Frontiers in Chemistry
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2022
·
IF 5.545
Zhao Jun,Deng Nengmei
The thermal decomposition performance of an oxidizer directly determines the thrust and specific impulse properties of the solid propellant. Hexagonal boron nitride (h-BN) has the characteristics of high catalytic activity and good stability, which can improve the heat release and decomposition temperature of the oxidant, and then improve the energy performance of the propellant. In this study, a novel hybrid material TiO2 NPs/h-BN was successfully prepared by in situ growth, and it was found that when 5 wt.% TiO2 NPs/h-BN was added, the initial decomposition temperature of ammonium perchlorate (AP) decreased by 67.6°C. Due to the addition of TiO2, the gap between the h-BN layers as well as the specific surface increased, which optimized its thermocatalytic performance, and it also proposed a catalytic mechanism for the thermal decomposition process of AP.
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JOURNAL OF RARE EARTHS
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2022
·
IF 4.632
Feng Lin,Yudan Zhong,Yulong Ma,Yonggang Sun,Xiuqin Men,Yingbo Zhu
Hydrodeoxygenation (HDO) of renewable lignin-derived biomass in aqueous-phase to produce high value-added products is of great significance. However, developing new catalysts with high activity and excellent stability in an aqueous phase faces considerable challenges. Rare earth doping can effectively regulate the water exchange rate constant (WERC) value of the catalyst and play an important role in promoting the hydrolysis of ether bonds. Therefore, in this paper the bimetallic supported catalyst Ni–La 2 O 3 /H-ZSM-5 doped with rare earth metal La 2 O 3 was prepared, and used to catalyze the conversion of the lignin model compound guaiacol to cyclohexanol in the aqueous phase. The conversion of guaiacol catalyzed by 10Ni–3La 2 O 3 /H-ZSM-5 reaches 100%, and the selectivity of the product cyclohexanol is 85%. A series of characterizations illustrate that the doping of La 2 O 3 causes the electron transfer between La 2 O 3 –Ni and changes the distribution of Ni, and a strong metal carrier interaction occurs between the bimetallic Ni–La 2 O 3 and H-ZSM-5. This can effectively promote the hydrolysis of the C–O ether bond in guaiacol and significantly improve the activity of the catalyst. The possible catalytic reaction mechanism of Ni–La 2 O 3 /H-ZSM-5 catalytic conversion of guaiacol was proposed.
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Polymer Chemistry
·
2022
·Vol. 13
·期 10
·1437-1445
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IF 5.364
Yongjie Zhang,Xiaopei Li,Wenqin Zhu,Pibo Liu,Juntao Ren,Shangtao Chen,Yanming Hu,Guangyuan Zhou
Post-modification of polyolefins by cutting-edge C–H activation has recently emerged as an attractive methodology for the incorporation of precise functionalities, thus expanding their applicability and creating value-added materials. In this report, chromone (CM), the core of naturally occurring molecules possessing manifold biological and pharmacological activities, was incorporated into polyethylene (PE) through the recently developed radical-mediated alkane C–H activation approach. The reaction was conducted in the presence of di-tertbutyl peroxide as the oxidant and a small amount of naphthalene as the solvent or under solvent-free conditions. The produced CM-grafted PEs (CM-PEs) exhibited intriguing antioxidative and fluorescence properties as revealed by thermogravimetric analysis (TGA) and fluorescence microscopy. Moreover, CM-PEs were successfully demonstrated to act as a polymer-bound antioxidant, a fluorescence marker for plastic sorting, and a traceable compatibilizer for the PE/polystyrene blend, revealing that CM-PE is a multi-functional material.
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CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Yongyang Zhu,Shaoyang Shen,Liuzhang Ouyang,Jiangwen Liu,Hui Wang,Zhenguo Huang,Min Zhu
Magnesium borohydride (Mg(BH 4 ) 2 ) is widely regarded as a promising hydrogen storage material due to its high capacity; however, it is still challenging to synthesize Mg(BH 4 ) 2 with low cost. Traditionally, Mg(BH 4 ) 2 has been mainly produced using other borohydride as the starting materials via exchange reactions. Herein, we report an economical method to synthesize Mg(BH 4 ) 2 by converting B-O bonds in widely available borates or boric acid to B-H. The borates or boric acid is ball-milled with MgH 2 under ambient conditions to form Mg(BH 4 ) 2 with high yield (>80%). Mg(BH 4 ) 2 was also successfully generated by reacting low-cost Mg with boric acid. Compared with previous approaches, this method avoids expensive boron sources such as LiBH 4 , NaBH 4 , and B 2 H 6 , and does not require high pressure H 2 gas and high temperatures, and therefore significantly reduces costs. This method could be an alternative to the current Mg(BH 4 ) 2 synthesis processes.
