Nitrogen Functionalities Research Articles

Influence of process parameters on hydrothermal modification of soybean residue: Insight into the nutrient, solid biofuel, and thermal properties of hydrochars

Soybean (SB) solid residue after oil extraction was investigated in a hydrothermal modification process to provide an eco-friendly solution to SB solid waste disposal for an actual environmental management effort. SB hydrochars (HCs) were derived either by conventional heating hydrothermal treatment (HTT) under intense conditions (200, 250, and 300 °C for 2 h) or by microwave-assisted hydrothermal treatment (MHTT) under mild conditions (160, 190, and 220 °C for 1 h). Physicochemical properties of SB HCs and the transformation of nitrogen (N) and phosphorus (P) functionalities during HTT and MHTT were characterized using several tools. Ultimate and XPS analyses elucidated N transformation, e.g., 5.51 wt % N of raw SB residue decreased to 3.48 and 3.51 wt % after HTT and MHTT, respectively. The P bioavailability of raw SB (3.46 mg/g) was improved after HTT (26.7 mg/g) and MHTT (10.9 mg/g), depicting the practical application of HCs for soil amendment. Atomic H/C and O/C ratios of SB HCs decreased as treatment temperature increased. HCs showed credible higher heating value (HHV; 22.3–25.5 MJ/kg for HTT and 20.5–22.1 MJ/kg for MHTT), higher than various low-rank coals. Besides, energy densification and fuel ratio improved in intense conditions. The thermogravimetric analysis showed HCs possessed better thermal stability. The improved performance of SB HCs indicated that HTT and MHTT provided a green environmental route of SB waste management, valorization, and utilization.

Oxidative Stress Produced by Paraquat Reduces Nitrogen Fixation in Soybean-Bradyrhizobium diazoefficiens Symbiosis by Decreasing Nodule Functionality

Soybean (Glycine max.) is one of the most important legumes cultivated worldwide. Its productivity can be altered by some biotic and abiotic stresses like global warming, soil metal pollution or over-application of herbicides like paraquat (1,1’-dimethyl-4,4’-bipyridinium dichloride). In this study, the effect of oxidative stress produced by paraquat addition (0, 20, 50 and 100 µM) during plant growth on symbiotic nitrogen fixation (SNF) and functionality of Bradyrhizobium diazoefficiens-elicited soybean nodules were evaluated. Results showed that the 50 µM was the threshold that B. diazoefficiens can tolerate under free-living conditions. In symbiosis with soybean, the paraquat addition statistically reduced the shoot and root dry weight of soybean plants, and number and development of the nodules. SNF was negatively affected by paraquat, which reduced total nitrogen content and fixed nitrogen close to 50% when 100 µM was added. These effects were due to the impairment of nodule functionality and the increased oxidative status of the nodules, as revealed by the lower leghaemoglobin content and the higher lipid peroxidation in soybean nodules from paraquat-treated plants.

Sustainable direct H2O2 synthesis over Pd catalyst supported on mesoporous carbon: The effect of surface nitrogen functionality

We employed oxygen- and nitrogen-functionalized mesoporous carbons (OMC and N-OMC) as supports for Pd nanoparticles pre-formed via a modified colloidal method. In the direct synthesis of hydrogen peroxide (H2O2) from H2 and O2, the prepared Pd/OMC catalyst outperformed a commercial Pd catalyst supported on activated carbon (Pd/AC) and a Pd catalyst on oxygen-functionalized carbon nanotubes (Pd/OCNT) in terms of H2O2 productivity, emphasizing the advantage of mesoporous carbon support. An even higher H2O2 productivity was obtained over Pd catalyst supported on N-OMC with 2.72 at.% nitrogen on the surface. However, a further increase of surface nitrogen content to 13.26 at.%, as the case of mesoporous carbon directly grown using N-containing carbon precursor (NMC), led to increased activity (in terms of H2 consumption) but poor H2O2 productivity. X-ray photoelectron spectroscopy analyses of the Pd/MC catalysts suggest that a suitable amount of N groups (ca. 2.72 at.%) on the MC surface led to a high fraction of Pd2+ in the Pd/MC catalyst, which is believed to be important for achieving high selectivity in direct H2O2 synthesis. These results highlight that tuning the surface properties of carbon supports is a versatile approach to fabricate highly selective supported Pd catalysts for the sustainable direct synthesis of H2O2 from H2 and O2.

