高效碳量子点/BiOCl纳米复合材料用于光催化污染物降解

doi:10.15541/jim20190211

摘要/Abstract

摘要：

为了克服单纯BiOCl光谱吸收范围窄和载流子复合几率高的缺点, 本研究制备了一种具有高效光催化活性的碳量子点(CQDs)/BiOCl纳米复合材料。光催化降解罗丹明B染料实验表明CQDs/BiOCl纳米复合材料的光催化性能远优于单纯的BiOCl, 其光催化性能约为后者的3.4倍。当CQDs的复合量为7.1wt%时, 样品的光催化性能最佳, 能够在2 min之内将罗丹明B完全脱色, 而单纯的BiOCl在相同时间内对罗丹明B的降解率仅为29.5%。通过紫外-可见漫反射谱、光电化学测试以及自由基捕获实验揭示了CQDs/BiOCl纳米复合材料的光催化性能提升机理, 结果表明CQDs可以拓展BiOCl的可见光吸收范围, 这有利于增强其光捕获能力以及促进电子-空穴对的产生。除此之外, CQDs独特的上转换发光行为, 以及光诱导的电子转移能力提升了CQDs/BiOCl纳米复合材料光催化性能。

关键词: 光催化, CQDs/BiOCl, 纳米复合材料, 上转换发光

Abstract:

To overcome the limitation of narrow photo-absorption range and high electron-hole recombination rate of pure BiOCl, a nanocomposite of carbon quantum dots (CQDs) and BiOCl with highly efficient photocatalytic activity was fabricated. The photocatalytic decomposition of rhodamine B (RhB) showed that the CQDs/BiOCl nanocomposite displayed superior photocatalytic performance to pure BiOCl, which was about 3.4 times higher than that of the latter. The optimal loading amount of CQDs was 7.1wt%, which could completely decolorize RhB within a short period of only 2 min, while the degradation rate of RhB was only 29.5% by pure BiOCl in the same period. UV-Vis diffuse reflectance spectra (UV-Vis DRS), photoelectrochemical measurement, and radicals trapping experiments were performed to elucidate the possible mechanism for the enhanced photocatalytic activity of the CQDs/BiOCl composite. The results show that CQD can expand the visible light absorption range of BiOCl, which is beneficial for light harvesting and generation of electron-hole pairs. Moreover, CQDs has unique up-converted photoluminescence behavior, as well as photo-induced electron transfer ability, which leads to enhanced photocatalytic performance of the CQDs/BiOCl composite.

Key words: photocatalysis, CQDs/BiOCl, nanocomposite, up-converted photoluminescence

中图分类号:

O641

张志洁,黄海瑞,程昆,郭少柯. 高效碳量子点/BiOCl纳米复合材料用于光催化污染物降解[J]. 无机材料学报, 2020, 35(4): 491-496.

ZHANG Zhijie,HUANG Hairui,CHENG Kun,GUO Shaoke. High Efficient Carbon Quantum Dots/BiOCl Nanocomposite for Photocatalytic Pollutant Degradation[J]. Journal of Inorganic Materials, 2020, 35(4): 491-496.

图/表 7

Fig. 1 XRD patterns of the products

Fig. 2 TEM images of CQDs (A) and CQDs/BiOCl composite (B, C) and high resolution TEM image of CQDs/BiOCl composite (D)

Fig. 3 UV-Vis diffuse re?ectance spectra of pure BiOCl and CQDs/BiOCl composites

Fig. 4 (A) Photocatalytic degradation of RhB by CQDs, pure BiOCl and CQDs/BiOCl composites under simulated sunlight irradiation, and (B) stability test of the CQDs/BiOCl composite

Fig. 5 Photocurrent responses of BiOCl and CQDs/BiOCl composite

Fig. 6 Trapping experiments of oxidative species during photo-degradation of RhB by CQDs/BiOCl composite

Fig. 7 Schematic illustration for the improved photo-activity of the CQDs/BiOCl composite

