NEW JOURNAL OF CHEMISTRY
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2018
·Vol. 42
·期 24
·19665-19670
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IF 3.201
Xiangyu Lu,Dan Wang,Liping Ge,Lihui Xiao,Haiyan Zhang,Lilai Liu,Jinqiu Zhang,Maozhong An,Peixia Yang
Nitrogen-doped graphene (N-G) is considered as a promising catalyst for the oxygen reduction reaction (ORR). However, the contributions of pyridinic N, pyrrolic N and graphitic N in N-G for the ORR catalytic activity are controversial. In this work, the contents of pyridinic N, pyrrolic N and graphitic N in N-G were transformed by annealing at different temperatures. It is found that the total N content in N-G is not the critical factor to determine the ORR activity. An increase in the annealing temperature can enhance the content of graphitic N in N-G, causing an improved catalytic ORR activity, which confirms that graphitic N is the active component. Moreover, the enriched graphitic N in the N-G-1000 catalyst shows a half-wave potential (E1/2) of 0.862 V, 29 mV higher than that of the commercial Pt/C catalyst (0.833 V), which is one of the best reported for ORR metal-free catalysts.
研究领域:
材料科学
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电化学
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产品关联
DOI
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2022
·
IF 10.753
Haoyuan Zhang,Peng Gao,Yongze Liu,Ziwen Du,Li Feng,Liqiu Zhang
Nitrogenous disinfection by-products (N-DBPs) raise increasing concerns because of their high genotoxicity, cytotoxicity, and carcinogenicity compared to carbonaceous disinfection by-products (C-DBPs). Nitrogen-containing disinfectants, dissolved organic nitrogen (DON), and inorganic nitrogen may all promote the formation of N-DBPs. Therefore, it is urgent to explore the dominant nitrogen source of N-DBPs under the coexistence of multiple nitrogen sources. In this study, the effects of amino acids, nitrate, ammonia, and chloramine as different types of nitrogen sources on the formation of five N-DBPs were investigated systematically, including chloroacetonitrile (CAN), dichloroacetonitrile (DCAN), bromochloroacetonitrile (BCAN), dibromoacetonitrile (DBAN) and dichloroacetamide (DCAcAm). L-Aspartic acid (L-Asp) as the organic nitrogen source showed a high potential on the formation of N-DBPs by forming acetonitrile intermediates. Ammonia as the inorganic nitrogen source consumed oxidants and changed the existing form of chloramine, thus inhibiting the formation of N-DBPs. Instead of providing nitrogen to N-DBPs, nitrate as a salt promoted the volatilization of N-DBPs, thereby reducing the detected N-DBPs. Furthermore, an isotope labeling method was applied to clearly trace the nitrogen sources of N-DBPs via GC–MS with electron ionization. 15 N-chloramine, 15 N-amino acid, 15 N-nitrate and 15 N-ammonia were selected as the corresponding isotopic nitrogen sources. The results indicated that chloramine was the major nitrogen contributor to five N-DBPs during the chloramination of L-Asp under the coexistence of multiple nitrogen sources, ranging from 61 % to 79 %. The influence of environmental factors (reaction time, pH, and bromide) on the formation of N-DBPs during chloramination was also investigated. There was competition between brominated N-DBPs and chlorinated N-DBPs in chloramination. With the increase of reaction time or bromine, the formation potentials of chlorinated N-DBPs gradually decreased, while brominated N-DBPs gradually increased. Moreover, higher pH inhibited the generation of N-DBPs.
研究领域:
环境科学
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公共卫生
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化学工程
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DOI
PubMed
高影响因子
Scientific Reports
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2016
·Vol. 6
·期 1
·1-10
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IF 5.228
Zhang Jia,Zhao Chao,Liu Na,Zhang Huanxi,Liu Jingjing,Fu Yong Qing,Guo Bin,Wang Zhenlong,Lei Shengbin,Hu PingAn
Single–layer and mono–component doped graphene is a crucial platform for a better understanding of the relationship between its intrinsic electronic properties and atomic bonding configurations. Large–scale doped graphene films dominated with graphitic nitrogen (GG) or pyrrolic nitrogen (PG) were synthesized on Cu foils via a free radical reaction at growth temperatures of 230–300 °C and 400–600 °C, respectively. The bonding configurations of N atoms in the graphene lattices were controlled through reaction temperature and characterized using Raman spectroscopy, X–ray photoelectron spectroscopy and scanning tunneling microscope. The GG exhibited a strong n–type doping behavior, whereas the PG showed a weak n–type doping behavior. Electron mobilities of the GG and PG were in the range of 80.1–340 cm 2 V −1 ·s −1 and 59.3–160.6 cm 2 V −1 ·s −1 , respectively. The enhanced doping effect caused by graphitic nitrogen in the GG produced an asymmetry electron–hole transport characteristic, indicating that the long–range scattering (ionized impurities) plays an important role in determining the carrier transport behavior. Analysis of temperature dependent conductance showed that the carrier transport mechanism in the GG was thermal excitation, whereas that in the PG, was a combination of thermal excitation and variable range hopping.