Total Synthesis of Talatisamine: Exploration of Convergent Synthetic Strategies

Abstract Talatisamine (1) is a highly oxygenated C19-diterpenoid alkaloid with K+ channel inhibitory, antiarrhythmic, and neuroprotective activities. Its intricately fused 6/7/5/6/6/5-membered hexacyclic structure (ABCDEF-ring) possesses one nitrogen functionality, five oxygen functionalities, and 12 contiguously aligned stereocenters. This account describes the development of convergent strategies to efficiently assemble this synthetically challenging natural product. First, we explored two radical-based strategies. Treatment of the AE-ring with Et3B and O2 generated a highly reactive C11-bridgehead radical, which sequentially added to the C-ring and the aldehyde via a radical-polar crossover mechanism to afford ACE-ring substructure 6 in a single step. Alternatively, after coupling of the AE-ring and C-ring, the C11-bridgehead radical was utilized to cyclize the central 7-membered B-ring. The 6-membered D-ring was then forged by selenium-induced 6-endo cyclization to furnish ABCDE-ring 3. Second, we pursued a skeletal rearrangement strategy, which culminated in the total synthesis of 1. The D-ring was coupled with the AE-ring as the aromatic ring. Oxidative dearomatization, followed by Diels-Alder reaction, led to the 6/6-membered ring system, which was transformed into the 7/5-membered BC-ring through a stereospecific Wagner-Meerwein rearrangement. Finally, Hg(OAc)2 induced an oxidative aza-Prins cyclization to form the remaining 5-membered F-ring, thereby completing the chemical construction of 1.

Bimetallic Pd–Fe Supported on Nitrogen-Doped Reduced Graphene Oxide as Electrocatalyst for Formic Acid Oxidation

This study was conducted to exploit the properties of nitrogen-doped reduced graphene oxide (N-rGO) as support material for formic acid fuel cell. Nitrogen-doped reduced graphene oxide was synthesized by the hydrothermal synthesis method using graphene oxide (GO) flakes and urea as a nitrogen source. Palladium and iron with controllable atomic ratio were used as the active metals. Graphene oxide and carbon nanotube-supported PdFe nanoparticles were synthesized for comparison. The structure, morphology, and chemical composition of the synthesized catalysts were ascertained by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The average particle sizes for Pd3Fe/N-rGO and Pd/N-rGO were 4.65 and 3.95 nm, respectively. The electrochemical characterizations (CO stripping, cyclic voltammetry, and chronoamperometry) showed that the Pd3Fe/N-rGO electrocatalyst had higher electrocatalytic activity and stability compared with that of Pd3Fe/rGO and Pd3Fe/CNT. The mass activity of Pd3Fe/N-rGO in 0.5 M of HCOOH and 0.5 M of H2SO4 solutions was 1463.9 mAmg−1 Pd, which was 3.3 and 1.35 times that of the activity obtained with graphene oxide and carbon nanotubes with the same composition, respectively. The superior performance of the Pd3Fe/N-rGO catalyst was ascribed to the presence of nitrogen functionalities in the nitrogen-doped reduced GO and the synergistic interaction between Pd and Fe nanoparticles. Nitrogen-doped reduced GO promoted the formation of smaller and narrowly distributed nanoparticles and exerted favorable electronic effects because of electron transfer from N to Pd. Therefore, Pd3Fe/N-rGO can serve as a potential electrocatalyst for the oxidation of formic acid.

