ACS Sustainable Chemistry & Engineering
·
2021
·
IF 8.198
Tao Yu,Tao Xie,Wei Zhou,Yizhong Zhang,Yiliang Chen,Boyu Shao,Wan-Qian Guo,Xin Tan
Tuning the structural defects of graphite carbon nitride (g-C3N4) is an effective strategy to modify its band structure and promote charge separation, but it is still limited by complex and harsh preparation processes. Herein, g-C3N4 with nitrogen defects were fabricated by one-pot thermal polymerization of urea and fumaric acid. The N–(C)3 site, being the active site for photocatalytic hydrogen evolution, reached at a rate of 94.1 μmol·h–1, which was approximately 2.64 times that of the original g-C3N4. Nitrogen defective g-C3N4 had more electrons and stronger H2O molecule adsorption capacity, identified by systematic experiments and DFT calculations. The carboxyl group of fumaric acid reacted with amino group of urea to prevent self-polymerization process of urea and induce nitrogen defects. The changed band structures promoted the absorption of visible light, effective separation of charge, and increased hydrogen evolution driving force. This work will provide a simple and green approach to prepare nitrogen defective g-C3N4 with tunable band structures.
研究领域:
材料科学
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能源化学
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DOI
高影响因子
MATERIALS RESEARCH BULLETIN
·
2021
·
IF 4.641
Xinshan Rong,Shixian Zhang,Jian Rong,Jing Wei,Xuchun Qiu,Zhiren Wu
Z-scheme nitrogen-deficient graphitic carbon nitride/ferric oxide (GCN x /FO) photocatalysts were obtained by a one-step calcination method. The number of nitrogen defects was tuned by the application of KOH, while the ferric oxide phase and magnetism was controlled by the usage of ferrous oxalate. Interconversion between the hematite (α) and maghemite (γ) phases of Fe 2 O 3 was analyzed by X-ray diffraction, and magnetism of the GCN x -0.1/FO products provided via vibrating sample magnetometer test. The introduction of nitrogen defects narrowed the bandgap and extended the spectral range of light absorption while improving the ability to capture and activate N 2 effectively. Surface defects were employed as active sites, and the ammonia generation concentration reached approximately 69.7 μmol/L/h by N 2 photofixation under visible light. Due to their ease of synthesis and tuning, high photocatalytic activity, convenient and rapid collection for reuse, and excellent stability, GCN x /FO composited photocatalysts possess vast potential for use in clean ammonia production.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
RSC Advances
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2021
·Vol. 11
·期 49
·30503-30509
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IF 3.361
Xiupei Yang,Lin Zhang,Dan Wang,Qian Zhang,Jie Zeng,Run Zhang
Developing a new photocatalyst for fast and highly efficient organic dye degradation plays an essential role in wastewater treatment. In this study, a photocatalyst graphite phase carbon nitride (g-C3N4) containing nitrogen defects (CN) is reported for the degradation of rhodamine B (RhB). The porous g-C3N4 photocatalyst is facilely synthesized through a polycondensation method and then characterized by X-ray diffraction (XRD), infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), N2 isotherm adsorption line, and X-ray photoelectron spectroscopy (XPS). The photocatalytic activity of the g-C3N4 is evaluated through the degradation of RhB under visible light irradiation. The results show that photocatalytic activity of the nitrogen-defective g-C3N4 can be improved by optimizating washing conditions, including washing temperature, washing dosage, drying time, and drying temperature. With the prepared nitrogen-defective g-C3N4, decolourization of RhB is able to be completed within 20 minutes, in which the degradation rate is 1.7 times higher than that of bulk g-C3N4. Moreover, the nitrogen-defective g-C3N4 has high stability and reusability in the degradation of RhB. Photocatalytic degradation mechanism investigations by ultraviolet-visible absorption spectroscopy, radical trapping experiments and high-performance liquid chromatography (HPLC) reveal that RhB achieved complete mineralization through the photocatalytic degradation reaction mediated by superoxide radicals (˙O2−). This work thus provides a new approach for the preparation of photocatalysts for organic pollutants treatment in wastewater samples.