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JOURNAL OF SOLID STATE CHEMISTRY
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2026
·
IF 3.2
Zheng-Xuan Ni,Wei Bao,Ming-Yang Shi,Jia-Jia Zhao,Li-Zhuang Chen
H/F substitution drives the coordination reconstruction of Mn 2+ in hybrid chlorides. • Isolated [MnCl 4 ] 2- tetrahedra change to face-sharing [Mn 2 Cl 9 ] 5- units. • The four-to-six coordination change enables green-to-red emission centered at 634 nm. • The fluorinated non-centrosymmetric crystal exhibits phase-transition and piezoelectric responses. Regulation of the Mn 2+ coordination environment is an effective approach for tuning the luminescence of Mn-based hybrid halides. However, the use of H/F substitution on organic cations to regulate the coordination environment of Mn 2+ and thereby tune the emission color remains rarely explored. In this work, H/F substitution was introduced into the piperidinium cation, driving the transformation of Mn-Cl coordination units from four-coordinate to six-coordinate structures and yielding the zero-dimensional hybrid chloride (4-F-Hpip) 5 [Mn 2 Cl 9 ]. This material crystallizes in the chiral non-centrosymmetric P 4 1 2 1 2 space group and contains face-sharing dinuclear [Mn 2 Cl 9 ] 5- units with octahedrally coordinated Mn 2+ . The resulting ligand-field change gives rise to broad red emission centered at 634 nm, while the compound also exhibits a reversible phase transition. In addition, a flexible PBAT composite film containing 10 wt% (4-F-Hpip) 5 [Mn 2 Cl 9 ] generates an open-circuit voltage of approximately 4.9 V. Its luminescent and piezoelectric responses were further integrated into a conceptual dual-input information encryption scheme. This work establishes H/F substitution as an effective cation engineering strategy for regulating Mn 2+ coordination and luminescence in hybrid manganese halides. Download: Download high-res image (198KB) Download: Download full-size image
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FOOD CHEMISTRY
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2023
·
IF 8.8
Chixuan Yao,Yaozhong Hu,Qisijing Liu,Jing-Min Liu,Xuemeng Ji,Huan Lv,Shuo Wang
To improve the performance of peanut allergen Ara h 3 detection, depending on boron and nitrogen carbon dots (B/ N -CDs), a nanobody (Nb) mediated dual-mode immunoassay was established, which combines the dominance of colorimetry with ratiometric fluorescence techniques. With the catalysis of Horseradish peroxidase (HRP), the oxidization of o-phenylenediamine (o-PD) in the presence of H 2 O 2 , leading to the production of yellow 2,3-diaminophenolazine (DAP) with an absorption peak at 431 nm. Owing to inner filter effect (IFE), DAP quenched the fluorescence of B/ N -CDs at 426 nm, and it emerged a new emission peak at 549 nm. The fluorescence intensity ratio and absorption intensity can be utilized for quantitative analysis of Ara h 3 concentration. Under optimal conditions, the detection limits were 6.61 and 9.79 ng·mL −1 , respectively. The dual-mode immunoassay was assessed containing specificity, stability, reproducibility, and practicability. This method paved the way for sensitive detection of Ara h 3 without background Interference.
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DIAMOND AND RELATED MATERIALS
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2021
·
IF 3.315
Xiaoyu Zhang,Juan Yi,Yanan Yin,Yiheng Song,Chuanxi Xiong
In recent years, with the increasing demands of portable and high-speed electronic devices, highly integrated equipment attracts people's attention more and more. However, it is a great challenge to guarantee the long-term stability of electronic products at high temperatures. Hexagon boron nitride (h-BN), which owned excellent thermal conductivity and insulation properties , was preferred for electronics. For better compatibility of inorganic fillers and silicone rubber, a biological modification by coating polydopamine (DA) on h-BN was adopted. Herein, the composites based on h-BN@PDA and silicone rubber were fabricated. Compared with h-BN/silicone rubber composites , the thermal conductivity of h-BN@PDA/silicone rubber composites increased and volume resistance of materials had been decreasing. When the amount of h-BN@PDA fillers was 30 wt%, the thermal conductivity of h-BN@PDA/silicone rubber composite increased to 0.95 W m −1 K −1 . The volume resistivity of 30 wt% h-BN@PDA/silicone rubber composite reached 2.5 × 10 11 Ω·cm, which was the lowest one among others, which still exceeded requirements of electronic materials.
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JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
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2020
·
IF 1.701
Mengyuan Ma,Jian Song,Lichen Bai,Guan Wei,Jianfeng Dai,Zhiyun Chen,Tianxiang Yin
The extraction of bovine serum albumin (BSA) was carried out by using reverse micelles formed by cationic surfactant dodecyltrimethylammonium bromide (DTAB), N-dodecyl-N-2-hydroxyethyl-N,N-dimethyl-ammonium bromide (HDAB) and N-dodecyl-N,N-2-dihydroxyethyl-N-methyl ammonium bromide (DHAB). The factors like pH, surfactant concentration, salt concentration, and co-solvent concentration were investigated. The good maintenance of the secondary structure of BSA after extraction was confirmed by UV spectra. A wider aqueous phase pH range was achieved and less amount of surfactant was needed on efficient forward extraction when hydroxyethyl group was presented in the surfactants’ head group, suggesting an important role of H-bonding effect. At lower pH or high salt concentration, reasonable backward extraction efficiencies were observed in all systems. The little difference of the head group of these surfactants resulted in quite different performance in the extraction process, which provided deeper insight on the effect of fine adjustment of surfactant structure on protein extraction.