Crop type drives soil bacterial community and functional structure on the Loess Plateau terraces of China

Although terraced fields play an important role in soil and water conservation and agricultural production, the effects of planting different crops on the terraced soil bacterial community and functional structure are still unclear. We compared bacterial communities and functional structures in terraced soils grown with different crops on the Loess Plateau using the MiSeq technique. Economic crop types (apple [<i>Malus domestica</i>], greenhouse, intercropping), traditional crop types (corn [<i>Zea mays</i>], potato [<i>Solanum tuberosum</i>]), and terraced fields abandoned for five years in two small catchment areas in Ansai, Shaanxi, were selected, and the composition of the bacterial communities and other physicochemical properties of the soil were analyzed. The numbers of operational taxonomic units and bacteria α-diversity in economic and traditional crop types were 1.05 to 1.23 times higher than those in abandoned land; the change in crop types had significant effects on the soil bacterial community, and soil available phosphorus (P) content and bulk density were the main factors affecting the soil bacterial community. The dominant phyla were Proteobacteria, Acidobacteria, Actinobacteria, and Gemmatimonadetes, and the Proteobacteria accounted for 35% of the community in greenhouses but 30% in abandoned land. The co-occurrence networks indicated that economic crop types increased the links between soil bacterial taxa and the intensity of stability for terraced agroecosystems, especially for copiotrophic groups (Proteobacteria). Economic crop types enhanced potential functions of nitrogen (N) fixation and the carbon (C) cycle and reduced soil pathogens. These observations indicate that scientific planting and management could improve soil quality and health, which is conducive to sustainable agricultural development on the Loess Plateau terraces.

Nano-rod like morphology of Ni@Fe3O4-NDCs on interaction of NDC-supported Fe3O4 with nickel NPs: An efficient catalyst for ligand free Chan-Lam coupling reaction in aqueous medium

Nitrogen doped carbons were synthesized and fabricated with magnetite nanoparticles leading to a new magnetic and nitrogen functionalities rich carbon material. This material has dual characteristics as the magnetization of carbons makes it easily separable and the nitrogen moieties act as a binder for both magnetite and metal nanoparticles. This excludes the need for extra binding sites. Nickel and/or iron supported five different catalysts were synthesized and their catalytic activity was tested for Chan-Lam coupling and satisfactory results were obtained with two catalysts- Ni@Fe–Fe3O4–NDCs and Ni@Fe3O4–NDCs, wherein the monometallic counterpart having an upper edge. The characterization of these catalysts provides sufficient evidence for the unexpected enhanced catalytic activity of the monometallic Ni catalyst as compared to its bimetallic counterpart. The most eye-catching thing observed was the difference in morphology of the two synthesized catalysts, which clearly indicated some major changes in the interaction of the metal nanoparticles with the support material in the two catalysts since same method was adopted for the preparation of both. Additional lattice fringes of NiFe2O4 in the HRTEM images along with their corresponding peaks in the XRD spectrum, and the presence of pure Ni2+ species in the XPS spectrum of the monometallic catalyst provides a clear vision of the reason behind the enhanced catalytic activity of the monometallic catalyst. The formation of nano-rod like supported NiFe2O4 particles with increased surface area, mean pore volume and large number of active sites increases the activity of monometallic-Ni for Chan-Lam cross-coupling.

Fully automated graphitic carbon nitride-based disposable pipette extraction-gas chromatography-mass spectrometric analysis of six polychlorinated biphenyls in environmental waters

A fully automated online emulsification-enhanced disposable pipette extraction-gas chromatography-mass spectrometry (EE-DPX-GC-MS) method has been developed for the extraction of six polychlorinated biphenyls (PCBs) from environmental waters. An in-house prepared material, graphitic carbon nitride (g-C3N4), was used as sorbent in a home-packed DPX device. The six PCBs studied include PCB 10, 28, 52, 153, 138 and 180. g-C3N4 was characterized successfully by X-ray diffraction, elemental analysis, scanning electron microscopy, Fourier-transform infrared and Raman spectroscopy. As a C-N analogue of graphite, the two-dimensional structure of g-C3N4 allows rapid analyte adsorption and desorption to take place. With a significant number of nitrogen functionalities in g-C3N4, the material dispersed well in aqueous sample, increasing the active surface area of contact between the sorbent and the sample. When coupled with a pre-emulsification step, PCBs in each portion of sample could be efficiently extracted by g-C3N4 within 20 s of gentle turbulence. Under the most favorable conditions, the automated online EE-DPX-GC-MS method achieved wide dynamic working ranges with good linearity (r2 ≥ 0.998) for all analytes. Limits of detection ranging between 4.35 and 7.82 ng L−1 were attained, with enrichment factors of between 34 and 57 and relative standard deviations (RSDs) for intra- and inter-day precision of ≤ 8.95% and ≤ 12.6%, respectively. Absolute recoveries were between 69.3% and 109%. The fully automated online EE-DPX-GC-MS approach was applied to industrial wastewaters and reservoir waters where good relative recoveries of PCBs of between 89.3% and 105% were obtained, with RSDs ≤ 11.6%.

