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Platinum on nitrogen doped graphene and tungsten carbide supports for ammonia electro-oxidation reaction

《化学科学与工程前沿(英文)》 2022年 第16卷 第6期   页码 930-938 doi: 10.1007/s11705-021-2130-2

摘要: Ammonia electrooxidation reaction involving multistep electron-proton transfer is a significant reaction for fuel cells, hydrogen production and understanding nitrogen cycle. Platinum has been established as the best electrocatalyst for ammonia oxidation in aqueous alkaline media. In this study, Pt/nitrogen-doped graphene (NDG) and Pt/tungsten monocarbide (WC)/NDG are synthesized by a wet chemistry method and their ammonia oxidation activities are compared to commercial Pt/C. Pt/NDG exhibits a specific activity of 0.472 mA∙cm–2, which is 44% higher than commercial Pt/C, thus establishing NDG as a more effective support than carbon black. Moreover, it is demonstrated that WC as a support also impacts the activity with further 30% increase in comparison to NDG. Surface modification with Ir resulted in the best electrocatalytic activity with Pt-Ir/WC/NDG having almost thrice the current density of commercial Pt/C. This work adds insights regarding the role of NDG and WC as efficient supports along with significant impact of Ir surface modification.

关键词: Ammonia electro-oxidation reaction     electrocatalyst supports     platinum     nitrogen doped graphene     tungsten carbide    

Nitrogen-doped graphene approach to enhance the performance of a membraneless enzymatic biofuel cell

Alireza AHMADIAN YAZDI, Jie XU

《能源前沿(英文)》 2018年 第12卷 第2期   页码 233-238 doi: 10.1007/s11708-018-0529-3

摘要: Heteroatom-doping of pristine graphene is an effective route for tailoring new characteristics in terms of catalytic performance which opens up potentials for new applications in energy conversion and storage devices. Nitrogen-doped graphene (N-graphene), for instance, has shown excellent performance in many electrochemical systems involving oxygen reduction reaction (ORR), and more recently glucose oxidation. Owing to the excellent sensitivity of N-graphene, the development of highly sensitive and fast-response enzymatic biosensors is made possible. However, a question that needs to be addressed is whether or not improving the anodic response to glucose detection leads to a higher overall performance of enzymatic biofuel cell (eBFC). Thus, here we first synthesized N-graphene via a catalyst-free single-step thermal process, and made use of it as the biocatalyst support in a membraneless eBFC to identify its role in altering the performance characteristics. Our findings demonstrate that the electron accepting nitrogen sites in the graphene structure enhances the electron transfer efficiency between the mediator (redox polymer), redox active site of the enzymes, and electrode surface. Moreover, the best performance in terms of power output and current density of eBFCs was observed when the bioanode was modified with highly doped N-graphene.

关键词: enzymatic fuel cell     nitrogen-doped graphene     reduced graphene oxide     catalyst-free synthesis    

Concurrent adsorption and reduction of chromium(VI) to chromium(III) using nitrogen-doped porous carbon

《环境科学与工程前沿(英文)》 2022年 第16卷 第5期 doi: 10.1007/s11783-021-1491-6

摘要:

• A high-efficiency N-doped porous carbon adsorbent for Cr(VI) was synthesized.

关键词: Chromium(VI)     Nitrogen-doped porous carbon     Adsorption     Reduction     Loofah sponge    

Size-controllable synthesis of monodispersed nitrogen-doped carbon nanospheres from polydopamine for

《化学科学与工程前沿(英文)》 2023年 第17卷 第11期   页码 1788-1800 doi: 10.1007/s11705-023-2326-8

摘要: Monodispersed nitrogen-doped carbon nanospheres with tunable particle size (100–230 nm) were synthesized via self-polymerization of biochemical dopamine in the presence of hexamethylenetetramine as a buffer and F127 as a size controlling agent. Hexamethylenetetramine can mildly release NH3, which in turn initiates the polymerization reaction of dopamine. The carbon nanospheres obtained exhibited a significant energy storage capability of 265 F·g–1 at 0.5 A·g–1 and high-rate performance of 82% in 6 mol·L–1 KOH (20 A·g–1), which could be attributed to the presence of abundant micro-mesoporous structure, doped nitrogen functional groups and the small particle size. Moreover, the fabricated symmetric supercapacitor device displayed a high stability of 94% after 5000 cycles, revealing the considerable potential of carbon nanospheres as electrode materials for energy storage.

