纳米TiO_2包覆微米Cr_2O_3粒子的制备及表征研究

目的研究室温条件下纳米TiO_2包覆微米Cr_2O_3粒子的物相、显微组织及其光催化活性。方法采用钛酸丁酯为原料,通过酸催化的胶溶-沉淀法制备纳米TiO_2包覆微米Cr_2O_3复合粒子,利用SEM,XPS,XRD,Raman及紫外-可见漫反射光谱等手段对复合粒子进行表征。结果 XPS分析表明,微米Cr_2O_3粒子的表面存在C,O,Ti,Sn,Cr等元素。场发射扫描电镜观察表明,粒径大小为10~15 nm左右的TiO_2颗粒包覆在Cr_2O_3微粒表面,从而形成纳米/微米复合结构。Raman光谱结果显示,空载实验获得的TiO_2颗粒样品呈现锐钛矿型。UV-Vis光谱分析表明,负载Cr_2O_3微粒后使半导体的吸收峰值明显红移,在370,460,600 nm处出现了3个吸收峰,最大吸收波长达到750 nm左右。结论锐钛矿相TiO_2成功包覆在微米Cr_2O_3粒子表面,扩展了复合半导体的光响应范围,有望实现可见光催化活性。

Preparation and Characterization of Micron Cr2O3 Particles Coated by TiO2 Nanoparticles

Objective To study phase constituent, microstructure and photocatalysis activity of micron Cr2O3 particles coated by nano TiO2 at room temperature. Methods Nano-TiO2/micro-size Cr2O3 composite particles were first prepared by gel-precipitation method and acid catalysis with Ti (OBu)4 as raw material. The composite particles were characterized by SEM, XPS, XRD, Raman, UV-Vis spectrum, etc. Results XPS analysis showed that the element C, O, Ti and Sn existed on the surfaces of composite particles. Observation by field emission scanning electronic microscope showed that TiO2 particles of 10-15 nm covered Cr2O3 powder surface and formed nanometer/micron composite particles. UV-Vis spectra analysis showed that samples of TiO2 particles obtained in the no-load test showed an anatase type. UV-Vis spectral analysis showed apparent red shift of the absorption peaks in the semiconductors after loading nano-TiO2. There were three peaks at 370 nm, 460 nm and 600nm, and the maximum absorption wavelength was about 750 nm. Conclusion TiO2 of anatase type can be synthesized on the surface of Cr2O3 particles. The optical response range of composite semiconductors is extended, and the visible light photocatalytic activity is expected to be realized.