Electrochemical performance of N‐doped superporous activated carbons in ionic liquid‐based electrolytes

The electrochemical performance of nitrogen-doped and non-doped superporous activated carbons as electrodes for supercapacitors was assessed in organic and ionic liquid-based electrolytes. The nitrogen functionalization was carried out through post-modification treatments at mild conditions to produce N-doped activated carbons that preserve the microporosity of the pristine carbon material. The electrodes based on these materials provide large capacitance values (up to 150–180 F/g) in both 1 M Pyr14TFSI/PC and 1 M Pyr14BF4/PC due to their tailored porous texture, given by their well-developed microporosity and low mesopore volume. The electrochemical double layer capacitors based on these materials displayed outstanding capacitance (37–40 F/g and 14 F/cm3) and energy values (44–48 Wh/kg and 16–17 Wh/L). The nitrogen-doped activated carbons evidence high stability at positive and negative polarization potentials due the presence of specific N functionalities. The results prove that surface chemistry of carbon materials plays a key role on their degradation under high operation voltage conditions. The durability of the devices can be improved by doping carbon electrodes with selected nitrogen groups, such as nitrogen heterocycles and amine-like surface functionalities.

Afforestation suppresses soil nitrogen availability and soil multifunctionality on a subtropical grassland

Microbes simultaneously drive multiple functions (multifunctionality) that support human well-being. However, the structure and function of microbial communities and their impact on soil multifunctionality following grassland afforestation remains unknown, thus hindering our ability to formulate conservation policies. We compared soil bacterial and fungal communities, soil abiotic properties, and soil nitrogen (N) function and multifunctionality in the afforested sites that were previously grassland, on a subtropical plateau in China. We also explored the degree to which the niche complementarity effect and the selection effect of microbes are linked to soil N function and multifunctionality. We found that afforestation of grassland significantly decreased pH, available N concentration and density, and soil multifunctionality. However, afforestation significantly increased C (carbon) limitation and shifted soil microbes from being limited by N to, instead, being co-limited by N and P (phosphorus). The significant decrease in available N was primarily driven by soil microbes. In shaping soil N availability, the effect of bacterial diversities was stronger than that of fungal diversities, and the effect of fungal functional diversities was stronger than that of bacterial functional diversities. The effect of functional diversities was greater than that of all the significant changes in the functions and, also, the significant changes in the N-related functions. These results further emphasized that functional niche complementarity dominated soil N availability. In addition, bacterial taxonomic diversities showed positive effects of niche complementarity on soil multifunctionality; ultimately, the losses in bacterial taxonomic diversities derived from the increases in C limitation and the shifts in NP limitation combined to impaired soil multifunctionality. Our results suggested that the optimization of soil microbial functional diversities might increase soil N availability, and that minimizing losses of soil microbial taxonomic diversities by optimizing soil abiotic environments might improve soil multifunctionality.

Understanding the synergy between N-doped ultra-microporous carbonaceous adsorbent and nitrogen functionalities for high performance of CO2 sorption

Porous carbonaceous adsorbents are believed to encourage contenders to CO2 uptake however their high production cost has urged researchers towards cheap renewable. In this study, nitrogen-doped carbonaceous adsorbents with high ultra-microporous structure were synthesized by carbonization and activation of chitosan along with urea and KOH simultaneously at various temperatures (600−900 °C). The effects of temperature, urea modification, and chemical activation on nitrogen functionalities and development of porous structure were analyzed. Results showed that porous carbons synthesized with urea and KOH modification at 700 °C exhibit the highest CO2 adsorption value (5.92 mmol g−1 at 0 °C and 4.45 mmol g−1 at 25 °C). Enhanced adsorption by NCABC-700 was found due to synergistic effect of nitrogen as well as high specific surface area (1404 m2 g−1) and micropore volume (0.68 cm3 g−1), respectively. Furthermore, best fitting of Freundlich isotherm model explained heterogeneous nature of adsorbent. Isosteric heat of adsorption with a value of 42.2 kJ mol-1, also indicated the presence of N containing functional groups and a high number of micropores that created a strong interaction between adsorbent and adsorbate, helping in high CO2 uptake.

