Science China-Materials
·
2023
·Vol. 66
·期 6
·2274-2282
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IF 8.1
Zhang Yang,Cao Ning,Liu Xiaoming,He Fengting,Zheng Bin,Zhao Chaocheng,Wang Yongqiang
Graphite carbon nitride (g-C 3 N 4 ) has become an emerging metal-free photocatalyst and attracted the attention of researchers. However, pure g-C 3 N 4 (PCN) prepared by traditional thermal condensation polymerization has a low polymerization of heptazine ring chains and a large number of charge recombination centers, which hinder in-plane charge transport, leading to undesirable photocatalytic performance. Herein, PCN fabrication by thermal treatment with ammonium oxalate monohydrate was performed to produce highly dispersed porous g-C 3 N 4 nanosheets, and the integrity of their in-plane heptazine ring chains was successfully improved without introducing heteroatoms. Electron paramagnetic resonance and 13 C nuclear magnetic resonance analyses revealed significantly increased electron density and delocalization of the π-conjugated structure. The obtained samples exhibited acceptable stability and photocatalytic activity, and the hydrogen reduction rates without and with the Pt co-catalyst were 11.2 and 5.3 times that of PCN.
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高影响因子
APPLIED SURFACE SCIENCE
·
2023
·
IF 6.7
Yanhong Wang,Hui Wang,Xuan Li,Le Gao,Yawen Li,Jiaqi Huo,Weiwei Kang,Chunxiao Zou,Lishan Jia
g-C 3 N 4 has attracted much attention in the field of photocatalysis. However, its high carrier recombination rate has always been an obstacle in practical application. g-C 3 N 4 -based heterostructures with an intimate interface contact is considered to be an effective solution to improve the separation and transmission of photogenerated carriers. Herein, an oxygen vacancy-mediated direct solid phase integration strategy is proposed to synthesize a 0D/2D/2D LaNiO 3 /RGO/g-C 3 N 4 S-scheme heterostructure with interface chemical bonds. The optimized LaNiO 3 /RGO/g-C 3 N 4 sample showed excellent hydrogen evolution rate of 1375 μmol/g/h, which is far superior to those of pristine g-C 3 N 4 (46 μmol/g/h), LaNiO 3 /g-C 3 N 4 (143 μmol/g/h), RGO/g-C 3 N 4 (307 μmol/g/h) and mechanically mixed sample LaNiO 3 -RGO-g-C 3 N 4 (625 μmol/g/h). Also, it is comparable to many g-C 3 N 4 -based heterojunction photocatalysts known at present. The improved performance can be attributed to interfacial charge transfer promoted by interfacial chemical bonds served as charge transfer channels and the high redox capacity of S-scheme charge transfer. This work opens up a new avenue for the predictive design of reinforced heterojunction with enhanced photocatalytic performance.
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Journal of Materials Chemistry C
·
2022
·Vol. 11
·期 3
·1165-1172
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IF 8.067
Yating Wang,Chaosheng Peng,Airu Liu,Jinyue Song,Xingang Li,Tao Jiang
The precise intramolecular-tailored strategy is deemed to have abundant potential to promote the activity of metal-free photocatalysts yet remains a daunting task. In this work, we report a simple one-step calcination method for skillfully incorporating alkyl into the tri-s-triazine ring of graphite carbon nitride (g-C3N4). The photocatalytic tetracycline photodegradation rate of the optimal ethyl modified g-C3N4 (CN-E-75) is significantly higher than that of the original g-C3N4. Experimental and theoretical calculation results show that the significantly enhanced photocatalytic activity is mainly due to the optimization of the electronic band structure of g-C3N4 by introducing ethyl defects attached to N atoms in the tri-s-triazine rings. The ethyl defect mainly splits the Np orbitals to generate mid gap states under the conduction band edge, thereby consequently narrowing the band gap to extend visible light harvesting, but also meanwhile accelerates charge delivery to boost the photogenerated charge separation, inhibiting electron–hole recombination, and thus considerably increases the photocatalytic properties. Moreover, as-fabricated CN-E-75 verifies the satisfied stability after five cycling runs for photocatalytic water splitting for H2 evolution and tetracycline photodegradation. This work sheds light on deep understanding of intramolecular tailored defect engineering and offers guidance to design other efficient photocatalytic systems.
