Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Xin Lei,Yu Lei,Shuangshuang Cheng,Xin Yang
N -nitrosamines are great concern in potable water reuse. This study investigated the reaction kinetics of chlorine radicals (Cl • and Cl 2 •− ) with N -nitrosamines. The second-order reaction rate constants of Cl • ( k Cl • ) and Cl 2 •− ( k Cl2 •− ) with eight N -nitrosamines at pH 7.0 varied in the range of (5.02 ± 0.41)–(57.1 ± 4.25) × 10 8 M −1 s −1 and (0.46 ± 0.04)–(10.6 ± 0.73) × 10 8 M −1 s −1 , respectively. The numbers of methylene groups (#−CH 2 −) showed a good positive correlation with k Cl • (R 2 = 0.71), but not with k Cl2 •− . The degradation of eight N -nitrosamines under UV/chlorine advanced oxidation process (AOP) slightly increased by 1–18% in contrast to UV irradiation alone, and Cl − in the AOPs cannot inhibit their removal. The results improved the understanding of the fate of N -nitrosamines in chlorine radical-involved AOPs.
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LUMINESCENCE
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2022
·Vol. 37
·期 10
·1725-1732
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IF 2.613
Ping Li
Developing artificial nanoparticles with peroxidase-like activity have attracted great interests because their catalytic activity is not easy to lose under harsh conditions compared with natural enzymes. In this work, the N-doped carbon dots (CDs) were prepared; it was found that the N-doped CDs showed high peroxidase-like catalytic activity towards the reaction system of hydrogen peroxide:3,3′,5,5′-tetramethylbenzidine (TMB). The catalytic mechanism of the N-doped CDs was explored using electron spin resonance spectra, cyclic voltammetry methods and simulation of density functional theory calculations. This work can offer a new feasible method for synthesizing N-doped carbon quantum dots used as artificial peroxidases in biological and environment applications.
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FUEL
·
2022
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IF 8.035
Ben Chen,Bowen Hui,Yuting Dong,Qiang Sheng,Xiang Li,Qinglan Hao,Chunjing Liu
The SiO 2 - and MCM-41-supported Ni catalysts were prepared by an incipient wetness impregnation method and their performance in the hydrogenation of liquid organic hydrogen carrier were evaluated using N-ethylcarbazole (NEC) as model compound. Ni particles were mainly located on the external surface of the SiO 2 -supported Ni catalysts. Both Ni particles on the external surface and filled in the mesopores of MCM-41 were found in the MCM-41-supported catalysts. The reduction of surface Ni particles occurred at low temperature (ca. 365 °C), but the complete reduction of Ni particles in the mesopores of MCM-41 required high temperature (ca. 555 °C). The MCM-41-supported Ni particles possessed lower electron densities than the SiO 2 -supported ones. The surface Ni particles showed the same activity in the hydrogenation of NEC, which were more active than those in the mesopores of MCM-41. A correlation between the electron density of Ni particles and their selectivity was observed. The higher the electron density of Ni particles, the higher the selectivity to the fully hydrogenated product (dodecahydro-N-ethylcarbazole) is.
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Journal of CO2 Utilization
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2022
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IF 8.321
Jinsong Shi,Hongmin Cui,Jianguo Xu,Nanfu Yan,Shengyong You
Influences of porous carbon’s physicochemical properties on CO 2 adsorption vary with CO 2 pressure. The clarification of such complicated influences will undoubtedly be beneficial to the design and synthesis of carbonaceous adsorbents. To this end, in the current work we synthesized a series of N-doped hierarchically ordered micro-mesoporous carbons (NHOMCs). Ordered mesoporous polymer was synthesized with a solvent-free method using F127 as the soft template. After removing F127, the polymer was activated with KHCO 3 in the presence of urea at 700–800 °C. The obtained NHOMCs inherited the ordered structure of the polymer, and exhibited high surface area and nitrogen content. Synergistic effects of urea and KHCO 3 on nitrogen content and textural properties were discussed and revealed. At 25 °C, high CO 2 uptakes of 4.02 mmol/g (1 bar) and 15.42 mmol/g (20 bar) were achieved by the NHOMCs. We then systematically investigated the correlation between CO 2 uptake and physicochemical properties. The decisive factors of CO 2 uptakes at different pressures (1 bar, 5 bar, 10 bar, 20 bar) were analyzed. We believe the current work will provide helpful insights into the research of porous carbons for CO 2 adsorption.
