ENVIRONMENTAL RESEARCH
·
2024
·
IF 7.7
Shi-Wen Lv,Jialu Pan,Xiaoran Wang,Yifan Shao,Yanqing Cong,Lin Che
It is of great significance to establish an effective method for removing Cr(VI) from wastewater. Herein, Fe-doped g-C 3 N 4 (namely Fe-g–C 3 N 4 –2) was synthesized and then employed as photocatalyst to conduct the test of Cr(VI) reduction. Notably, the embedding of Fe ion in g-C 3 N 4 can offer the Fe 2+ /Fe 3+ redox couples, so reducing the interfacial resistance of charge transfer and suppressing the recombination of photogenerated electrons and holes. The impurity energy levels will form in g-C 3 N 4 after the introduction of Fe ion , thereby boosting the light absorption capacity of catalyst. Thus, Fe-g–C 3 N 4 –2 showed good performance in photocatalytic Cr(VI) reduction, and the reduction efficiency of Cr(VI) can reach 39.9% within 40 min. Different with many previous studies, current work unexpectedly found that the addition of p -benzoquinone (BQ) can promote the Cr(VI) reduction, and the reduction efficiency of Cr(VI) over Fe-g–C 3 N 4 –2 was as high as 93.2% in the presence of BQ (1.5 mM). Further analyses showed that BQ can be reduced to hydroquinone (HQ) by photogenerated electrons, and UV light can also directly induce BQ to generate HQ by using H 2 O as the hydrogen donor . The HQ with reducing ability can accelerate the Cr(VI) reduction. In short, current work shared some novel insights into photocatalytic Cr(VI) reduction in the presence of BQ. Future research should consider possible reactions between photogenerated electrons and BQ. For the UV-induced photocatalysis , the suitability of BQ as the scavenger of O 2 •‒ must be given carefully consideration.
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高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2024
·Vol. 50
·期 7
·2971-2991
·
IF 2.8
Liu Huadong,Du Kezhen,Sun Hao
In this study, nitrogen and sulfur co-doped carbon quantum dots (NSCQDs) were prepared by hydrothermal method, carbon nitride (C 3 N 4 ) was fired in a muffle furnace in an air atmosphere, and finally, the ternary heterostructure of NSCQDs, C 3 N 4 and bismuth oxide bromide (BiOBr) was synthesized by a hydrothermal method (NSCQDs/C 3 N 4 /BiOBr). The morphology of the catalyst was observed through SEM and TEM. The chemical bonds were analyzed by XPS and FT-IR to further confirm that NSCQDs and C 3 N 4 were successfully attached to BiOBr. The photocatalytic activity of the synthesized catalysts was studied by degrading RhB under simulated light source. The experiment results showed that under optimal conditions, the degradation rate of RhB by NSCQDs/C 3 N 4 /BiOBr within 20 min was as high as 99.9%, which was much higher than that of pure BiOBr (33.5%). The degradation curve was combined with a pseudo-first-order kinetic model with a kinetic constant of 0.32578 min −1 , which was 17.7 times that of BiOBr (0.01837 min −1 ). Catalyst recycling tests showed that NSCQDs/C3N4/BiOBr had extremely high stability. The active species quenching test showed that \({\text{O}}_{2}^{ \cdot - }\) and 1 O 2 were the main active species during the photocatalytic process. The inhibition effect of NSCQDs and C 3 N 4 on BiOBr photogenerated carrier recombination was analyzed by photoluminescence and transient photocurrent tests. This study is expected to provide an attractive strategy for constructing efficient and environmentally friendly photocatalysts for environmental remediation.
