Environmental Science-Nano
·
2022
·Vol. 9
·期 9
·3407-3416
·
IF 9.473
Han Song,Xinwen Ou,Mengye Wang,Yan Zhang,Zhang Lin
H2 production during the transformation of Fe(OH)2 into magnetite (i.e., Schikorr reaction), has a significant impact on many environmental applications, including the long-term effectiveness of permeable reactive barriers composed of zerovalent iron and the stability of geological radioactive waste repository. However, the reactivity of the Schikorr reaction is not systematically evaluated and its chemical mechanism still remains controversial. Here, we investigate water reduction on the Fe(OH)2 surfaces with the help of an interface-reaction model between water and Fe(OH)2. The Fe(OH)2 hexagonal nanosheets prepared using a coprecipitation method possess dominantly exposed (001) and (100) facets. As unveiled by the DFT simulations, the (001) Fe(OH)2 facet only exposes OH, which is, therefore, inert to water reduction. Moreover, the active Fe-exposed (100) Fe(OH)2 facet is more thermodynamically favourable for water adsorption and dissociation than the (101) and (102) facets. However, the high energy barrier for water dissociation (2.79 eV) may restrict the rate of water reduction on the Fe(OH)2 facet. In addition, the capacity of (100), (101), and (102) Fe(OH)2 facets to adsorb OH− is stronger than that for H2O, which further inhibits water reduction. Furthermore, DOS calculations manifest that Fe d orbitals play a significant role in H2O adsorption, indicating that manipulating the electronic structure of the Fe site is a critical path to mediate water reduction in Fe(OH)2. Our study provides new insights into the understanding of the mechanism of the phase transformation of Fe(OH)2 under anaerobic conditions in environmental and earth sciences.
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Journal of Environmental Chemical Engineering
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2023
·
IF 7.7
Guo-chang Song,Xing-yu Yang,Zhong-wei Li,Qiang Song
Arsenic (As) pollutants are highly toxic and using Ca-based minerals to adsorb As 2 O 3 is effective for emission control. In this study, a fixed-bed experimental system was used to study the adsorption of As 2 O 3 by the mixture of CaO, SiO 2 , and Al 2 O 3 at 1200 °C. The amount of As adsorbed by multiple minerals was higher than that by single minerals, indicating enhanced adsorption of As 2 O 3 under the coupling effects of Ca, Si, and Al. The adsorption amount of As first increased and then decreased with an increase in the CaO:(SiO 2 +Al 2 O 3 ) and SiO 2 :Al 2 O 3 ratios. Adsorbed As was mainly enriched in Ca-Si-Al mineral, including Ca 2 Al 2 SiO 7 . Density Functional Theory calculation was conducted to study the As 2 O 3 adsorption on the Ca 2 Al 2 SiO 7 (0 0 1) surface. The analysis of Mulliken charge and density of states showed that As 2 O 3 molecules formed Al-O, O-As, and Ca-O bonds with the Al, O, and Ca sites. Si and Al in Ca 2 Al 2 SiO 7 enhanced the adsorption ability of Ca sites by promoting electron transfer . Si/Al ratio close to 1:1 is conducive to the formation of Si-O-Al structures, thus further enhancing the adsorption. The results can help optimize coal blending strategies and modify adsorbents to further reduce As emissions during coal combustion .
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高影响因子
RENEWABLE ENERGY
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2021
·
IF 8.001
Ying Li,Shengli Niu,Jun Wang,Wenbo Zhou,Yongzheng Wang,Kuihua Han,Chunmei Lu
A pure mesoporous SrTiO 3 with a honeycomb pore structure is synthesized by the sol-gel method and applied to catalyze transesterification of palm oil with methanol for the biodiesel production . The catalyst is characterized by XRD , CO 2 /NH 3 -TPD, N 2 adsorption-desorption, SEM-EDX, Raman and XPS to reveal its catalytic performances. The highest FAME yield of 93.14% is achieved in transesterification with the molar ratio of methanol to oil of 15:1 and catalyst concentration of 6 wt % at 170 C for 3 h. Besides, the catalyst is highly tolerant of FFAs and moisture, where the FAME yields of 83.80% and 86.50% are achieved even with the oleic acid and water addition of 10 wt % and 5 wt %. Meanwhile, the catalyst is found to be an effective catalyst for the simultaneous esterification and transesterification. The molecular simulation results show that the Ti sites are more easily attacked by FFAs and the Sr active sites are thus retained for the adsorption of methanol to catalyze transesterification, which explains the bifunctionality of the catalyst.
