ANALYTICAL CHEMISTRY
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2019
·
IF 6.35
Heng Zhou,Feng Luo,Zhipu Luo,Dan Li,Cong Liu,Xueming Li
Microcrystal electron diffraction (MicroED) is becoming a powerful tool in determining the crystal structures of biological macromolecules and small organic compounds. However, wide applications of this technique are still limited by the special requirement for radiation-tolerated movie-mode camera and the lack of automated data collection methods. Herein, we develop a stage-camera synchronization scheme to minimize the hardware requirements and enable the use of the conventional electron cryo-microscope with a single-frame CCD camera, which ensures not only the acquisition of ultrahigh-resolution diffraction data but also low cost in practice. This method renders the structure determination of both peptide and small organic compounds at ultrahigh resolution up to ∼0.60 Å with unambiguous assignment of nearly all hydrogen atoms. The present work provides a widely applicable solution for routine structure determination of MicroED and demonstrates the capability of the low-end 120 kV microscope with a CCD camera in solving ultrahigh resolution structures of both organic compounds and biological macromolecules.
研究领域:
结构生物学
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生物物理学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ICARUS
·
2022
·
IF 3.657
A. García Muñoz
Photoelectrons , the fast electrons produced in the photoionization of planetary atmospheres , drive transformations in the atmospheric gas that are often inhibited by energy considerations for thermal electrons. The transformations include excitation and ionization of atoms and molecules, which affect the detectability of these gases and constrain the fraction of incident stellar radiation that transforms into heat. To gain insight into these important questions, we build a Monte Carlo model that solves the slowing down of photoelectrons in a gas with arbitrary amounts of H and He atoms and thermal electrons. Our novel multi-score scheme differs from similar tools in that it efficiently handles rare collisional channels, as in the case of low-abundance excited atoms that undergo superelastic and inelastic collisions . The model is validated and its performance demonstrated. Further, we investigate whether photoelectrons might affect the population of the excited hydrogen H(2) detected at some exoplanet atmospheres by transmission spectroscopy in the H- α line. For the ultra-hot Jupiter HAT-P-32b, we find that photoelectron-driven excitation of H(2) is inefficient at the pressures probed by the line core but becomes significant (yet sub-dominant) deeper in the atmosphere where the line wings form. The contribution of photoelectrons to the destruction of H(2) either by collisional deexcitation or ionization is entirely negligible, a conclusion likely to hold for exoplanet atmospheres at large. Importantly, photoelectrons dominate the gas ionization at the altitudes probed by the H- α line, a fact that will likely affect, even if indirectly, the population of H(2) and other tracers such as metastable helium. Future modeling of these excited levels should incorporate photoelectron-driven ionization.
研究领域:
天文学
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行星科学
✓ 已验证
DOI
高影响因子
JOURNAL OF ORGANIC CHEMISTRY
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2024
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IF 3.3
Jun-Feng Yang,Yun-Fei Liu,Lin-Lin Wei,Kai-Kai Qiao,Yan-Qiu Zhao,Lei Shi
The Minisci-type dehydrogenative coupling of N-heteroaromatic rings with inert C–H or Si–H partners via visible-light-catalyzed hydrogen atom transfer has been reported. This methodology allows the coupling reactions to be carried out in water as a solvent under air atmospheric conditions with visible-light illumination. A wide range of inert C–H and Si–H partners could be directly coupled with various N-aromatic heterocycles to deliver products in good to excellent yields.
