RSC Advances
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2019
·Vol. 9
·期 50
·29109-29119
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IF 3.049
Tao Wang,Manqi Huang,Xiawei Liu,Zhen Zhang,Yonghong Liu,Wei Tang,Shaopan Bao,Tao Fang
With the expansion of industrialization, dye pollution has become a significant hazard to humans and aquatic ecosystems. In this study, α-Fe2O3/g-C3N4-R (where R is the relative percentage of α-Fe2O3) composites were fabricated by a one-step method. The as-prepared α-Fe2O3/g-C3N4-0.5 composites showed excellent adsorption capacities for methyl orange (MO, 69.91 mg g−1) and methylene blue (MB, 29.46 mg g−1), surpassing those of g-C3N4 and many other materials. Moreover, the ionic strength and initial pH influenced the adsorption process. Relatively, the adsorption isotherms best fitted the Freundlich model, and the pseudo-second-order kinetic model could accurately describe the kinetics for the adsorption of MO and MB by α-Fe2O3/g-C3N4-0.5. Electrostatic interaction and π–π electron donor–acceptor interaction were the major mechanisms for MO/MB adsorption. In addition, the photocatalytic experiment results showed that more than 79% of the added MO/MB was removed within 150 min. The experimental results of free-radical capture revealed that holes (h+) were the major reaction species for the photodegradation of MO, whereas MB was reduced by the synergistic effect of hydroxyl radicals (·OH) and holes (h+). This study suggests that the α-Fe2O3/g-C3N4 composites have an application potential for the removal of dyes from wastewater.
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PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2019
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IF 7.65
Yanping Hou,Guiyun Yuan,Shuangfei Wang,Zebin Yu,Shanming Qin,Lingli Tu,Yimin Yan,Xixi Chen,Hongxiang Zhu,Yankui Tang
In this study, a self-biased bio-photoelectrochemical system (SB-BPES) was constructed using a bioanode and the g-C 3 N 4 /CdS heterojunction photocathode for nitrofurazone (NFZ) degradation under solar irradiation. The physio-chemical properties and optical performance of photocatalysts were characterized, and photo-electrochemical properties of various photocathodes were analyzed. Results showed that g-C 3 N 4 /CdS exhibited the broadest visible light absorption range (to 594 nm) and the most efficient e − -h + separation; and its corresponding photocathode showed the highest photocurrent (9.8 μA), and the lowest charge transfer resistance (5.43 ☓ 10 3 Ω). In the solar-illuminated SB-BPES with g-C 3 N 4 /CdS photocathode, about 80% of NFZ removal rate was achieved within 10 h. More importantly, TOC removal of 62.6% was achieved in 24 h, which was 1.8 times of that from the open circuit SB-BPES, and 4.3 folds of that from microbial degradation; also, about 1.5 times of those from SB-BPES with g-C 3 N 4 and CdS photocathodes. Besides, reproducible current generations (∼1.0 mA) were produced. These verified that it was a self-sustained system for spontaneously pollutants degradation and electricity generation. Moreover, possible degradation mechanism and pathways were proposed according to the identified intermediates. This study provides inspiration for synchronic improving refractory organics degradation and net energy recovery.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Shizong Wang,Yong Liu,Jianlong Wang
In this study, the iron and sulfur co-doped graphite carbon nitride (FeO y /S-g-C 3 N 4 ) was easily prepared by one-step pyrolysis using thiourea and ferric chloride hexahydrate as precursors and applied to activate peroxymonosulfate (PMS) for the degradation of sulfamethoxazole (SMX). The characterization results showed that iron existed as Fe 2 O 3 and Fe 3 O 4 . Partial nitrogen atoms in the frame of g-C 3 N 4 were substituted by sulfur atoms. FeO y /S-g-C 3 N 4 can effectively activate PMS to produce sulfate radicals, hydroxyl radicals and singlet oxygen contributing to the SMX degradation. According to the density functional theory (DFT) calculation, the co-doping of iron and sulfur altered the charge density and its distribution of g-C 3 N 4 surface, which enhanced the PMS activation. The effect of initial concentrations of SMX and PMS, pH, temperature and inorganic ion concentrations on SMX degradation was investigated. 0.8 mM of PMS could degrade up to 10 mg/L of SMX. The initial pH had no obvious effect on the SMX degradation. Higher temperature accelerated the SMX degradation, and the activation energy was calculated to be 43.7 kJ/mol. The effect of inorganic ions was dependent on their initial concentration. Based on the comparison of XPS spectrum before and after reaction, the decreased catalytic activity of FeO y /S-g-C 3 N 4 after five cycle reuse was due to the breakdown of surface functional groups. Seven intermediate products were identified, and the possible degradation pathway was proposed. This study could provide a facile and cost-effective method to synthesize the efficient activator of PMS, and a mechanistic insight into PMS activation by FeO y /S-g-C 3 N 4 for the degradation of emerging pollutants in water and wastewater.
