CHEMICAL ENGINEERING JOURNAL
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2020
·
IF 10.652
Xin Wang,Wangyang Lu,Zhiguo Zhao,Huitian Zhong,Zhexin Zhu,Wenxing Chen
Peroxymonosulfate (PMS) activation with the generation of strongly oxidizing hydroxyl radicals (•OH) and sulfate radicals (SO 4 • − ) has attracted widespread attention for the elimination of organic contaminants. However, the design of an eco-friendly catalytic system with high mineralization rate and high stability remains a challenge. Here, an iron-based photocatalyst (β-FeOOH@g-C 3 N 4 ) for the activation of PMS was prepared by a cyclic microwave-assisted reaction, whereby Fe 3+ was introduced at the nitrogen sites of g-C 3 N 4 , resulting in in situ growth and a uniform distribution of nano-β-FeOOH thereon. β-FeOOH@g-C 3 N 4 maintained high catalytic activity after acid treatment or repeated tests, demonstrating excellent stability and reusability. Moreover, compared with the catalytic systems with β-FeOOH or g-C 3 N 4 alone, the catalytic activity of β-FeOOH@g-C 3 N 4 was increased 5–10 times for the catalytic oxidation of carbamazepine (CBZ) and other emerging contaminants under solar irradiation. Importantly, the CBZ mineralization rate with the β-FeOOH@g-C 3 N 4 /PMS system under solar irradiation was as high as 92%. From the results of electron paramagnetic resonance spectroscopy and radical trapping experiments, large amounts of O 2 • − , 1 O 2 , and Fe V = O are present at the beginning of the reaction, which contribute to the rapid oxidative removal of CBZ, while SO 4 • − and •OH contribute to the deep oxidation, leading to a significantly enhanced total organic carbon (TOC) removal efficiency. This work provides an alternative method for the design of a highly efficient and stable catalyst for PMS activation to eliminate emerging contaminants.
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APPLIED SURFACE SCIENCE
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2020
·
IF 6.182
Y.Q. He,Fangling Zhang,Bei Ma,Na Xu,Lucas Binnah Junior,Binghua Yao,Qian Yang,Dongjie Liu,Zhanying Ma
In this study, a highly efficient ternary 6.7%Au/Ni 2 P/g-C 3 N 4 nanocomposite is rationally fabricated through a two-step hydrothermal followed by green photoreduction strategy. The XPS analysis, SEM and HRTEM images reveal that Ni 2 P and good nanoparticles (AuNPs) are successfully loaded onto the surface of g-C 3 N 4 and heterojunction formed among them. The optimized 6.7%Au/0.5%Ni 2 P/g-C 3 N 4 demonstrates the highest photocatalytic efficiency towards decomposition of levofloxacin hydrochloride with 88.23% removal rate and hydrogen generation rate of 78.65 μmol·g −1 ·h −1 , in comparison with the binary 0.5%Ni 2 P/g-C 3 N 4 (76.86%, 47.06 μmol·g −1 ·h −1 ) and pristine g-C 3 N 4 (61.26%, 45.61 μmol·g −1 ·h −1 ). Notably, this is the first time using Ni 2 P and AuNPs co-modified g-C 3 N 4 -based nanocomposites to evaluate the photocatalytic degradation performance of levofloxacin hydrochloride. The study of the corresponding enhanced mechanism indicates that the dramatically improved photocatalytic performance is originated from the synergistic effects: including (1) the strong optical absorption property of Ni 2 P and the SPR effect of AuNPs endows the remarkably improved visible-light harvesting for increasing charge carrier production; (2) the co-catalysts of Ni 2 P and AuNPs play key roles as interfacial electron sinkers and facilitate photogenerated electron-hole pairs separation and migration; (3) the co-integration improves the specific surface area of final product which can provide more active sites for the improvement of photocatalytic performance. Moreover, a plausible degradation pathway for levofloxacin hydrochloride is proposed based on the UPLC-MS analysis. Our work highlights a good example for designing and constructing other highly-efficient g-C 3 N 4 -based multicomponent photocatalysts for both solar energy conversion and environmental remediation.
