介孔钛酸锶的可控生长及其光催化性能研究

发布时间：2018-06-26 21:59

本文选题：SrTiO_3 + 可控生长　；参考：《西南石油大学》2017年硕士论文

【摘要】：本文采用水热法合成得到介孔钛酸锶(SrTi03,STO),利用羧甲基纤维素钠(CMC)和十六烷基三甲基溴化铵(CTAB)作为形貌、孔径控制剂分别获得了孔径更小的介孔STO和微孔STO。结果表明CMC和CTAB均能达到控制STO的平均孔径尺寸的目的,介孔STO的平均孔径范围在10nm左右,比控制生长前减小37.45%,微孔STO的平均孔径在1.89 nm左右,比控制生长前减小88.45%,对产物性能进行了评价,并分析了孔径、染料分子对降解的影响机理。(1)通过对比STO对罗丹明B(RhB)和甲基橙(MO)一元染料的降解性能,发现介孔和微孔STO均对RhB的降解相比MO具有优势;STO降解染料的降解速率大小依次为:RhBMO;(2)将介孔STO和微孔STO对二元复合染料(RhB+亚甲基蓝(MB))降解的选择性进行探究,结果表明经过CMC控制生长得到的介孔STO降解RhB+MB混合二元染料,对MB的选择性更强,MB与RhB的一级动力学常数之比达到3.50,10 nm孔径的介孔STO对MB更具有偏向性和选择性降解,降解速率大小依次为:MBRhB;(3)为了提高STO的光催化降解活性,我们进行了Fe和Ag的掺杂及非晶Pd-Ni-P的修饰,Fe和Ag掺杂形成的氧化物降低产物禁带宽度0.1 eV,发现了在光照30 min内,改性后产物MO的降解率分别提升了30%、50%和40%,Pd-Ni-P的修饰改变了 STO表面状态,合金促进了 MO的降解;(4)以pH和染料种类为变量,探究不同pH的一元染料降解和不同二元染料降解的情况进行探究,利用ζ电位与染料分子轨道LUMO-HOMO值,得到了二元染料降解的模型,解释了 RhB敏化STO和STO敏化MB促进了载流子的分离的过程。再利用循环伏安测试法对pH改变引起的动力学常数增加现象进行了解释,得到染料的降解先后顺序:MBRhBMO,说明H+浓度的改变影响了染料分子与H+的竞争吸附,并导致染料分子氧化电位降低。
[Abstract]:In this paper, strontium titanate (SrTi03STO) was synthesized by hydrothermal method. The mesoporous STO with smaller pore size and micropore STO were obtained by using sodium carboxymethyl cellulose (CMC) and cetyltrimethylammonium bromide (CTAB) as morphology. The results show that both CMC and CTAB can control the average pore size of mesoporous STO. The average pore size of mesoporous STO is about 10nm, which is 37.45% smaller than that before controlling growth, and the average pore size of micropore STO is about 1.89 nm. The effect of pore size and dye molecule on the degradation of Rhodamine B (RhB) and methyl orange (MO) were analyzed. (1) by comparing STO with Rhodamine B (RhB) and methyl orange (MO), the degradation properties of Rhodamine B (RhB) and methyl orange (MO) were compared. It was found that both mesoporous STO and micropore STO had advantages over MO in degradation of RhB. The degradation rate of STO was 1: RhBMO.The selectivity of mesoporous STO and micropore STO to the degradation of binary composite dyes (RhB methylene blue (MB) was studied. The results show that the mesoporous STO prepared by CMC-controlled degradation of RhB MB mixed binary dyes has a higher selectivity to MB and the ratio of the first order kinetic constant of MB to RhB reaches 3.50 ~ 10 nm pore size, and the mesoporous STO has a more biased and selective degradation of MB. (3) in order to improve the photocatalytic degradation activity of STO, the doping of Fe and Ag and the modification of amorphous Pd-Ni-P were carried out to reduce the band gap of the products. After modification, the degradation rate of Mo increased by 30% and 40%, respectively, and the modification of Pd-Ni-P changed the surface state of STO, and the alloy promoted the degradation of MO. (4) the pH and the type of dyes were taken as variables. The degradation model of binary dyes was obtained by using 味 potential and molecular orbital LUMO-Homo value of dyes. It is explained that RhB-sensitized STO and STO-sensitized MB promote the separation of carriers. The phenomenon of increasing kinetic constant caused by pH change was explained by cyclic voltammetry, and the degradation sequence of dye was obtained, which indicated that the change of H concentration affected the competitive adsorption of dye molecule with H. The oxidation potential of dye molecule decreases.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703;O643.36

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