Advanced Materials Interfaces
·
2018
·Vol. 5
·期 23
·1801149
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IF 4.834
Shuguang Wang,Jinwen Qin,Lirong Zheng,Donglei Guo,Minhua Cao
Controllable synthesis of 2D carbon nanosheets with high heteroatom-doping level, large specific surface area, and hierarchically pore structure is difficult and desired. In this work, a novel and simple self-sacrificing in situ formed dual-template strategy is first developed to synthesize N/S codoped hierarchically porous carbon nanosheets. The in-situ formed g -C 3 N 4 and amorphous ZnO act as self-sacrificing templates on account of their thermal decomposition and evaporation at higher temperature. The N/S codoped hierarchically porous carbon nanosheets simultaneously possess high heteroatom-doping level (N: 10.51 wt%; S: 1.71 wt%), large specific surface area (904.63 m 2 g −1 ), and abundant hierarchically porous structure. Particularly, this material possesses a high content of pyridinic-N and pyrrolic-N configuration (65.66%). These unique structure advantages of N/S codoped hierarchically porous carbon nanosheets contribute to high oxygen reduction electrocatalytic activity in both basic and acidic environments. Additionally, as the anode material for sodium-ion batteries, the material also displays a high reversible capacity of 270.1 mAh g −1 at a current density of 100 mA g −1 and high stability (160.1 mAh g −1 after 2000 cycles at 1000 mA g −1 with a capacity retention of 82.3%). These results indicate a great potential of the material in energy conversion and storage applications.
研究领域:
材料科学
·
能源化学
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产品关联
DOI
高影响因子
ACS ES&T Engineering
·
2024
·
IF 7.4
Hanling Jiang,Jingwen Wang,Aijuan Zhou,Yong Liu
Advanced oxidation processes (AOPs) for removing ammonia nitrogen (NH4+-N) are of increasing interest in wastewater treatment. In this paper, the UV-activated persulfate (PS) process with CaO was applied to oxidize NH4+-N to nitrogen gas (N2). Nearly all of the NH4+-N (30 mg N/L) could be removed within 15 min, and the N2 selectivity was achieved at 95.0%. The addition of CaO made NH4+-N exist in the form of NH3, and HO• was the critical reactive species for NH4+-N oxidation. NO, N2H4, and NO2– were identified as oxidation intermediates and could be further removed. The reaction between N2H4 and NO2– with the assistance of UV/CaO promoted N2 generation during NH4+-N oxidation. The increased dosages of CaO (0.2 to 4.0 g/L) and PS (0.6 to 2.4 g/L) could enhance the NH4+-N oxidation, while the presence of CO32– (100 mM) significantly retarded the removal of NH4+-N. As high removal of NH4+-N (100%) and high N2 selectivity (>79.5%) could be achieved in lake water and secondary wastewater, the proposed UV/PS/CaO process could be potentially applied for the oxidation of NH4+-N in practical water treatment.
研究领域:
环境科学
·
废水处理
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DOI
高影响因子
JOURNAL OF CATALYSIS
·
2022
·
IF 8.047
Chaoxin Zhang,Yanmei Huang,Bohang Zhao,Yu Yu,Yifu Yu,Bin Zhang
Photocatalytic nitric oxide (NO) synthesis from air is an attractive way to supersede the conventional nitrogen fixation manufacturing technique accompanied by high energy requirements and greenhouse gas emission. The development of efficient photocatalysts for direct solar-driven N 2 oxidation to NO without external thermal assistance is highly challenged. Here, CuO x clusters decorated TiO 2 nanoflowers with various copper contents are constructed and used for solar-driven air reaction into NO under ambient conditions. When the copper content is 1 wt%, the sample shows the optimal performance with a yield rate of 35.0 mmol m −2 h −1 (7.7 μmol h −1 ) and an apparent quantum efficiency of 1.77% at 365 nm. A series of in situ and ex situ characterizations reveal Cu 2 O species and TiO 2 support form direct Z-scheme heterojunction over 1%Cu-TiO 2 . This heterojunction can promote the adsorption and activation of nitrogen and oxygen reactants, leading to the performance enhancement of NO photosynthesis from air. Also, we proposed a possible NO photosynthesis reaction pathway over 1%Cu-TiO 2 .