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ACS Central Science
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2021
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IF 14.553
Junhui Wang,Jiaxing Yu,Qi Fu,Huangsheng Yang,Qing Tong,Zhengping Hao,Gangfeng Ouyang
Holes (h+) on heterogeneous photocatalysts could act as important oxidative species or precursors for reactive oxygen species (ROS). However, due to the ultrafast recombination of photoinduced electrons and holes, a majority of carriers are consumed prior to surface reactions. Herein, we report an unprecedented nonphotomediated hole oxidation system constructed from carbon nanotubes (CNTs) and superoxides. This system exhibited high catalytic activity for the degradation of organic pollutants, which outperforms the classical oxidation processes in the remediation of actual wastewater and is comparable to that of the best single cobalt atom catalyst. Theoretical and experimental results reveal that the intrinsic defects with unpaired spins on CNTs served as adsorptive sites to activate superoxides. This is the first report on exploring the oxidation properties of nonphotomediated hole carriers on heterogeneous catalysts, which will be of broad interest for researchers in environmental remediation, chemical synthesis, and biological fields.
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APPLIED ORGANOMETALLIC CHEMISTRY
·
2020
·Vol. 34
·期 11
·e5925
·
IF 3.14
Jie Yao,Yan Wang,Suleiman Sabo Bello,Guangwen Xu,Lei Shi
As it is well known, Brønsted acid sites in 8-MR of H-MOR (mordenite) are selective for dimethyl ether (DME) carbonylation to methyl acetate, whereas those in 12-MR are more prone to methanol to olefin reaction. Interestingly, we observed that the Brønsted acid sites in 12-MR of H-MOR are highly active for dimethoxymethane (DMM) carbonylation to methyl methoxyacetate (MMAc), whereas those in 8-MR led to the formation of DME. A series of modified H-MOR catalysts with accurate regulation of Brønsted acid sites in 12-MR or 8-MR were successfully synthesized by selective Na + exchange or pyridine (Py) adsorption. Fourier-transform infrared (FT-IR) spectra, NH 3 -temperature-programmed desorption, Py-FT-IR, and inductively coupled plasma analyses suggested that Na + first occupied Brønsted acid sites in 8-MR and then replaced those in 12-MR. All Na + -exchanged catalysts exhibited significant acceleration on MMAc selectivity, and the ratio of Brønsted acid amount in 12-MR/total had a positive correlation with MMAc selectivity. The MMAc selectivity (78%) of H-MOR-0.15Na was nearly 2.5 times more than that of untreated H-MOR (31%). However, H-MOR-Py showed almost no carbonylation activity (<1% MMAc) and a highest DME selectivity (98%), indicating that Brønsted acid sites in 12-MR were the only active sites for DMM carbonylation, whereas those in 8-MR tended to accelerate DMM disproportionation to DME.
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EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
·
2020
·Vol. 2020
·期 25
·3889-3895
·
IF 2.889
Xinpeng Jiang,Zongchen Zhao,Zhifeng Shen,Keda Chen,Liyun Fang,Chuanming Yu
Graphical A metal-free aerobic oxidative C–H sulfenylation of aryl-fused cyclic amines with various thiols was developed with excellent functional compatibility. While flavin I catalyzed the C–H sulfenylation of indolines to afford 3-sulfenylindoles, flavin II enabled transformations resulting in substitution at the position para to the N atom on the aryl ring to obtain 6-sulfenylquinolines. We report an aerobic oxidative C–H sulfenylation of aryl-fused cyclic amines with various thiols catalyzed by flavin/I 2 for the first time. While flavin I catalyzed the C–H sulfenylation of indolines to afford 3-sulfenylindoles, flavin II enabled transformations resulted in substitution at the position para to the N atom on the aryl ring to obtain 6-sulfenylquinolines. The advantages of this metal-free oxidative C–S coupling approach utilizing ambient oxygen as the terminal oxidant were that it was conducted under mild conditions with good atom-efficiency and excellent functional compatibility.
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Materials Chemistry Frontiers
·
2020
·Vol. 4
·期 4
·1158-1163
·
IF 6.788
Zewen Zhuang,Yu Wang,Zheng Chen,Dingsheng Wang,Chen Chen,Qing Peng,Yadong Li
Densely populated metal atomic site catalysts play a key role in practical catalysis applications. Herein, we report an amorphous nanobox with high-density atomic platinum species which are uniformly dispersed into the ZIF-8 skeleton through cation exchange. During the dispersing process, the ZIF-8 core was gradually etched into the hollow structure though the Kirkendall effect, and a great amount substitutions of Pt with Zn breaks the initial long-range ordered ZIF-8 topology into a distorted skeleton which leads to the significantly unsaturated coordination of atomic Pt species. The high-density atomic Pt nanoboxes exhibit excellent performance in direct C–H bond borylation of arenes which are usually catalyzed by homogeneous complexes. Such high-density atomic site heterogeneous catalysts could serve as a bridge to convert from homogeneous to heterogeneous catalysis.
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