INDUSTRIAL CROPS AND PRODUCTS
·
2022
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IF 6.449
Yachong Zhu,Yehong Chen,Chaojun Wu,Dongmei Yu,Qijun Ding,Ronggang Li
In this study, cellulose nanofibrils (CNFs) were directly prepared after autohydrolysis of eucalyptus raw materials. The effect of different autohydrolysis times on the hydrogen bond structure, micro-structure and properties of CNFs were analyzed by FTIR peak fitting, two-dimensional infrared, TGA, TEM and X-ray diffractometer. The results showed that the autohydrolysis treatments could obviously lead to the sequence of hydrogen bond changes in CNFs as follows: v (weak hydrogen bond) > v (free hydroxyl) > v (O(3)H.O(5)) > v (O(2)H.O(6)) > v (O(6)H.O(3′)), and further impact in crystallite size of CNFs. With the increase of the autohydrolysis strength, the crystallite size of CNFs on the 1 1 ¯ 0 crystal plane could be reduced by up to 26%, but the crystallite size on the 110 crystal plane and the 200 crystal plane increased by 24.5% and 22.6%, respectively. These microstructure changes finally increased the crystallinity index of CNFs, and then resulted in their high thermal stability.
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ADVANCED SYNTHESIS & CATALYSIS
·
2022
·Vol. 364
·期 8
·1450-1459
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IF 5.981
Feng Cheng,Jia-Min Zhang,Zhen-Tao Jiang,Xiao-Hu Wu,Ya-Ping Xue,Yu-Guo Zheng
Chiral amino acids are extensively applied in the pharmaceutical, food, cosmetic, and agricultural industries. As a representative example, l -phosphinothricin ( l -PPT, a chiral non-natural amino acid) is a broad-spectrum herbicide. An NAD(H)-driven biocatalytic system for the asymmetric synthesis of chiral amino acids (focused on l -PPT) with high efficiency and low cost is highly desired. The key for the development of such biocatalytic system is to obtain an NADH-dependent biocatalyst with high catalytic performance toward l -PPT pro-ketone PPO. Herein, an engineered glutamate dehydrogenase from Lysinibacillus composti ( Lc GluDH) with desired activity was obtained by gene mining and protein engineering. In silico analyses suggested that the volume of substrate-binding pocket was substantially enlarged from 330.5 Å 3 to 409.6 Å 3 . The stability of Lc GluDH was increased ( T m value increased from 47.3 °C to 65.3 °C) by introducing positively charged amino acids or aromatic amino acids at position 375. The desired biocatalytic system was constructed by coupling the engineered Lc GluDH and an NAD + -dependent FDH. Through this biocatalytic system, the batch production of l -PPT exhibited high space-time yield (207.3 g ⋅ L −1 ⋅ day −1 ) with strict stereoselectivity ( ee of l -PPT>99%). Furthermore, eight other chiral amino acids were synthesised by the developed NAD(H)-driven biocatalytic system with high ee values.