研究领域:
材料科学
·
环境科学
·
化学工程
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产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2023
·Vol. 26
·期 4
·3263-3273
·
IF 3.3
Ziwei Zhai,Bofeng Zhang,Yutong Wang,Guozhu Liu
Based on the disturbance of electronic density, nitrogen-doped nanocarbons show promising properties to anchor metal clusters. However, precisely regulating the coordination mode between N species and the active site remains challenging. Herein, we rationally designed three N types (graphitic N, pyridinic N and pyrrolic N) in nanocarbons to anchor Pt clusters for the benchmark propane dehydrogenation. The specific activity of the pyridinic-N-doped catalyst was 147.54 molC3H6 molPt−1 h−1 at 550 °C, which was 1.3 times higher than those of graphitic- and pyrrolic-N-doped catalysts. Unlike the regular tetrahedron Pt cluster in the graphitic-N catalyst or the distorted three-layered Pt cluster in the pyrrolic-N catalyst, the Pt cluster in the pyridinic-N catalyst was an inverted tetrahedron, which increased the contact degree without geometric repulsion towards C–H bond scission. The geometric parameters of detached H and C atoms in the methylene group for the pyridinic N catalyst was decreased to strengthen the C–H bond scission. After CH3CHCH3* adsorption, the Bader charge of the Pt active site also became highly positive, which tailored the d-band center closer to the Fermi level and provided more vacant orbitals for C–H bond breakage. Therefore, pyridinic N in nanocarbons is promising to anchor small-sized Pt for alkane dehydrogenation in terms of geometric and electronic effects.
研究领域:
催化化学
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材料科学
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产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Channa Wang,Fuzhu Liu,Mingjin Du,Mi Zhang,Xiangdong Ding,Changsheng Xiang
Identical fluorescent emission in carbon dots (CDs) is crucial for applications such as anti-counterfeiting which requires precise spectrum control. However, the optical properties of CDs are highly sensitive to reaction conditions, which complicate their consistency. In this study, nitrogen-doped CDs (N-CDs) were synthesized using a single precursor (2,4-dihydroxypyridine) under different conditions, all exhibiting identical blue fluorescence, regardless of size and reaction parameters. X-ray photoelectron spectroscopy (XPS) and elemental analysis confirmed a high concentration of graphitic and pyridinic nitrogen in the N-CDs. Density functional theory (DFT) calculations were employed to explore the influence of these nitrogen species on the optical properties of the N-CDs. The results demonstrated that graphitic nitrogen plays a pivotal role in size-independent emission by disrupting the conjugated sp2-carbon domains, effectively eliminating the quantum confinement effect. This study offers new insights into the role of graphitic nitrogen in band gap engineering and the fluorescence mechanism of CDs, revealing a path to achieve CDs with identical fluorescent emission. The stable and reproducible emission under various reaction conditions positions these N-CDs as ideal candidates for large-scale production of blue CDs, minimizing the need for complex purification processes. Furthermore, N-CDs were modified with urea to enhance hydrophilicity, making them suitable for use as markers in aqueous products. The resulting hydrogen-bond-enhanced reticulated structure also endowed the material with room-temperature phosphorescence (RTP) properties. This innovation grants N-CDs substantial potential for anti-counterfeiting applications across various media.
研究领域:
材料科学
·
光学
·
化学工程
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产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2020
·
IF 6.215
Hui Jiang,Lin Liu,Kai Zhao,Zhen Liu,Xinsheng Zhang,Shuozhen Hu
Nitrogen doping was widely used to increase the electronic density of carbon materials and to enhance the adsorption of the supported metal catalysts . However, the exact interaction between various doped nitrogen species and palladium (Pd) have rarely been reported for formic acid electrooxidation (FAO). In this study, the effect of the doped pyridinic-N and pyrrolic-N on the electronic structure and the electrochemical activity of Pd toward FAO are investigated. The oxidation state of Pd is reduced and more metallic Pd is formed when Pd nanoparticles supported on pyridinic-N and pyrrolic-N doped carbon materials . Density functional theory (DFT) calculations simulate that the adsorption energy of HCOO* and *COOH on Pd/pyrrolic-N are lower than those on Pd/pyridinic-N. Both DFT and electrochemical measurements suggest that the FAO activity of Pd is more correlated with the pyrrolic-N than pyridinic-N. The catalyst contains more pyrrolic-N species exhibits higher electrochemical activity and faster kinetics for FAO reaction. Moreover, Pd 2+ -N complexes are formed in all the nitrogen doped catalysts and display good activity for FAO. In this study, Pd supported on urea treated carbon (Pd/UR) owns the highest content of pyrrolic-N and exhibits the best activity for FAO.