关键词: carbon nanospheres     size-controlled     nitrogen-doped     high-rate     supercapacitors    

Nitrogen-doped carbon black supported Pd nanoparticles as an effective catalyst for formic acid electro-oxidation

Na SUN, Minglei WANG, Jinfa CHANG, Junjie GE, Wei XING, Guangjie SHAO

《能源前沿(英文)》 2017年 第11卷 第3期   页码 310-317 doi: 10.1007/s11708-017-0491-5

摘要: Pd nanoparticles supported on nitrogen doped carbon black (Vulcan XC-72R) with two different levels of doping were prepared by the microwave-assisted ethylene glycol reduction process and used as catalyst for the formic acid electro-oxidation (FAEO). The results indicate that the different nitrogen doping contents in Pd/N-C catalysts have a significant effect on the performance of FAEO. A higher N content facilitates the uniform dispersion of Pd nanoparticles on carbon black with narrow particle size distribution. Furthermore, the electrochemical results show that the catalyst with a higher N-doping content possesses a higher catalytic activity and a long-term stability for FAEO. The peak current density of the Pd/N-C (high) catalyst is 1.27 and 2.31 times that of the Pd/N-C (low) and homemade Pd/C-H catalyst. The present paper may provide a simple method for preparation of high-performance anode catalyst for direct formic acid fuel cells (DFAFCs).

关键词: formic acid electro-oxidation     nitrogen doped     oxidized carbon     nitrogen content    

Catalytic fast pyrolysis of walnut shell for alkylphenols production with nitrogen-doped activated carbon

Shanwei Ma, Hang Li, Guan Zhang, Tahir Iqbal, Kai Li, Qiang Lu

《环境科学与工程前沿(英文)》 2021年 第15卷 第2期 doi: 10.1007/s11783-020-1317-y

摘要: Abstract • N-doped activated carbon was prepared for catalytic pyrolysis of walnut shell. • Alkylphenols were selectively produced from catalytic pyrolysis process. • The alkylphenols yield increased by 8.5 times under the optimal conditions. • Formation mechanism of alkylphenols was proposed. Alkylphenols are a group of valuable phenolic compounds that can be derived from lignocellulosic biomass. In this study, three activated carbons (ACs) were prepared for catalytic fast pyrolysis (CFP) of walnut shell to produce alkylphenols, including nitrogen-doped walnut shell-derived activated carbon (N/WSAC), nitrogen-doped rice husk-derived activated carbon (N/RHAC) and walnut shell-derived activated carbon (WSAC). Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were carried out to reveal the influences of AC type, pyrolytic temperature, and AC-to-walnut shell (AC-to-WS) ratio on the product distributions. Results showed that with nitrogen doping, the N/WSAC possessed stronger capability than WSAC toward the alkylphenols production, and moreover, the N/WSAC also exhibited better effects than N/RHAC to prepare alkylphenols. Under the catalysis of N/WSAC, yields of alkylphenols were significantly increased, especially phenol, cresol and 4-ethylphenol. As the increase of pyrolytic temperature, the alkylphenols yield first increased and then decreased, while high selectivity could be obtained at low pyrolytic temperatures. Such a trend was also observed as the AC-to-WS ratio continuously increased. The alkylphenols production achieved a maximal yield of 44.19 mg/g with the corresponding selectivity of 34.7% at the pyrolytic temperature of 400°C and AC-to-WS ratio of 3, compared with those of only 4.67 mg/g and 6.1% without catalyst. In addition, the possible formation mechanism of alkylphenols was also proposed with the catalysis of N/WSAC.