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Catalysis Science & Technology
·
2022
·Vol. 12
·期 15
·4893-4902
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IF 6.177
Keting Feng,Tao Sun,Xiaoyun Hu,Jun Fan,Dongyuan Yang,Enzhou Liu
Photocatalytic H2 evolution is a promising way to obtain green H2 due to its clean and sustainable characteristics. Herein, a series of 0D/2D Co0.85Se/TiO2 heterojunctions were fabricated through a successive two-step hydrothermal strategy. Among them, 15%-Co0.85Se/TiO2 displays the most excellent H2 rate of 2312.5 μmol g−1 h−1, which is 10.3 times and 10.8 times higher than that of TiO2 and Co0.85Se, respectively. And the H2 production rate per electrochemically active surface area of 15%-Co0.85Se/TiO2 is 127.41, which is obviously more than that of TiO2 (14.17) and Co0.85Se (5.39). Based on the core-level alignment method and free radical capture tests, the enhanced activity mainly resulted from the higher electrochemically active surface area and the formation of a p–n heterostructure between TiO2 and Co0.85Se. This research provides a strategy for the development of noble metal-free nanocomposites for efficient photocatalytic H2 production.
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MACROMOLECULES
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2022
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IF 6.057
Gaopeng Shi,Xiaoning Geng,Yuanbiao Liu,Guozhang Wu
Enthalpy hysteresis (ΔHR), an easily accessible quantity determined from a well-defined cooling and subsequent heating cycle of heat capacity curves, was recently reported to bear a proportional relationship with the α-related excess entropy of polymers at glass transition temperature( Tg). The kinetic fragility m of polymers was thus verified to link with thermodynamic parameters of Tg·ΔCp/ΔHR, as predicted by the Adam–Gibbs equation. In this work, enthalpy hysteresis of poly(n-alkyl methacrylate)s was investigated systematically to clarify whether ΔHR is influenced by multifarious non-α-related contributions. The results showed that the ΔHR for higher poly(n-alkyl methacrylate)s is abnormally suppressed, as manifested by failure of the theoretic correlation between m and Tg·ΔCp/ΔHR. The anomalous suppression appears non-related to the βJG relaxation but stems from nanophase separation of the alkyl sidechains. Once the PE-like nanophase is completely destroyed, either by increasing the steric hindrance of side groups or by introducing small molecule-bridged hydrogen bonds, ΔHR recovers, and the theoretic correlation between m and Tg·ΔCp/ΔHR is re-established. Further experiments revealed that the abnormal ΔHR suppression occurs only when the periodicity of phase separation is comparable to the size of the cooperative rearrangement region of bulk α relaxation at Tg. Accordingly, the deviation of m and Tg·ΔCp/ΔHR correlations from the theoretic prediction must be related to the existence of two different but partly coupled glass transitions in higher poly(n-alkyl methacrylate)s. The extremely hindered and confined glass transition in the PE-like nanodomains is likely to cause the anomalous suppression of global enthalpy hysteresis.
