ENERGY CONVERSION AND MANAGEMENT
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2022
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IF 11.533
Donghua Xu,Junhao Lin,Shichang Sun,Rui Ma,Mingliang Wang,Jinlong Yang,Juan Luo
Microwave pyrolysis of nitrogen-rich biomass for bio-oil is a green and sustainable pathway to realize energy conversion and produce high-value nitrogenous chemicals. This work selected three typical amino acids (serine (Ser), glutamic acid (Glu), and phenylalanine (Phe)) as nitrogenous model compounds for biomass, and the distribution characteristics and formation mechanisms of the nitrogenous chemicals in bio-oil were studied in depth. Results showed that the amino acid structure and pyrolysis temperature were the crucial factors affecting the distribution and selectivity of nitrogenous chemicals. The nitrogenous chemicals were mainly produced at 200–500 °C from the model amino acids, and the nitrogen in Ser was more prone to accumulating in bio-oil compared with Glu and Phe. At 300 °C, the model amino acids generated numerous amines and cyclic amides through decarboxylation, decarbonylation, and dehydration. Higher temperatures (400 and 500 °C) promoted amines/amides to form nitriles and N-heterocycles, with the releasing of H 2 . Nitriles (including propionitrile and phenylacetonitrile) were typically produced by the straight-chain dehydrogenation of amines. Ser, Glu, and Phe produced N-heterocycles (including pyrazine, pyrrole, 2-pyrrolidone, and indole) based on the cyclization and dehydration between carbonyl and amino compounds, intramolecular dehydration, and cyclization dehydrogenation of phenethylamine, respectively. Finally, the possible formation pathways of the main nitrogenous chemicals were proposed, and the kinetics and thermodynamic analyses were performed through density functional theory (DFT) calculations. The findings could provide theoretical support for the nitrogenous chemicals production from microwave pyrolysis of amino acids and biomass.
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Journal of Environmental Chemical Engineering
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2022
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IF 7.968
Yiqun Chen,Jiandeng Ruan,Baitian Zeng,Wei Jiang,Liting Luo,Qing Shao,Zizheng Liu
This paper offers novel insights into the recently reported cobalt(II) sulfide (CoS) activated sulfite (S(IV)) process. After adding 0.5 g/L CoS and 0.4 mM S(IV) at pH 9.0, 83.1% of acetaminophen (ACP) was removed in 10 min. However, this effect was subject to the inhibition of coexisting chloride or humic acid . Dissolved O 2 played an important role in the reaction. The interactive impacts between S(IV) concentration and initial pH were found the most significant. The CoS/S(IV) system involved synchronous homogeneous and heterogeneous catalysis, which demonstrated sizable ACP degradation. The generated sulfate radical (SO 4 •− ) and hydroxyl radical (HO • ) were primarily responsible for ACP degradation. DFT-based first-principle calculations show the electrons transferred from sulfite to the CoS surface in heterogeneous activation. The pathway of ACP degradation was determined to primarily comprise addition and substitution reactions based on the detected intermediates. Besides, the CoS/S(IV) system demonstrated good reusability and was successful in degrading the other five organics: bisphenol A, metoprolol, estriol, atenolol, and imipramine. The ACP removal performance under real water background was also acceptable. As a result, the CoS/S(IV) system is expected to be a reliable approach for water treatment .
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APPLIED SURFACE SCIENCE
·
2022
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IF 7.392
Kean Chen,Binxian Chu,Qiuju Qin,Xuemei Ou,Runqi Zhao,Xiaoling Wei,Huan Wu,Bin Li,Lihui Dong
As an ideal substitute for the precious metals in the selective catalytic reduction of NO by CO, transition metal oxides perform very well. Thus, a series of CuO - Co 3 O 4 symbiotic oxide porous nanosheet catalysts are prepared with a CTAB-assisted hydrothermal method. Cu5 with the ratio of Cu and Co is 5 : 10, has the best activity on the premise of maintaining the nanosheet structure. Reduction pretreatment of Cu5 with H 2 is carried out, and the surface will be rapidly oxidized in air. In this period, Cu, CuO and Co 3 O 4 were produced and coexisted on surface. Cu5-re-163 exhibits greatly higher N 2 selectivity but a little inferior NO conversion. Further DFT calculation and characterizations proved that [N] free radicals exist during the reaction. The reaction on Cu5 and Cu-re-163 follow L-H and E-R mechanism respectively. [N] radicals on the latter are much easier to desorb, so that they are easy to combine with each other to form N 2 rather than with NO to generate N 2 O, as the reason why Cu5-re-163 has better selectivity.