关键词: Pyrolysis     Walnut shell     Alkylphenols     Nitrogen-doped activated carbon    

Cobalt-nitrogen co-doped porous carbon sphere as highly efficient catalyst for liquid-phase cyclohexane

《化学科学与工程前沿(英文)》 2024年 第18卷 第3期 doi: 10.1007/s11705-024-2395-3

摘要: The selective oxidation of cyclohexane to cyclohexanone and cyclohexanol (KA oil) is a challenging issue in the chemical industry. At present the industrial conversion of cyclohexane to cyclohexanone and cyclohexanol is normally controlled at less than 5% selectivity. Thus, the development of highly active and stable catalysts for the aerobic oxidation of cyclohexane is necessary to overcome this low-efficiency process. Therefore, we have developed a cobalt-nitrogen co-doped porous sphere catalyst, Co-NC-x (x is the Zn/Co molar ratio, where x = 0, 0.5, 1, 2, and 4) by pyrolyzing resorcinol-formaldehyde resin microspheres. It achieved 88.28% cyclohexanone and cyclohexanol selectivity and a cyclohexane conversion of 8.88% under Co-NC-2. The results showed that the introduction of zinc effectively alleviated the aggregation of Co nanoparticles and optimized the structural properties of the material. In addition, Co0 and pyridinic-N are proposed to be the possible active species, and their proportion efficiently increased in the presence of Zn2+ species. In this study, we developed a novel strategy to design highly active catalysts for cyclohexane oxidation.

关键词: KA oil production     cyclohexane selective oxidation     cobalt-nitrogen co-doped porous carbon spheres     metal-organic framework    

Impact of H2S on Hg0 capture performance over nitrogen-doped carbon microsphere

《化学科学与工程前沿(英文)》 2024年 第18卷 第3期 doi: 10.1007/s11705-024-2396-2

摘要: A nitrogen-doped carbon microsphere sorbent with a hierarchical porous structure was synthesized via aggregation-hydrothermal carbonization. The Hg0 adsorption performance of the nitrogen-doped carbon microsphere sorbent was tested and compared with that of the coconut shell activated carbon prepared in the laboratory. The effect of H2S on Hg0 adsorption was also investigated. The nitrogen-doped carbon microsphere sorbent exhibited superior mercury removal performance compared with that of coconut shell activated carbon. In the absence of H2S at a low temperature (≤ 100 °C), the Hg0 removal efficiency of the nitrogen-doped carbon microsphere sorbent exceeded 90%. This value is significantly higher than that of coconut shell activated carbon, which is approximately 45%. H2S significantly enhanced the Hg0 removal performance of the nitrogen-doped carbon microsphere sorbent at higher temperatures (100–180 °C). The hierarchical porous structure facilitated the diffusion and adsorption of H2S and Hg0, while the nitrogen-containing active sites significantly improved the adsorption and dissociation capabilities of H2S, contributing to the generation of more active sulfur species on the surface of the nitrogen-doped carbon microsphere sorbent. The formation of active sulfur species and HgS on the sorbent surface was further confirmed using X-ray photoelectron spectroscopy and Hg0 temperature-programmed desorption tests. Density functional theory was employed to elucidate the adsorption and transformation of Hg0 on the sorbent surface. H2S adsorbed and dissociated on the sorbent surface, generating active sulfur species that reacted with gaseous Hg0 to form HgS.

关键词: nitrogen-doped carbon microsphere     H2S     Hg0 removal     adsorption mechanism    

Experimental and DFT insights into nitrogen and sulfur co-doped carbon nanotubes for effective desulfurization

《环境科学与工程前沿(英文)》 2021年 第15卷 第5期 doi: 10.1007/s11783-021-1397-3

摘要:

• Synthesis of NS-CNTS is used in a high desulfurization performance.