Controllable synthesis of worm-nest-like nanocarbons doped with all-electroactive nitrogen species for high-energy-density supercapacitors

Because of the instability and uncontrollability of the nitrogen-containing precursor upon high-temperature carbonization, it is very hard to obtain nanocarbon with high nitrogen content over 10 atom% and controllable electrochemically-active nitrogen species. Herein, we report a role-divided templating/doping strategy for the fabrication of porous nanocarbon supercapacitor materials with all-electroactive nitrogen species and ultrahigh energy density based on MgO and g-C3N4, in which MgO first acts as a polymerization catalyst to form carbon source and then as template for porous structure, while the g-C3N4 acts as a single nitrogen source. Systematic investigations reveal that the carbonization temperature and the single g-C3N4 nitrogen source are vital to obtaining all-electroactive nitrogen species. The obtained nanocarbon (WNLC973-C1N5) owns a worm-nest-like morphology, high surface area and all-electrochemically-active nitrogen functionalities (21.3 atom%). The symmetric supercapacitor based on WNLC973-C1N5 achieves an energy density of 53.2 Wh/kg at a power density of 1000 W/kg, about four times bigger than that of normal carbon-based material. This work highlights the importance of the special nitrogen source to form the all-electrochemically-active nitrogen functionalities for high-performance energy materials and presents facile strategy to fabricate carbon-based materials for extensive applications, such as catalyst, adsorbent, catalyst support, energy material and so on.

A Competitive Growth Model for the Simulation of Cyanobacterial Blooms Under Eutrophic Conditions

This study presents a novel competitive growth model between Microcystis sp. (cyanobacteria) and Cyclotella meneghiniana (bacillariophyta) as a function of nitrogen and phosphorus concentrations, a...

Context-dependency of tree species diversity, trait composition and stand structural attributes regulate temperate forest multifunctionality

High species diversity is generally thought to be a requirement for sustaining forest multifunctionality. However, the degree to which the relationship between species-, structural-, and trait-diversity of forests and multifunctionality depend on the context (such as stand age or abiotic conditions) is not well studied. Here, we hypothesized that context-dependency of tree species diversity, functional trait composition and stand structural attributes promote temperate forest multifunctionality including above- and below-ground multiple and single functions. To do so, we used repeated forest inventory data, from temperate mixed forests of northeast China, to quantify two above-ground (i.e. coarse woody productivity and wild edible plant biomass), five below-ground (i.e. soil organic carbon, total soil nitrogen, potassium, phosphorus and sulfur) functions, tree species diversity, individual tree size variation (CVDBH) and functional trait composition of specific leaf area (CWMSLA) as well as stand age and abiotic conditions. We found that tree species diversity increased forest multifunctionality and most of the single functions. Below-ground single and multifunctionality were better explained by tree species diversity. In contrast, above-ground single and multifunctionality were better explained by CVDBH. However, CWMSLA was also an additional important driver for maintaining above- and below-ground forest multifunctionality through opposing plant functional strategies. Stand age markedly reduced forest multifunctionality, tree species diversity and CWMSLA but substantially increased CVDBH. Below-ground forest multifunctionality and tree species diversity decreased while above-ground forest multifunctionality increased on steep slopes. These results highlight that context-dependency of forest diversity attributes might regulate forest multifunctionality but may not have a consistent effect on above-ground and below-ground forest multifunctionality due to the fact that those functions were driven by varied functional strategies of different plant species. We argue that maximizing forest complexity could act as a viable strategy to maximizing forest multifunctionality, while also promoting biodiversity conservation to mitigate climate change effects.