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Environmental Science-Nano
·
2022
·Vol. 9
·期 9
·3562-3580
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IF 9.473
Zhengwen Wei,Xiang-fei Lü,Wei Wang,Giuseppe Mele,Zhen-Yi Jiang
Owing to the more significant health and environmental risks of 9-phenanthrol (9-PROL) compared to phenanthrene, it is imminent to solve the 9-PROL pollution issue. Herein, Fe3O4-0.75-4,4′-biphenyldicarboxaldehyde (Fe3O4-0.75BIPHENY) was synthesized via a silane coupling reaction and condensation reaction and employed as an efficient nanocomposite for the removal of 9-PROL. The magnetic core provided the possibility for its fast and convenient separation and the aromatic rings on the BIPHENY shell contributed to improving the capturing ability of 9-PROL molecules via the formation of π–π interactions. Multiple characterization techniques were employed to obtain a comprehensive understanding of the prepared magnetic adsorbents. Fe3O4-0.75BIPHENY not only exhibited an excellent adsorption performance towards 9-PROL, but also showed a relatively excellent regeneration performance. The homogeneous surface of Fe3O4-0.75BIPHENY provided adsorption sites for the adsorption of 9-PROL molecules, which adhered in monolayer molecular form. Importantly, density functional theory calculations provided novel deep insights into the most possible adsorption bonding mode and verified that π–π interactions existed in the offset stacking form. Furthermore, the visible electrostatic potential and energy orbital distribution plots demonstrated the validity of the adsorption reaction and stability of a specific configuration. This study provides guidance for the assembly of novel magnetic nanocomposites for alleviating traditional and secondary pollution caused by polycyclic aromatic hydrocarbons.
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2021
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IF 5.302
Xiangzhao Zhang,Puhao Xu,Xinyue Wu,Xinyi Gui,Guiwu Liu,Mingfen Zhang,Haining Meng,Guanjun Qiao
The wetting of ZrB 2 ceramic by molten pure Cu, Cu-(20, 30, 40, 50 at.%)Ti alloys were performed by the sessile drop method under vacuum of ∼4 × 10 −4 Pa in the 1030−1070 °C temperature range. The wetting and interfacial behaviors of Cu-Ti/ZrB 2 systems were analyzed and discussed. Furthermore, the work of adhesion and electronic properties of the Cu(1 1 1)/ZrB 2 (0 0 0 1) and Ti(0 0 0 1)/ZrB 2 (0 0 0 1) atomic interfaces were quantitatively evaluated by first-principles method. The wettability is significantly improved with the Ti concentration or wetting temperature increasing as a result of the formation of (Ti) solid solution at interface. The calculated results show that the B-terminated ZrB 2 (0 0 0 1) surface is preferable to bond with Ti(0 0 0 1) surface, and the electronic structure reveals that the dominant interfacial bonding is the Ti-B ionic bond for the Ti/B-terminated ZrB 2 interface.
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CHEMOSPHERE
·
2020
·
IF 5.778
Pin Wang,Lingjun Bu,Yangtao Wu,Wangchi Ma,Shumin Zhu,Shiqing Zhou
The study investigated the degradation kinetic and transformation mechanism of ibuprofen (IBP) in UV/H 2 O 2 process from both experimental and theoretical aspects. Impacts of H 2 O 2 dosage, solution pH, quenching agent, and concentration of nitrite (NO 2 − ) on IBP degradation in UV/H 2 O 2 process were evaluated. Both experimental results and theoretical calculations indicated that • OH played an important role in the degradation of IBP and its transformation products . The second-order rate constants of • OH and • NO 2 with IBP were calculated as 3.93 × 10 9 M −1 s −1 and 5.59 × 10 −3 M −1 s −1 , based on the transition state theory, which explained the phenomenon that addition of NO 2 − inhibited IBP degradation. Further, according to the results of ultra-high-resolution mass and density functional theory calculations, mechanisms of a detailed degradation pathway for IBP were clarified. Namely, the detailed mechanistic formation pathways for hydroxylated and keto-based products were proposed. Then, possible active sites of the keto-based products, as well as the corresponding subsequent products were predicted by Condensed Fukui Function. Our study can broaden the knowledge of the reactions of emerging contaminants with • OH, and provide theoretical foundation for the optimization of UV/H 2 O 2 process.