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Nanomaterials
·
2025
·Vol. 15
·期 18
·1443
·
IF 4.3
Shicheng Liu,Na Li,Qulan Zhou
Elucidating the mechanisms of CO2photocatalytic conversion systems is crucial for tackling the challenges of carbon neutrality. In this study, a series of Ag@g-C3N4photocatalysts were constructed with metal particle size modulation as the core strategy to systematically reveal the modulation mechanism of Ag nanoparticles (Ag NPs) size variation on the selectivity of CO2photoreduction products. Systematic characterizations revealed that increasing Ag size enhanced visible light absorption, promoted charge separation, and improved CH4selectivity. Photocatalytic tests showed Ag3.0%@CN achieved optimal activity and electron utilization. Energy band analyses indicated that Ag modification preserved favorable conduction band positions while increasing donor capacity. Further density-functional theory (DFT) calculations reveal that Ag NPs size variations significantly affect the adsorption stability and conversion energy barriers of intermediates such as *COOH, CO and CHO, with small-sized Ag7NPs favoring the CO pathway, while large-sized Ag NPs stabilize the key intermediates and drive the reaction towards the CH4pathway evolution. The experimental and theoretical results corroborate each other and clarify the dominant role of Ag NPs size in regulating the reaction path between CO and CH4. This study provides mechanistic guidance for the selective regulation of the multi-electron reduction pathway, which is of great significance for the construction of efficient and highly selective CO2photocatalytic systems.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2021
·
IF 5.816
Zhaoxu Li,Xinyi Luo,Meifang Luo,Yuan Qin,Chaozhong Guo,Yao Liu,Zhongli Luo
To design inexpensive carbon catalysts and enhance their oxygen reduction reaction (ORR) activity is critical for developing efficient energy-conversion systems. In this work, a novel Fe-N-C hybrid electrocatalyst with carbon nanolayers-encapsulated Fe 3 O 4 nanoparticles is synthesized successfully by utilizing the molecular-level confinement of graphitic C 3 N 4 structures via hemin biomaterial. Benefiting from the Fe-N structure prevalent on the carbon nanosheets and large mesopore-dominated specific surface area, the synthesized catalyst under optimized conditions shows excellent electrocatalytic performance for ORR with an E ORR at 1.08 V versus reversible hydrogen electrode (RHE) and an E 1/2 at 0.87 V vs. RHE, and outstanding long-term stability, which is superior to commercial Pt/C catalysts (E ORR at 1.04 V versus RHE and E 1/2 at 0.84 V versus RHE). Moreover, the low hydrogen peroxide yield (<11%) and average electron transfer number (~3.8) indicate a four-electron ORR pathway. Besides, the maximum power density of the home-made Zn-air battery using the obtained catalyst is 97.6 mW cm −2 . This work provides a practical route for the synthesis of cheap and efficient ORR electrocatalysts in metal-air battery systems.
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ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
·
2019
·
IF 4.527
Wei Liu,Jiabin Zhou,Jun Yao
In this work, the shuttle-like CeO 2 modified g-C 3 N 4 composite was synthesized and was combined with persulfate (PS) for the efficient photocatalytic degradation of norfloxacin (NOR) under visible light. Scanning and transmission electron microscopy (SEM and TEM), X-ray diffraction (XRD), UV–vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) emission spectra were used to characterize the structural and optical properties of the as-prepared catalysts. Active species trapping experiments demonstrated that additional sulfate radicals (·SO 4 - ) formed upon the addition of PS which could cooperate with superoxide radicals ( O 2 - ), holes (h + ) and hydroxyl radicals ( OH) to decompose NOR. Singlet oxygen ( 1 O 2 ) was also formed during the reaction and acted as an important active species. The degradation products of NOR were also identified and analyzed by using LC-MS technology , and the possible degradation mechanism and pathways were proposed and discussed. This work indicated that the shuttle-like CeO 2 modified g-C 3 N 4 coupled with PS displayed promising applications in the field of pharmaceutical wastewater purification.