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高影响因子
CHINESE JOURNAL OF CATALYSIS
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2019
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IF 4.914
Lijie Xu,Lanyue Qi,Yang Sun,Han Gong,Yiliang Chen,Chun Pei,Lu Gan
Excitation of metal-free graphitic carbon nitride (g-C 3 N 4 ) under visible light can successfully achieve efficient activation of peroxymonosulfate (PMS). Synergistic effects and involved mechanism were systematically investigated using a light-inert endocrine disrupting compound, dimethyl phthalate (DMP), as the target pollutant. Under visible light irradiation, DMP could not be degraded by direct g-C 3 N 4 -mediated photocatalysis , while in the presence of PMS, the dominant radicals were converted from •O 2 to SO 4 • - and •OH, resulting in effective DMP degradation and mineralization. Results showed that higher dosage of PMS or g-C 3 N 4 could increase the activation amount of PMS and corresponding DMP degradation efficiency, but the latter approach was more productive in terms of making the most of PMS. High DMP concentration hindered effective contact between PMS and g-C 3 N 4 , but could provide efficient use of PMS. Higher DMP degradation efficiency was achieved at pH lower than the point of zero charge (5.4). Based on intermediates identification, the DMP degradation was found mainly through radical attack (•OH and SO 4 • - ) of the benzene ring and oxidation of the aliphatic chains.
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APPLIED SURFACE SCIENCE
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2019
·
IF 5.155
Xiuquan Xu,Songmei Wang,Xiaofeng Yu,Jila Dawa,Dongliang Gui,Ronghui Tang
Photocatalytic inactivation has been proved to be an effective strategy for controlling biohazards. Herein, the novel Ag deposited phosphorus and sulfur co-doped g-C 3 N 4 (PSCN) composites with different Ag content were constructed via a facile calcination combining with biogenic-reduction method for inactivating Escherichia coli ( E. coli ). The detailed characterization results indicated that P and S elements were successfully co-doped into g-C 3 N 4 (CN) lattice and Ag nanoparticles (NPs) were evenly deposited on the surface of PSCN with diameter range of 4–20 nm. The Ag/PSCN at depositing amount of 4 wt% (Ag/PSCN-4) achieved the strongest photocatalytic inactivation along with excellent stability, which could completely inactivate 7.0 log cells of E. coli within 60 min of visible light irradiation. This improved bactericidal performance was mainly attributed to the synergistic effects of P-S co-doped together with Ag deposition, which resulted in the increased visible light utilization, the improved separation and transfer efficiency of photo-induced charge carriers. Moreover, active species trapping experiments revealed that the generated superoxide radicals ( O 2 − ) and holes (h + ) played the significant roles in photocatalytic inactivation process. Our present work presented a promising and environmentally friendly strategy to enhance the photocatalytic capacities of CN based composites for pathogens inactivation.