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ACS Applied Materials & Interfaces
·
2022
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IF 10.383
Zhenzhong Li,Huating Jiang,Jinxiu Liu,Tiantian Ning,Nam T. S. Phan,Fang Zhang
Conformational dynamics of active sites in enzymes enable great control over the catalytic process. Herein, we constructed a metal–organic framework with conformationally dynamic active sites (Rh2-ZIF-8). The active sites in Rh2-ZIF-8 were composed of the imidazolate-bridged bimetallic center with a catalytic dirhodium moiety and structural zinc site. Even though the coordination sphere of the dirhodium species was saturated with two circularly arranged esp groups and two axial 2-MeIm ligands, it could still effectively catalyze the direct synthesis of N–H aziridines from olefins with high activity. We found that such a self-adaptive catalytic process was based on the dynamic breakage and reformation of the rhodium–zinc imidazolate bridges. Interestingly, the in situ generated dirhodium site with a unique Rh2(esp)2(2-MeIm)1 configuration was able to exhibit obviously enhanced selectivity compared to homogeneous catalyst Rh2(esp)2. Furthermore, the surrounding zinc imidazolate groups could effectively protect the dirhodium moieties from harsh environments, and this ultimately endowed it with high stability.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2022
·
IF 7.139
Kexin Liu,Shilong Yang,Yi Chen,Wenlei Zhang,Pu Liu,Xiucheng Zheng
The hydrolysis of ammonia borane (NH 3 BH 3 , AB) is an efficient strategy for high-purify hydrogen evolution . However, it is indispensable to develop a suitable catalyst because this reaction is kinetically infeasible at room temperature . In this work, we prepared a series of nano hexagonal boron nitride (h-BN) supported CuNi bimetallic catalysts through a facile adsorption-chemical reduction procedure. The effects of various molar ratios of Cu to Ni and CuNi loadings on AB hydrolysis were investigated in details. Benefitting from the proper porous structure , the interesting alloy effect of Cu and Ni, as well as the synergistic effect between h-BN and CuNi, 20 wt% Cu 0.5 Ni 0.5 /h-BN displays the highest catalytic activity among the as-prepared catalysts. Apart from satisfactory durability, the corresponding hydrogen generation rate, turnover frequency at 303 K in base solution and apparent activation energy are 2437.0 mL g −1 min −1 , 6.33 min −1 and 23.02 kJ mol −1 , respectively, which are very outstanding compared with many previous results. Our work not only provides a proper non-precious metal catalyst for hydrogen generation from the hydrolysis of chemical hydrogen storage materials but also offers a facile strategy for synthesizing metallic functional materials .
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PROGRESS IN ORGANIC COATINGS
·
2022
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IF 6.206
Cheng Li,Xiao Wang,Meng Zhang,Yue Sun,Yexiang Cui,Yanji Zhu,Huaiyuan Wang
Inert inorganic anti-corrosion fillers enjoy the advantages of stable performance, but most of them face the problems of poor compatibility and disability. Therefore, strategies about addressing the above problems need to be developed. Herein, based on interface enhancement strategy, one typical inert inorganic filler h-BN was armed with fluoro-substituted polyaniline (PFAN). To this end, diazotization reaction was utilized to introduce aniline group to h-BN, and emulsion polymerization was employed to grow the micro-size copolymer of aniline and 2-fluoroaniline. Benefitting from the above interface enhancement attempt, the compatibility of h-BN with resin was enhanced, which was explained by the chemical armed PFAN participated in the curing process of epoxy. Moreover, the disability of h-BN was also improved owed to this interface armor. Therefore, combining the fully developed barrier properties of h-BN with passivate ability of PFAN, the coating containing a small addition amount (0.9 wt%) of the composite fillers to epoxy coatings significantly improved their long-term corrosion resistance , which was confirmed by the EIS result that its low frequency impedance value was maintained above 10 10 and was about 10 3 times larger than that of pure EP coating after being immersed in 3.5 wt% NaCl solution for 120 days.
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FUEL
·
2022
·
IF 8.035
Yueqing Wang,Hongxing Wang,Junbo Zhang,Hongyan Zheng,Long Huang,Yulei Zhu
Selectively converting fructose into furfural by H-beta catalyst is a very interesting catalytic process. However, it is a challenging task to clearly elucidate the roles of framework Al for selective scission of C C and C O bond. Herein, selective elimination of framework Al atoms is realized. Several detailed investigations showed that the framework Al species located in different sites play important role in furfural formation. The framework Al atoms of pristine H-beta mainly occupied at T1, T2, T5, T6 and T7 sites. These Al species at pore mouth can be removed by citric acid, while the treatment of nitric acid mainly eliminated the framework Al atoms from T2 and T7 sites. As for oxalic acid, the Al atoms occupied at T2, T5, T6 and T7 was primarily leached. Upon citric acid and nitric acid treatment afforded the similar yield of furfural, indicating that the formation of furfural could not be governed by these Al species at pore mouth, T2 and T7 sites. However, in the case of oxalic acid treatment, complete removal of the Al species on T2, T5, T6 and T7 sites decreased the yield of furfural. Thus, it is reasonably inferred that these Al atoms populated at T1 sites and intersecting channels is more encouraging for the splitting of C C bond, while the Al species occupied at T5, T6 sites and the larger straight channels is probably more favorable to scission of C O bond.
