Molecular Catalysis
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2021
·
IF 5.062
Zhenning Xu,Yanhong Wang,Jiayuan Zhuang,Yawen Li,Lishan Jia
Herein, we proposed a facile method to synthesize N doped carbon quantum dots (NCQDs) using g-C 3 N 4 as carbon-nitrogen source, and the NCQDs-modified CdS nanocomposite catalysts for photocatalytic water splitting were synthesized by one-step hydrothermal method. The results showed that the NCQDs with a size of 3.2 nm obtained by hydrothermal etching were adsorbed on the surface of CdS particles with a size of 80 nm and induced the regulation of the surface morphology of CdS particles. There was strong interaction between NCQDs and CdS through C-S bond. The introduction of NCQDs in composite catalysts not only increased the photo-absorption performance but also suppressed the recombination of photo-generated carriers, which enabled the photo-generated electrons to transfer to NCQDs effectively and quickly and improved the photocatalytic performance of hydrogen production from water splitting. The composite photocatalysts showed good response to visible light in UV-Vis DRS and the photocatalytic water splitting experiment showed that the photocatalytic hydrogen production activity of composite catalysts was significantly improved under visible light (λ > 400 nm). And the maximum hydrogen production rate reached 2306.1 μmol/g/h, which was about 7 times the amount of unsupported NCQDs sample.
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高影响因子
DIAMOND AND RELATED MATERIALS
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2021
·
IF 3.315
Rui Zhang,Kunlin Zeng
Preparation of Z-scheme composite photocatalyst to degrade organic matter in water is the most popular research trend. However, due to the strict requirements of band edge energy level arrangement and interface contact, it is a great challenge to explore suitable photocatalytic materials to form Z-scheme photocatalytic system. In our work, a novel visible light driven double Z-scheme photocatalyst BiSI/Bi 2 WO 6 /g-C 3 N 4 was successfully prepared by hydrothermal synthesis . The physicochemical properties of the materials were characterized by XRD , XPS, SEM, BET, UV–vis, PL , EIS and LC-MS. The photocatalytic degradation of tetracycline (TC), chlortetracycline (CTC) and rhodamine B (RhB) showed that BiSI/Bi 2 WO 6 /(20%) g-C 3 N 4 had the best photocatalytic activity . The results free radical trap experiments demonstrate that h + and O 2 − are the main free radicals in the photocatalytic process. Because of the heterojunction formed between BiSI, Bi 2 WO 6 and g-C 3 N 4 , the electron conduction was accelerated, the photogenerated electrons and holes were separated effectively, and the photocatalytic performance of the composite was improved. Additionally, cycle test showed that BiSI/Bi 2 WO 6 /g-C 3 N 4 hybrid material had stable degradation ability in the process of photodegradation . This unique heterojunction photocatalysis material has broad application prospects in the removal of organic pollutants and environmental treatment.
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JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2021
·Vol. 96
·期 6
·1580-1592
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IF 3.174
Yicheng Dou,Xingyu Shen,Jinte Zou,Runzhe Shi,Tingting Yan,Qiya Sun,Lin Wang
BACKGROUND In this study, sulfur-doped g-C 3 N 4 (SCN) nanosheets were synthesized using thiourea as a precursor, and then used to catalyze the degradation of oxytetracycline (OTC) under visible-light irradiation. OTC was chosen as target contaminant because of it being an important precursor of N -nitrosodimethylamine (NDMA). RESULTS The removal of OTC was influenced by its initial concentration, initial pH, SCN dosage and water matrices. OTC (≤10 mg L −1 ) was almost completely removed in 40 min under the conditions of an initial pH of 7.0 and a SCN dose of 1.0 g L −1 , and its degradation was well described by the pseudo-first-order kinetics model. Water matrices would also influence the degradation of OTC in the system. Electron paramagnetic resonance analysis and trapping experiments confirmed that the function of the radicals for OTC removal followed the order of • O 2 − > • OH > h + . Eight transformation products were determined during the degradation of OTC, it being removed through four pathways: methyl oxidization, demethylation, decarbonylation and secondary alcohol oxidation. SCN was stable in the system, as the removal efficiency of OTC was not significantly reduced even after three recycles. In addition, 55.5% of NDMA formation potential of OTC was reduced after SCN catalytic oxidation. CONCLUSIONS The results imply that the visible-light-driven SCN catalytic oxidation is an effective technology not only for the removal of OTC but also for the reduction of NDMA formation potential. © 2021 Society of Chemical Industry