参考文献 31

[1]	LEI Y, WANG G, SONG S , et al. Synthesis, characterization and assembly of BiOCl nanostructure and their photocatalytic properties. CrystEngComm, 2009,11:1857-1862.
[2]	YE L Q, DENG K J, XU F , et al. Increasing visible-light absorption for photocatalysis with black BiOCl. Physical Chemistry Chemical Physics, 2012,14:82-85.
[3]	ZHANG X, AI Z, JIA F , et al. Generalized one-pot synthesis, characterization, and photocatalytic activity of hierarchical BiOX (X=Cl, Br, I) nanoplate microspheres. Journal of Physical Chemistyr C, 2008,112:747-753.
[4]	HENLE J, SIMON P, FRENZEL A , et al. Nanosized BiOX (X=Cl, Br, I) particles synthesized in reverse microemulsions. Chemistry of Materials, 2007,19:366-373.
[5]	ZHANG K L, LIU C M, HUANG F Q , et al. Study of the electronic structure and photocatalytic activity of the BiOCl photocatalyst. Applied Catalysis B-Environmental, 2006,68:125-129.
[6]	CHAI S Y, KIM Y J, JUNG M H , et al. Heterojunctioned BiOCl/Bi₂O₃, a new visible light photocatalyst. Journal of Catalysis, 2009,262:144-149.
[7]	LI T B, CHEN G, ZHOU C , et al. New photocatalyst BiOCl/BiOI composites with highly enhanced visible light photocatalytic performances. Dalton Transactions, 2011,40:6751-6758.
[8]	LI H T, HE X D, LIU Y , et al. One-step ultrasonic synthesis of water-soluble carbon nanoparticles with excellent photoluminescent properties. Carbon, 2011,49:605-609.
[9]	TANG L B, JI R B, CAO X K , et al. Deep ultraviolet photoluminescence of water-soluble self-passivated graphene quantum dots. ACS Nano, 2012,6:5102-5110.
[10]	RAY S C, SAHA A, JANA N R , et al. Fluorescent carbon nanoparticles: synthesis, characterization, and bioimaging application. Journal of Physical Chemistry C, 2009,113:18546-18551.
[11]	ZONG J, ZHU Y H, YANG X L , et al. Synthesis of photoluminescent carbogenic dots using mesoporous silica spheres as nanoreactors. Chemical Communications, 2011,47:764-766.
[12]	SHEN J H, ZHU Y H, YANG X L , et al. One-pot hydrothermal synthesis of graphene quantum dots surface-passivated by polyethylene glycol and their photoelectric conversion under near-infrared light. New Journal of Chemistry, 2012,36:97-101.
[13]	LI Y, HU Y, ZHAO Y , et al. An electrochemical avenue green- luminescent graphene quantum dots potential electron-acceptors photovoltaics. Advanced Materials, 2011,23:776-780.
[14]	SHI W, LI X H, MA H M . A tunable ratiometric pH sensor based on carbon nanodots for the quantitative measurement of the intracellular pH of whole cells. Angewandte Chemie International Edition, 2012,51:6432-6435.
[15]	BAKER S N, BAKER G A . Luminescent carbon nanodots: emergent nanolights. Angewandte Chemie International Edition, 2010,49:6726-6744.
[16]	ZHANG H C, MING H, LIAN S Y , et al. Fe₂O₃/carbon quantum dots complex photocatalysts and their enhanced photocatalytic activity under visible light. Dalton Transactions, 2011,40:10822-10825.
[17]	LI H T, LIU R H, LIU Y , et al. Carbon quantum dots/Cu₂O composites with protruding nanostructures and their highly efficient (near) infrared photocatalytic behavior. Journal of Materials Chemistry, 2012,22:17470-17475.
[18]	YU H, ZHANG H C, HUANG H , et al. ZnO/carbon quantum dots nanocomposites: one-step fabrication and superior photocatalytic ability for toxic gas degradation under visible light at room temperature. New Journal of Chemistry, 2012,36:1031-1035.
[19]	ZHANG H, HUANG H, MING H , et al. Carbon quantum dots/Ag₃PO₄ complex photocatalysts with enhanced photocatalytic activity and stability under visible light. Journal of Materials Chemistry, 2012,22:10501-10506.
[20]	LIU J Y, LIU N Y, HAN Y Z , et al. Metal-free efficient photocatalyst for stable visible water splitting via a two-electron pathway. Science, 2015,347:970-974.
[21]	YU H J, SHI R, ZHAO Y F , et al. Smart utilization of carbon dots in semiconductor photocatalysis. Advanced Materials, 2016,28:9454-9477.
[22]	KE J, LI X Y, ZHAO Q D , et al. Upconversion carbon quantum dots as visible light responsive component for efficient enhancement of photocatalytic performance. Journal of Colloid and Interface Science, 2017,496:425-433.
[23]	HU Y D, XIE X F, WANG X , et al. Visible-light upconversion carbon quantum dots decorated TiO₂ for the photodegradation of flowing gaseous acetaldehyde. Applied Surface Science, 2018,440:266-274.
[24]	DI J, XIA J X, JI M X , et al. Carbon quantum dots modified BiOCl ultrathin nanosheets with enhanced molecular oxygen activation ability for broad spectrum photocatalytic properties and mechanism insight. ACS Applied Materials & Interfaces, 2015,7:20111-20123.
[25]	GUO C X, ZHAO D, ZHAO Q , et al. Na+-functionalized carbon quantum dots: a new draw solute in forward osmosis for seawater desalination. Chemical Communications, 2014,50:7318-7321.
[26]	LI H, HE X, KANG Z , et al. Water-soluble fluorescent carbon quantum dots and photocatalyst design. Angewandte Chemie International Edition, 2010,49:4430-4434.
[27]	ZHANG X, HUANG H, LIU J , et al. Carbon quantum dots serving as spectral converters through broadband upconversion of near- infrared photons for photoelectrochemical hydrogen generation. Journal of Materials Chemistry A, 2013,1:11529-11533.
[28]	ZHANG Z J, ZHENG T T, XU J Y , et al. Carbon quantum dots/Bi₂WO₆ composites for efficient photocatalytic pollutant degradation and hydrogen evolution. Nano, 2017,12:1750082.
[29]	KIM H G, BORSE P H, CHOI W Y , et al. Photocatalytic nanodiodes for visible light photocatalysis. Angewandte Chemie International Edition, 2005,44:4585-4589.
[30]	ZHU Y Y, LIU Y F, LV Y H , et al. Enhancement of photocatalytic activity for BiPO₄ via phase junction. Journal of Materials Chemistry A, 2014,2:13041-13048.
[31]	YUE D, CHEN D M, WANG Z H , et al. Enhancement of visible photocatalytic performances of a Bi₂MoO₆-BiOCl nanocomposite with plate-on-plate heterojunction structure. Physical Chemistry Chemical Physics, 2014,16:26314-26321.