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PubMed
高影响因子
RSC Advances
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2020
·Vol. 10
·期 61
·37014-37022
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IF 3.119
Shengfu Liao,Jianguo Liu,Long Yan,Qiying Liu,Guanghui Chen,Longlong Ma
Anthraquinones are recognized as high efficiency photocatalysts which can perform various redox reactions in aqueous or organic phases. We have experimentally proven that 2-BrAQ can undergo hydrogen transfer with an alpha-aromatic alcohol under light conditions, thereby efficiently oxidizing the aromatic alcohol to the corresponding product. The yield of 1-phenethanol to acetophenone can reach more than 96%. In subsequent catalyst screening experiments, it was found that the electronegativity of the substituent at the 2 position of the anthraquinone ring and the acidity of the solvent affect the photocatalytic activity of anthraquinones. After using various aromatic alcohol substrates, 2-BrAQ showed good conversion and selectivity for most aromatic alcohols, but showed C–C bond cleavage and low selectivity with non-α-position aromatic alcohols. In order to explore the mechanism of the redox reaction of 2-BrAQ in acetonitrile solution, the corresponding free radical reaction pathway was proposed and verified by density functional theory (DFT). Focusing on calculations for 2-BrAQ during the reaction and the first-step hydrogen transfer reaction between the 2-BrAQ triplet molecule and the 1-phenylethanol molecule, we recognized the changes that occurred during the reaction and thus have a deeper understanding of the redox reaction of anthraquinone compounds in organic systems.
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PubMed
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2020
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IF 5.774
Weike Zhao,Bo Zhou
In recent years, multi-walled carbon nanotubes (CNTs), which are emerging nanocatalysts, have received much attention in advanced oxidation processes. CNTs were introduced into H 2 O 2 /Fe(III) Fenton-like process to enhance the degradation of bisphenol A (BPA) in this study. The results of the study suggests that CNTs could effectively promote electron transfer from H 2 O 2 to Fe(III) and directly reduce Fe(III) to Fe(II) to accelerate Fe(III)/Fe(II) cycles, in which carbonyl groups and structural defects of CNTs were identified as the major active sites via SEM, Raman, XRD, FTIR and XPS analyses. It was revealed that hydroxyl radical (·OH) majorly contributed to the degradation of BPA, and the generation efficiency of ·OH was significantly increased by 3.2 times with the addition of CNTs. Also, nine intermediate products were identified, and the possible degradation pathways of BPA were proposed through the density functional theory (DFT) calculations and HPLC-MS/MS analysis. The ecotoxicity evaluation of BPA demonstrates that the oxidative degradation of BPA in CNTs/H 2 O 2 /Fe(III) system could effectively reduce its environmental risk. The critical experimental parameters including the dosage of Fe(III), H 2 O 2 , CNTs, initial pH and various anions (Cl − , HCO 3 – , SO 4 2− ) were investigated, and the reusability experiments indicate that CNTs maintained high stability and reusability during the reaction.
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高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2020
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IF 4.939
Xuhan Li,Ran Zhang,Xiao Zhu,Liqiang Zhang
A series of N-doped activated carbon (NAC) with varying N contents were prepared to study the effect of N-doping on hydrogen iodide (HI) decomposition over activated carbon in sulfur-iodine (SI) cycle for hydrogen production . Element analysis , XPS and N 2 adsorption were performed for samples’ characterization. The HI conversion was proportional to the N content and the sample with 6.006% N content gave the highest HI conversion of 22.84%. Density functional theory (DFT) calculations confirmed the experimental results and elucidated the influence mechanism. The increase of N contents was favor to the decomposition of HI by enhancing the chemisorption of HI molecule on carbon structure. The role of N-doping was to remodel the local electronic density and charge distribution on the carbon surface . In addition, the effect of types of N-containing functional groups on HI decomposition was calculated. Results showed that the N-6 structure was conducive to the chemisorption of HI but N-5 and N-Q structures had a reverse effect. However, when the three N-containing functional groups exist simultaneously, the overall chemisorption of HI was enhanced, which, in turn, enhanced the decomposition of HI. This study can provide underlying guidance for preparing highly efficient NAC for HI decomposition.