研究领域:
环境科学
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材料科学
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产品关联
DOI
PubMed
高影响因子
Frontiers of Chemical Science and Engineering
·
2022
·Vol. 17
·期 1
·93-101
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IF 4.803
Xu Huilin,Peng Xiangfeng,Zheng Jingxuan,Wang Zhao
Defect construction and heteroatom doping are effective strategies for improving photocatalytic activity of carbon nitride (g-C 3 N 4 ). In this work, N defects were successfully prepared via cold plasma. High-energy electrons generated by plasma can produce N defects and embed sulfur atoms into g-C 3 N 4 . The N defects obviously promoted photocatalytic degradation performance that was 7.5 times higher than that of pure g-C 3 N 4 . The concentration of N defects can be tuned by different power and time of plasma. With the increase in N defects, the photocatalytic activity showed a volcanic trend. The g-C 3 N 4 with moderate concentration of N defects exhibited the highest photocatalytic activity. S-doped g-C 3 N 4 exhibited 11.25 times higher photocatalytic activity than pure g-C 3 N 4 . It provided extra active sites for photocatalytic reaction and improved stability of N defects. The N vacancy-enriched and S-doped g-C 3 N 4 are beneficial for widening absorption edge and improving the separation efficiency of electron and holes.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2024
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IF 8.1
Ruiting Li,Tengyang Gao,Yao Wang,Yan Chen,Wen Luo,Yang Wu,Yu Xie,Yong Wang,Yifan Zhang
The application of metal catalysis has gained prominence as a study area in recent years. In this work, we use adsorptive reduction and calcination to create Au–Pd alloy catalysts on COCN-2 with varying metal loadings. The plasma resonance effect of the alloys increases the photoresponse of the catalysts, and the engineering of nitrogen defects strengthens the strong bonds between Au–Pd alloy particles and carbon nitride graphite, optimizing the electronic structure, encouraging electron-directed migration, and increasing the efficiency of the reduction reaction. As a result, the efficiency of hydrogen generation by the Au–Pd 0.6 /COCN-2 catalyst is 5.089 mmol g −1 h −1 , which is 2367 times higher than that of the g-C 3 N 4 catalyst. Our findings highlight the crucial part that flaws play in strengthening the strong bonds that exist between the metal and the support, which enhances photocatalytic hydrogen generation. This work offers insightful information about creating effective photocatalysts.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
DIAMOND AND RELATED MATERIALS
·
2024
·
IF 4.3
Daopeng Zhong,Xiangchen Jia,Xianxi Zhang,Jinsheng Zhao,Fanpeng Meng,Dongting Wang,Yuzhen Fang,Zhiliang Zhang
Nitrogen defect engineering has been deemed to be a promising strategy to overcome the inherent shortcomings, i.e., sluggish charge separation and limited spectral response range, of g-C 3 N 4 photocatalyst . Herein, the construction of nitrogen-deficient g-C 3 N 4 has been developed via a simple approach of modulating the type of urea precursor. The experimental investigation and theoretical calculations reveal that this novel route endows g-C 3 N 4 with distinctive nitrogen defects, accompanying the decreased bandgap and the formation of midgap states under the conduction band edge , thus remarkably broadening the visible-light harvesting capability. Furthermore, the N defect also results in enhanced electrical conductivity , which greatly improves the charge carrier transfer and separation for photoredox reaction. As a result, the novel g-C 3 N 4 , named DCN, delivers a significantly high visible-light-responsive H 2 evolution rate of 6.0 mmol h −1 g −1 under visible light irradiation, which is more than 5 times higher than that of the g-C 3 N 4 (CN) synthesized using the common urea precursor. This work opens a novel avenue to fabricate nitrogen defect-regulated g-C 3 N 4 for highly efficient H 2 evolution and must intrigue a new wave of research upsurge on this kind of photocatalyst .
