Preparation and visible light catalytic performance of WO3/g-C3N4 composite photocatalyst
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摘要: 将自制层状石墨相氮化碳(g-C3N4)和WO3纳米片均匀混合，经煅烧制备WO3/g-C3N4复合半导体。利用XRD、SEM、TEM、UV-Vis DRS和PL对其进行表征。结果表明，g-C3N4呈现类石墨烯状片层结构，WO3为纳米片状结构，且分散在g-C3N4表面；与WO3复合后，UV-Vis吸收边发生了红移，拓宽了g-C3N4对可见光的响应。以罗丹明B(RhB)为模拟污染物，考察WO3/g-C3N4的光催化降解性能。WO3/g-C3N4质量比为1∶5时，表现出最佳的光催化活性，可见光照60 min后，RhB降解率可达到94.9%。光催化剂具有良好的稳定性，重复使用6次后，RhB的降解率依然达到88.9%。光催化机制研究表明，超氧自由基(·O2−)是光催化降解RhB的主要活性物种。
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关键词:
- WO3/g-C3N4 /
- 复合半导体 /
- 罗丹明B /
- 光催化降解 /
- 纳米片
Abstract: The WO3/graphite phase carbon nitride (g-C3N4) composites were prepared by mixing self-made layered g-C3N4 with WO3 nanoplates and afterward calcination process, and were characterized by XRD, SEM, TEM, UV-Vis DRS and PL. The results show that g-C3N4 presents graphene-like layered structure, and WO3 indicates nanoplate structure, and scatters on the surfaces of g-C3N4. After compounding with WO3, the absorption edge of UV-Vis spectrum shifts to red, which widens the response of g-C3N4 to visible light. The photocatalytic degradation properties of WO3/g-C3N4 were examined using rodamine B (RhB) as a simulated pollutant. When the mass ratio of WO3/g-C3N4 is 1∶5, the best photocatalytic activity is obtained. After 60 min of visible light irradiation, the degradation rate of RhB can reach 94.9%. The photocatalyst shows good stability, as the photodegradation rate of RhB reaches 88.9% after repeated use of the same photocatalyst for 6 times. The study of photocatalytic mechanism shows that superoxide radical (·O2−) is the main active species for photocatalytic degradation of RhB.-
Key words:
- WO3/g-C3N4 /
- composite semiconductor /
- RhB /
- photocatalytic degradation /
- nanoplate
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图 1 g-C3N4、WO3和WO3/g-C3N4的XRD图谱
Figure 1. XRD patterns of g-C3N4, WO3 and WO3/g-C3N4 composites
图 2 g-C3N4 (a)、WO3 (b)、WO3/g-C3N4 (c) 的SEM图像和WO3/g-C3N4的HR-TEM图像(d)
Figure 2. SEM images of g-C3N4 (a), WO3 (b), WO3/g-C3N4 (c) and HR-TEM image of WO3/g-C3N4 (d)
图 3 g-C3N4、WO3和WO3/g-C3N4的UV-Vis DRS谱图
Figure 3. Uv-Vis DRS spectra of g-C3N4, WO3 and WO3/g-C3N4
图 4 g-C3N4、WO3和WO3/g-C3N4的PL图谱
Figure 4. PL spectra of g-C3N4, WO3 and WO3/g-C3N4 composite
图 5 g-C3N4、WO3和不同质量比WO3/g-C3N4对RhB的光降解曲线 (a) 和误差棒图 (b)
Figure 5. Photodegradation curves (a) and error bar chart (b) of RhB by g-C3N4, WO3 and WO3/g-C3N4 with different mass ratios
图 6 不同光照时间RhB溶液的HPLC色谱图
Figure 6. HPLC chromatograms of different RhB solutions under different illumination time
图 7 不同光照时间RhB溶液的UV-Vis谱图
Figure 7. UV-Vis spectra of different RhB solutions under different illumination time
图 8 WO3/g-C3N4重复使用次数对RhB降解率的影响
Figure 8. Effect of repeated use of WO3/g-C3N4 on RhB degradation rate
图 9 WO3/g-C3N4光催化剂使用前后的XRD图谱
Figure 9. XRD patterns of WO3/g-C3N4 photocatalyst before and after use
图 10 活性物质捕获剂对RhB降解率的影响
Figure 10. Effect of active substance capture agent on RhB degradation rate
EDTA—Ethylene diamine tetraacetic acid; TBA—Tert butanol; BQ—P-benzoquinone
图 11 WO3/g-C3N4复合光催化剂的电荷转移和分离示意图
Figure 11. Schematic diagram of charge transfer and separation of WO3/g-C3N4 composite photocatalyst
表 1 石墨相氮化碳(g-C3N4)复合材料质量比参数
Table 1. Mass ratio parameters of graphite phases carbon nitride (g-C3N4) composites
Sample Mass ratio of WO3 to g-C3N4 WO3/g 5%WO3/g-C3N4 5∶100 0.005 10%WO3/g-C3N4 10∶100 0.010 15%WO3/g-C3N4 15∶100 0.015 20%WO3/g-C3N4 20∶100 0.020 25%WO3/g-C3N4 25∶100 0.025 
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