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APPLIED SURFACE SCIENCE
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2019
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IF 5.155
Fang He,Lan Luo,Zhenxing Wang,Shaoqin Peng,Yuexiang Li
Design of highly condensed g-C 3 N 4 is a prospective way to optimize the photoreactivity of g-C 3 N 4 as it possesses condensed structure with decreased interlayer spacing, which benefits both charge transfer and light harvesting. Herein, we report that novel condensed carbonized-tannic acid (C-TA)/g-C 3 N 4 composites have been acquired via a supramolecular self-assembly of TA and melamine into TA/melamine precursors followed by thermal condensation. The acquired condensed C-TA/g-C 3 N 4 composites present superior visible-light photocatalytic activity for H 2 evolution. The 1 wt% C-TA/g-C 3 N 4 composite shows 4.2 times enhancement of photocatalytic activity for H 2 evolution compared to pristine g-C 3 N 4 . The TA with distinct adhesion properties and functional groups of OH, which is firmly linked with melamine, can confine the melamine inside to promote the condensation to gain more condensed g-C 3 N 4 . The condensed C-TA/g-C 3 N 4 composites with decreased interlayer distance effectively promote charge transfer and photocatalytic H 2 evolution.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
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IF 8.355
Mengmeng Dou,Jin Wang,Boru Gao,Ce Xu,Fan Yang
β-Lactam antibiotics are generally used for disease prevention in humans and animals. The antibiotics, which have been excreted into the surrounding environment, have caused serious concerns. In this study, mesoporous carbon nitride (MCN) was synthesized using a template-free method. The photocatalytic degradation of the two typical β-lactam antibiotics, amoxicillin (AMX) and cefotaxime (CFX), was performed using MCN. Considering the complexity of the actual environment, four factors that may influence the photocatalytic degradation of AMX and CFX were studied, containing the initial antibiotics concentration, catalyst dosage, pH and humic acid (HA). The possible mechanism of photocatalysis was presented using ESR spectroscopy and free radical trapping experiments. Furthermore, rational photocatalytic degradation pathways were proposed through the combination of LC-Q-TOF-MS/MS and density functional theory (DFT). Toxicity Estimation Software Tool (TEST) was used to predicate the toxicity of the byproducts. This study identified the catalytic activity difference between AMX and CFX firstly and elucidated their degradation mechanisms. The new findings are very meaningful for optimizing the conditions of photocatalytic degradation of β-lactam antibiotics. In addition, the results of wastewater test and stability experiments indicated that MCN has excellent performance. Therefore, MCN is a promising treatment material for the elimination of the antibiotic activity and mineralization of antibiotics under visible light.
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APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Xianlong Zhang,Dong An,Dexin Feng,Fengbing Liang,Zhen Chen,Weimin Liu,Zhenzhen Yang,Mo Xian
Herein, in situ surfactant-free synthesis of ultrathin BiOCl/g-C 3 N 4 (BOC/CN) nanosheets for enhanced visible-light photodegradation of rhodamine B was described. The formation procedure, microstructural morphology, structure, optical properties , and photocatalytic activity were researched in detail. The results show that ultrathin BOC/CN heterojunctions nanosheets were successfully constructed via one-step surfactant-free solvothermal method by introducing CN into the synthesis system of BOC, and the thickness of BOC/CN nanosheets was ~3.5 nm. The ultrathin 2D/2D BOC/CN heterojunctions significantly enhanced the photodegradation of RhB dye under visible-light irradiation. The best-performing sample BOC/CN-60 had 3.9 and 12.8 times higher photocatalytic efficiency for visible-light RhB removal compared to pure BOC and CN, respectively. The large enhancement in the photodegradation activity should be attributed to the synergistic effect of BOC and CN in BOC/CN nanosheets. The synergism reflects in the widened optical window for effective light absorption , enlarged interfacial area for more efficient electron-hole separation, and a shorter diffusion distance for facilitated charge transfer. A possible visible-light RhB photodegradation mechanism was proposed, based on theoretical analysis and active species trapping experiments.
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高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Weixuan Zeng,Yuan Bian,Sheng Cao,Anquan Zhu,Lulu Qiao,Yongjin Ma,Pengfei Tan,Quanyin Ma,Rui Dong,Jun Pan
Visible light-driven photocatalytic hydrogen production has been deemed a potential means to solve the increasingly serious energy shortage problem. Herein, two dimensional (2D) Sr 2 Ta 2 O 7 /S-doped g-C 3 N 4 nanocomposites that applied in photocatalytic water reduction were fabricated through thermal condensation of thiourea with hydrothermal-prepared Sr 2 Ta 2 O 7 . The resulted Sr 2 Ta 2 O 7 /S-doped g-C 3 N 4 nanocomposite exhibited enhanced hydrogen evolution rate (11.36 μmol g −1 h −1 ) under visible light irradiation, which is about 3.5 times higher than that of pure S-doped g-C 3 N 4 . In light of the UV–vis diffuse reflectance spectroscopy, Mott-Schottky curve and photoluminescence spectra, the enhanced photocatalytic performance could be mainly attributed to the conduction band difference between Sr 2 Ta 2 O 7 and S-doped g-C 3 N 4 . In addition, transient photoluminescence spectra, electrochemical impedance spectra and photocurrent responses proved that the presence of Pt cocatalyst also plays an important role in facilitates the transport of photoexcited electron-hole pairs, subsequently promoting the photocatalytic performance.
