APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Ming Lei,Zhiying Wang,Lihua Zhu,Wenshan Nie,Heqing Tang
Deep debromination of polybrominated diphenyl ethers (PBDEs) by visible light photocatalysis is still a challenge in the field of halogenated pollutants control. Here, an efficient photocatalyst (Pd/g-C 3 N 4 ) was prepared by a simple impregnation-chemical reduction method with bulk g-C 3 N 4 and PdCl 2 as precursors. Under preferred reaction conditions (visible light irradiation for 120 min), the use of the 0.5% Pd/g-C 3 N 4 composites (0.4 g L −1 ) yielded an almost complete debromination of BDE47 (10 μmol L −1 ) in methanol-water mixture, while the debromination of BDE47 did not occur on pure g-C 3 N 4 . A “Pd-promoted active H atom species attack and C-Br bond cleavage” route was proposed according to the identified degradation intermediates. A catalytic mechanism was further clarified: Pd nanoparticles exerted affinity interaction with bromine atoms, and the storing of electrons on Pd would increase the binding interaction. In the debromination process, methanol acts as both a hole scavenger and a hydrogen donor to provide active H atom species through the reaction of H + and photogenerated electrons on Pd nanoparticles. The initiation of BDE47 debromination on Pd nanoparticles required an induction period to enrich a critical amount of electrons for stretching the C-Br bond and its subsequent being attacked by active H atoms. The generated 2,2′-dibromodiphenyl ether (BDE4) would be further reduced to bromine-free products by hydro-debromination process or coupling reaction.
研究领域:
环境科学
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化学
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DOI
高影响因子
NANOTECHNOLOGY
·
2024
·Vol. 35
·期 15
·155402
·
IF 2.9
Wei Zhang,Xing Zhang,Lina Zhang,Jinwen Ma,Xiaotong Yin,Yuxin Tian,Chuang Wang,Qiushi Wang
A novel 3D hierarchical TiO2/CaIn2S4/C3N4 arrays with dual heterojunctions photoanode is constructed by stepwise deposition of CaIn2S4 nanosheets and ultrathin C3N4 onto the well-aligned TiO2 nanorods arrays. Integrating the merit of the superior ability of CaIn2S4 and C3N4 to harvest visible light, dual type-Ⅱ heterojunction band structure and one-dimensional ordered nanostructures, the TiO2/CaIn2S4/C3N4 photoanode exhibits simultaneous significant improvements in visible-light harvesting, charge separation and electron transfer capability. At 1.23 V (versus reversible hydrogen electrode) under AM 1.5 G irradiation, the TiO2/CaIn2S475/C3N4 photoanode exhibits a photocurrent density of 4.5 mA cm−2, which is 5.2 and 51.1-fold higher than that of TiO2/CaIn2S475 and pristine TiO2 photoanode, respectively. Moreover, the applied bias photo-to-current efficiency (ABPE) of the TiO2/CaIn2S475/C3N4 photoanode reaches 3.5% at 0.36 V (versus reversible hydrogen electrode). These results are helpful for fabricating more efficient heterostructure photoelectrodes.
研究领域:
材料科学
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光催化
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能源转换
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2016
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IF 5.31
Yuanzhi Hong,Changsheng Li,Guangyi Zhang,Yadong Meng,Bingxin Yin,Yong Zhao,Weidong Shi
The removal of pollutant using photocatalysis technology has received much attention due to the increasing serious environmental contamination. In this study, novel Nb 2 O 5 /g-C 3 N 4 heterojunctions were fabricated via a facile one-step heating strategy for the first time. Compared to pure g-C 3 N 4 and Nb 2 O 5 , the as-prepared Nb 2 O 5 /g-C 3 N 4 samples exhibited remarkably enhancing photocatalytic activity for degradation of tetracycline hydrochloride (TC-HCl) both under visible and simulated solar light irradiation. It was found that the 3% Nb 2 O 5 content of heterojunction (3%NO/CN) showed the highest photocatalytic efficiency for TC-HCl degradation, which is about 2.9-fold and 2.4-fold higher than that of pristine g-C 3 N 4 under visible and simulated solar light irradiation, respectively. In addition, the 3%NO/CN sample not only displayed excellent photocatalytic recyclability, but also can efficiently remove TC-HCl even under strong acidic condition (pH = 1). Moreover, the 3%NO/CN heterojunction also exhibited dramatically enhancement of photocatalytic activity for degradation of other fluoroquinolones antibiotic, such as ciprofloxacin (CIP) and levofloxacin (LEV). The highly enhancing photoactivity was attributed to the formation of a heterojunction between g-C 3 N 4 and Nb 2 O 5 , which could greatly suppresses the photogenerated electron–hole pair’s recombination. The active species trapping and ESR experiments indicated that superoxide radicals and holes are the major active species in which contributing to the photocatalytic process. This work will bring about potential application in treatment of antibiotic pollutant and solar energy conversion.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