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Batteries & Supercaps
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2021
·Vol. 5
·期 1
·e202100203
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IF 7.093
Yaqian Dong,Yaohui Zhang,Nana Wang,Guifu Zou,Qiang Zhang,Shengquan Gan,Liang He,Zhongchao Bai
Graphical Materials for better SIB anode : The synergistic effects of the one-dimensional N-doped carbon and ultra-small Fe 7 S 8 particles in the reported pod-like Fe 7 S 8 @N−C nanocomposite, improve electrical conductivity and alleviate the volume expansion of the anode of SIB during cycling. One dimensional Fe 7 S 8 @N−C nanocomposite, consisting of Fe 7 S 8 nanoparticles homogeneously embedded in N-doped carbon nanowires, was synthesized by a facile hydrothermal-annealing process. As an anode material for sodium-ion batteries, the electrode exhibited capacities of 481 mA h g −1 after 1000 cycles at 5 A g −1 and 591 mA h g −1 at 200 mA g −1 with a retention ratio of 91 %. The excellent rate performance and cycling stability can be attributed to the synergistic effects of the one-dimensional N-doped carbon and ultra-small Fe 7 S 8 particles, which will improve electrical conductivity and alleviate the volume expansion of the electrode during cycling. This work will afford a great reference for further development of iron sulfides-based anode materials towards high-performance sodium-ion batteries.
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SOLAR ENERGY MATERIALS AND SOLAR CELLS
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2021
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IF 7.267
Ping Hu,Yang Feng,Qi Li,Chuan-Huang Lin,Yu-Hao Ning,Yi-Ting Li,Lin-Ping Yu,Zhong Cao,Ju-Lan Zeng
Microencapsulation of phase change materials (PCMs) with functional shell materials such as luminescent material could endow the obtained microencapsulated PCMs (MPCMs) with improved latent heat storage properties. The PCM core in turn could protect the luminescence shell from large temperature shifting and thus improve its performance. In this work, a series of MPCMs derived from n -octadecane (ODE) core and CaF 2 shell were synthesized via a self-assembly method. The effects of the preparation conditions, including the core/shell mass ratio, the dosage of the emulsifier (styrene-maleic anhydride copolymer , SMA) and the dosage of the chelator (Na 3 Cit), on the properties of the prepared ODE@CaF 2 MPCMs were investigated and the optimal preparation condition was obtained. The MPCM obtained according to the optimal procedure (MPCM1) exhibited an encapsulation ratio of 54.02% and a latent heat of 131 J/g with negligible leakage. It also possessed excellent thermal reliability and significantly improved thermal conductivity . The MPCM1 could not only be utilized as good latent heat storage material and thermal regulation material, but also provided one new idea to prevent the thermal quenching of luminescence materials. In addition, this work could shed some light on the high-value utilization of recovered fluorine resources.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2021
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IF 5.816
Zhen Hu,Jian Chen,Peiyao Pan,Chao Liu,Jingming Zeng,Yang Ou,Xiaopeng Qi,Tongxiang Liang
Exploration for an earth-rich and competent electrocatalyst for the hydrogen evolution reaction (HER) is a significant and challenging approach to confronting the resources shortage and environmental crisis. Porous N-doped Mo 2 C@C (N-Mo 2 C@C) nanoparticles self-encapsulated in nanospheres are presented as a high-performing HER electrocatalyst fabricated through a one-pot solvothermal method followed by hydrogen calcination . Structural analyses show that acetamide can regulate the size of the nanospheres, provide a N source for doping and form porous structures composed of Mo 2 C, which suggests the exposure of extensive active sites as well as the contact and diffusion among the medium, electrodes, and gas. Theoretical calculations show that the N doping can enhance the activity of the Mo-C bond, reduce the energy of capturing hydrogen intermediates, and increase the catalytic conductivity. This work offers a simple and promising strategy to understand the catalytic mechanism required to optimize the activity of Mo-based electrocatalysts via N doping.