关键词: Dibenzothiophene (DBT)     Tertiary methyl mercaptan     Adsorption     Carbon nano tube (CNT)     Desulfurization     Doping    

Efficient removal of Cr(VI) and Pb(II) from aqueous solution by magnetic nitrogen-doped carbon

Wanyue Liu, Xiaoqin Liu, Jinming Chang, Feng Jiang, Shishi Pang, Hejun Gao, Yunwen Liao, Sheng Yu

《化学科学与工程前沿(英文)》 2021年 第15卷 第5期   页码 1185-1196 doi: 10.1007/s11705-020-2032-8

摘要: The magnetic nitrogen-doped carbon (MNC) was prepared from polypyrrole by a simple high temperature calcination process in this paper. The structure and properties of MNC were analyzed by scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, Brunner Emmet Teller, vibrating sample magnetometer, and X-ray photoelectron spectroscopy. The capacity of MNC to adsorb Cr(VI) and Pb(II) was evaluated. The effects of the initial pH, dosage, concentration and temperature on the adsorption capacity of MNC were measured. MNC had a large specific surface area and a special porous structure. Its nitrogen and carbon sources were rich, and the ratio of carbon to nitrogen was fixed. The maximum Cr(VI)-adsorption capacity and maximum Pb(II) adsorption capacity of MNC could reach 456.63 and 507.13 mg∙g at 318 K, respectively. The pseudo-second-order model was used to describe the adsorption kinetics of MNC, and the Freundlich model was employed to discuss its isotherms. The adsorption process was affected by the electrostatic force, the reducing reaction, pores and chelation. The results of this study suggest that MNC is a material with superior performance, and is very easily regenerated, reused, and separated in the adsorption process.

关键词: magnetic     nitrogen-doped carbon     adsorption     Cr(VI)     Pb(II)    

Insight into the selective separation of CO from biomass pyrolysis gas over metal-incorporated nitrogen-doped

《化学科学与工程前沿(英文)》 2024年 第18卷 第3期 doi: 10.1007/s11705-024-2388-2

摘要: The composition of biomass pyrolysis gas is complex, and the selective separation of its components is crucial for its further utilization. Metal-incorporated nitrogen-doped materials exhibit enormous potential, whereas the relevant adsorption mechanism is still unclear. Herein, 16 metal-incorporated nitrogen-doped carbon materials were designed based on the density functional theory calculation, and the adsorption mechanism of pyrolysis gas components H2, CO, CO2, CH4, and C2H6 was explored. The results indicate that metal-incorporated nitrogen-doped carbon materials generally have better adsorption effects on CO and CO2 than on H2, CH4, and C2H6. Transition metal Mo- and alkaline earth metal Mg- and Ca-incorporated nitrogen-doped carbon materials show the potential to separate CO and CO2. The mixed adsorption results of CO2 and CO further indicate that when the CO2 ratio is significantly higher than that of CO, the saturated adsorption of CO2 will precede that of CO. Overall, the three metal-incorporated nitrogen-doped carbon materials can selectively separate CO2, and the alkaline earth metal Mg-incorporated nitrogen-doped carbon material has the best performance. This study provides theoretical guidance for the design of carbon capture materials and lays the foundation for the efficient utilization of biomass pyrolysis gas.

关键词: CO2 capture     biomass pyrolysis gas     selective adsorption     carbon materials     first-principles    

Boron and nitrogen co-doped porous carbon derived from sodium alginate enhanced capacitive deionization

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2014-2024 doi: 10.1007/s11705-023-2346-4

摘要: Capacitive deionization can alleviate water shortage and water environmental pollution, but performances are greatly determined by the electrochemical and desalination properties of its electrode materials. In this work, B and N co-doped porous carbon with micro-mesoporous structures is derived from sodium alginate by a carbonization, activation, and hydrothermal doping process, which exhibits large specific surface area (2587 m2·g‒1) and high specific capacitance (190.7 F·g‒1) for adsorption of salt ions and heavy metal ions. Furthermore, the materials provide a desalination capacity of 26.9 mg·g−1 at 1.2 V in 500 mg·L‒1 NaCl solution as well as a high removal capacity (239.6 mg·g‒1) and adsorption rate (7.99 mg·g‒1·min‒1) for Pb2+ with an excellent cycle stability. This work can pave the way to design low-cost porous carbon with high-performances for removal of salt ions and heavy metal ions.