研究领域:
材料科学
·
电化学
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DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Jinchuan Wang,Li Zhang,Jinping Weng,Juntao Wei,Deliang Xu,Bin Li,Shu Zhang,Mortaza Gholizadeh,Electo Silva Lora,Hong Zhang
The retention and transformation of nitrogen in hydrochars prepared from co-hydrothermal carbonization (Co-HTC) of fiberboard (FB) and glucose were mainly investigated in this study. This study showed that more than 90 wt% nitrogen has transferred into aqueous solution at 180–220 °C during the hydrothermal carbonization (HTC) of FB. When the HTC temperatures were higher than 220 °C, some dissolved nitrogen recombined into hydrochars due to the enhancement of nitrogen fixation reactions (Maillard reactions). The addition of glucose could significantly increase nitrogen retention rate in hydrochars, which was due to abundant oxygen-containing intermediates (5-HMF, furfural, etc.) formed in aqueous phase by the hydrothermal decomposition of glucose. Besides, the hydrochars with more microspheres formed on the surface could apparently enhance nitrogen fixation due to the increased contacting area. In Co-HTC, the temperature range of 220–280 °C favored the nitrogen retention in hydrochars. Additionally, nitrogen retention rate increased significantly with increasing residence time and mixture ratio of glucose in a certain extent. While the heterocyclic-N was the main nitrogen functional group in hydrochars and it transformed from pyridinic-N, pyrrolic-N to quaternary-N with higher HTC temperatures and longer residence times, additionally, some amine-N was clearly formed when the nitrogen returned from the aqueous phase into hydrochars.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2014
·
IF 3.674
Lei Zeng,Wulin Song,Minghui Li,Xiaoqin Jie,Dawen Zeng,Changsheng Xie
Nitrogen-doped TiO 2 nanomaterial attracts enormous attention due to its excellent visible photocatalytic activity. A simple annealing method assisted by adjusting gas composition to control the positions of nitrogen dopants in TiO 2 lattice is presented. The nitrogen doping sites are confirmed by XPS. The photo-degradation results of gaseous benzene under visible light illumination reveal that photocatalytic activity in as-prepared samples containing the substitutional nitrogen species is higher than that in samples containing interstitial nitrogen species. The improvement of photocatalytic performance is ascribed to the increased amounts of surface hydroxyl group in N-TiO 2 samples. The efficient separation of electron-hole pairs was also responsible for the enhanced photocatalytic activity. In addition, an important conclusion is pointed out: the presence of oxygen during annealing process has an important effect on the formation of interstitial nitrogen dopants. The present work is believed to have guiding significance for preparing nitrogen-doped TiO 2 with high photocatalytic activity.
研究领域:
材料科学
·
光催化
·
纳米材料
·
环境化学
·
半导体催化
✓ 已验证
DOI
高影响因子
DIAMOND AND RELATED MATERIALS
·
2022
·
IF 3.806
Shuchun Li,Yiling Ke,Xuefei Zhang,Shuchang Wu,Yiquan Chen,Zailai Xie
Nitrogen-doped carbon materials as metal-free catalysts have attracted considerable attention in selective oxidation of benzyl alcohol. However, the real active sites are still ambiguous due to complexities of surface functional groups and nitrogen species. Herein, a series of nitrogen-doped nanosheets with different N species content are simply fabricated, which exhibits excellent catalytic activity with 82–93 % conversion and 89–99 % selectivity in selective oxidation of benzyl alcohol into benzaldehyde. Moreover, it is demonstrated that the conversion of benzyl alcohol mainly depends on the hydroxyl functional groups, while both graphitic and pyridinic nitrogen are key factors to determine the selectivity of benzaldehyde. The present work demonstrates the structure-activity relationships between the catalytic performance for catalytic oxidation of benzyl alcohol and the surface functional groups of catalysts, paving the way for development of highly efficient nanocarbon catalysts.