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Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 36
·20878-20890
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IF 10.733
Aolei Gao,Xinjuan Hou,Zhenhua Sun,Shaopeng Li,Huiquan Li,Jianbo Zhang
Spinel-type lithium manganese oxides (LMOs) are the most promising lithium-adsorption materials. LMOs can be in the form of solid solutions of LiMn2O4, Li1.33Mn1.67O4, and Li1.6Mn1.6O4. However, uncertainty about the lithium-desorption mechanism restricts material development. The synthesis of intermediate products of spinel-type LMOs during acid treatment is important to investigate such a mechanism. In this work, precisely controlled acid treatment experiments were performed to successfully obtain the intermediate products of LiMn2O4, Li1.33Mn1.67O4, and Li1.6Mn1.6O4. For LiMn2O4, lithium was desorbed with the dissolution of manganese. For Li1.33Mn1.67O4 and Li1.6Mn1.6O4, the lithium-desorption mechanism was an ion-exchange reaction, where lithium ions (Li+) in the 8a sites were prioritized for the ion-exchange reaction compared with Li+ in the 16d sites. Density functional theory (DFT) calculation results confirmed the experimental results and explained that the prioritization of Li+ in the 8a sites arose from its lower reaction-energy barrier, thereby revealing that Li+ preferred to move to the nearest vacant 8a sites when lithium was desorbed because of the lower diffusion-energy barrier. This work is the first to clarify the lithium-desorption mechanism through experiments and DFT calculations, and thus lays a foundation for the further exploitation of LMOs.
研究领域:
材料科学
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电化学
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计算化学
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高影响因子
CHEMICAL ENGINEERING JOURNAL
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2024
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IF 13.3
Fengliang Cao,Qingshan Zhao,Xiaojie Tan,Libo Wang,Yikun Zhao,Wei Deng,Linjie Zhi,Mingbo Wu
Optimizing the local environment of metal active centers bonded by nitrogen ligands (M−N 4 ) through additional axial coordination provides a promising approach to enhance the reaction kinetics of heterogeneous catalysis. However, achieving precise targeting and construction of efficient active sites remains a major challenge. In this study, under the guidance of density functional theory (DFT) calculations, we precisely position and engineer atomic Co–N 4 active sites with axial O coordination on porous carbon nanosheets (Co 1 /NOC) for boosted aromatic nitroreduction through a novel template-anchoring strategy. The resulting Co 1 /NOC catalyst exhibited unprecedented catalytic activities towards a series of functionalized nitroaromatics with a record overall turnover frequency (TOF) of 38022 h −1 under mild reaction conditions, 7.6- and 38 times higher than that of Co–N 4 sites (Co 1 /NC) and commercial Pd/C catalysts, respectively, standing ahead of the reported catalysts. Targeted DFT calculations reveal that axial oxygen coordination efficiently promotes the electronic delocalization of the Co center, which dramatically facilitates the formation and utilization of reactive H* species, enhances the selective adsorption of nitroaromatics, and accelerates the conversion of aromatic nitroreduction, eventually attaining exceptional catalytic performance. This work offers a new avenue for precisely tailoring the coordination environment of single-atom catalysts to achieve advanced catalytic performance in chemical transformations.
研究领域:
催化化学
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材料科学
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理论计算
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高影响因子
JOURNAL OF MOLECULAR STRUCTURE
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2024
·
IF 4
Lei Zhang,Baicheng Feng,Shibo Pang,Huifen Xin,Kun Li,Yan Jin
Six N‑hydroxy-5-norbornene-2,3-dicarbonylimine sulfonates(3a-3f) were created in this paper and produced as non-ionic photoacid generators (PAGs) in good yields. 1 H NMR and 13 C NMR were used to confirm the structures of the compounds and 19 F NMR was used to further justify the structure of 3a. Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) showed that all six PAGs have good thermal stability. Additionally, the solvent's influence on PAG compounds was examined using Ultraviolet and visible spectrum (UV–vis) and 254 nm fluorescence spectra (FS). The changes in the six PAG components of the products were monitored by HPLC on exposure to UV light (254 nm). An exposure acid production assay based on the spectrophotometric approach was developed using Rhodamine B (RB) as the acid sensor. The degradation and acid production quantum yields of the six PAGs were tested, and the results showed that all PAGs exhibited a high acid-producing capacity. In addition, we present a potential mechanism for the photogeneration of sulfonic acid, and DFT time calculations using Gaussian calculations support the N O bond cleavage mechanism of PAG 3c.
研究领域:
材料科学
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化学合成
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光化学
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