关键词: capacitance deionization     porous carbon     B/N co-doping     heavy metal ions     water purification    

One-step ball milling-prepared nano Fe

Xingguo Guo, Qiuying Wang, Ting Xu, Kajia Wei, Mengxi Yin, Peng Liang, Xia Huang, Xiaoyuan Zhang

《环境科学与工程前沿(英文)》 2020年 第14卷 第2期 doi: 10.1007/s11783-019-1209-1

摘要: • Nano Fe2O3 and N-doped graphene was prepared via a one-step ball milling method. • The maximum power density of Fe-N-G in MFC was 390% of that of pristine graphite. • Active sites like nano Fe2O3, pyridinic N and Fe-N groups were formed in Fe-N-G. • The improvement of Fe-N-G was due to full exposure of active sites on graphene. Developing high activity, low-cost and long durability catalysts for oxygen reduction reaction is of great significance for the practical application of microbial fuel cells. The full exposure of active sites in catalysts can enhance catalytic activity dramatically. Here, novel Fe-N-doped graphene is successfully synthesized via a one-step in situ ball milling method. Pristine graphite, ball milling graphene, N-doped graphene and Fe-N-doped graphene are applied in air cathodes, and enhanced performance is observed in microbial fuel cells with graphene-based catalysts. Particularly, Fe-N-doped graphene achieves the highest oxygen reduction reaction activity, with a maximum power density of 1380±20 mW/m2 in microbial fuel cells and a current density of 23.8 A/m2 at –0.16 V in electrochemical tests, which are comparable to commercial Pt and 390% and 640% of those of pristine graphite. An investigation of the material characteristics reveals that the superior performance of Fe-N-doped graphene results from the full exposure of Fe2O3 nanoparticles, pyrrolic N, pyridinic N and excellent Fe-N-G active sites on the graphene matrix. This work not only suggests the strategy of maximally exposing active sites to optimize the potential of catalysts but also provides promising catalysts for the use of microbial fuel cells in sustainable energy generation.

关键词: Microbial fuel cells     Air cathodes     Nano Fe2O3 and nitrogen-doped graphene     Oxygen reduction reaction    

Construction of nitrogen-doped carbon cladding LiMnO film electrode with enhanced stability for electrochemically

《化学科学与工程前沿(英文)》 2023年 第17卷 第12期   页码 2050-2060 doi: 10.1007/s11705-023-2343-7

摘要: Reducing the dissolution of Mn from LiMn2O4 (LMO) and enhancing the stability of film electrodes are critical and challenging for Li+ ions selective extraction via electrochemically switched ion exchange technology. In this work, we prepared a nitrogen-doped carbon cladding LMO (C-N@LMO) by polymerization of polypyrrole and high-temperature annealing in the N2 gas to achieve the above purpose. The modified C-N@LMO film electrode exhibited lower Mn dissolution and better cyclic stability than the LMO film electrode. The dissolution ratio of Mn from the C-N@LMO film electrode decreased by 42% compared to the LMO film electrode after 10 cycles. The cladding layer not only acted as a protective layer but also functioned as a conductive shell, accelerating the migration rate of Li+ ions. The intercalation equilibrium time of the C-N@LMO film electrode reached within an hour during the extraction of Li+ ions, which was 33% less compared to the pure LMO film electrode. Meanwhile, the C-N@LMO film electrode retained evident selectivity toward Li+ ions, and the separation factor was 118.38 for Li+ toward Mg2+ in simulated brine. Therefore, the C-N@LMO film electrode would be a promising candidate for the recovery of Li+ ions from salt lakes.