研究领域:
材料科学
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能源化学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Wei Ma,Na Wang,Yan Guo,Liuqing Yang,Manfei Lv,Xu Tang,Songtian Li
A novel porous structure g-C 3 N 4 with nitrogen defect photocatalysts (DCN-P) was successfully prepared by in-situ doping strategy and freeze-dried method, it exhibits enhanced photo-reduction CO 2 performance with satisfactory CO, CH 4 productivity about 19.7 umol g −1 , 37.1 umol g −1 , which is more higher than that of bulk g-C 3 N 4 (B-CN). Systematically characterization demonstrated that the synergistic effect of unique porous structure and the nitrogen defection in DCN-P can effect enhance CO 2 adsorption, increase reactive sites, improve optical absorption and narrowed band gap of g-C 3 N 4 , which is supported by both experimental and density functional theory (DFT) calculations results. More importantly, this work provides a new ideas for constructing other high-performance metal-free photocatalytic systems for CO 2 reduction.
研究领域:
材料科学
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环境科学
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理论化学
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产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Mingrui Guo,Meng Chen,Jixiang Xu,Chao Wang,Lei Wang
Introducing defects and heteroatoms on carbon nitride (g-C 3 N 4 , CN) framework are effective ways to enhance its photocatalytic activity by regulating light absorption and charge carriers separation. Herein, a mechanochemical method was employed to synthesize Br-doped C, N-deficient CN (CN V -mCN-Br) via ball-milling of N-containing precursor and 6-Bromopyridine-3-carbaldehyde (BrPyCHO) followed by calcining. The ball-milling-evolved mechanical forces and BrPyCHO-derived HBr induced formation of C, N vacancies and C-Br bond in CN V -mCN-Br framework. The CN V -mCN-Br exhibited curled nanosheets morphology and separated electrons-holes distribution. The photocatalytic H 2 evolution rates of 1 %Pt-loaded CN V -mCN-Br in distilled water and simulated seawater were 22.21 and 34.41 mmol g –1 h −1 , respectively with 10% triethanolamine . The corresponding apparent quantum yields were 25.87% and 40.08% at 420 nm. This work provides a facile technique to simultaneously introduce defect and heteroatom in CN for high-efficiency photocatalytic H 2 evolution.
研究领域:
材料科学
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能源化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2025
·
IF 6.9
Di Wang,Jing Wang,Yiqiang Wu,Delin Sun,Wenlei Wang
Transition metal ions and non-metal co-doped carbon-based materials have attracted extensive attention due to their unique properties and excellent catalytic effect. Fe 2 O 3 /TiO 2 @Fe/Ti-N-C multifunctional photocatalyst with Fe-Ti alloy and abundant nitrogen defects was reported. The photocatalytic results showed that the removal rates of Cr (VI), Congo red (CR) and levofloxacin (LFX) in water by Fe 2 O 3 /TiO 2 @Fe/Ti-N-C were 88.46, 96.71 and 99.06 %, respectively. The photoelectric test results show that bimetallic conjugated structure of Fe and Ti can effectively increase the light absorption range and accelerate the carrier separation. N-defects can significantly increase the lifetime and concentration of photogenerated holes, thereby improving the catalytic efficiency of the photocatalyst. The single factor experiments proved that the optimal pH for the degradation of Cr(VI), CR and LFX by Fe 2 O 3 /TiO 2 @Fe/Ti-N-C was 1, 11 and 9, respectively. In addition, Ca 2+ and Mg 2+ promoted the degradation of Cr(VI) and inhibited the degradation of CR and LFX. SO 4 2- inhibited the degradation of Cr(VI) and promoted the degradation of CR and LFX. Cl - inhibited the degradation of Cr(VI), CR and LFX. This study elucidates the mechanism of N-defects and bimetallic sites in photocatalytic reactions, and provides theoretical support for efficient removal of heavy metals and organic pollutants in water.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
Catalysts
·
2022
·Vol. 12
·期 12
·1496
·
IF 4.501
Fengyun Su,Zhishuai Wang,Haiquan Xie,Yezhen Zhang,Chenghua Ding,Liqun Ye