研究领域:
有机化学
·
光化学
✓ 已验证
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2019
·
IF 5.589
Rui Wang,Ting Tang,Guining Lu,Zhiqiang Zheng,Kaibo Huang,Huafeng Li,Xueqin Tao,Hua Yin,Zhenqing Shi,Zhang Lin,Fengchang Wu,Zhi Dang
This study investigated the relative significance of electron transfer (e-transfer) and H-atom transfer (H-transfer) in a nanoscale zerovalent iron (n-ZVI) system and six n-ZVI-based bimetallic systems (Fe/Cu, Fe/Ni, Fe/Pd, Fe/Ag, Fe/Pt, and Fe/Au) through a case study of the debromination of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47). The results revealed that the reactivities of these bimetallic particles to BDE-47 decreased in the following order: Fe/Pd > Fe/Ag > Fe/Cu > Fe/Ni > Fe/Au > Fe/Pt ≈ n-ZVI. Debromination of BDE-47 in metal-H 2 systems suggested that Ni, Pd, Pt, Cu and Au can utilize H 2 to debrominate BDE-47. In the H-transfer process, BDE-47 preferentially debrominated the para‑ bromine substituent to generate BDE-17, whereas in the e-transfer process, BDE-47 preferentially debrominate ortho‑ bromine substituent to generate BDE-28. The debromination pathways of BDE-47 in bimetallic and NaBH 4 -metal systems suggested that Fe/Ni, Fe/Pd and Fe/Pt debrominate polybrominated diphenyl ethers (PBDEs) through a H-transfer dominant mechanism, while Fe/Ag debrominate PBDEs through an e-transfer dominant mechanism. In the cases of Fe/Cu and Fe/Au, the e-transfer and H-transfer may be equally involved in the debromination of PBDEs. These results greatly improve our understanding of the relative significance of e-transfer and H-transfer in the dehalogenation of halogenated aromatic compounds (HACs) in various n-ZVI-based bimetallic systems.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Yu Wang,Qian-Yuan Wu,Min-Yong Lee,Yu-Jia Nong,Wen-Long Wang,Jörg E. Drewes
Electrocatalytic hydrodechlorination is a promising approach for simultaneous pollutant purification and valorization. However, the lack of electrocatalysts with high catalytic activity and selectivity limits its application. Here, we propose a palladium–palladium oxide (Pd-PdO) heterostructure for efficient electrocatalytic hydrodechlorination of recalcitrant chlorophenols and selective formation of phenol with superior Pd-mass activity (1.35 min–1 mgPd–1), which is 4.4 times of commercial Pd/C and about 10–100 times of reported Pd-based catalysts. The Pd-PdO heterostructure is stable in real water matrices and achieves selective phenol recovery (>99%) from the chlorophenol mixture and efficient detoxification along chlorophenol removal. Experimental results and computational modeling reveal that the adsorption/desorption behaviors of zerovalent Pd and PdO sites in the Pd-PdO heterostructure are optimized and a synergy is realized to promote atomic hydrogen (H*) generation, transfer, and utilization: H* is efficiently generated at zerovalent Pd sites, transferred to PdO sites, and eventually consumed in the dechlorination reaction at PdO sites. This work provides a promising strategy to realize the synergy of Pd with different valence states in the metal–metal oxide heterostructure for simultaneous decontamination, detoxification, and resource recovery from halogenated organic pollutants.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
·
2020
·Vol. 50
·期 2
·715-721
·
IF 4.174
Jianhui Xie,Bing Li,Huijing Liu,Yijun Li,Jian-Bo He,Yanzhen Zheng,Kai-Chung Lau,Tai-Chu Lau
Ferrate(VI), [FeO4]2−, is a very powerful oxidant that can oxidize a wide variety of inorganic and organic compounds. However, the mechanisms of many of these oxidation reactions have not been studied in detail. In this work, we have investigated the kinetics and mechanism of the oxidation of 4-alkylbenzenesulfonates by ferrate in aqueous solutions at pH 7.45–9.63 by UV/Vis spectrophotometry. The reactions are first order with respect to both [ferrate] and [4-alkylbenzenesulfonate]. The second-order rate constants for the oxidation of 4-isopropylbenzenesulfonate by ferrate at 25 °C and I = 0.3 M are found to be (5.86 ± 0.08) × 10−1 M−1 s−1 and (4.11 ± 1.50) × 10−3 M−1 s−1 for [Fe(O)3(OH)]− and [FeO4]2−, respectively, indicating that [Fe(O)3(OH)]− is two orders of magnitude more reactive than [FeO4]2− and is the predominant oxidant in neutral and slightly alkaline solutions. This is further supported by the effect of the ionic strength on the rate constant. No solvent kinetic isotope effect (KIE) was found but a moderate primary KIE = 1.6 ± 0.1 was observed in the oxidation of 4-ethylbenzenesulfonate and 4-ethylbenzenesulfonate-d9. Alkyl radicals were trapped by CBrCl3 in the oxidation of alkylarenes by ferrate. Combined with DFT calculations, a hydrogen atom transfer (HAT) mechanism was proposed for the reactions between [Fe(O)3(OH)]− and 4-alkylbenzenesulfonates.