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ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Yihua Tang,Jingjing Chen,Xiao Wang,Xinxin Wang,Yang Zhao,Zhiyong Mao,Dajian Wang
Nitrogen atoms doping was widely recognized as the promising technique to improve the electrochemical performances of various carbonaceous materials application for energy storage devices. Herein, we reported a facial fabrication of highly N-doped graphene-like carbon (NGC) through the carbonization of a mixture containing polypyrrole and g-C 3 N 4 nanosheets , which was employed as sacrificial template and extra nitrogen source simultaneously. The resultant NGC material integrate a range of excellent features including high nitrogen contents (17.54 at%), large specific surface areas (635.73 m 2 g −1 ) and abundant mesopores with high pore volume (1.9483 cm 3 g −1 ). As anode material in Li-ions batteries, the NGC material exhibits an promising initial discharge capacity of 2749 mAh g −1 at a current density of 50 mA g −1 and encouraging cycling stability (1143 mAh g −1 after 200 cycles) as well as excellent rate performance (440 mAh g −1 at 2 A g −1 ). This feasible fabrication presents a new guidance to exploit high performance N-doped carbon materials for the applications in energy storage devices.
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CHEMOSPHERE
·
2022
·
IF 8.943
Yunjin Zhong,Haixiang Chen,Xiufang Chen,Bingying Zhang,Wenxing Chen,Wangyang Lu
As some of the most promising alternatives to traditional non-degradable materials, photodegradable materials have advantages of environmental benignity and rapid degradation under simple conditions. In this work, nontoxic TiO 2 and cost-effective g-C 3 N 4 have been compounded in a weight of 9:1 to form a photocatalytic additive with high activity. A 25 wt% loading of this photocatalytic additive has been incorporated into the polyacrylonitrile (PAN) by centrifugal electrospinning to prepare an abiotic degradable PAN material. Our results showed that the PAN chain could be almost fully degraded within 90 h in an aqueous medium under simulated sunlight in the absence of microorganisms . Product analysis implied that degradation of the PAN chain mainly involved the breaking of –CN and C–C bonds by radicals, followed by oxidation of terminal groups to carboxyl and gradual mineralization to CO 2 and H 2 O. This design strategy may provide new insight for the production and degradation mechanism of photodegradable polymer.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2020
·
IF 5.774
Islam A. Abdelhafeez,Jiabin Chen,Xuefei Zhou
Herein, we report a scalable, green and “bottom-up” approach for the synthesis of ultralight g-C 3 N 4 nanosheets . The ultralight g-C 3 N 4 nanosheets (9.6 mg cm −3 ) have been entirely synthesized in a wet atmosphere in one step without pretreatment or any other additives. The as-prepared material (UMCN-wet) appears as a foam-like exterior with ultrathin nanosheets (3.5 nm), short-order polymerization and sharp edges. The X-ray diffraction (XRD), Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses confirm the formation of melon units with edge-enriched active sites. UMCN-wet exhibits a higher specific surface area (137.44 m 2 g −1 ) and pore volume (0.2076 cm 3 g −1 ), compared with that of the as-synthesized materials in the air (MCN-air) and nitrogen (MCN-N 2 ) atmospheres. The optical and electrochemical analyses reveal that UMCN-wet manifests fast photogenerated charge separation and transfer with slow decay kinetics. As a result, UMCN-wet nanosheets exhibit superb photocatalytic degradation of rhodamine B (RhB), methylene blue (MB) and methyl orange (MO) under visible light irradiation with photodegradation rate constant ( k ) of 0.17687, 0.02409 and 0.00537 min −1 , respectively. Moreover, UMCN-wet exhibits excellent stability and reusability performance. Such a sustainable approach does not only overcome the prolonged time processing, extra energy consumption and utilization of hazardous chemicals for synthesis ultrathin g-C 3 N 4 nanosheets, but also paves a new pathway for industrial upscale production with numerous expected environmental applications.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Xueming Dang,Shuai Wu,Haiguang Zhang,Xie Quan,Huimin Zhao