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DESALINATION
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2024
·
IF 8.3
Li Wang,Jianfeng Zhang,Shixin Meng,Huiyong Wu,Yunze Zhao,Zhen Meng,Lei Feng,Huanting Wang,Yuan Cheng,Liangrong Yang,Huizhou Liu
The dissolution loss of extractant into aqueous solution during lithium solvent extraction from salt lakes poses a significant issue. We found that branched chains of neutral organophosphorus extractants provide suitable steric hindrance, enhancing lithium extraction efficiency and Li/Mg selectivity. Additionally, increasing the number of alkyl chains in organophosphorus extractants increases their hydrophobicity, thereby reducing extractant dissolution loss during the extraction process. Based on these findings, a novel extraction system comprising tri(2-ethylhexyl) phosphate (TOP), FeCl 3 , and 4-methyl-2-pentanone (MIBK) was explored. The extraction conditions, including the Fe/Li molar ratio, diluents, phase ratio, and stripping conditions, were thoroughly investigated and optimized. The extraction mechanism was elucidated at the molecular level using FT-IR, Raman, NMR, and density functional theory (DFT) calculations. The results demonstrated that the TOP-FeCl 3 -MIBK system achieved an 85 % extraction efficiency for Li + in a single stage, with a Li + /Mg 2+ separation factor reaching 5842, surpassing previously reported data in the literature. 31 P NMR and 7 Li NMR analyses revealed that the TOP and tributyl phosphate (TBP) complexes existed in different forms within the organic phase. Slope analysis indicated that the stoichiometric ratio of the extraction complex involving Li + , TOP, and MIBK was LiFeCl 4 ·TOP·MIBK. Furthermore, DFT calculations indicated that the TOP complex was more stable than the TBP complex after extraction. We anticipate that our findings will pave the way for the development of a series of novel extractants with higher Li/Mg selectivity by enhancing steric hindrance and incorporating longer alkyl chains to minimize dissolution loss. We expect this research to inspire the development of similar neutral organophosphorus extractants.
研究领域:
化学工程
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材料科学
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
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IF 5.518
Yuping Gai,Wei Deng,Junbo Hu,Dan Li,Wenshuo Xie,Xiang Li,Jingjing Zhang,Dewu Long,Fei Jiang
The preparation of stable electrocatalyst for oxygen evolution reaction is of the utmost importance to realize high performance water decomposition reaction . Metal-organic framework (MOF) nanostructures have become promising materials. Herein, we report three kinds of electrocatalysts with different structures and properties for the oxygen evolution reaction, which were constructed by using different binding sites of three kinds of ligands following a mechanism which involved only *O and *OH species as intermediates. CoFeBTC-MOF shows excellent overpotential η = 261 mV at 10 mA cm −2 (1.481 V vs. RHE), Tafel slope of 59.29 mV dec −1 and pretty excellent stability (48 h of continuous testing), making it become one of the best acid-resistant catalysts for oxygen evolution reaction. The DFT calculations show that there are different ways to transfer electrons . In addition, the coupling effect between Co and Fe metals is the key to regulate the electrocatalytic activity , confirming the cooperative catalysis mechanism with a reduced energy barrier.
研究领域:
材料科学
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电化学
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高影响因子
JOURNAL OF ORGANIC CHEMISTRY
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2024
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IF 3.3
Jingjie Tang,Luying Xie,Jiayu Liu,Shangyu Shi,Qikun Yang,Bo Zhang,Yingying Wang,Lin Chen,Shaohui Jia,Mingfang Ma,Zengyang Xie
Highly efficient and practical carbon–chalcogen (S, Se) and amide bonds formation methodologies for the synthesis of thio- and seleno-acetamides were developed, via the base-promoted one-pot two-step reactions of 2-amino(benzo)thiazoles and aryl acetyl chlorides with dichalcogenides. This cross-coupling reaction afforded the goal products that had been chalcogenated regioselectively in moderate to good yields. Further transformations of the new synthesized compounds, DFT calculations and preliminary mechanism studies are discussed as well.