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IF 5.518
Qiang Li,Hao Zhou,Meng Tan,Lingxuan Yang,Xiao Hu,Guoxiang Yang,Hao Du,Qing Wei,Qi Wang
High visible light utilization and rapid charge separation are of great importance for environmental photocatalysis . Single photocatalyst always suffers from high recombination of photogenerated electron-hole pairs and low redox ability. Elemental doping and heterojunction construction are effective approaches to improve the photocatalytic performance. Herein, we designed and synthesized a novel Bi x Fe y VO 4 /g-C 3 N 4 (BFC) binary heterojunction via facile coprecipitation followed by calcination processes. The doping of Fe endows BiVO 4 with narrower bandgap, which boosts its light response and redox ability. The construction of heterojunction facilitates charge separation that makes BFC heterojunction displaying much higher photocatalytic activity than those of single semiconductors. The highest Cr(VI) photoreduction rate ( k ) of BFC binary heterojunction is 78 (45) times of BiVO 4 (FeVO 4 ). Additionally, the binary heterojunction can still maintain high photoreduction efficiency (98%) of Cr(VI) even after five cycling tests showing excellent photocatalytic stability. This research provides novel idea for synergistic application of doping and heterojunction in environmental photocatalysis.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2018
·
IF 4.667
Ming Wu,Hongying Lv,Teng Wang,Zhimin Ao,Hongqi Sun,Chengyin Wang,Taicheng An,Shaobin Wang
Graphitic carbon nitride (g-C 3 N 4 ), a promising metal-free photocatalyst, shows a high thermal stability, excellent chemical stability, and great optical absorption of solar light. However, a short life of activated electron-hole pairs limits g-C 3 N 4 in practical applications. In this work, Ag 2 MoO 4 nanoparticles encapsulated in g-C 3 N 4 (Ag 2 MoO 4 /g-C 3 N 4 ) was synthesized with a facile in-situ precipitation method. A variety of characterization techniques were applied for analyzing the compositions, morphologies and optical properties of Ag 2 MoO 4 /g-C 3 N 4 . The band structure of Ag 2 MoO 4 produces a synergistic effect with g-C 3 N 4 , which can efficiently increase solar light absorption and reduce the recombination rate of the photo-induced electron-hole pairs. Therefore, this hybrid catalyst presents a much higher photocatalytic activity for the degradation of various organic pollutants (bisphenol A, acyclovir, and methyl orange) and strong stability under both artifical and real sunlight, which is promising for practical application.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
ChemCatChem
·
2018
·Vol. 11
·期 3
·1069-1075
·
IF 4.674
Rui Tong,Zhi Sun,Xiongwei Zhong,Xina Wang,Jincheng Xu,Ye Yang,Baomin Xu,Shuangpeng Wang,Hui Pan
Graphical Photocatalytic hydrogen production : g-C 3 N 4 /CeCO 3 OH/CeO 2 ternary composite showed greatly enhanced photocatalytic performance for hydrogen production under visible light irradiation. Promoting the separation of photo-generated carriers is significantly important to improve the efficiency of photocatalytic hydrogen production. Therefore, we prepared g-C 3 N 4 /CeCO 3 OH/CeO 2 (CeCeCN) ternary nanocomposite via an easy synthetic way using g-C 3 N 4 and CeO 2 as reactants. A CeCO 3 OH layer was formed and resulted in the novel ternary photocatalyst. The CeCeCN composite shows superior photocatalytic (PC) H 2 generation performance in sunlight excitation. The H 2 evolution rate is about 764 μmol h −1 g −1 , which is over 11 times larger than those of g-C 3 N 4 and CeO 2 . Compared with g-C 3 N 4 and CeO 2 , CeCeCN further shows a larger photo-response current density and a lower charge-transfer resistance. The remarkably increased photocatalytic property of CeCeCN is because of the efficient charge migration induced by the formed heterojunction. Our findings demonstrate that building multi-heterostructures can liberate more excited electrons for efficient hydrogen production under sunlight.