研究领域:
催化化学
·
材料科学
·
有机合成
✓ 已验证
产品关联
DOI
高影响因子
SOIL BIOLOGY & BIOCHEMISTRY
·
2023
·
IF 9.7
Jipeng Wang,Qian Zhao,Yiqiu Zhong,Shuhao Ji,Guanrui Chen,Qingqing He,Yanhong Wu,Haijian Bing
Free-living nitrogen fixation (FLNF) is a vital source of nitrogen for the initiation and development of ecosystems on bare lands. This process is catalyzed by the enzyme nitrogenase and is energy intensive. Of the three nitrogenase isoforms, molybdenum nitrogenase (Mo-Nase) is more efficient than its vanadium (V) and iron (Fe) counterparts at room temperature. However, the acquisition of Mo, one of the scarcest biometals in soils, represents a major resource investment for soil diazotrophs. In a vegetation restoration chronosequence developed on barren (low carbon and nitrogen) soils of a high-V region, we tested the following two hypotheses. First, the FLNF rate would be limited by the supply of energy. Second, high V availability would cut the cost of V acquisition, and it would be beneficial for diazotrophs to use V-Nase as a complement of Mo-Nase. For the soils collected along the chronosequence, the addition of a carbon cocktail remarkably stimulated the FLNF rate by relieving the energy constraint and by enriching the diazotrophic genus Paenibacillus . Despite the high V content in the soils, we failed to detect the vnf genes of V-Nase by metagenomic sequencing. Meanwhile, we observed a limited contribution of V-Nase activity to FLNF by checking the R ratio (ratio of FLNF rates measured by acetylene reduction and 15 N 2 incorporation) and the production of ethane during acetylene reduction. The reason might be that the Mo availability and temperature in our study area did not reach the thresholds for the onset of V-Nase activity. Overall, our results highlight the importance of carbon supply for FLNF in barren soils, indicating that plants may effectively regulate rhizosphere diazotrophs by secreting root exudates. This may be an important mechanism by which nonnitrogen-fixing plants survive on nitrogen-poor soils at the beginning of primary succession.
研究领域:
生态学
·
微生物学
·
土壤学
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2025
·
IF 3.9
Peng Guo,HongWei Li,BoYu Huang,Dong Ji,GuiXian Li,XinHong Zhao
Despite nitrogen-doped carbons (NC) enhancing metal–support interactions (MSI) in electrocatalysts, how specific N-configurations (pyridinic, pyrrolic, and graphitic) synergistically govern methanol oxidation reaction (MOR) pathways over Pd surfaces remains unknown. Herein, we hypothesize that precise thermal programming of ZIF-8 pyrolysis can tailor synergistic pyridinic-pyrrolic-graphitic N-triads to simultaneously enhance activity, CO tolerance, and stability. Guided by DFT predictions, Pd/NC-T catalysts (T = 700–1100) were synthesized, where in situ pyrolysis controls N-configurations (validated by XPS) and wet impregnation immobilizes ultrafine Pd nanoparticles (3.6 ± 0.8 nm). Furthermore, experimental and theoretical analyses reveal that pyrrolic-N facilitates the adsorption of methanol on Pd, while pyridinic-N suppresses the CHO* → CO* reaction pathway, thus enhancing the catalyst’s tolerance to poisoning, and graphitic-N prevents support dissolution and collapse during the electrocatalytic reaction, thus mitigating active site loss. Notably, Pd/NC-900 achieves 4195.0 mA·mg–1Pd in the alkaline electrolyte, maintaining 80.5% of its initial current density after 500 cycles at 200 mV/s, highlighting its exceptional catalytic activity and long-term stability. This work offers profound insights into the intricate MSI, serving as a crucial framework for guiding the future design and advancement of MOR electrocatalysts.
研究领域:
电化学
·
催化
·
材料科学
·
纳米技术
·
表面化学
·
能量转换
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CATALYSIS TODAY
·
2017
·
IF 4.636
Yuhai Sun,Limin Chen,Yunfeng Bao,Guannan Wang,Yujun Zhang,Mingli Fu,Junliang Wu,Daiqi Ye
Cu-ZrO 2 catalysts supported on nitrogen-doped CNTs were tested for CO 2 hydrogenation to methanol in a fixed-bed plug flow reactor. The characterization results indicate that the presence of pyridinic nitrogen increases the copper oxide dispersion, promotes their reduction, decreases the Cu particle size and enhances H 2 adsorption capability; the activated CO 2 adsorption predominantly controls CO 2 conversion. In addition, pyridinic nitrogen contributes to the strong adsorption of CO 2 , stimulating methanol formation, while pyrrolic nitrogen contributes to the medium adsorption of CO 2 , mainly boosting CO formation. Thus, pyridinic nitrogen dominant CNTs supported catalyst (CZ/CNT-N) possesses more active sites compared with the other three catalysts, leading to maximum methanol yield (8.64%) and space time yield (102.21 mg g −1 cat h −1 ); pyrrolic nitrogen dominant CNTs supported catalyst (CZ/CNT-NH 2 ) obtains more highly active structure, giving the highest intrinsic activity (TOF values).
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）