研究领域:
化学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2020
·
IF 7.864
Ruiyang Zhang,Tao Ran,Yuehan Cao,Qian Zhang,Fan Dong,Guidong Yang,Ying Zhou
Catalysis oxidization has been known to be an effective technique in environmental remediation. However, low efficiency for oxygen activation and difficult recovery of the catalysts in powdery form significantly limit the practical application. In this work, a new-type monolithic α-Ni(OH)2/Ni-foam was fabricated by the hydrothermal process. We found that H atoms of α-Ni(OH)2 can significantly promote oxygen activation, which endows it with favorable NO and NO2 oxidization confirmed by theoretical calculation and in situ DRIFTS. Furthermore, the introduction of Ni foam accelerated the pollutant gas transfer and charge carriers’ separation because of its abundant porous structure and high conductivity and its monolithic property simplified the recycling operation. Consequently, the obtained α-Ni(OH)2/Ni-foam achieved an excellent NO oxidation (69.0%) and no toxic NO2 was detected under visible light illumination (λ > 420 nm), indicating its highly promising potential in environmental remediation. Our work provides a conceptually different fresh perception to promote oxygen activation for highly efficient gas purification.
研究领域:
环境科学
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催化材料
·
理论计算
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Catalysts
·
2021
·Vol. 11
·期 1
·77
·
IF 4.146
Shiwei Ma,Yunyun Huang,Ruoyu Hong,Xuesong Lu,Jianhua Li,Ying Zheng
In this work, zinc oxide (ZnO) nanoparticles were modified in a circulating fluidized bed through argon and hydrogen (Ar–H) alternating-current (AC) arc plasma, which shows the characteristics of nonequilibrium and equilibrium plasma at the same time. In addition, a circulating fluidized bed with two plasma jets was used for cyclic processing. The catalytic degradation performance on Rhodamine B (Rh B) by Ar–H plasma-modified ZnO and pure ZnO was tested in aqueous media to identify the significant role of hydrogen atoms in Rh B degradation mechanism. Meanwhile, the effects of plasma treatment time on the morphology, size and photocatalytic performance of ZnO were also investigated. The results demonstrated that ZnO after 120-min treatment by Ar–H plasma showed Rh B photocatalytic degradation rate of 20 times greater than that of pure ZnO and the reaction follows a first kinetics for the Rh B degradation process. Furthermore, the photocatalyst cycle experiment curve exhibited that the modified ZnO still displays optimum photocatalytic activity after five cycles of experiment. The improvement of photocatalytic activity and luminescence performance attributes to the significant increase in the surface area, and the introduction of hydrogen atoms on the surface also could enhance the time of carrier existence where the hydrogen atoms act as shallow donors.Keywords:plasma;zinc oxide;photocatalysis;nanomaterials
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Chundi Zhou,Minghao Sui,Yali Guo,Songhang Du
Efficiently removing hexavalent chromium (Cr(VI)) using iron-based adsorbents under neutral pH conditions continues to pose a challenge. In this study, we constructed nano zero-valent iron (nZVI) supported by carboxylated multi-walled carbon nanotubes (OCNT) composites with iron-based dual active sites through the nitrilotriacetic acid modification (FOC-NA). The acid dissolution experiment, high-resolution transmission electron microscopy (HRTEM), thermogravimetric analyzer (TGA), X-ray photoelectron spectroscopy (XPS), and Raman analysis proved these active sites consisted of iron-carboxylate complex (−COOFe(II)) and OCNT-confined nZVI (Fe 0 -in-OCNT). The existence of iron-based dual active sites enhanced electron transfer efficiency in Cr(VI) removal under neutral pH conditions. This leaded to a superior adsorption capacity for Cr(VI), as evidenced by a maximum adsorption capacity of 141.29 mg·g −1 at a pH of 6.5. Meanwhile, the formation of a Cr-containing product (−COOFe-O-Cr) on the surface of FOC-NA substantially hindered the re-release of chromium into the environment. Furthermore, this study proposed the significant involvement of active hydrogen atoms (H*) in the reduction of Cr(VI), as confirmed by quenching experiments and analyses using electron spin resonance (EPR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The formation pathway and energy barrier of H* and the −COOFe-O-Cr complex were analyzed by density functional theory (DFT) calculations. This study provided insights for the rational design of iron-based adsorbents with dual active sites to facilitate the activation of H* for Cr(VI) reduction under neutral pH conditions.