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高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2019
·
IF 14.229
Zizheng Ai,Yongliang Shao,Bin Chang,Lei Zhang,Jianxing Shen,Yongzhong Wu,Baibiao Huang,Xiaopeng Hao
As a metal-free polymeric semiconductor, graphitic carbon nitride (g-C 3 N 4 ) is a promising candidate for photocatalytic water splitting but suffers from the insufficient optical absorption and sluggish utilization of photocarriers. Herein, based on the energy band engineering theory, a new design philosophy of tunable p-n homojunction is proposed and realized in a novel P-doped g-C 3 N 4 (PCN) material. Through regulating the tendency of transformation in p-n homojunction, a strong internal electric field is built and integrated with two secondary internal electric fields by further decorating with Ti 3 C 2 , leading to the formation of a triple-internal electric field system. Thus the spatial separation efficiency of photocarriers is improved and their lifetime is prolonged. The specific photocatalyst exhibits excellent overall water splitting performance in pure water with a notable quantum yield. This work presents a peculiar concept of adjustable p-n homojunction and holds great significance for the rational design of advanced photocatalyst in water splitting.
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高影响因子
APPLIED SURFACE SCIENCE
·
2019
·
IF 5.155
Qiao Wang,Peng Xu,Guangshan Zhang,Limin Hu,Peng Wang
Visible-light responsive g-C 3 N 4 catalysts were successfully prepared by the calcination of urea, i.e., the thermal polycondensation method, and a series of ZnS/g-C 3 N 4 composite photocatalysts were then synthesized using a rapid microwave hydrothermal method . The physicochemical properties of the resulting g-C 3 N 4 and ZnS/g-C 3 N 4 catalysts were characterized via several microscopy and spectroscopy techniques . The reduction of Cr(VI) was used to evaluate the photocatalytic performance of the as-synthesized catalysts under visible light irradiation. The results showed that the calcination temperature substantially affected the crystallinity , specific surface area and photocatalytic performance of g-C 3 N 4 . The optimal temperature for thermal polycondensation in the g-C 3 N 4 synthesis was 600 °C. The bulk g-C 3 N 4 catalyst exhibited no Cr(VI) reduction ability, while a certain amount of ZnS nanoparticles coupling with g-C 3 N 4 significantly improved the Cr(VI) reduction efficiency, creating a synergistic effect between g-C 3 N 4 and ZnS. The simultaneous Cr(VI) reduction and rhodamine B decolorization by the ZnS/g-C 3 N 4 composite catalyst were also accomplished. In addition, a Cr(VI) reduction mechanism under visible light irradiation was proposed.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Huiping Zhao,Guangfang Li,Fan Tian,Qintao Jia,Yunling Liu,Rong Chen
To overcome the issue of UV-light response character of Bi 2 O 2 CO 3 due to its wide band gap, we primarily attempted to understand the possibility of improving the photocatalytic activity of Bi 2 O 2 CO 3 via g-C 3 N 4 surface-decoration by the theoretical calculation. Subsequently, g-C 3 N 4 surface-decorated Bi 2 O 2 CO 3 was successfully prepared via a facile hydrothermal method. It was found that the g-C 3 N 4 surface-decorated Bi 2 O 2 CO 3 samples exhibited enhanced activities for the photodegradation of tetracycline compared with pure Bi 2 O 2 CO 3 upon simulated solar light irradiation. Among them, the 10 wt% g-C 3 N 4 surface-decorated Bi 2 O 2 CO 3 sample showed the highest photocatalytic efficiency. First principle calculation and experimental data confirmed that the charge transfer at the interface between g-C 3 N 4 and Bi 2 O 2 CO 3 could significantly suppress the recombination of photo-generated electron-holes pairs, thus improving the photocatalytic performance. The proposed mechanism for the enhanced photocatalytic activity was also discussed. Moreover, the photodegradation of antibiotics over g-C 3 N 4 surface-decorated Bi 2 O 2 CO 3 was also performed in actual water matrix.
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高影响因子
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