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ANALYTICA CHIMICA ACTA
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2020
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IF 5.977
Jun-Tao Cao,Yu-Xiang Dong,Yan Ma,Bing Wang,Shu-Hui Ma,Yan-Ming Liu
Photoactive materials with high photo-electron transfer efficiency and stable signal output hold a key role in constructing the photoelectrochemical (PEC) biosensing systems. In this study, the ternary [email protected] 3 N 4 heterojunction was first prepared and characterized, and its application in PEC bioanalysis was explored. The gold nanoparticles sandwiched between CdS and g-C 3 N 4 , acting as both plasmonic photosensitizer and electron relay, significantly boosted the light absorption and accelerated the charge transfer from g-C 3 N 4 to CdS, both of which contributed to the enhancement of photoelectric conversion efficiency. Signal quenching with graphene oxide-CuS efficiently weakened the photocurrent from [email protected] 3 N 4 . The combination of the excellent PEC properties of [email protected] 3 N 4 and the remarkable quenching effects of graphene oxide-CuS enabled construction of a sandwich-type PEC immunosensor for prostate specific antigen (PSA) detection. This immunosensor achieved sensitive PSA analysis by multiple signal amplification mechanisms, with a detection limit of 0.6 pg mL −1 and a wide linear range from 1.0 pg mL −1 to 10 ng mL −1 . This work not only demonstrates the great potential of noble metal sandwiched ternary heterojunctions in the PEC field, but also lays a foundation for developing the general PEC immunoassays .
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JOURNAL OF HAZARDOUS MATERIALS
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2019
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IF 7.65
Jiafeng Ding,Shihuan Lu,Lilai Shen,Ruopeng Yan,Yinan Zhang,Hangjun Zhang
Polychlorinated dibenzo- p -dioxins (PCDDs), characterized by their high persistency and bioaccumulation, are widely detected in the environment. In this study, high-performance g-C 3 N 4 /NiO heterojunctions were fabricated to degrade 2-chlorodibenzo- p -dioxin (2-CDD) under ultraviolet-visible (UV–vis) light illumination. Experiments revealed that the pure g-C 3 N 4 and range of g-C 3 N 4 /NiO heterojunctions were synthesized by the mixing and heating method, and then were characterized by XRD, TEM, XPS and PL etc. The composites exhibited enhanced dechlorination activities under anoxic conditions. After comparison, the g-C 3 N 4 /NiO (4:6) showed optimal dechlorination performance such that 70.4% of 2-CDD was removed within 8 h and 52.3% of 2-CDD was transformed to dibenzo- p -dioxin (DD), about fourfold higher than the pristine g-C 3 N 4 . The transformation of 2-CDD was accompanied by the resale of Cl ion, and the additional oxygen was proven to be able to consume electrons and hydrogen ions, thus greatly inhibiting the degradation of PCDD in systems. The g-C 3 N 4 /NiO (4:6) can be reused at least seven times, and the mechanism was proposed in detail to promote photoinduced electrohole separation and provide active sites. This study extends the use range of g-C 3 N 4 /NiO heterojunctions and develops a new technology to degrade PCDDs with striking activity and stability.
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MICROCHIMICA ACTA
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2019
·Vol. 186
·期 6
·1-9
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IF 5.479
Lv Yuanxia,Jiang Caiyan,Hu Kun,Huang Yong,He Yunfeng,Shen Xiaoying,Zhao Shulin
Cobalt oxyhydroxide (CoOOH) was grown on the surface of graphitic-phase C 3 N 4 nanosheets to obtain an activatable fluorescent nanoprobe for ascorbic acid (AA). The probe was applied to the detection of AA in biological fluids and to image AA in HeLa cells. The negatively charged nanosheets first adsorb Co 2+ , and then the CoOOH nanoflakes are generated in-situ on the surface of g-C 3 N 4 . This results in the quenching of the blue fluorescence (with excitation/emission maxima of 345/435 nm) via fluorescence resonance energy transfer from g-C 3 N 4 to CoOOH. The AA-induced redox reaction reduces the trivalent cobalt ion in CoOOH to Co 2+ which then becomes released from the nanosheets. This leads to the recovery of fluorescence. The method can quantify AA in the 1.0 to 800 μM concentration range at near neutral pH values. When applied to cell extracts, the limit of detection is 0.14 μM. The nanoprobe was successfully applied to the determination of AA in serum and urine, and to image AA in living HeLa cells. Additional attractive features include the ease of preparation, low cytotoxicity, rapid fluorometric turn-on response, and good biocompatibility.
Schematic presentation of an activatable fluorescent nanoprobe. It consists of CoOOH nanoflakes that were modified withg-C 3 N 4 nanosheets. It enables monitoring of AA in the biological samples as well as imaging of AA in living cells.