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SEPARATION AND PURIFICATION TECHNOLOGY
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2020
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IF 5.774
Fengzhen Zhang,Jianbo Liao,Jianjiang Lu,Junfeng Niu
Carbon nitride (CN), oxygen-doped carbon nitride (CNO), HNO 3 oxidized CN (CN-10) and CNO (CNO-10), were synthesized and used to catalyze ozonation of para -chlorobenzoic acid ( p -CBA) and atrazine in aqueous solution. Pre-doping oxygen atom into CN could create extra defects for grafting more carboxyl groups during HNO 3 oxidation , which was verified by much lower formation energy of CNO-10 than that of CN-10. Density functional theory and room temperature electron paramagnetic resonance (EPR) analysis signified the changes of electronic structure afforded by extensively grafted carboxyl groups. The incorporation of carboxyl groups distorted the carbon nitride framework and changed the spatial dimensions of CN and CNO, which attenuated the characters of delocalized π-electrons in conjugated structure. Moreover, the introduction of carboxyl groups reduced the pore diameter and nano-size distributed in aqueous solution for CN-10 and CNO-10 relative to those of CN and CNO. Results showed that the elimination efficiency of p -CBA by catalytic ozonation and R ct (standard reactivity metric for catalytic ozonation process) with CNO-10 improved 1.12- and 1.48-fold relative to those with CN-10, respectively, far surpassing non-catalytic ozonation. The removal of ozone-resisted compounds by CNO-10 catalyzed ozonation was not significantly affected by bicarbonate and NOM, and it was promoted by natural surface water resulting in 87.4% p -CBA removal in 30 min. Mechanistic evaluation demonstrated that carboxyl groups were the main active sites, catalyzing ozone decomposition into hydroxyl radical through radical chain reaction. This work provides fundamental supportive of pre-doping oxygen atom into CN before HNO 3 functionalization, which could incorporate more carboxyl groups on surface compared to conventional strategy, further enhancing catalytic activity in ozonation.
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ELECTROCHIMICA ACTA
·
2020
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IF 6.215
Mengjie Zhang,Zixuan Chen,Haixin Qin,Xiaoyan Yang,Wei Cao,Shufeng Liu
Abtract Heme binds to amyloid β -peptide (A β ) in the brain of Alzheimer΄s disease (AD) patients, thus forming heme-A β complexes and leading the characteristic pathological features of AD. The heme-A β complexes reduce O 2 by 2e − to obtain co-reactant H 2 O 2 . In this work, two-dimensional graphite-like carbon nitride (g-C 3 N 4 ) was hybridized with heme via π-π interaction to construct an electrochemiluminescence (ECL) biosensor for detection of A β peptides. The capture aptamer was firstly immobilized on the gold electrode, and then incubated with target A β peptides and g-C 3 N 4 -heme. The g-C 3 N 4 -heme-A β composite was subsequently anchored on the electrode and showed a signal-on, label-free ECL emission based on dual co-reactants enhancement attributed to in-situ generated H 2 O 2 and original K 2 S 2 O 8 in PBS buffer. Under the optimum experimental conditions, the ECL biosensor has a sensitive response to A β peptides with a linear range of 10 fM-0.1 μM and a detection limit of 3.25 fM. Considering prominent specificity, reproducibility, and stability, the proposed biosensor was used to assess recovery of A β peptides in human serum and the result was satisfactory. We believe that the established method would offer a useful analytical means for quantifying A β peptides in a biological matrix.