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2025
·
IF 4.8
Zheng Cui,Yueli Wen,Bin Wang,Maohong Fan,Faraz Ahmad,Hui Bai,Wei Huang
Activation of hydrogen atoms of methyl in toluene and methanol is crucial for side-chain alkylation of toluene with methanol. Herein, two strategies were applied, introducing dehydrogenation component (Cu) and tailoring the catalyst acid-base property with NaOH. A series of Cu and NaOH dual-modified PAl-NaX catalysts were prepared by in-situ hydrothermal method, the synergistic effect of Cu and NaOH was investigated. It is revealed that the product of (medium base)* (weak acid) and surface Cu δ+ percentage is crucial in controlling the total yield of side chain alkylation products by enhancing ethyl benzene selectivity. Cat-3Cu-13Na exhibits the optimal catalytic performance with an average methanol conversion of 97.25 % and an average total yield of side chain alkylation products of 77.46 % without obvious deactivation occurs in 192 h, and Cat-3Cu-19Na shows a promising styrene selectivity of 44.06 %. The decrease of weak acid sites might result in the decline in selectivity of styrene.
研究领域:
化学工程
·
催化反应
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2022
·
IF 24.319
Yuyao Sun,Yi Han,Xinyi Zhang,Wenwen Cai,Yanyun Zhang,Yan Zhang,Zhenjiang Li,Bin Li,Jianping Lai,Lei Wang
Titanium dioxide (TiO 2 ) is widely used as a representative transition metal oxides (TMOs) catalyst for electrocatalytic nitrogen reduction reaction (NRR). However, the low stability, low selectivity, low ammonia (NH 3 ) yield and high overpotential of TiO 2 towards NRR strongly restricted its application in NRR. Here, we firstly add H to the lattice to synthesize a black TiO 2−x with oxygen vacancies (OVs) (B-TiO 1.8 ) for electrocatalytic NRR. After we optimized the amount of H and OVs, the NH 3 yield and stability can achieve 31.6 μg h −1 mg cat −1 and 100 h at − 0.1 V ( vs . RHE), respectively, the faradaic efficiency (FE) can achieve 47.7% at 0 V ( vs . RHE). In situ FTIR / ESR / XPS / TPD illustrate that OVs can promote the adsorption and activation of nitrogen (N 2 ), and lattice H can increase the number of OVs and stabilize them, suppress the hydrogen evolution reaction (HER) and promote the hydrogenation of N 2 .
研究领域:
材料科学
·
电催化
✓ 已验证
产品关联
DOI
高影响因子
Sustainable Energy & Fuels
·
2023
·Vol. 7
·期 22
·5374-5384
·
IF 5.6
Ji Mi,Xinyang Chen,Panxi Wu,Yitong Dai,Yongsheng Guo,Wenjun Fang
Pinane is a product derived from turpentine, a renewable resource that is highly valued. Due to its unique multicyclic ring structure, pinane has a relatively high energy density of 35.6 MJ L−1, making it an excellent potential alternative to jet fuel. In this work, the low-temperature oxidation of pinane is comprehensively studied concerning the oxidative stability requirement of jet fuels. The apparent activation energy Ea and pre-exponential factor A of pinane oxidation are acquired according to the Kissinger method using a P-DSC apparatus as 97.6 ± 2.7 kJ mol−1 and 5.3 ± 3.7 × 1010 min−1, respectively, rendering it a relatively more oxygen-susceptible hydrocarbon compared to non-strained hydrocarbons. DFT calculations and experimental investigations have shown that the low-temperature oxidation of pinane begins with the hydrogen atom transfer (HAT) reaction and the rupture of the strained ring. Interestingly, although pinane can be easily oxidized, it shows very low deposition propensity in the JFTOT test, qualifying it as a potential jet fuel.
研究领域:
能源生物学
·
化学动力学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）