研究领域:
材料科学
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物理化学
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DOI
PubMed
高影响因子
Materials
·
2018
·Vol. 11
·期 1
·159
·
IF 2.467
Liqing Li,Xiancheng Ma,Ruofei Chen,Chunhao Wang,Mingming Lu
Nitrogen-doped porous carbon (ZC) is prepared by modification with ammonia for increasing the specific surface area and surface polarity after carbonization of zeolite imidazole framework-8 (ZIF-8). The structure and properties of these ZCs were characterized by Transmission electron microscopy, X-ray diffraction, N2sorption, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Through static adsorption tests of these carbons, the sample obtained at 600 °C was selected as an excellent adsorbent, which exhibited an excellent acetone capacity of 417.2 mg g−1(25 °C) with a very large surface area and high-level nitrogen doping (13.55%). The microporosity, surface area and N-containing groups of the materials, pyrrolic-N, pyridinic-N, and oxidized-N groups in particular, were found to be the determining factors for acetone adsorption by means of molecular simulation with density functional theory. These findings indicate that N-doped microporous carbon materials are potential promising adsorbents for acetone.
研究领域:
材料科学
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环境科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2025
·
IF 13.2
Zhihao Song,Lei Xu,Cheng Xie,Yanzhi Liu,Zhaohui Han,Junyu Lu
Visible light-driven photo-oxidation reactions hold significant potential for the treatment of gaseous pollutants. However, the weak internal electric field of carbon nitride (g-C 3 N 4 ) leads to sluggish migration of photogenerated carriers, while inefficient electron-hole pair separation further limits the overall photo-oxidation efficiency. In this study, nitrogen-vacancy (Nv) rich crystalline (Cs)/amorphous g-C 3 N 4 was synthesized using a two-step calcination method. The increased crystallinity facilitates faster carrier migration, broadens the potential difference between the crystalline and amorphous regions, and enhances the piezoelectric response. On the other hand, the incorporation of nitrogen vacancies (Nv) introduces asymmetry, generating a dipole field that significantly improves the efficiency of electron-hole pair separation. Moreover, the presence of NV improves the adsorption and activation of O 2 molecules, promoting the photo-oxidation of adsorbed NO via the generation of single linear oxygen ( 1 O 2 ). The resulting material, Cs-Nv-630, demonstrated excellent oxidative NO removal efficiency, achieving a removal rate of 95.3 % under visible light irradiation. This study highlights a novel strategy for enhancing photo-oxidation activity through structural engineering, leveraging crystallinity and dipole fields to optimize carrier migration and complexation.
研究领域:
材料科学
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环境科学
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化学
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产品关联
DOI
高影响因子
Energy Storage Materials
·
2025
·
IF 20.2
Nengbiao Zhang,Luming Yin,Letian Chen,Bingbing Ma,Yuantonghe Li,Xinyi Zhang,Junqing Liu,Zhen Zhou
Abstact Lithium-nitrogen (Li-N 2 ) battery is not only an electrochemical energy storage platform, but also an environmentally friendly nitrogen fixation technology. However, a great challenge remains in regulating catalyst activity to accelerate cathode reaction kinetics. Herein, we proposed an oxygen vacancy-mediated modulation of Fe active sites in FeO x nano-particle catalysts and Fe single-atom catalysts to enhance nitrogen reduction reaction in Li-N 2 batteries. High-concentration oxygen vacancy is generated through a size- and crystallinity-dependent oxygen vacancy engineering based on the precise atomic layer deposition of reducible oxides. The oxygen vacancy on FeO x drives the electron redistribution of Fe 3+ d-orbitals to provide electron-donating Fe active sites for N 2 fixation. Meanwhile, oxygen vacancy-rich MoO y is used as a support to anchor Fe single atoms. Adjacent oxygen vacancy drives the stable coordination between Fe single atoms and O atoms to facilitate the directional electron transfer from MoO y to Fe to N 2 . Therefore, the Li-N 2 batteries exhibit large discharge capacity, excellent rate performance, and reliable cycle stability. In addition, the formation and decomposition of the discharge product Li 3 N indicate a reversible N 2 fixation. This work provides a precise regulation mechanism of catalytic active sites based on oxygen vacancy engineering, which is expected to promote the development of high-performance Li-N 2 batteries.