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PROGRESS IN ORGANIC COATINGS
·
2022
·
IF 6.206
Changhua Li,Chen Zhang,Yi He,Hongjie Li,Yang Zhao,Zhijun Li,Dan Sun,Xiangying Yin
Multi-dimensional composite nanocontainers provided an opportunity to prolong the service life of waterborne self-healing coatings through combining intelligent protection with physical barrier. Herein, we constructed a benzotriazole (BTA) corrosion inhibitor loaded nanocontainer with barrier/controlled release/corrosion inhibition properties by assembling graphitic (g)-C 3 N 4 lamella, hollow polyaniline capsule and outer polydopamine wall. Hollow polyaniline and g-C 3 N 4 lamella with adsorption properties provide effective space and sites for loading BTA corrosion inhibitor. Outer polydopamine wall can not only realize the controlled release of corrosion inhibitor, but also ensure the good compatibility between the composite container and the water-based epoxy resin . In addition, polydopamine (PDA) and polyaniline (PANI) as a container frame can also serve as active inhibitors after the release of corrosion inhibitor to enhance the self-healing protection effect of waterborne coatings. In comparative evaluation, the composite coatings containing BTA-loaded nanocontainers (0.5 wt.%) exhibit obviously physical barrier effect after soaking in 3.5 wt.% NaCl solution for 40 days, and maintains good protective performance after immersion for 80 days. Meanwhile, the artificial scratch experiment verified the effective self-repair protection of the composite container to the coating under the condition of damage. To be sure, it will provide an effective improvement idea for the long-term application of waterborne epoxy coating in marine environment.
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NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 13
·6267-6273
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IF 3.925
Qinyi Mao,Dandan Li,Yuming Dong
Recently, much attention has been focused on the development of photocatalysts for hydrogen evolution. Up to now, efficient hydrogen generation is still greatly challenging due to the restraints of the surface redox reaction rate, and the introduction of a co-catalyst is one of the keys to this problem. Here, dual non-noble co-catalysts NixP and Mn3O4 were proposed and prepared on a g-C3N4/red phosphorus (CNP) hybrid structure with a high light adsorption capability by a two-step photo-deposition method. The photo-excited charge on the composite catalyst separate and transfer from C3N4 to red phosphorous due to a type I heterojunction structure. NixP and Mn3O4 act as reductive and oxidative co-catalysts, respectively. The hydrogen production rate was 5851.3 μmol g−1 h−1, 12.4 times that of pure CNP. The consistent catalytic activity in an actual 25 mL flask for hydrogen evolution over eight hours accumulated 245.08 μmol H2 under solar simulated irradiation. This work provides practical reference for the development of a novel inexpensive photocatalyst system.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Ganghua Zhou,Lirong Meng,Xin Ning,Weiqin Yin,Jianhua Hou,Qiao Xu,Jianjian Yi,Shengsen Wang,Xiaozhi Wang
Constructing type II heterojunction is an efficient strategy to enhance the light absorption and promote the charge transport. However, the improvement effect is limited by the decreased redox ability of charge carriers. The rational design of heterojunction from type II to Z-scheme is expected to overcome this obstacle. Herein, we demonstrate that the introduction of interfacial oxygen vacancies (OVs) can switch charge transfer of g-C 3 N 4 /BVO heterojunction from type II to Z-scheme. The interfacial OVs acted as the reactive center of charge carriers to quench the electrons of BVO and holes of g-C 3 N 4 , thereby promoting charge separation and migration. As a result, the interfacial OVs mediated Z-scheme g-C 3 N 4 /BVO heterojunction kept the strong oxidation/reduction potential of two single-component photocatalysts thereby significantly enhancing the photodegradation of tetracycline and CO 2 photoreduction. The kinetic constant of tetracycline degradation on the optimal g-C 3 N 4 /BVO-20 sample was 2.04-fold and 2.29-fold higher than those on g-C 3 N 4 nanosheets and pure BVO, respectively. This work provides a feasible strategy by the interfacial vacancy engineering of heterojunction for enhanced photocatalysis .
