Photocatalytic activity of anatase powders for oxidation of methylene blue in water and diluted NO gas
Photocatalytic activity of anatase powders for oxidation of methylene blue in water and diluted NO gas
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锐钛矿粉末氧化水和稀NO气体中亚甲基蓝的光催化活性
DOI：
10.1016/j.apcatb.2004.02.017
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发表时间：
2004
影响因子：
22.1
通讯作者：
B. Tryba
中科院分区：
文献类型：
--
作者：
M. Inagaki;Tsutomu Imai;T. Yoshikawa;B. Tryba
以四氢异丙醇钛(TTIP)为原料，经不同的老化时间(10min和24小时)，在室温下制备了两个系列的样品，并在不同温度下进行了退火处理。考察了这些样品对水中亚甲基蓝(MB)和稀释态NO气体的光催化活性。对于MB的分解，速率常数k由MB在水中残留的相对浓度的对数与紫外线照射时间的线性关系确定。对于NO，测定了其辐照10h后的分解分数。时效时间不同，析出物的结晶状态不同，时效10min析出的物相为结晶度较差的锐钛矿相，时效24h后析出物为无定形。这两种沉淀物对MB和NO的结晶度和光活性随退火温度的变化不同。在101衍射线的半最大光强(FWHM)为0.6°左右时，获得了MB分解的最大速率常数k。对于NO气体，半高宽在1.6°左右时，分解分数最大。MB在水和无气体中的分解需要不同的锐钛矿相结晶度，前者锐钛矿相的结晶度较高，而后者的结晶度较低。
Two series of samples were prepared from titanium tetraisopropoxide (TTIP) through hydrolysis with different aging times, 10min and 24h, at room temperature and then annealed at different temperatures. Photocatalytic activities of these samples for methylene blue (MB) in water and for diluted NO gas were examined. For MB decomposition, rate constant k was determined from linear relation between logarithm of relative concentration of MB remained in water and UV irradiation time. For NO, its decomposition fraction after 10h irradiation was determined. Difference in aging time gave different crystalline state of the precipitates, anatase phase with poor crystallinity after 10min aging, but amorphous state after 24h aging. These two precipitates showed different changes in crystallinity and in photoactivity for MB and NO with annealing temperature. Maximum rate constant k for MB decomposition was obtained at around 0.6° of full width at half maximum intensity (FWHM) of 101 diffraction line. For NO gas, a maximum decomposition fraction was obtained at FWHM of around 1.6°. Different crystallinity of anatase was shown to be required for the decomposition of MB in water and NO gas, high crystallinity of anatase phase for the former but poor crystallinity for the latter.