　处：《现代技术陶瓷》2024年第4期349-359,共11页Advanced Ceramics

摘　　要：La_(2)Ce_(2)O_(7)具有良好的紫外吸收性能和光稳定性,可替代TiO_(2)和ZnO作为防晒剂在防晒霜中应用。La_(2)Ce_(2)O_(7)粉体通常采用固相法合成,存在合成温度、比表面积小、光吸收能力差等问。本研究以金属硝酸盐为原料,柠檬酸为络合剂,乙二醇为稳定剂,采用溶胶-凝胶法合成了La_(2)Ce_(2)O_(7)粉体。通过TG-DSC、XRD、SEM及XPS分析了前体的转化过程、产物的物相变化、粉体的形貌以及其中元素的价态,并且采用紫外可见分光光度计测试了产物的紫外吸收性能,最后利用光催化降解罗丹明B染料的实评价了产物的光稳定性。研究结果表明,溶胶-凝胶法在250℃温度下即可合成出纯相La_(2)Ce_(2)O_(7)粉体,合成温度比传统固相法低1000℃以上。溶胶-凝胶法合成的La_(2)Ce_(2)O_(7)粉末的比表面积最大可达10.04 m^(2)/g,而固相法合成粉体的比表面积仅为0.19 m^(2)/g。当煅烧温度为300℃时,所合成粉体具有最佳的紫外吸收性能,且比固相法合成粉体的性能提升了25%。与TiO_(2)相比,La_(2)Ce_(2)O_(7)不仅具有更好的紫外吸收性能,而且还基本没有光催化活性。La_(2)Ce_(2)O_(7) exhibits intense absorption ability in the ultraviolet(UV)region with excellent photostability,and can replace TiO_(2) and ZnO as an UV absorber in sunscreen formulations.Traditionally,La_(2)Ce_(2)O_(7) powder is synthesized by the solid-state method,which has problems such as high synthesis temperature,small specific surface area of the powder,and poor light absorption ability.In this study,La_(2)Ce_(2)O_(7) powder was successfully synthesized by a sol-gel method with metal nitrates,citric acid and ethylene glycol as raw materials,chelating agent and stabilizer,respectively.The conversion process of the precursor,phase change of the product,morphology of the powder,and the valence state of the elements were analyzed by TG-DSC,XRD,SEM and XPS.The UV absorption performance of the product was tested using a UV-visible spectrophotometer.The photostability of the product was evaluated by photocatalytic degradation of Rhodamine B dye.The results show that pure phase La_(2)Ce_(2)O_(7) powder can be synthesized by the sol-gel method at 250℃,which is more than 1000℃lower than that of the traditional solid-state method.The maximum specific surface area of the La_(2)Ce_(2)O_(7) powder synthesized by the sol-gel method is 10.04 m^(2)/g,while that of the powder synthesized by the solid-phase method is only 0.19 m^(2)/g.The La_(2)Ce_(2)O_(7) powder synthesized at 300℃shows the best UV absorption performance,25%higher than that synthesized by the solid-state method.Compared with TiO_(2),La_(2)Ce_(2)O_(7) exhibits better UV absorption performance and almost no photocatalytic activity.

关 键 词：溶胶-凝胶法 La_(2)Ce_(2)O_(7) 立方萤石结构 紫外吸收剂 

分 类 号：O643[理学—物理化学]