(1. 浙江工业大学 化工学院,杭州 310014;
2. 绿色化学合成技术国家重点实验室培育基地,杭州 310014)
摘 要: 本文以硫酸氧钛为原料,氢氟酸(HF)和尿素为导向剂,采用一步水热法制备出具有(001)晶面优势取向的纳米颗粒构筑的TiO2空心微球。采用XRD、SEM、TEM和BET等手段对微球的形貌、结构和组成进行分析表征,以亚甲基蓝(MB)为模拟污水考察样品光催化降解MB的能力。结果表明:样品颗粒为直径1~3 μm的空心微球,球壁由锐钛矿相(A-TiO2)纳米晶和孔隙构成,A-TiO2纳米晶的晶面具有明显的优势取向,以(001)为主,平均孔径为12.90 nm,属介孔范围;制备过程中适量的HF可以增强A-TiO2纳米晶的结晶程度,诱导(001)晶面的形成及稳定保存下来;当制备过程中钛与氟的摩尔比为0.40时,A-TiO2微球具有蛋黄结构,其比表面积可达21.05 m2/g,对亚甲基蓝的降解率高达99.9%,表现出最佳的光催化活性。
关键字: 二氧化钛;(001)晶面;空心微球;光催化
(1. School of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, China;
2. State Key Breeding Base of Green Chemistry Synthesis Technology, Hangzhou 310014, China)
Abstract:Mesoporous TiO2 microspheres self-assembled by TiO2 nano-slices were fabricated by a hydrothermal approach, using TiOSO4 as precursor, HF and urea as initiating agent. The crystal phases, morphologies, microstructures, and chemical components of the microspheres were characterized by XRD, SEM, TEM, and BET. Furthermore, the photo-catalytic property of the microspheres was investigated using methylene blue solution as simulated sewage. The results show that the morphology of the sample particles is microsphere with a diameter 1-3 μm, the wall of the microsphere is constituted of anatase (A-TiO2) nano-crystallites and cavities. The crystal planes of the A-TiO2 nano-crystallite show preferential crystallographic orientation, most of them are belong to (001) plane. The average value is 12.90 nm, which can be attributed to mesoporosity. During the fabricating process, the suitable dosage of HF improves the crystallinity of A-TiO2 nano-crystallite, induces the formation of (001) crystal plane of A-TiO2 nano-crystallite, and preserves the (001) planes stably. When the mole ratio of Ti to F is 0.40, the microstructure of A-TiO2 microsphere displays egg yolk structure, its specific surface area reaches 21.05 m2/g,its photocatalytic rate to MB reaches 99.9%,and exhibits the best photocatalytic property.
Key words: titanium dioxide; (001) crystal plan; hollow microspheres; photocatalysis