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CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Jiaxing Huang,Daguang Li,Ruobai Li,Qianxin Zhang,Tiansheng Chen,Haijin Liu,Yang Liu,Wenying Lv,Guoguang Liu
Non-metal doping has been frequently used in g-C 3 N 4 (CN) as a feasible and economical technique for maintaining its metal-free properties, while improving its photocatalytic performance. In this study, a novel phosphorus and oxygen co-doped graphitic carbon nitride (POCN) was successfully synthesized through a one-step thermal polymerization method and exhibited remarkable photocatalytic activity for the photocatalytic degradation of fluoroquinolones (FQs). The degradation rate of enrofloxacin (ENFX) was 6.2 times higher than that of CN. Based on the results of X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance spectroscopy (NMR), P atoms replaced the corner and bay carbon sites, whereas O atoms replaced the nitrogen sites in the g-C 3 N 4 framework. The improvement of the photocatalytic effect of POCN0.01 was attributed to its narrow bandgap, effective charge separation and enhanced specific surface area. This is the first report to describe the use of phosphorus doping to promote the generation of reactive oxygen species (ROS). ROS scavenging tests revealed that O 2 − was the primary active species during the degradation of ENFX. Furthermore, pathways for the degradation of ENFX were proposed via the detection of intermediate products via HRAM LC–MS/MS and the prediction of active sites using the Fukui function.
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JOURNAL OF MATERIALS SCIENCE
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2019
·Vol. 54
·期 17
·11417-11434
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IF 3.442
Wang Dadao,Li Jian,Xu Zhifeng,Zhu Yeran,Chen Guoxin,Cui Zheng
A novel three-dimensional ball-flower-like g-C 3 N 4 /NiO (GN) photocatalyst was firstly fabricated by a simple two-step calcination method for enhanced degradation capability. Our investigation focuses on the construction of p–n heterojunction and specific ball-flower-like structure to overcome limitations of single-component semiconductors, such as low surface area, poor light response and fast recombination of the photogenerated electrons and holes. Detailed photocatalytic experiments revealed that the novel ball-flower-like GN (50%) exhibited much higher activity for the removal of TC and Cr 6+ than single g-C 3 N 4 , NiO and traditional layered GN. The trapping experiments proved that the superoxide radicals ( \( ^{ \cdot } {\text{O}}_{2}^{ - } \) ), holes (h + ) and electrons (e − )were the main active species in the photodegradation process. Moreover, three different degradation pathways and fourteen intermediate products of TC were also determined by the LC/MS analysis and these intermediates could be further degraded completely into CO 2 , H 2 O, \( {\text{NH}}_{4}^{ + } \) , carboxylic acids and any other inorganic intermediates. These results will benefit the fabrication of other 3D p–n heterojunction photocatalysts and their potential application in treatment of organic pollutants.
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MICROCHIMICA ACTA
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2019
·Vol. 186
·期 9
·1-7
·
IF 5.479
Zhang Bing,Jia Yejing,Wang Jing,Hu Xing,Zhao Zhihuan,Cheng Yan
A sensitive photoelectrochemical (PEC) immunoassay for the carcinoembryonic antigen (CEA) is described that is based on the use of C 3 N 4 -BiOCl semiconductor on an ITO electrode. The photocurrent of the modified electrode was measured under visible light illumination. It increased in presence of L-cysteine due to rapid separation of the photoexcited electrons and holes. A sandwich-type immunoassay in a 96-well microtiter plate format used CuO nanoparticles as label for the secondary antibody. The Cu 2+ is released from the CuO in the sandwich complex by treatment with acid. The free Cu 2+ combined with both the cysteine and the electron receptors of C 3 N 4 and BiOCl. Under optimal conditions, this dual action immensely decreases the photocurrent of the PEC system, and the response is inversely proportional to the CEA concentrations from 0.1 pg mL −1 to 10 ng mL −1 at the working voltage of 0 V (vs. SCE). The detection limit is 0.1 pg mL −1 , and the method is exhibited satisfactory selective, repeatable and stable.
Schematic representation of an immunoassay based on cysteine-assisted C 3 N 4 -BiOCl photoelectrochemical platform. CuO nanoparticles were utilized as labels in immunocomplex to release Cu 2+ in acidic condition. Carcinoembryonic antigen in sample was detected sensitively by dual function of Cu 2+ with cysteine and C 3 N 4 -BiOCl semiconductor.
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MATERIALS RESEARCH BULLETIN
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2019
·
IF 3.355
Xiaofeng Hu,Jisong Hu,Qingqi Peng,Xinguo Ma,Shijie Dong,Huihu Wang
In this work, a special hybrid structure with 2D configuration comprising of g-C 3 N 4 , reduced graphene oxide (RGO), and BiOI (g-C 3 N 4 /BiOI/RGO) was rationally constructed and immobilized on Ni foam with RGO functioned as electron transfer mediator and binder. The immobilized 2D g-C 3 N 4 /BiOI/RGO hybrid structure exhibited the enhanced photocatalytic CO 2 reduction to CO and the methyl orange (MO) degradation efficiency under visible light irradiation. Particularly, the hybrid heterojunction with a mass ratio 6% of BiOI to g-C 3 N 4 displayed the highest CO yield and degradation rate constant for MO, which was 1.6 times and 3 times of g-C 3 N 4 /RGO binary heterojunction immobilized on Ni foam. The enhanced photocatalytic activity was ascribed to the rapid charge separation. More importantly, combined with the theoretical calculations on the work functions of g-C 3 N 4 , rGO and BiOI, the experimental results clarified the charges transfer route of g-C 3 N 4 /BiOI/RGO heterojunction conforming to the Z-scheme mechanism.