关键词: LiMn2O4     lithium extraction     surface coating     cyclic stability     Mn dissolution    

Ultrafine Fe-modulated Ni nanoparticles embedded within nitrogen-doped carbon from Zr-MOFs-confined conversion

《化学科学与工程前沿(英文)》 2022年 第16卷 第7期   页码 1114-1124 doi: 10.1007/s11705-021-2087-1

摘要: Improvement of the low-cost transition metal electrocatalyst used in sluggish oxygen evolution reaction is a significant but challenging problem. In this study, ultrafine Fe-modulated Ni nanoparticles embedded in a porous Ni-doped carbon matrix were produced by the pyrolysis of zirconium metal-organic-frameworks, in which 2,2′-bipyridine-5,5′-dicarboxylate operating as a ligand can coordinate with Ni2+ and Fe3+. This strategy allows formation of Fe-modulated Ni nanoparticles with a uniform dimension of about 2 nm which can be ascribed to the spatial blocking effect of ZrO2. This unique catalyst displays an efficient oxygen evolution reaction electrocatalytic activity with a low overpotential of 372 mV at 10 mA·cm–2 and a small Tafel slope of 84.4 mV·dec–1 in alkaline media. More importantly, it shows superior durability and structural stability after 43 h in a chronoamperometry test. Meanwhile, it shows excellent cycling stability during 4000 cyclic voltammetry cycles. This research offers a new insight into the construction of uniform nanoscale transition metals and their alloys as highly efficient and durable electrocatalysts.

关键词: metal-organic framework     pyrolysis     ultrafine     Fe-modulated Ni nanoparticles     oxygen evolution reaction    

标题 作者 时间 类型 操作

Platinum on nitrogen doped graphene and tungsten carbide supports for ammonia electro-oxidation reaction

期刊论文

Nitrogen-doped graphene approach to enhance the performance of a membraneless enzymatic biofuel cell

Alireza AHMADIAN YAZDI, Jie XU

期刊论文

Concurrent adsorption and reduction of chromium(VI) to chromium(III) using nitrogen-doped porous carbon

期刊论文

Size-controllable synthesis of monodispersed nitrogen-doped carbon nanospheres from polydopamine for

期刊论文

Nitrogen-doped carbon black supported Pd nanoparticles as an effective catalyst for formic acid electro-oxidation

Na SUN, Minglei WANG, Jinfa CHANG, Junjie GE, Wei XING, Guangjie SHAO

期刊论文

Catalytic fast pyrolysis of walnut shell for alkylphenols production with nitrogen-doped activated carbon

Shanwei Ma, Hang Li, Guan Zhang, Tahir Iqbal, Kai Li, Qiang Lu

期刊论文

Cobalt-nitrogen co-doped porous carbon sphere as highly efficient catalyst for liquid-phase cyclohexane

期刊论文

Impact of H2S on Hg0 capture performance over nitrogen-doped carbon microsphere

期刊论文

Experimental and DFT insights into nitrogen and sulfur co-doped carbon nanotubes for effective desulfurization

期刊论文

Efficient removal of Cr(VI) and Pb(II) from aqueous solution by magnetic nitrogen-doped carbon

Wanyue Liu, Xiaoqin Liu, Jinming Chang, Feng Jiang, Shishi Pang, Hejun Gao, Yunwen Liao, Sheng Yu

期刊论文

Insight into the selective separation of CO from biomass pyrolysis gas over metal-incorporated nitrogen-doped

期刊论文

Boron and nitrogen co-doped porous carbon derived from sodium alginate enhanced capacitive deionization

期刊论文

One-step ball milling-prepared nano Fe

Xingguo Guo, Qiuying Wang, Ting Xu, Kajia Wei, Mengxi Yin, Peng Liang, Xia Huang, Xiaoyuan Zhang

期刊论文

Construction of nitrogen-doped carbon cladding LiMnO film electrode with enhanced stability for electrochemically

期刊论文

Ultrafine Fe-modulated Ni nanoparticles embedded within nitrogen-doped carbon from Zr-MOFs-confined conversion

期刊论文