Hydrogen evolution by photocatalytic technology has been one of the most promising and attractive solutions, and can harvest and convert the abundant solar energy into green, renewable hydrogen energy. As a new kind of photocatalytic material, graphitic carbon nitride (g-C3N4) has drawn much attention in photocataluytic H2production due to its visible light response, ease of preparation and good stability. For a higher photocatalyic performance, N defects were introduced in to the traditional g-C3N4in this work. The existence of N defects was proved by adequate material characterization. Significantly, a new absorption region at around 500 nm of N-deficient g-C3N4appeared, revealing the exciting n-π* transition of lone pair electrons. The photocatalytic H2production performance of N-deficient g-C3N4was increased by 5.8 times. The enhanced photocatalytic performance of N-deficient g-C3N4was attributed to the enhanced visible light absorption, as well as the promoted separation of photo-generated carries and increased specific surface area.Keywords:N defects;g-C3N4;H2evolution;photocatalysis;n-π* transition
研究领域:
材料科学
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能源科学
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2019
·Vol. 30
·期 16
·15267-15276
·
IF 2.195
Zhang Qingji,Jing Jiangping,Chen Zhuoyuan,Sun Mengmeng,Li Jiarun,Li Yan,Xu Likun
g-C 3 N 4 is a promising material for the application in the area of photoelectrochemical cathodic protection. However, it suffers from limited light absorption and lower charge separation efficiency. In this work, a N defects and C deposition co-modified g-C 3 N 4 , C–g-C 3 N x , was prepared by NaOH-assisted sintering and ethanol-assisted hydrothermal treatment. The presence of N defects and C deposition was verified by the XRD, SEM and XPS tests. The N defects changed the band structure of g-C 3 N 4 by lowering down the conduction band position, therefore widening the light absorption range of g-C 3 N 4 . In addition, the N defects and C deposition co-modification promotes the charge transfer process of g-C 3 N 4 , leading to increased separation efficiency of the photogenerated charge carriers. Therefore, C–g-C 3 N x shows enhanced photoelectrochemical cathodic protection performance for the coupled 316L stainless steel. It can provide a photoinduced potential drop of 120 mV and a photoinduced current density of 9.1 μA cm −2 , which is three times that of pristine g-C 3 N 4 .
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Linjie Fan,Yixun Cao,Yushuai Jia,Ruolan Zhu,Deji Zhang,Xin Liu
Engineering of the defective structure and crystallinity of semiconductor photocatalysts to promote carrier dynamics has attracted considerable attention. This study presents the design of surface nitrogen defect modified crystalline carbon nitride spheres (QCN) with synergistically boosted surface and bulk carrier separation through a rapid thermal treatment coupled with a flux assisted strategy. Using supramolecular self-assembled polymer as the precursor, spherical crystalline CN heterojunctions are firstly prepared by a molten salt method to improve the separation of bulk carriers. Abundant nitrogen defects are then introduced onto the surface of crystalline CN through the following quick thermal treatment in air, which can generate a higher exciton density and drive rapid migration of surface carriers by acting as effective electron sinks. Furthermore, the defect level also improves the visible light utilization and provides more active centers for reactant adsorption and activation. As a result, QCN samples exhibit excellent performance in photocatalytic hydrogen evolution, with an optimal hydrogen production rate 4.3 times higher than that of pristine bulk CN under visible light irradiation. Moreover, the photocatalytic activities of QCN are dependent on the concentration of nitrogen defects, which can be flexibly adjusted via thermal treatment temperature. Such a two-step regulation strategy combining the distinctive advantages of surface defect structure and high crystallinity is beneficial for synergistic enhancement of photocatalytic performance, and provides new insights for sustainable energy production in the future.
研究领域:
材料科学
·
能源科学
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化学工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）