研究领域:
有机化学
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计算化学
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PubMed
高影响因子
Molecular Catalysis
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2024
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IF 3.9
Jianfu Luan,Jiayou Liu,Xiaoxiang Huang,Zhongchao Tan,Hesheng Yu
The NH 2 -MIL-125 (NM-125) or modified NM-125 materials are used for photocatalytic removal of nitric oxide (NO). Most researchers attributed few NO 2 emission during NO photocatalysis to high selectivity towards the formation of nitrate ions due to the neglect of the principle of electroneutrality and pore structure of NM-125. This may cause misleading photocatalytic mechanism of NO removal. Herein, this work proposes a new mechanism behind NO removal using NM-125 based on experimental investigations and theoretical calculations. First, experimentally, the highest NO removal efficiency of 88.54 % with negligible NO 2 emission occurs at the anhydrous condition. In addition, in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements verify the presence and accumulation of NO 2 as product during photocatalytic conversion of NO. Furthermore, density functional theory (DFT) calculations and grand canonical Monte Carlo (GCMC) computations demonstrate that there exist strong interactions between NO 2 and -NH 2 group within pores. Few NO 2 is detected during experiments is probably due to its subsequent adsorption in the pores of NM-125. The new NO removal mechanism including photocatalytic conversion NO into NO 2 and subsequent NO 2 adsorption in the pores of NM-125 is thus proposed. This work provides a deeper insight into photocatalytic NO removal over NM-125 and its variants.
研究领域:
环境科学
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材料科学
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高影响因子
Molecular Catalysis
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2024
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IF 3.9
Jingjing Zhang,Yang Feng,Lixia Ling,Caiping Ma,Jungang Wang,Riguang Zhang,Maohong Fan,Bo Hou,Debao Li,Baojun Wang
The direct conversion of syngas to ethanol faces challenges due to catalyst inefficiencies and low ethanol yield. Bulk alloys with an appropriate atomic ratio can exhibit excellent catalytic performance. In this work, a series of Rh x Ni y (111) with different Rh/Ni ratios was rationally designed, and the ethanol preparation from syngas was explored based on density functional theory (DFT) calculation and microkinetic analysis. The results show that Rh 1 Ni 1 (111) was screened out to show optimum catalytic performance for ethanol production. This was attributed to a moderate quantity of charge transfer from Ni to Rh atoms, and a medium distance from the d -band center to the Fermi level. Further, to verify the catalytic performance of the catalysts at a Rh: Ni ratio of 1: 1, 1Rh1Ni/γ-Al 2 O 3 catalyst was prepared and its catalytic performance for ethanol preparation from syngas was investigated by comparing it with that of Rh/γ-Al 2 O 3 and Ni/γ-Al 2 O 3 . The catalytic performance of 1Rh1Ni/γ-Al 2 O 3 has been further confirmed to be preferred over Rh/γ-Al 2 O 3 and Ni/γ-Al 2 O 3 , achieving a 23.0 % CO conversion rate with 31.2 % ethanol selectivity.
研究领域:
催化化学
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材料科学
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能源化学
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高影响因子
APPLIED SURFACE SCIENCE
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2025
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IF 6.9
Jian Guan,Yuqi Liu,Qiuyi Zhu,Guojun Ma,Jiayu Zhang,Zheyong Fan,Wei Chen,Jiawei Yang,Ning Han,Yunfa Chen
At present, near-ground ozone still acts as an air pollutant, posing threats to human’s health. In this study, Fe-based catalysts with different coordination environments and valance states were synthesized and the coordination environments were verified using EXAFS and XRD Rietveld fitting, while in-situ Raman and in-situ DRIFTs were employed to investigate the oxygen intermediates of ozone catalytic reaction. The following activities order for ozone catalytic reaction was obtained: [FeO 6 ] 3+ ≫ [FeO 4 ] 3+ > [FeO 6 ] 2+ ≈ [FeO 4 ] 2+ proven by DFT calculations, and α-Fe 2 O 3 with [FeO 6 ] 3+ coordination structure has a high efficiency of about 80 % after 2 h at a WHSV of 720000 mL g -1 h −1 and ozone concentration of 1000 ppm. The superior catalytic activity could be attributed to the high crystal splitting energy in the octahedral coordination structure, which could offer electrons easily for the catalytic reaction. This study provides valuable insights for the development of Fe-based ozone catalysts as well as for other transition metal oxides.