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Catalysts
·
2019
·Vol. 10
·期 1
·6
·
IF 3.444
Jia Huang,Gang Nie,Yaobin Ding
To develop highly efficient heterogeneous photocatalysts for the activation of dissolved oxygen is very interesting in the field of green degradation of organic pollutants. In the paper, oxygen atom doped g-C3N4(O-g-C3N4) was prepared via a facile chemical oxidation of g-C3N4by peroxymonosulfate. X-ray photoelectron spectroscopy analysis suggests the oxidative treatment of g-C3N4by peroxymonosulfate evidently increased atomic percentage of oxygen on O-g-C3N4surface to 6.9% as compared with 1.8% for g-C3N4. Meanwhile, the doped oxygen atom mainly existed as carbonyl and carboxyl groups. Optical characterization indicates the introduction of oxygen improved the response of O-g-C3N4to visible light, and more obviously, separation of photo-generated h+-e−. 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) probe measurement indicates the formation of O2•−was dramatically enhanced through activation of dioxygen by photo-generated electrons in the O-g-C3N4photocatalytic system. Through high performance liquid chromatography (HPLC) and Liquid chromatography–mass spectrometry (LC-MS) analysis, it was found rhodamine B (RhB) photocatalytic degradation by O-g-C3N4followed step by step N-deethylation reaction pathways induced by the formed O2•−, rather than the non-selective decomposition of the chromophore in RhB by other radicals, such as hydroxyl radicals. This study provides a facile method to develop oxygen atom doped g-C3N4photocatalyst, and also clarifies its photocatalytic activation mechanism of molecular oxygen for N-deethylation reaction of RhB.Keywords:photocatalysis;oxygen doped g-C3N4;activation of dioxygen;superoxide radicals;selective N-deethylation of rhodamine B
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JOURNAL OF HAZARDOUS MATERIALS
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2019
·
IF 7.65
Jiaxing Huang,Daguang Li,Ruobai Li,Ping Chen,Qianxin Zhang,Haijin Liu,Wenying Lv,Guoguang Liu,Yiping Feng
Anatase TiO 2 nanoparticles coated with P and O co-doped g-C 3 N 4 were prepared via a single-step procedure. The resulting POCN/anatase TiO 2 demonstrated remarkable performance in the degradation of enrofloxacin (ENFX). The photocatalytic activity of this heterojunction was 28.9 and 3.71 times better than that of the CN and anatase TiO 2 , respectively. The microtopography of the POCN/anatase TiO 2 was revealed in this study. Co-doping with P and O increased the visible light adsorption capacity of the g-C 3 N 4 , whereas the anatase TiO 2 nanoparticles enhanced the adsorption properties of the ENFX and the separation of the photoinduced carriers of the POCN/anatase TiO 2 . The O 2 ·− and h + were the main reactive oxidative species in the photocatalytic degradation of ENFX. The results of the detection of H 2 O 2 and ESR confirmed that POCN/anatase TiO 2 was a type Z-scheme photocatalyst. Finally, the ENFX degradation pathways were estimated through the detection of by-products.
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CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Bin Ou,Jixiao Wang,Ying Wu,Song Zhao,Zhi Wang
Magnetic and recyclable calcined CoFe-LDH/g-C 3 N 4 catalyst was prepared by co-precipitation and calcination method, and used as a multifunctional material to remove hexavalent chromium (VI) via the synergistic effect of adsorption and photocatalysis. The calcined CoFe-LDH provide surface adsorption in the composite, which could lead to the adsorption of Cr (VI) with high adsorption capacity and fast speed. The g-C 3 N 4 nanosheets have high photocatalytic activity in situ for the composite to reduce Cr (VI) into Cr (III). The results demonstrated that 60% Cr (VI) (50 mg L −1 ) can be adsorbed by the nanocomposite in 10 min and the removal efficiency of Cr (VI) reached 100% in 90 min under visible light irradiation by adsorption and photocatalysis. In addition, the calcined CoFe-LDH/g-C 3 N 4 exhibits a mostly pore size about 2.58 nm, large specific surface area (101.61 m 2 g −1 ) with the high structural stability and saturation magnetization (23.06 emu g −1 ), hence, could be easily recycled for ten subsequent runs with little activity loss.
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