研究领域:
材料科学
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能源科学
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DOI
高影响因子
International Journal of Environmental Research and Public Health
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2022
·Vol. 19
·期 14
·8683
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IF 4.614
Xiang Guo,Lei Rao,Zhenyu Shi
Adsorption can quickly remove pollutants in water, while photocatalysis can effectively decompose organic matter. B-TiO2/g-C3N4ternary composite photocatalytic materials were prepared by molten method, and their adsorption–degradation capability under visible light conditions was discussed. The morphology of the B-TiO2/g-C3N4materials was inspected by SEM, TEM, BET, and EDS, and the results showed that close interfacial connections between TiO2and g-C3N4, which are favorable for charge transfer between these two semiconductors, formed heterojunctions with suitable band structure which was contributed by the molten B2O3. Meanwhile, the molten B2O3effectively increased the specific surface area of TiO2/C3N4materials, thereby increasing the active sites and reducing the recombination of photogenerated electron–hole pairs and improving the photocatalytic degradation abilities of TiO2and g-C3N4. Elsewhere, the crystal structure analysis (XRD, XPS, FTIR) results indicated that the polar -B=O bond formed a new structure with TiO2and g-C3N4, which is not only beneficial for inhibiting the recombination of electron holes but also improving the photocatalytic activity. By removal experiment, the adsorption and degradation performances of B-TiO2/g-C3N4composite material were found to be 8.5 times and 3.4 times higher than that of g-C3N4. Above all, this study prepared a material for removing water pollutants with high efficiency and provides theoretical support and experimental basis for the research on the synergistic removal of pollutants by adsorption and photocatalysis.Keywords:adsorption;degradation;B2O3;TiO2/C3N4;molten
研究领域:
环境科学
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材料科学
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DOI
PubMed
高影响因子
MOLECULES
·
2022
·Vol. 27
·期 21
·7178
·
IF 4.927
Yan Chen,Ao Li,Xiuli Fu,Zhijian Peng
The difficulty of exposing active sites and easy recombination of photogenerated carriers have always been two critical problems restricting the photocatalytic activity of g-C3N4. Herein, a simple (NH4)2MoO4-induced one-step calcination method was successfully introduced to transform bulk g-C3N4into g-C3N4/MoO2composites with a large specific surface area. During the calcination, with the assistance of NH3and water vapor produced by ammonium molybdate, the pyrolytical oxidation and depolymerization of a g-C3N4interlayer were accelerated, finally realizing the exfoliation of the g-C3N4. Furthermore, another pyrolytical product of ammonium molybdate was transformed into MoO2under an NH3atmosphere, which was in situ loaded on the surface of a g-C3N4nanosheet. Additionally, the results of photocatalytic hydrogen evolution under visible light show that the optimal g-C3N4/MoO2composite has a high specific surface area and much improved performance, which is 4.1 times that of pure bulk g-C3N4. Such performance improvement can be attributed to the full exposure of active sites and the formation of abundant heterojunctions. However, with an increasing feed amount of ammonium molybdate, the oxidation degree of g-C3N4was enhanced, which would widen the band gap of g-C3N4, leading to a weaker response ability to visible light. The present strategy will provide a new idea for the simple realization of exfoliation and constructing a heterojunction for g-C3N4simultaneously.Keywords:g-C3N4;MoO2;exfoliation;photocatalytic hydrogen evolution
研究领域:
材料科学
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化学
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环境科学
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产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2018
·Vol. 8
·期 6
·427
·
IF 3.504
Meiyin Wang,Hui Wang,Yuanhang Ren,Cheng Wang,Zhewei Weng,Bin Yue,Heyong He
A series of composites consisting of g-C3N4sheet and mesoporous Nb2O5(mNb2O5) microsphere were fabricated by in situ hydrolysis deposition of NbCl5onto g-C3N4sheet followed by solvothermal treatment. The samples were characterized using powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), N2adsorption-desorption, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS) and photoluminescence spectroscopy (PL). The photocatalytic activity of the composites was studied by degradation of rhodamine B (RhB) and tetracycline hydrochloride (TC-HCl) in aqueous solution under visible light irradiation (λ> 420 nm). Compared with g-C3N4and mNb2O5, g-C3N4-mNb2O5composites have higher photocatalytic activity due to synergistic effect between g-C3N4and mNb2O5. Among these composites, 4% g-C3N4-mNb2O5has the highest efficiency and good recyclability for degradation of both RhB and TC-HCl.Keywords:photocatalytic degradation;g-C3N4;mesoporous Nb2O5;organic pollutant