Nanoscale characterization of plasma functionalized graphitic flakes using tip-enhanced Raman spectroscopy

The chemical functionalization of graphene nanomaterials allows for the enhancement of their properties for novel functional applications. However, a better understanding of the functionalization process by determining the amount and location of functional groups within individual graphene nanoplatelets remains challenging. In this work, we demonstrate the capability of tip-enhanced Raman spectroscopy (TERS) to investigate the degree and spatial variability of the appearance of disorder in graphitic nanomaterials on the nanoscale with three different levels of nitrogen functionalization. TERS results are in excellent agreement with those of confocal Raman spectroscopy and chemical analysis, determined using x-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry, of the functionalized materials. This work paves the way for a better understanding of the functionalization of graphene and graphitic nanomaterials at the nano-scale, micro-scale, and macro-scale and the relationship between the techniques and how they relate to the changes in material properties of industrial importance.

Effect of Transition Metals on the Oxygen Reduction Reaction Activity at Metal‐N3/C Active Sites

AbstractThe roles of various transition and post‐transition metals in model non‐precious‐metal catalysts for the oxygen reduction reaction (ORR) are reported after being prepared via a molecularly defined terpyridine unit covalently attached to a carbon black support. We previously reported the use of a terpyridine‐modified iron‐based catalyst that allowed for the controlled deposition of highly active nitrogen functionalities on the carbon support, which adopts a Fe−N3/C active site formation. In this work, we expand on this idea by altering the metal center in the predefined active sites M−N3/C and compare the ORR reactivity of the isostructural set of catalysts, where M=Fe, Co, Ni, Mn, and Sn. The results show that the iron‐based material was the most active catalyst in acid, whereas the cobalt‐based catalyst was most active in base. In addition, nickel‐ and manganese‐based materials showed promising activity for the ORR in both acidic and basic media. We demonstrate that, with a suitable templating bis‐chelating nitrogenous ligand, the M−N3/C active site geometry is adopted with a wide range of non‐precious‐metal centers on a Vulcan carbon surface, and the resulting catalysts are ORR active in a range of conditions, further confirming the tunability and versatility of the N3 site. As expected, post‐transition metals, such as tin, do not coordinate to the N3 nitrogenous ligand under synthetic conditions and deposits tin oxides(s). This study confirms the generality of the phenomenon of M−N3/C as an ORR catalytic site.

Porous and ultrafine nitrogen-doped carbon nanofibers from bacterial cellulose with superior adsorption capacity for adsorption removal of low-concentration 4-chlorophenol

Porous and Ultrafine Nitrogen-doped carbon nanofibers (NCNFs) were successfully obtained from bacterial cellulose (BC) by carbonization/activation in NH3/N2 atmosphere at higher temperatures. Thanks to the ammonia treatment, the as-obtained NCNFs have nanoarchitectures constructed of one-dimensional (1-D) nanofiber with ultrafine fibers, hierarchically porous structures, abundant nitrogen functionalities leading to the basic and hydrophobic surface, which render them as excellent adsorbents for the adsorption removal of organic pollutants from aqueous solutions. Their adsorption performance for low-concentration 4-chlorophenol (4-CP) were investigated systematically under different conditions. In comparison with the carbon nanofibers (CNFs) without ammonia treatment and commercial activated carbon (CAC), NCNFs displayed greatly enhanced adsorption capacity, short equilibrium time and wide pH range. NCNF-1000 prepared at 1000 °C had adsorption capacity of 4-CP up to 604.1 mg/g for the initial low-concentration of 100 mg/L, which was superior to the previously reported adsorbents. Analyses of the equilibrium adsorption and kinetic data revealed that the adsorption process of 4-CP onto NCNFs were fitted well with the Liu isotherm and pseudo-second-order kinetic models. The thermodynamic parameters (ΔH°, ΔS°, ΔG°) for 4-CP adsorption onto NCNFs confirmed that the essence of 4-CP adsorption was exothermic, feasible and spontaneous. The possible adsorption mechanism of 4-CP on NCNFs was proposed. The excellent adsorption performance of NCNFs for 4-CP were mainly ascribed to their maximum effective surface area, short mass transfer path and hydrophobic surface, which resulted from their nanoarchitectures with many exposed, shallow and accessible pores and a great deal of nitrogen functionalities.

