Preparation of carbon fiber supported layered TiC/TiO2 catalyst with potassium ion tuning
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摘要: 采用原位生长方法制备了一种碳纤维为载体，通过钾离子（K+）调谐的具有TiC/TiO2层状异质结的复合催化剂，用FE-SEM、XRD、Raman、XPS和AFM对制备的催化剂进行了表征，并进行了光催化降解污染物罗丹明B试验。研究表明钾离子对异质结的调谐对光催化效率有重要影响。在紫外-可见光催化降解过程中，CFs@TiC/TiO2对污染物RhB的去除率达到98%。经过3次循环使用后，该复合材料对污染物光催化去除效率仍大于90%，表明能重复稳定使用。K+协同的原位生长过程经过熔盐体系在碳纤维(CFs)表面生长TiC，并在KOH水溶液中进行水热反应，将部分TiC转化为钛酸钾纳米粒子，随后将钛酸钾纳米颗粒浸泡在稀释的HCl溶液中，将酸中的H+交换为钛酸钾中的K+经过热处理和脱水后，纳米颗粒形成片状锐钛矿型TiO2，最终形成碳纤维支撑的TiC/TiO2层状异质结的CFs@TiC/TiO2复合催化剂。钛酸钾纳米晶形成的花状结构具有较大的比表面积，这种结构为制备CFs@TiC/TiO2复合材料构建了结构特征和催化活性位点。
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关键词:
- 光催化剂 /
- TiC/TiO2层状异质结 /
- 碳纤维 /
- 原位生长 /
- 钾离子
Abstract: A carbon fiber supported layered TiC/TiO2 composite catalyst with heterojunction was prepared by in-situ synthesis with potassium ion (K+) tuning. The prepared catalysts were characterized by FE-SEM, XRD, Raman, XPS and AFM. The photocatalytic degradation of pollutants rhodamine B (RhB) by the catalysts was carried out. The results show that the tuning of potassium ion to heterojunction plays an important role in photocatalytic efficiency. In the process of UV-visible-light catalytic degradation, the removal rate of RhB by CFs@TiC/TiO2 reaches 98%. The repeated experiments show that the photocatalytic removal efficiency is more than 90% after three cycles, indicating a well stability. TiC can be grown on the surface of carbon fibers (CFs) via the in-situ growth collaborated by K+, and partial TiC can be transformed into potassium titanate nano particles through hydrothermal process in NaOH solution. The potassium titanate nano particles were then soaked in dilute HCl solution, and flake anatase TiO2 can be formed via heat treatment and dehydration. Finally, carbon fiber supported CFs@TiC/TiO2 composite catalyst with layered heterojunction can be obtained. The flower-like structure formed by potassium titanate nanocrystals has a large specific surface area, which provides the structural characteristics and catalytic activity sites for preparation of CFs@TiC/TiO2 composites.-
Key words:
- photocatalysis /
- TiC/TiO2 layered heterojunction /
- carbon fiber /
- in-situ growth /
- K+
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图 1 CFs@TiC/TiO2光催化剂制备工艺流程
Figure 1. Schematic diagram of the process for constructing CFs@TiC/TiO2 catalyst
图 2 (a) CFs，CFs@TiC，CFs@TiC/TiO2的XRD图谱，(b) CFs@TiC/TiO2的拉曼图谱
Figure 2. (a) XRD patterns of CFs，CFs@TiC，CFs@TiC/TiO2, (b) Raman spectrum of CFs@TiC/TiO2
图 3 (a-f)为扫描电子显微镜(SEM)形貌: (a-b) CFs@TiC，(c-d) CFs@TiC/K2Ti6O13，(e-f) CFs@TiC/TiO2，(g-h) CFs@TiC/TiO2的AFM图，(I-J) Na+调谐的CFs@TiC/TiO2的AFM图[25]
Figure 3. SEM images of (a-b) CFs@TiC, (c-d) CFs@TiC/K2Ti6O13, (e-f) CFs@TiC/TiO2; (g-h) AFM images of CFs@TiC/TiO2, (I-J) AFM images of Na+ tunning CFs@TiC/TiO2[25]
图 4 XPS谱图 (a) C 1s, (b) Ti 2p和(c) O 1s of CFs@TiC/TiO2
Figure 4. (a) C 1s XPS spectra, (b) Ti 2p XPS spectra and (c) O 1s XPS spectra of CFs@TiC/TiO2
图 5 (a) CFs，CFs@TiC和CFs@TiC/TiO2在紫外-可见光照射下光催化降解RhB的C/C0；(b) CFs@TiC/TiO2在紫外-可见光下经过3轮光催化测试后的稳定性试验；c、d为在相同条件下测试的Na+调谐的CFs@TiC/TiO2的光催化降解性能(c)[25]和循环稳定性(d)[25]
Figure 5. (a) The rate of C/C0 catalytic degradation of RhB under UV-Vis irradiation of CFs, CFs@TiC and CFs@TiC/TiO2; (b) Repeating experiments of RhB with CFs@TiC/TiO2 after 3 cycles；Photocatalytic degradation activity (c) and stability testing (d) of Na+ tuning CFs@TiC/TiO2 with the uniform condition[25]
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