研究领域:
材料科学
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环境科学
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DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2022
·Vol. 10
·期 42
·22819-22833
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IF 14.511
Renzhi Xiong,Changcun Tang,Kunjiao Li,Jiabao Wan,Weifeng Jia,Yanhe Xiao,Baochang Cheng,Shuijin Lei
It is an effective method to promote the activity of photocatalysts by exploiting their own photothermal effects to increase the temperature of the reaction center and thus accelerate the kinetic process of photocatalysis. In this study, for the first time, a CoCr2O4/g-C3N4 composite photocatalyst is designed through the construction of CoCr2O4 nanoparticles decorated tremella-like porous g-C3N4. On the one hand, the type-II heterostructure can be formed and effectively improves the separation efficiency of photogenerated carriers. On the other hand, the photothermal effect of plasmonic CoCr2O4 nanoparticles can significantly increase the temperature of the reaction system, thereby enhancing the photocatalytic efficiency. CoCr2O4 nanoparticles exhibit a broad-band strong absorption in the near-infrared region. Under full spectrum illumination for 300 s, their surface temperature can be increased by 113 °C, demonstrating excellent photothermal properties. Although the bare CoCr2O4 nanoparticle sample does not show the photocatalytic activity of water splitting for hydrogen evolution, the optimized g-C3N4/CoCr2O4 heterostructure composite exhibits an average hydrogen production rate as high as 1525.1 μmol g−1 h−1 under UV-Vis-IR illumination, which is 4.0 and 5.8 times higher than that of bare g-C3N4 under UV-Vis-IR and UV-Vis light illumination, respectively. This work provides a new guide for designing novel photothermal-assisted photocatalytic composite materials.
研究领域:
材料科学
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能源科学
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DOI
高影响因子
CARBON
·
2024
·
IF 10.5
Xiqing Xie,Qiaoqi Guo,Shujing Yu,Huajun Feng,Yingfeng Xu
The photothermal effect has been recognized as a universal promoter in various photocatalytic reactions. However, in many promising nanocomposite systems, the integration of heterogeneous photothermal materials with photocatalysts remains a significant technical challenge. Focusing on the emerging graphitic carbon nitride (g-C 3 N 4 ) based photocatalyst, we identified that the segregation of the introduced photothermal particles results from the dynamic instability of the original solid-solid dispersion system, which essentially origins from a sluggish two-step solid-liquid-solid phase transformation of urea towards g-C 3 N 4 . By taking advantages of the photothermal particles to be loaded, we developed a photothermal-polymerization strategy to create a rapid heating to overcome their undesired segregation during g-C 3 N 4 formation. The strategy enables a one-step loading of various photothermal particles on the g-C 3 N 4 , presenting a versatile methodology. This sustainable technique enhances the synthesis yield of g-C 3 N 4 by 352 % with reduced energy consumption. The derived photothermal particles-dispersed g-C 3 N 4 shows 290 % improvement in photocatalytic CO 2 reduction compared to the separated system, which is obtained from the traditional heating synthesis. Beyond enriching the accessible categories of composite catalysts, this study may deepen physiochemical insights into the dynamic transformation of the novel dispersion system.
研究领域:
材料科学
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催化化学
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环境科学
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产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Ruizheng Xu,Guiyu Wei,Zhemin Xie,Sijie Diao,Jianfeng Wen,Tao Tang,Li Jiang,Ming Li,Guanghui Hu
Increasing the efficiency of charge transfer and separation efficiency of photogenerated carriers are still the main challenges in the field of semiconductor-based photocatalysts. Herein, we synthesized g-C 3 N 4 @V 2 C MXene photocatalyst by modifying g-C 3 N 4 using V 2 C MXene. The prepared photocatalyst exhibited outstanding photocatalytic performance under visible light. The degradation efficiency of methyl orange by g-C 3 N 4 @V 2 C MXene photocatalyst was as high as 94.5%, which is 1.56 times higher than that by g-C 3 N 4 . This was attributed to the V 2 C MXene inhibiting the rapid recombination of photogenerated carriers and facilitating rapid transfer of photogenerated electrons (e − ) from g-C 3 N 4 to MXene. Moreover, g-C 3 N 4 @V 2 C MXene photocatalyst showed good cycling stability. The photocatalytic performance was higher than 85% after three cycles. Experiments to capture free radicals revealed that superoxide radicals (·O 2 − ) are the main contributors to the photocatalytic activity. Thus, the proposed g-C 3 N 4 @V 2 C MXene photocatalyst is a promising visible-light catalyst.
研究领域:
材料科学
·
环境科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）