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Stem Cell Research & Therapy
·
2021
·Vol. 12
·期 1
·1-14
·
IF 6.832
Zhang Jiayu,Lan Tingting,Han Xue,Xu Yuchan,Liao Li,Xie Li,Yang Bo,Tian Weidong,Guo Weihua
Background The low survival rate or dysfunction of extracellular matrix (ECM)-based engineered organs caused by the adverse effects of unfavourable local microenvironments on seed cell viability and stemness, especially the effects of excessive reactive oxygen species (ROS), prompted us to examine the importance of controlling oxidative damage for tissue transplantation and regeneration. We sought to improve the tolerance of seed cells to the transplant microenvironment via antioxidant pathways, thus promoting transplant efficiency and achieving better tissue regeneration. Methods We improved the antioxidative properties of ECM-based bioroots with higher glutathione contents in dental follicle stem cells (DFCs) by pretreating cells or loading scaffolds with the antioxidant NAC. Additionally, we developed an in situ rat alveolar fossa implantation model to evaluate the long-term therapeutic effects of NAC in bioroot transplantation. Results The results showed that NAC decreased H 2 O 2 -induced cellular damage and maintained the differentiation potential of DFCs. The transplantation experiments further verified that NAC protected the biological properties of DFCs by repressing replacement resorption or ankylosis, thus facilitating bioroot regeneration. Conclusions The following findings suggest that NAC could significantly protect stem cell viability and stemness during oxidative stress and exert better and prolonged effects in bioroot intragrafts.
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PubMed
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NEW CARBON MATERIALS
·
2021
·
IF 1.905
Jing Zhang,Lianghao Song,Chenfei Zhao,Xiuping Yin,Yufeng Zhao
Although the Co and N co-doped carbon catalyst (Co-NC) has attracted much attention because of its low cost and the natural abundance of the dopants, it has a low oxygen reduction reaction (ORR) activity and a high selectivity for the two-electron (2e - ) reduction of oxygen to H 2 O 2 , which affects its use in fuel cells. Co-NC catalysts were prepared by the pyrolysis of a mixture of cobalt chloride and chitosan pretreated with zinc chloride at 650, 750 and 850 o C, followed by washing with nitric acid and annealing at 900 o C. The results indicate that zinc chloride helps the complexing of chitosan with Co 2+ , which is also a chemical activator that generates pores, and annealing caused the evaporation of the spherical Zn metal nanoparticles formed by the carbothermal reduction of Zn ions, leading to a unique porous structure of the catalysts with spherical pores filled with spherical carbon nanoparticles formed by the growth of nitrogen-doped carbon as a result of the Co catalyst. The degree of graphitization is also improved by the Co catalyst. The Co-NC catalyst obtained at a pyrolysis temperature of 750 o Cshows the same four-electron (4e - ) reduction of oxygen as a commercial Pt/C catalyst, and a significantly higher ORR catalytic activity, longer-term stability and better methanol tolerance than a commercial Pt/C catalyst. These are due to its large specific surface area, high contents of pyridinic nitrogen and graphitic nitrogen that disperse the Co species and its excellent electrical conductivity.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Yuming Tu,Hui Yu,Wei He,Zhiyong Zhou,Wei Liu,Fan Zhang,Yixin Qu,Zhongqi Ren
The separation of aromatic and alkane is one of the most important and challenge chemical separation process. This study reports the high-efficiency separation of aromatics/alkanes in the pervaporation process based on a series of novel ionic liquid gel membranes. The ionic liquid gel membrane was characterized by FT-IR, SEM, AFM, TGA, and XRD techniques. The results revealed that the IL was maintained in the three-dimensional structure of polymer support and the membrane kept its stability when the temperature was over 300 °C. The relevant parameters i.e. polymer concentration, IL concentration, IL type, film-forming temperature, membrane thickness, feed concentration, operating temperature and feed flow rate on membrane process were investigated. The optimal membrane was prepared when the P(VDF-HFP) and [Amim][Tf 2 N] concentrations were 15 wt% and 45 wt%, the film-forming temperature was 15 °C and the membrane thickness was 120 μm. When the initial toluene concentration was 50 wt% and the flow rate was 200 mL/min, the best flux (120 g·m −2 ·h −1 ) and separation factor (11.3) were observed at 25 °C. Moreover, the separation factor was over 10 and the flux maintained at the same level after working continuously for 30 h, which indicates that the membrane has good stability.
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