摘要
为获得高效催化活性的光催化材料,研究不同煅烧氛围对材料在可见光下催化性能的影响,以膨胀珍珠岩(EP)为载体,采用溶胶-凝胶法,在不同煅烧氛围(O2和/或NH_3)下制备Fe_2O_3/TiO_2负载EP的光催化复合材料[Fe_2O_3-TEP(O2)、Fe_2O_3-TEP(NH_3)、Fe_2O_3-TEP(O2,NH_3)、Fe_2O_3-TEP(NH_3,O2)],采用EDS(X-射线色散能谱)、BET(比表面积及孔径分析)、XRD(X射线衍射)、SEM(扫描电子显微镜)、XPS(X射线光电子能谱)等对复合材料进行表征,并研究了其在可见光下对罗丹明B的光催化降解效果.结果表明:(1)复合材料成功负载了Ti、Fe元素,负载的TiO_2以锐钛矿型存在,Fe_2O_3的掺杂增强了TiO_2对可见光的响应能力;(2)不同的煅烧氛围明显影响复合材料的晶粒尺寸、比表面积和光催化性能,其中,Fe_2O_3-TEP(O2,NH_3)的光催化性能最好,4 h后罗丹明B降解率达到87.59%,Fe_2O_3-TEP(NH_3,O2)、Fe_2O_3-TEP(O2)和Fe_2O_3-TEP(NH_3)4 h后对罗丹明B的降解率则分别为65.02%、62.48%和47.48%;(3)在试验条件下,复合材料的光催化反应符合一阶反应动力学方程,Fe_2O_3-TEP(O2,NH_3)、Fe_2O_3-TEP(NH_3,O2)、Fe_2O_3-TEP(O2)和Fe_2O_3-TEP(NH_3)相应的降解速率常数分别为0.008 3、0.004 3、0.004 3和0.002 7min-1.研究显示,通过溶胶-凝胶法所制备的复合材料(Fe_2O_3-TEP)经煅烧后所得矿相均一;Fe_2O_3掺杂TiO_2可形成Ti—O—Fe键,减小TiO_2固有的禁带宽度;复合材料光催化性能也受到煅烧氛围的影响,先O2后NH_3煅烧条件下所得材料的光催化性能最佳.
In order to obtain photocatalytic materials with better catalytic act ivity and study the influence of different calcination atmosphere on photocatalytic properties of materials under visible light, expanded pe rl ite was used to support nano Fe2O3/T iO 2 photocatalysts （FesOg-TEP （O 2 ） ,Fe2O3-TEP（NH 3） ,Fe2O3-T E P （O 2,N H 3） and Fe2O3-T E P （N H 3,O2） ） . The nanocomposites were calcinated in oxygen and/or ammonia atmosphere. The as-prepared materials were characterized by X-ray dispersive spectrometer （EDS ）, specific surface area and pore size analyzer （BET）,X - ra y d iffraction （ XRD ）, scanning electron microscope （ S EM ） and X -ra y photoelectron spectroscopy （ XPS）. The photocatalytic degradation of Rhodamine B （ RhB） was examined with visible light irradiation. The results confirmed that both anatase and Fe oxides were present in the nanocomposites. The batch catalytic experiment revealed that the Fe2O3 increased photolytic capacity of TiO 2 under visible l ig h t exposure. The calcination conditions greatly affected the crysta l lite size, specific surface area and the photocatalytic properties of the as-prepared materials. The calcination with oxygen and ammonia yielded the most capable ca ta lyst, with a highest degradation rate of87. 59% after 4 hours. The results of Fe2 O3 -T E P （N H 3 ,O2 ）, Fe2 O3 -TEP （ O2 ） and Fe2 O3 -TEP （ N H 3 ） were 6 5 .0 2 %, 6 2 .48% and 4 7 .4 8 %, respectively. The RhB degradation followed the f irs t order k in e t ic model under experimental con ditions, and the corresponding degradation rate constants of Fe2 O3 -T E P （O 2 ,NH 3 ）,Fe2O3 -T E P （N H 3 ,O 2 ） ,Fe2O3 -T E P （O 2 ） and Fe2O3- TEP（NH 3） were 0.0083 , 0.0043 , 0.0043 and 0.0027 min -1, respectively. This study showed that the composites （Fe2O3- TEP） prepared by sol-gel method were anatase after calcination. Fe2O 3 doped TiO 2 formed Ti- O-Fe bond narrowed band gap of TiO 2 - Thephotocatalytic property of composites was also affected by the calcination atmosphere;the optimum condition for calcination was O 2 followed by NH3 .
出处
《环境科学研究》
EI
CAS
CSCD
北大核心
2017年第12期1961-1969,共9页
Research of Environmental Sciences
基金
国家自然科学基金项目(51602281)
江苏省重点研发计划-社会发展项目(BE2015661)
江苏省环境材料与环境工程重点实验室项目