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Journal of Composites Science
·
2021
·Vol. 5
·期 8
·207
·
IF 0
Ying Zhou,Cuihuan Song,Zhixiang Chen,Qixin Zhou
In this study, we prepared a novel coating composed of hexagonal molybdenum oxide (h-MoO3) nanofiller and waterborne epoxy resin (WEP) to provide corrosion protection. We optimized the h-MoO3nanorod synthesis methodology first by changing different parameters (pH, temperature, etc.). Furthermore, the as-prepared h-MoO3rods were characterized using a scanning electron microscope (SEM) and X-ray diffraction (XRD). Finally, the electrochemical impedance spectroscopy (EIS) test results verified that the anticorrosive performance of the composite coatings was improved by incorporation of low content of MoO3nanofiller (0.5 wt.%) compared to pure WEP sample. This developed composite will provide a new insight for the design and fabrication of one-dimensional (1D) nanomaterial (e.g., nanorod) reinforced epoxy coating and other polymeric coating processes.Keywords:waterborne epoxy;molybdenum trioxide nanorod;composites
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ChemCatChem
·
2021
·Vol. 13
·期 14
·3312-3318
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IF 5.686
Ding Ding,Bing Yan,Yang Wang,An-Hui Lu
Graphical Nanofiber Catalysis : Hexagonal boron nitride has been regarded as a potential inorganic nonmetallic catalyst for the oxidative dehydrogenation of propane. Herein, a novel nanofiber catalyst consisting of hexagonal boron nitride/silica oxide ( h -BN/SiO 2 ) was prepared via electrospinning method, which exhibited remarkable 24.9 g olefins ⋅ g BN −1 ⋅ h −1 productivity of olefins in oxidative dehydrogenation of propane. Fibrous nanomaterials have drawn considerable attention in the field of catalysis due to the promoted utilization of the surface and facilitated mass transfer process. In this study, we prepared one-dimensional nanofiber catalysts consisting of hexagonal boron nitride/silica oxide ( h -BN/SiO 2 ) via electrospinning method. The key is to prepare uniform sols consisting of exfoliated h -BN. The diameters of the nanofiber catalysts can be tuned in the range of 150–300 nm through h -BN loading change. When used in oxidative dehydrogenation of propane (ODHP), the obtained nanofibrous catalysts exhibited a 12.4 % conversion of propane and 85.1 % selectivity towards propylene, with remarkable olefins productivity of 24.9 g olefins ⋅ g BN −1 ⋅ h −1 , which is more than 5 times higher than that of bulk ODHP catalysts reported to date. This study shines light on the specific one-dimensional fibrous structure containing dispersed h -BN as well as a new strategy of preparing more efficient boron-based catalysts in the ODHP process.