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CHEMICAL ENGINEERING JOURNAL
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2020
·
IF 10.652
Juying Lei,Bin Chen,Liang Zhou,Ningkai Ding,Zhengqing Cai,Lingzhi Wang,Su-Il In,Changzheng Cui,Yanbo Zhou,Yongdi Liu,Jinlong Zhang
The efficient degradation of fluoroquinolone antibiotics and the reduction of their antimicrobial activity were achieved in different water matrices through the photocatalysis of inverse opal potassium-doped carbon nitride (IO K-CN). The IO K-CN photocatalyst with optimum doping ratio of potassium performed much better than bulk carbon nitride and pure inverse opal carbon nitride for removing fluoroquinolone antibiotics, such as levofloxacin (LVX) and norfloxacin (NOR). The remarkably narrowed band gap resulting from potassium doping and the unique properties of the inverse opal construction jointly contributed to enhancing the activity of the photocatalyst. A possible mechanism and degradation pathway for LVX was proposed on the basis of a series of characterizations including electron spin resonance (ESR) experiments, and liquid chromatography-mass spectrometry (LC-MS) analysis. Meanwhile, the byproducts during the LVX photocatalytic degradation were shown to have much lower sterilization effect, implying that the toxicity and the potential risk of LVX were excellently reduced. The potential application for the treatment of antibiotic-containing wastewater was indicated by the excellent treatment efficiency and favorable durability of this photocatalyst.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2020
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IF 5.774
Hao Xu,Qian Ye,Qingguo Wang,Peng Zhou,Xiaowei Huo,Yunqi Wang,Xue Huang,Guanyu Zhou,Jing Zhang
Developing a low-cost and environmental friendly way to promote the Fe(III)/Fe(II) cycling is crucial to enhance the efficiency of Fenton reaction. In this study, g-C 3 N 4 was introduced into the Fe(III)/H 2 O 2 system as electron donor to accelerate Fe(III)/Fe(II) cycling and improve the degradation of organic pollutants under visible light. The g-C 3 N 4 /Fe(III)/H 2 O 2 /light system can achieve excellent degradation of different kinds of organic pollutants under low Fe(III) and H 2 O 2 dosages. The central composite design (CCD) and response surface methodology (RSM) were applied to evaluate the effects of g-C 3 N 4 dosage, Fe(III) dosage, H 2 O 2 dosage and light intensity on the DMP degradation efficiency. The mechanisms were investigated by quenching experiments and electron spin resonance (EPR) analyses that the photo-generated electrons and O 2 – were responsible to the Fe(III) reduction through interfacial and aqueous pathways, respectively. OH was the dominant reactive radical in the DMP degradation. Moreover, DMP degradation routes were proposed including the elimination of specific groups, the hydroxylation process and the ring-opening reactions. This study demonstrates an economical and green approach which provides a promising direction for the practical application of g-C 3 N 4 based photocatalysis by integrating it with the Fe(III)/H 2 O 2 Fenton process.
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NANOTECHNOLOGY
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2018
·Vol. 29
·期 31
·315601
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IF 3.404
Gang Xiao,Shengnan Xu,Peifeng Li,Haijia Su
Heterostructured photocatalysts based on g-C3N4 and TiO2 represent a promising kind of photocatalyst in environmental fields, but the synthesis methods are always complex and not green. In the present paper, a facile and green one-step calcination procedure at lower temperature (450 °C) with the assistance of water is developed to synthesize a visible-light-active TiO2@g-C3N4 heterostructured photocatalyst, which shows higher visible-light-driven activity (k = 0.014 min−1) than pure g-C3N4 (k = 0.0036 min−1) and TiO2 (k = 0.0067 min−1) for methyl orange degradation. Excellent performance (over 90% conversion) was also observed for the removal of rhodamine B, phenol, and Cr(VI) under visible light. The heterostructured photocatalyst showed favorable reusability, preserving 86% of its activity after five successive cycles. A mechanism study demonstrates that the enhanced photocatalytic activity results from the efficient separation of the photo-generated charge carriers through the intimate interface between the two semiconductors based on their appropriate band structures and light-induced mechanism. The heterostructured photocatalyst will certainly find wide applications in the treatment of various toxic pollutants in wastewater using abundant solar energy. Furthermore, this facile and green procedure and the proposed synergistic mechanism will provide guidelines in designing other g-C3N4 based organic–inorganic composite photocatalysts for various applications.
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PubMed
高影响因子
DALTON TRANSACTIONS
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2018
·Vol. 47
·期 20
·6924-6933
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IF 4.099
Fengliang Wang,Yingfei Wang,Yanyan Li,Xuhui Cui,Qianxin Zhang,Zhijie Xie,Haijin Liu,Yiping Feng,Wenying Lv,Guoguang Liu
Enabling the optimal usage of solar energy is considered to be one of the most pressing challenges in the photocatalytic remediation of water resident contaminants. Herein, a single-atom dispersed Ag loaded ultrathin g-C3N4 hybrid (AgTCM/UCN) was prepared through a facile co-polymerization of dicyandiamide with silver tricyanomethanide (AgTCM) and NH4Cl, and used as a visible light driven photocatalyst for the degradation of sulfamethazine (SMT) in the presence of peroxymonosulfate (PMS). Under UV light, visible light and simulated sunlight irradiation, the AgTCM/UCN/PMS process showed higher efficiency for SMT degradation than AgTCM/UCN, UCN/PMS, and g-C3N4/PMS systems. This enhanced photocatalytic activity may be attributed to the synergistic effects encompassing the surface plasmon resonance (SPR) of Ag, high surface area of UCN, and efficient charge separation of PMS. Electron–spin resonance (ESR) and reactive species (RSs) scavenger-quenching experiments revealed that SO4˙− was generated following the addition of PMS, whereas O2˙− and h+ were predominantly responsible for the degradation of SMT. Three degradation pathways of SMT were deduced, including the cleavage of sulfonamide bonds, SO2 extrusion, and the oxidation of the aniline moiety, based on mass spectrometry and theoretical calculations. The degradation of SMT in ambient water revealed that the AgTCM/UCN/PMS photocatalytic process can be efficaciously applied for the remediation of SMT contaminated natural waters, particularly sea water.