研究领域:
环境科学
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材料科学
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高影响因子
SENSORS
·
2018
·Vol. 18
·期 10
·3493
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IF 2.475
Yingang Gui,Xiaoxing Zhang,Peigeng Lv,Shan Wang,Chao Tang,Qu Zhou
SF6decomposition components detection is a key technology to evaluate and diagnose the insulation status of SF6-insulated equipment online, especially when insulation defects-induced discharge occurs in equipment. In order to detect the type and concentration of SF6decomposition components, a Ni-modified carbon nanotube (Ni-CNT) gas sensor has been prepared to analyze its gas sensitivity and selectivity to SF6decomposition components based on an experimental and density functional theory (DFT) theoretical study. Experimental results show that a Ni-CNT gas sensor presents an outstanding gas sensing property according to the significant change of conductivity during the gas molecule adsorption. The conductivity increases in the following order: H2S > SOF2> SO2> SO2F2. The limit of detection of the Ni-CNT gas sensor reaches 1 ppm. In addition, the excellent recovery property of the Ni-CNT gas sensor makes it easy to be widely used. A DFT theoretical study was applied to analyze the influence mechanism of Ni modification on SF6decomposition components detection. In summary, the Ni-CNT gas sensor prepared in this study can be an effective way to evaluate and diagnose the insulation status of SF6-insulated equipment online.Keywords:SF6decomposition components;carbon nanotube sensor;Ni modification;adsorption;DFT calculations
研究领域:
材料科学
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电气工程
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理论化学
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PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
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2025
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IF 11.3
Pengtao Cai,Tong Chen,Mingxiu Zhan,Xiaojun Ma,Masaki Takaoka,Chen Sun,Xiaodong Li
Per- and polyfluoroalkyl substances (PFAS) are known for their strong C-F bonds, which make them highly persistent in the environment and resistant to degradation. Among PFAS, perfluorobutane sulfonate (PFBS), a short-chain PFSA widely used as a replacement for long-chain PFAS like perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), has garnered attention due to its environmental persistence and toxicity. Although PFBS has lower bioaccumulation potential than its long-chain counterparts, it remains a significant pollutant with limited data available on its degradation mechanisms. To address this, the present study investigates PFBS degradation under subcritical water hydrothermal conditions. Various alkaline substances and additives were tested, and degradation products were analyzed by liquid and gas chromatography-mass spectrometry. Results show that 2 M NaOH at 325°C achieved an ∼99.4 % PFBS removal rate, and the degradation pathway began with the breakdown of the S-C bond, followed by C-F bond cleavage, resulting in the formation of smaller fluorinated compounds, including trifluoroacetic acid. Density functional theory (DFT) calculations provided detailed insights into the degradation mechanism, identifying hydroxide ion attack on the sulfonic acid group as the initial step and elucidating three distinct pathways for subsequent reactions. This study provides key insights into PFBS degradation mechanisms, emphasizing the synergistic effect of alkaline bases and additives. The findings support the optimization of subcritical hydrothermal treatment for PFAS removal, providing a scalable and environmentally sustainable solution.
研究领域:
环境科学
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化学工程
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理论计算
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PubMed
高影响因子
APPLIED SURFACE SCIENCE
·
2025
·
IF 6.9
Hao Yang,Li Han,Dongrui Hou,Yongchang Liu,Shuaijun Huang,Zirui Peng,Zirui Yang,Tianliang Lu,Xiaoqin Si,Xin liu,Jinrong Li,Jianfeng Wang
A series of S-scheme heterojunctions, XCN@MoO 3 (XCN@M, X = Cl, Br, I), were synthesized via a simple thermal polymerization, and the effect of halogen doping on construction of S-scheme heterojunctions was systematically explored. The ICN@M heterojunction showed exceptional photocatalytic performance, achieving 100 % degradation of 50 mg/L RhB in 90 min, 40.37 times and 2.34 times higher than pure g-C 3 N 4 and CN@M, respectively. Notably, ICN@M outperformed CN@M and some other photocatalysts reported. DFT result revealed halogen doping reduced the work function of CN, proved the maximum work function difference of ICN@M and the formation of the strongest built-in electric field between the surface of MoO 3 with an electron-rich region and the surface of ICN with a hole-rich region, thus facilitating electron transfer at the heterojunction interface, reducing recombination of photogenerated carriers and promoting the catalytic performance. Fukui function and frontier orbital theory identified a possible degradation pathway of RhB dominated by ∙O 2 – and 1 O 2 and the toxicity of final products during the photocatalysis degradation of RhB was evaluated. This work highlighted the importance of work function differences in designing photocatalyst heterostructures and offered a new option for environmental treatment.
研究领域:
环境科学
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材料科学
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高影响因子
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