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NEW JOURNAL OF CHEMISTRY
·
2022
·Vol. 46
·期 8
·3727-3737
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IF 3.925
Zhujun Huang,Dongying Zhu,Haiyan Wang,Jinhua Luo,Chenxi Zhao,Fuyou Du
Developing excellent photocatalysts for pollutant degradation is of vital significance but still a big challenge. In this work, an electrospun g-C3N4/Bi12O17Cl2/poly(acrylonitrile-co-maleic acid) (E-spun g-C3N4/Bi12O17Cl2/PANCMA) nanofiber photocatalyst was fabricated by coaxial electrospinning of g-C3N4/Bi12O17Cl2 and PANCMA and showed high adsorption capacity and excellent visible light catalytic degradation performance with the adsorption amount and degradation rate of antibiotic ofloxacin (OFL) as high as 4.44 mg g−1 within 6 min and 94% within 20 min, respectively. Compared to pure g-C3N4 and Bi12O17Cl2, the g-C3N4/Bi12O17Cl2 heterojunction showed higher visible light absorption and degradation ability, ascribed to the synergistic effect of g-C3N4 and Bi12O17Cl2 on the separation and utilization efficiency of photogenerated electron–hole pairs. E-spun g-C3N4/Bi12O17Cl2/PANCMA nanofibers exhibited highly efficient photocatalytic activity over a wide pH range of 4.0–8.0 and some interference of metal ions and inorganic anions, and the reactive species including holes (h+), superoxide radicals , and hydroxyl radicals (˙OH) all participated in the photocatalytic degradation of OFL. Moreover, the E-spun g-C3N4/Bi12O17Cl2/PANCMA possessed excellent cycling stability of 81.9% efficiency retention after fifteen consecutive tests. In addition, the possible degradation mechanism, intermediate products and degradation pathways of OFL were investigated by ESR tests, radical scavenger experiments, and LC-MS analysis. This study developed a feasible exemplificative strategy for fabricating new highly efficient and reusable photocatalyst candidate materials to remove environmental pollutants.
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CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Xufei Li,Yanling Qiu,Zhiliang Zhu,Ting Chen,Hua Zhang,Daqiang Yin
Insufficient photocatalytic activity and poor recyclability are considered as two main factors that limit the further application of photocatalysts in environmental remediation. Herein, a new magnetic g-C 3 N 4 /α-Fe 2 O 3 /Bi 3 TaO 7 (CN/FO/BTO) heterojunction with dual Z-scheme system was first synthesized via an ultrasound-assisted calcination process. The results showed that the removal efficiency of ciprofloxacin (CIP) by optimized CN/FO/BTO heterojunction could reach 95.6% within 120 min illumination of visible light, which was 6.1, 15.9, 5.2, 3.7 and 2.3 times as much as that of single CN, FO, BTO, binary CN/FO and CN/BTO, respectively. Characterization analysis indicated that the improved photocatalytic activity derived from the synergistic effects of the three components, including the dispersion of FO and BTO by CN sheet, the enhanced light absorption of CN by addition of FO and BTO, and the reduced photogenerated charge recombination by their intimate contact. Further mechanism study revealed that the dual Z-scheme system of CN/FO/BTO leaded to efficient photoexcited carrier separation and strong redox capacity, in which •O 2 – and •OH were main radicals during photocatalytic process. Meanwhile, CN/FO/BTO possessed supreme adaptability to pH as well as co-existing matters, favorable magnetic separation property and excellent stability, making it a potential candidate for environmental remediation applications.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2022
·Vol. 33
·期 7
·4482-4496
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IF 2.779
Wang Tao,Ding Huihui,Xiao Huan,Sun Tianyi,Xu Jiahui,Zhang Zhengmei,Bian Haiqin,Li Shuang,Zhang Hengyang
In this article, P-g-C 3 N 4 /TiO 2 (the protonated g-C 3 N 4 is noted as P-g-C 3 N 4 ) heterojunction photocatalytic materials with hollow sphere structure were synthesized mainly by high-temperature calcination and secondary hydrothermal methods. To obtain highly efficient heterojunction catalytic materials with more uniform surface compounding, we protonated and exfoliated ultrasonically the obtained g-C 3 N 4 before compounding further, which changed its morphology while retaining its semiconductor properties and optical band gap unchanged, and finally obtained the ultra-thin nanoflake structures. On this basis, an optimal proportion of the highest catalytic activity between these two substances was explored by degrading RHB. It was found that the highest catalytic activity of the complexes was achieved at 110 min with a weight ratio of 0.1 of P-g-C 3 N 4 to TiO 2 after protonating under the same conditions, and complete degradation was reached at 110 min. Afterward, to further investigate its physicochemical properties, we made various characterizations and proposed a suitable catalytic mechanism of Z-scheme regarding its excellent catalytic properties.