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RSC Advances
·
2015
·Vol. 5
·期 32
·24944-24952
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IF 3.84
Xinshan Rong,Fengxian Qiu,Jie Yan,Hao Zhao,Xiaolu Zhu,Dongya Yang
A coupled system for the photodegradation of Rhodamine B dye was realized using a Bi2S3/g-C3N4 composite as a photocatalyst under visible light irradiation. The Bi2S3/g-C3N4 composite was prepared by a hydrothermal method and characterized by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Compared with pure g-C3N4, the Bi2S3/g-C3N4 sample exhibits an enhanced photocatalytic activity and the best photocatalytic efficiency is 3.68 times more than that of pure g-C3N4. The obtained results indicate that a coupled system of Bi2S3 and g-C3N4 could overcome the drawback of low photocatalytic efficiency brought by electron–hole recombination and a narrow photoresponse range. On the basis of the corresponding energy band positions, the mechanism of photocatalytic activity enhancement was proposed.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2017
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IF 9.446
Fengliang Wang,Yingfei Wang,Yiping Feng,Yongqin Zeng,Zhijie Xie,Qianxin Zhang,Yuehan Su,Ping Chen,Yang Liu,Kun Yao,Wenying Lv,Guoguang Liu
The development of highly efficient photocatalysts with broad spectrum light response is a primary goal in the photocatalysis domain. Here we report on a novel ternary photocatalyst comprised of single atom-dispersed silver and carbon quantum dots, co-loaded with ultrathin g-C 3 N 4 (SDAg-CQDs/UCN), which exhibited a highly enhanced photoresponse and broad-spectrum (UV, visible, and near-infrared light) photocatalytic activity. The content of 1.0 wt% of CQDs and 3.0 wt% of Ag resulted in a 10-fold higher reaction rate than that of UCN under visible light irradiation. This improved broad-spectrum photocatalytic performance may be attributed to the surface plasmon resonance effect of Ag, up-converted fluorescent properties of CQDs, narrowed energy gap, as well as the electron separation and transfer capacity of both the Ag and CQDs. An electron spin resonance (ESR) technique, and reactive species (RS) scavenging experiments indicated that 1 O 2 and O 2 − were the dominant active species involved in the degradation of naproxen (NPX). Product identification and reaction site prediction revealed that the photocatalytic degradation of NPX included decarboxylation, hydroxylation, as well as the opening of the naphthalene ring. Mineralization experiments indicated that NPX and its degradation products would be finally transformed into CO 2 and H 2 O. Reactions in different water matrices indicated that SDAg-CQDs/UCN can be effectively employed for the degradation of NPX under ambient water conditions. Therefore, SDAg-CQDs/UCN offers a new strategy for the broad-spectrum utilization of solar light and provides a promising method for the remediation of water contamination.
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RSC Advances
·
2017
·Vol. 7
·期 54
·34096-34103
·
IF 3.108
Yuehan Su,Ping Chen,Fengliang Wang,Qianxin Zhang,Tiansheng Chen,Yingfei Wang,Kun Yao,Wenying Lv,Guoguang Liu
A novel visible-light-driven carbon dot (CDs)/TiO2/g-C3N4 photocatalyst was successfully synthesized by doping CDs in TiO2 nanoparticles and the surface of g-C3N4 nanosheets via a facile hydrothermal process and was confirmed by characterization methods. UV-vis diffuse reflectance spectra (DRS) revealed that CDs/TiO2/g-C3N4 showed obvious additional absorption in the 370–450 nm region. DMPO spin-trapping ESR spectra demonstrated the existence of O2˙− and ·OH. The photocatalytic activity of the CDs (1.0 wt%)/TiO2/g-C3N4 was remarkably enhanced as compared to that of the single components (TiO2 and g-C3N4) and double component (TiO2/g-C3N4) towards the degradation of enrofloxacin (ENX) under visible-light irradiation. About 91.6% of ENX was decomposed by CDs (1.0 wt%)/TiO2/g-C3N4 in 1 h, which is nearly 3.95 times, 4.82 times, and 1.69 times that for TiO2, g-C3N4, and TiO2 (90.0 wt%)/g-C3N4, respectively. Scavenging experiments revealed that O2˙− and ·OH played key roles during the photocatalytic degradation of ENX. This study provides a simple and convenient method to modify materials with enhanced photocatalytic performance, and the CDs/TiO2/g-C3N4 catalyst is efficient, stable, and reusable for environmental practical applications.
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