Influence of Co-Ce co-doping on photocatalytic DeNOx of TiO2 catalyst at room temperature
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摘要: 将钛酸丁酯作为Ti源，硝酸铈作为Ce源，硝酸钴作为Co源，采用溶胶-凝胶水热法制备出Ce-TiO2和Ce-Co-TiO2催化剂。对所制备的改性TiO2催化剂进行BET、XRD、SEM、UV-vis、XPS、NH3-TPD等表征分析测试，并以NO为研究对象对不同改性TiO2催化剂进行了可见光催化实验，探究改性TiO2催化剂脱除NO的效率。结果表明，以硝酸铈为Ce源（掺杂物质的量比1%），硝酸钴为Co源（掺杂物质的量比5%），在水热反应温度为160 ℃的条件下反应24 h后在200 ℃下煅烧得到的Ce（1%）-Co（5%）-TiO2催化剂性能最好。其对浓度为762 μg/m3的NO可见光催化效率高达92.69%，在浓度提高至1148 μg/m3时在室温下的可见光催化效率仍可达85.94%，与纯TiO2相比效率提高了近50%。而且Ce（1%）-Co（5%）-TiO2催化剂的抗硫性能与连续使用次数都比商用催化剂（掺杂有V2O5的商用TiO2）好。
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关键词:
- Ce-Co-TiO2 /
- 脱硝 /
- 室温 /
- 可见光催化
Abstract: Ce-TiO2 and Ce-Co-TiO2 powders were prepared by the sol-gel hydrothermal method with butyl titanate as the source of Ti, cerium nitrate as the source of Ce, cobalt nitrate for Co source. The modified TiO2 catalysts were characterized with BET, XRD, SEM, UV-vis, XPS and NH3-TPD. The NO reduction efficiency by visible light over the modified TiO2 catalysts was carried out. The experimental results show that the catalyst Ce (1% molar)-Co (5% molar)-TiO2 prepared under the conditions of 24 h hydrothermal synthesis at 160 and 200 ℃of calcination showed the best performance. At room temperature, the visible light catalytic efficiency of the catalyst reached 92.69% when the NO initial concentration was 762 μg/m3. When the NO initial concentration was 1148 μg/m3, the visible light catalytic efficiency could still reach 85.94%, which was improved by nearly 50% compared with pure TiO2. Moreover, it was found that in the resistance of SO2 and continuous usage, the efficiency of the Ce (1%)-Co (5%)-TiO2 catalyst was better than the commercial catalysts (TiO2 with V2O5 doping).-
Key words:
- Ce-Co-TiO2 /
- denitration /
- room temperature /
- visible light catalysis
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图 1 自制光催化反应装置示意图
Figure 1 Homemade photocatalytic reaction device
1: multiorifice plate; 2: energy saving lamp; 3: external power receptacle; 4: sampling port/air outlet 5: viewing window; 6: fan; 7: air inlet
图 2 不同催化剂及光照条件的催化活性
Figure 2 Catalytic activity of different catalysts and different lighting conditions
■ : Ce(1%)-Co(5%)-TiO2; ● : Ce(1%)-TiO2; ▲ : Ce(1.5%)-TiO2; ▼: Ce(0.5%)-TiO2; ◆ : commercial catalyst (reaction condition: 3 g of catalyst, cNO= 672μg/m3); ◀: TiO2
图 3 催化剂的孔径分布及吸附-脱附等温线
Figure 3 Adsorption-desorption curves and pore size distributions of the catalysts a: desorption; b: adsorption
(a), (b):TiO2; (c), (d): Ce(1%)-TiO2; (e), (f): Ce(1%)-Co(5%)-TiO2
图 5 纯TiO2、Ce(1%)-TiO2与Ce(1%)-Co(5%)-TiO2的SEM照片
Figure 5 SEM images of TiO2 (a), Ce(1%)-TiO2 (b), and Ce(1%)-Co(5%)-TiO2 (c)
图 7 纯TiO2、Ce-TiO2、Ce-Co-TiO2催化剂的XPS谱图
Figure 7 XPS spectra of different TiO2 catalysts (TiO2, Ce-TiO2, Ce-Co-TiO2)
a: TiO2; b: Ce(1%)-Co(5%)-TiO2; c: Ce(1%)-TiO2
图 8 不同催化剂的NH3-TPD(a)和in-situ DRIFT(b)谱图
Figure 8 NH3-TPD (a) and in-situ DRIFT (b) spectra of different catalysts
表 1 共掺不同元素的催化效率
Table 1 Catalytic efficiency of different element doping (initial concentration of NO:1148 μg/m3)
Zr-Ce(1%)-TiO2 Efficiency/% Mn-Ce(1%)-TiO2 Efficiency/% Co-Ce(1%)-TiO2 Efficiency/% 0.5% 54.55 0.5% 55.41 1% 66.67 1.0% 71.43 1.0% 60.29 3% 71.64 1.5% 72.73 1.5% 66.15 5% 85.94 2.0% 75.76 2.0% 66.70 7% 64.71 
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表 2 样品表面结构数据
Table 2 Surface structural data of the samples
Sample ABET/(m2·g-1) rp/nm vm/(cm3·g-1，STP) vp/(cm3·g-1) TiO2 89.5 10.98 20.87 0.25 Ce(1%)-TiO2 104.9 10.10 24.09 0.27 Ce(1%)-Co(5%)-TiO2 126.1 10.40 25.88 0.33
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表 3 不同类型催化剂光催化反应氧化率
Table 3 Photocatalytic oxidation rate of different types of catalysts
Sample Commercial catalyst TiO2 Ce(1%)-TiO2 Ce(1%)-Co(5%)-TiO2 Oxidation rate/% 18.35 16.37 20.31 23.45
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