A phosphorus (P) doped g-C 3 N 4 needle (PCNN) electrode with great photoelectrochemical (PEC) property is fabricated by a facile solid thermal melting approach. The proposed thermal melting method owns the advantages of low-cost, simple and easy operation, as only the solid mixing of melamine (C and N precursor) and triphenylphosphine oxide (P precursor) is needed in electrode preparation procedure. This method is further conducive to the formation of uniform film with doped heteroatom and unique microstructure on fluorine-doped tin oxide- coated glass (FTO). The PCNN photoelectrode holds a tip structure, which highly inhibits the recombination of photo-generated electron and hole. Particularly, the doped P in PCNN can further accelerate the photo-generated carrier separation and enhance the optical absorption property. As a result, the PCNN photoelectrode displays a five-fold enhancement of photocurrent density over pristine g-C 3 N 4 , reaching up to 127.4 µA cm - 2 at 1.23 V versus reversible hydrogen electrode (RHE), as well as good optical, chemical and physical stability. The PCNN photoelectrode further exhibits great property in PEC removal of pollutant in water. This study provides an effective fabrication method and opens new avenues for the significant improvement of g-C 3 N 4 based electrode in their various energy conversion and environmental application.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Fengyan Xie,Guofa Dong,Kechen Wu,Yafeng Li,Mingdeng Wei,Shaowu Du
TiO 2 -based electron transport layers (ETLs) show tremendous advantages in constructing efficient perovskite solar cells (PSCs), but the power conversion efficiency (PCE) needs further improvements. Thus, in this study, graphitic carbon nitride (g-C 3 N 4 ), a typical two-dimensional material, was synthesized in-situ and introduced into TiO 2 -based ETLs as an additive via a facile glass-assisted annealing route. The results demonstrated that the addition of g-C 3 N 4 positively influenced the crystalline quality of the perovskite layers, as well as the conductivity and photovoltaic properties of the devices. Furthermore, favorable energy level alignment facilitated rapid migration of electrons and suppressed charge recombination at the interfaces. Consequently, the champion device fabricated using the g-C 3 N 4 -modified ETL achieved a maximum PCE of 20.46% owing to the remarkable improvement in the V oc , J sc , and fill factor. The PCE is approximately 20% higher than that obtained for the pristine device, i.e., 17.18%.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Bingqing Wei,Jiayi Luo,Shiya Lin,Zifan Li,Xiang Zhu,Zhimin Dong,Songtao Xiao,Xiaohong Cao,Yunhai Liu,Zhibin Zhang
Photocatalytic uranium extraction from nuclear effluent is a promising method to avoid environmental damage and recover uranium resources. Here, the hollow tubular D-A organic semiconductor photocatalyst was fabricated by grafting 2,7-dibromo carbazole (Dbc) onto the g-C 3 N 4 (TCN) framework. The intra-molecular D-A system promoted visible light absorption, enhanced charge transfer, and improved the separation of photogenerated electron-hole pairs. Additionally, the incorporation of the carbazole structure increased the volume separation and the surface separation, adjusted the electron excitation model, and reduced the energy required for exciton dissociation. The results showed that the removal rate of U(VI) by DCN 3 reached 96.4% in 120 min and 93.3% removal of U(VI) under sunlight, and it was stable and reusable with little change under sunlight and after 5 consecutive cycles. Therefore, the D-A photocatalyst established a high photocatalytic uranium separation efficiency under sunlight and high concentrations of interfering anions and cations. This study provides insight and guidance for a deeper understanding of photocatalytic uranium separation.
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NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 42
·期 1
·489-496
·
IF 3.269
Zengyu You,Qianhong Shen,Yuxuan Su,Yang Yu,Hui Wang,Tian Qin,Fang Zhang,Di Cheng,Hui Yang
A novel Z-scheme core–shell g-C3N4/MCNTs/BiOI heterojunction was successfully designed and fabricated through filling multi-walled carbon nanotubes (MCNTs) with g-C3N4, followed by the loading of BiOI on the outer surface of the MCNTs. The structure–property relationship was analyzed by X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (DRS), photoluminescence spectra (PL), ESR probe tests and reactive species trapping measurements. The results show that the BiOI nanoparticles are uniformly loaded on the surface of the MCNTs which are fully filled by g-C3N4. The MCNTs connect the two semiconductors of g-C3N4 and BiOI, and serve as electron mediating conductors to promote the transfer of the photo-generated electrons, thereby constructing a Z-scheme heterojunction between g-C3N4 and BiOI. With this unique structure, enhanced visible-light photocatalytic activities are achieved because of the synergistic effect of light harvesting and improved separation efficiency of photo-generated carriers.
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