研究领域:
材料科学
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电化学
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催化科学
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DOI
高影响因子
Small
·
2020
·Vol. 16
·期 13
·1906880
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IF 11.459
Weikang Wang,Hongjian Zhou,Yanyan Liu,Shengbo Zhang,Yunxia Zhang,Guozhong Wang,Haimin Zhang,Huijun Zhao
It is an important issue that exposed active nitrogen atoms (e.g., edge or amino N atoms) in graphitic carbon nitride (g-C 3 N 4 ) could participate in ammonia (NH 3 ) synthesis during the photocatalytic nitrogen reduction reaction (NRR). Herein, the experimental results in this work demonstrate that the exposed active N atoms in g-C 3 N 4 nanosheets can indeed be hydrogenated and contribute to NH 3 synthesis during the visible-light photocatalytic NRR. However, these exposed N atoms can be firmly stabilized through forming B N C coordination by means of B-doping in g-C 3 N 4 nanosheets (BCN) with a B-doping content of 13.8 wt%. Moreover, the formed B N C coordination in g-C 3 N 4 not only effectively enhances the visible-light harvesting and suppresses the recombination of photogenerated carriers in g-C 3 N 4 , but also acts as the catalytic active site for N 2 adsorption, activation, and hydrogenation. Consequently, the as-synthesized BCN exhibits high visible-light-driven photocatalytic NRR activity, affording an NH 3 yield rate of 313.9 µmol g −1 h −1 , nearly 10 times of that for pristine g-C 3 N 4 . This work would be helpful for designing and developing high-efficiency metal-free NRR catalysts for visible-light-driven photocatalytic NH 3 synthesis.
研究领域:
材料科学
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化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2022
·
IF 9.965
Menglei Yuan,Lei Zhang,Tianxin Wang,Yiming Liu,Qiongguang Li,Jinxiong Wu,Junwu Chen,Jintong Zhang,Hailun Yang,Guangjin Zhang
Electrocatalytic water splitting in an alkaline medium is recognized as the promising technology to sustainably generate clean hydrogen energy via hydrogen evolution reaction (HER), while the sluggish water dissociation and subsequent *H adsorption steps greatly retarded the reaction kinetics and efficiency of the overall hydrogen evolution process. Whilst nitrogen (N)-doped carbon-based materials are attractive candidates for promoting HER activity, the facile fabrication and gaining a deeper insight into the electrocatalytic mechanism are still challenging. Herein, inspired by the Diels-Alder reaction, we precisely tailored six-membered pyridinic N and five-membered pyrrolic N sites at the edge of the carbon substrates. Comprehensive analysis validates that the participation of pyridinic N (electron-withdrawing) and pyrrolic N (electron-releasing) will induce the charge rearrangements, and further generate local electrophilic and nucleophilic domains in adjacent carbon rings, which guarantees the occurrence of water dissociation to generate protons and the subsequent adsorption of *H intermediates through electrostatic interactions, thereby facilitating the overall reaction kinetics. To this end, the optimal NC-ZnCl 2 -25 % electrocatalysts present excellent alkaline HER activity (η 10 = 45 mV, Tafel slop of 37.7 mV dec -1 ) superior to commercial Pt/C.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Water
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2023
·Vol. 15
·期 24
·4272
·
IF 3.4
Xueyuan Bai,Jianwei Li,Sheng Chang
Amidst rapid urbanization, municipal wastewater treatment plants remain a significant source of nitrogen compounds, which stems from their effluents. Constructed wetlands, employing denitrification processes, have been proven effective at nitrogen removal. Variations in influent nutrient concentrations are often seen as limiting factors affecting nitrogen removal and influencing microbial communities. This study evaluates the impact of nutrient limitation on nitrogen removal by analyzing changes in microbial communities within constructed wetlands under different influent water C/N ratios. The findings indicate that both excessively high and low C/N ratios constrain nitrogen decomposition, with optimal nitrogen removal observed at C/N ratios of 6 or 7. Moderate C/N values (6–7) support diverse and stable microbial networks, ensuring treatment system stability. Microorganisms play a pivotal role in nitrogen transformation, with thenirkgene being crucial for NH4+−N conversion, while theAOAgene dominates NO2−−N and TN conversion. This study offers practical guidance for identifying a suitable C/N ratio for wastewater treatment and establishes a theoretical foundation for regulating nitrogen removal by microbial communities in constructed wetlands within nitrogen removal systems.