A General Synthetic Strategy toward Highly Doped Pyridinic Nitrogen‐Rich Carbons

AbstractDoping carbon materials with p‐block elements such as nitrogen is an effective approach to tune electronic properties of the framework and can endow the host's new characters. To date, highly doped carbons with tunable nitrogen speciation are still less explored due to the grand challenge in fabrication; for example, the typical synthesis based on the pyrolysis of nitrogen‐containing precursors shows a trade‐off between the total nitrogen content and the carbonization temperature, limiting the value to ≈12 wt% at 1073 K. Herein, intensifying ring opening of cross‐linked polymers through controlled pre‐oxidation followed by conventional pyrolysis is demonstrated as an elegant method to circumvent this challenge. In addition to fine tunability at different nitrogen speciation, this strategy can increase the nitrogen content by two‐ to threefold (maximum ≈22 wt%) and shows general viability in six different N‐bearing (co)polymers. The highly doped pyridinic nitrogen‐rich carbons show i) a remarkable capacity of 879 mAh g−1 at 0.1 A g−1 and excellent cycling performance in lithium ion batteries, and ii) significantly boosted catalytic performance in the selective oxidation of diverse substrates. Therefore, this facile synthetic strategy and the tunability at nitrogen functionalities will greatly broaden the applications of this new class of functional materials.

Fabrication of vertically aligned N-doped carbon nanotube arrays on vermiculite by horizonal chemical vapor deposition

Efficient synthesis of large-scale vertically aligned nitrogen-doped carbon nanotube arrays (VA-NCNTs) has always been a challenge. In this study, we proposed a facile way to obtain mass VA-NCNTs between vermiculite layers by horizonal chemical vapor deposition (CVD). Vermiculite with layered compound as the catalyst substrate, Fe and Mo as the active metal phase is evenly distributed between the vermiculite layers, melamine is pyrolyzed as a single source for both carbon and nitrogen to synthesize nitrogen-doped carbon nanotube (CNT) array materials with relatively uniform length and diameter at an optimum temperature of 800 °C. We explored the effect of temperature on synthesis of VA-NCNTs, the results indicated that the VA-NCNTs are sensitive to temperature changes during the CVD synthesis process, the arrangement, diameter, nitrogen content, and the type of nitrogen function of CNTs could be modified. This work contributes to the study of how the growth temperature affecting the morphology of the as-prepared CNTs, and provides a potential method for the controllable mass production of oriented NCNTs.

In vivo glucose-6-phosphatase inhibitory, toxicity and antidiabetic potentials of 2-picolylamine thioureas in Swiss albino mice.

The 2-picolylamine is a simplest analogue of the alkaloid that has secondary and tertiary nitrogen function in its cyclic structure like that of alkaloids that can be derivatized to a number of biologically active compounds. In connection to our previous work, in the present work, three thiourea derivatives (I = 1,3-bis(2-benzyl-3-phenyl-1-(pyridine-2-yl) propyl) thiourea, II = 1,3-bis (pyridin-2-ylmethyl) thiourea, and III = 1-(2-benzyl-3-phenyl-1-(pyridine-2-yl) propyl)-3-phenylthiourea) were synthesized using 2-picolylamine template which is a readily available synthetic analogue of naturally occurring alkaloid. The biological effect of the synthesized derivatives were monitored on the activity of glucose-6-phosphatase in Swiss albino mice (21-days). The derivatives were also tested for their potential toxicity in a 28-days sub-chronic toxicity studies by assessing their effects on different parameters like hematological, serum biochemistry and liver histology. The therapeutic effect of the safe derivative (I) was examined in streptozotocin-induced diabetic mice as well. The derivatives showed inhibition of the enzyme activity from good to an excellent degree. Compound I had the highest inhibition with 21.42 ± 5.113 mg of the released phosphate as compared to that of the positive control group (84.55 ± 3.213 mg). Only I turned out to be safe for use in animals without exerting any toxic or lethal effects on any of the assessed parameters in the used animal model. Compound I efficiently reversed the effects like hyperglycemia, hyperlipidemia and weight loss in the test animals. Out of these three-tested compounds, I was found safe to be use as therapeutic agent in diabetes complications. However, further toxicological studies in other animal models are needed as well.