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ANALYTICA CHIMICA ACTA
·
2022
·
IF 6.911
Haoye Wang,Aijuan Xie,Shuji Li,Jiajun Wang,Kaixuan Chen,Zilong Su,Ningning Song,Shiping Luo
A three-dimensional g-C 3 N 4 /MWNTs/GO hybrid modified electrode was constructed as an electrochemical sensor for the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Due to the high conductivity of MWCNTs and the strong synergy between g-C 3 N 4 and GO , the combination of the three effectively improved the electrocatalytic activity of the modified electrode for the oxidation of AA, DA, and UA, and solved the problems such as overlapping anodic peaks. The electrochemical performance of the as-constructed sensor was investigated and optimized by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The linear response range of AA, DA, and UA in the optimal condition was 0.2–7.5 mM, 2–100 μM, and 4–200 μM, respectively. The detection limits (S/N = 3) of AA, DA, and UA were 96, 0.22, and 1.36 μM, respectively. The recoveries of AA, DA and UA in serum samples from three groups were 92.82–106.50%, and the relative standard deviations were less than 2%. The results show that the as-constructed g-C 3 N 4 /MWNTs/GO modified electrode has the advantages of simplicity, high sensitivity and good selectivity , and can simultaneously determine AA, DA, and UA.
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PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2022
·
IF 5.723
Chao Yin,Yali Liu,Xiaorong Kang,Xin Li
Graphitic carbon nitride (g-C 3 N 4 , CN) has been applied to degrade a variety of pollutants. However, two major defects, the low utilization of light energy and the high recombination of photogenerated electron and hole (e - -h + ) pairs, need to be improved. In this study, a LED-light-driven photocatalyst, carbon dots decorated graphitic carbon nitride (CNC), was successfully prepared by simple thermal polymerization. Due to the remarkable up-conversion photoluminescence properties and superior charge transport capability of CDs, CNC had higher e - -h + separation efficiency and broader visible light response. In this experiment, a combined process of CNC and persulfate (CNC/PS) was used for tetracycline (TC) degradation. High-efficient photocatalytic degradation rate of 81.9% was obtained in the CNC/PS system. Moreover, the mechanism analysis indicated that the reaction between PS and photogenerated e - effectively promoted the separation of electrons-holes pairs, thereby enhancing the formation of dominant active radicals •O 2 - and holes for TC degradation.
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Journal of Environmental Chemical Engineering
·
2022
·
IF 7.968
Yashi Qing,Yanxiang Li,Zhiwei Guo,Yujie Yang,Wangliang Li
17β-estradiol (E2) is one of the endocrine disrupting chemicals (EDCs) ubiquitously with significant impacts on ecosystem and organisms even at extremely low concentrations. Photocatalytic membranes, with the combination of photocatalysis and membrane filtration, have great potential to enhance E2 removal. In this work, a photocatalytic membrane was fabricated from the polyamide (PA) microfiltration membrane and visible light responsive Bi 2 WO 6 /protonated g-C 3 N 4 (BPG) photocatalyst. The BPG photocatalyst was embedded into calcium alginate hydrogel followed by immobilizing onto PA membrane through vacuum filtration and crosslinking. The transparent calcium alginate hydrogel guaranteed 100% light transmittance which contributed to visible light induced photodegradation . Under static and dynamic conditions, the removal efficiency of E2 reached 99.5% and remained 95.1%, which was mainly owing to the synergistic effects of the adsorption of PA and photodegradation of the BPG nanocomposites . The synergistic interaction was fitted by modified Elovich model, and a strong positive correlation (r = 0.834, r s = 0.965) was confirmed by Pearson’s and Spearman’s correlation coefficient , indicating that adsorption could enhance photocatalysis by concentrating contaminants around the photocatalyst and photocatalysis could promote the adsorption by regenerating adsorption sites. The photocatalytic membrane can be reused, and the removal efficiency of E2 was 96.6% after 5 cycles. This work provided not only a facile fabrication of photocatalytic membrane, but also a deep understanding of the synergistic adsorption-photocatalysis for effective removal of E2.
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