研究领域:
环境科学
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微生物学
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DOI
高影响因子
Frontiers of Materials Science
·
2023
·Vol. 17
·期 4
·1-12
·
IF 2.7
Liu Fangfang,Niu Jinan,Chuan Xiuyun,Zhao Yupeng
Nitrogen atom doping has been found to enhance the electrochemical performance of porous carbon (PC). In this study, hollow tubular nitrogen-doped porous carbon (N/PC) was synthesized using polyvinylpyrrolidone as the carbon–nitrogen source and fibrous brucite as the template through carbonization. The effects of nitrogen and argon protective atmospheres on the nitrogen content, the specific surface area (SSA), and electrochemical properties of N/PC were investigated. The results showed that compared with N/FBC-Ar, N/FBC-N 2 prepared in nitrogen protective atmosphere had a higher nitrogen content and a larger proportion of pyrrolic nitrogen (N-5) and pyridinic nitrogen (N-6). N/FBC-N 2 displayed a specific capacitance ( C ) of 194.1 F·g −1 at 1 A·g −1 , greater than that of N/FBC-Ar (174.3 F·g −1 ). This work reveals that the nitrogen doping with a higher nitrogen content in nitrogen protective atmosphere is more favorable. Furthermore, a larger proportion of pyrrolic nitrogen and pyridinic nitrogen in the doped nitrogen atoms significantly enhances the electrochemical performance.
研究领域:
材料科学
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电化学
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DOI
高影响因子
CHINESE CHEMICAL LETTERS
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2022
·
IF 8.455
Han-Qing Zhao,Wen-Qiang Li,Nannan Hou,Lei Li,Yiran Wang,Peili Lu,Yang Mu
Pyrogenic carbonaceous matter (PCM) catalyzes azo dye decolorization by sulfide, but the nitrogen doping catalytic mechanisms are poorly understood. In this study, we found that stagnate time of azo dye methyl orange (MO) decolorization was reduced to 0.54-18.28 min in the presence of various nitrogen-doped graphenes (NGs), remarkably lower compared to graphene itself. Particularly, graphitic nitrogen played a critical role in NGs-catalyzed MO decolorization by sulfide. Gas chromatography-mass spectrometry and in-situ surface Raman analysis demonstrated that doping nitrogen, especially graphite one facilitated reactive intermediate polysulfides formation. This is attributed to the improved electron conductivity through graphitic nitrogen doping, and the enhanced interactions between sulfide and carbon atoms bonded to graphitic nitrogen. This study not only provides a better understanding of PCM impact on transformations and fates of organic pollutants in natural environments, but also offer a new regulation strategy for more efficient wastewater treatment processes in PCM-catalyzed engineering systems.
研究领域:
环境科学
·
化学工程
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产品关联
DOI
高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2024
·
IF 5.5
Shengrong Liu,Boyang Wang,Yimeng Huang,Xing Xu,Yujiao Kan,Yanan Shang
Background Advanced oxidation processes (AOPs) based on sulfate radicals (SO 4 •– ) have proven to be highly effective in degrading organics in wastewater. Carbon-based materials have emerged as promising catalysts for activating persulfate, which generates environmentally friendly sulfate radicals (SO 4 •– ), for remediation purposes. The nitrogen doping technique is an effective method for site-specific regulation and can significantly enhance the performance of carbon-based catalysts, which could promote the application of carbon-based catalysts in the future. Endogenous and exogenous nitrogen sources can provide nitrogen sources for N doping. However, there are few reports on the comparison of the structure and catalytic mechanism of these two types of N-doped biochar. It is also of great significance to reveal the mechanisms of constructing catalytic sites using endogenous and exogenous nitrogen. Methods Herein, the preparation of endogenous nitrogen-doped biochar (BC) was achieved by using soybean as the precursor material, which is rich in natural nitrogen-containing components of proteins. Subsequently, the BC was doped by mixing it with urea and pyrolysis, resulting in the preparation of exogenous nitrogen-doped biochar (NBC). Significant findings The characterization of XRD and HRTEM showed that g-C 3 N 4 formed in NBC. The results of catalytic degradation and quenching experiments demonstrate that the exogenous nitrogen-doped catalysts have a better performance than endogenous nitrogen-doped catalysts. The OFL removal rate in BC/PMS was higher than that in the BC/PMS system (71.68% vs. 61.83 %). The k obs in NBC/PMS are also higher than that in BC/PMS (0.00943 min −1 vs. 0.01369 min −1 ). The NBC could be a promising catalyst for PMS activation in practical application. DFT results showed that the g-C 3 N 4 generated from exogenous nitrogen can improve PMS activation performance in the g-C 3 N 4 /graphene bilayer structure. The influence on the charge distribution of surrounding carbon materials makes endogenous nitrogen doping a good choice for optimizing the local performance of the material in the absence of natural nitrogen components.
研究领域:
环境科学
·
材料科学
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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）