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PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
·
2019
·
IF 2.87
Jiang Zhu,Kai Tian,Christopher A. Reilly,Xinghui Qiu
Helicoverpa armigera and H. assulta are two of the few insects that can feed on hot pepper fruits. Capsaicin and dihydrocapsaicin ( i.e. , capsaicinoids) are the principal pungent compounds in hot peppers. To explore possible molecular mechanisms of adaptation that allow these two species to consume capsaicinoids, the capacity of the three detoxification tissues (fat body, midgut, and Malpighian tubule) of the two pests, to metabolically degrade capsaicin and dihydrocapsaicin, was compared. The results showed that capsaicin and dihydrocapsaicin were metabolized by crude enzyme preparations from all three tissues of the two pests. Five metabolites of capsaicin, and five metabolites of dihydrocapsaicin were identified. Tissue and species differences in the degree of capsaicin and dihydrocapsaicin metabolism were observed. The specialist H. assulta had an overall greater capacity to degrade the capsaicinoids compared to the generalist H. armigera. Further, the midgut was the most significant contributor to capsaicinoid metabolism. The notably high specific activity in Malpighian tubules of H. armigera also further highlights the significance of this organ in xenobiotic detoxification. Alkyl hydroxylation and dehydrogenation were the main pathways for the oxidative biotransformation of both capsaicin and dihydrocapsaicin by cytochrome P450s. This study provides evidence that enhanced metabolic decomposition of capsaicinoids may be an adaptation explaining dietary preferences for Capsicum fruits by these two pests.
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Mao chen,Fan Zhang,Hailong Wang,Gang Shao,Bingbing Fan,Rui Zhang,Hongxia Li,Yongqiang Chen
The dense h-BN/ZrO 2 (30 wt%) composites without additives were rapidly fabricated by spark plasma sintering . The relative density, apparent porosity, fracture toughness, flexural strength , phase composition and microstructure of h-BN/ZrO 2 composites were systematically investigated. Besides, the corrosion resistance of h-BN/ZrO 2 composites in molten steel was also studied in detail. Especially, the h-BN/ZrO 2 composites were sintered at 1800 °C exhibiting a relative density of 96.6% and the flexural strength of ≈ 157 MPa. The corrosion of h-BN/ZrO 2 composites was mainly due to the oxidative decomposition of BN, and the corrosion process was clarified by a parabolic law. The excellent corrosion resistance of the h-BN/ZrO 2 composites was attributed to ZrO 2 residual layer formed at the interface. The corrosion thickness of h-BN/ZrO 2 composites was only ∼116 µm even using the longest corrosion time (80 min). The composites could be a promising candidate material applied to fabricated thin strip continuous casting side sealing plates.
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JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Xu Yin,Jiatian Yu,Zhifeng Gao,Wei Li,Kajia Wei,Yun Jiang,Yonghao Zhang,Haoming Chen,Weiqing Han
Bromate (BrO 3 – ) is a common by-product of advanced oxidation water treatment processes. In this study, a catalyst combining MXene and Pd was synthesized to eliminate BrO 3 – by electrochemical reduction in flow-through mode. The fabricated Ti/Pd@MXene filter showed superior activity for BrO 3 – reduction compared with Ti/MXene filter. A satisfactory BrO 3 − removal performance by Ti/Pd@MXene filter was obtained at pH values of 5–7 with a current density of 1.0–2.5 mA·cm –2 . The mechanism explored by quenching experiments and EPR analysis demonstrated that atomic hydrogen (H*)-mediated reduction was dominant in the Ti/Pd@MXene filter system and contributed to 84.2 % of the BrO 3 − removal, which was greater than that of Ti (7.1 %) and Ti/MXene (43.9 %). DFT calculations revealed the introduction of Pd nanoparticles on MXene lowered the energy barrier for generating H* from OH* -H* , thus boosting H* formation. Furthermore, the Ti/Pd@MXene filter had favorable stability and applicability, and nearly 90 % of BrO 3 − could be eliminated in different water matrices. Moreover, energy consumption of the Ti/Pd@MXene filter was more competitive than that previously reported (0.348 kWh·mmol −1 ), especially for high BrO 3 − removal (≥75 %). This work highlighted an effective flow-through electrocatalytic filter to induce H* -mediated electrochemical reduction of BrO 3 − .
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Journal of Materials Chemistry A
·
2024
·
IF 10.7
Yuhui Huang,Yehan Tao,Qingqing Wang,Jian Du,Jinwen Hu,Jie Lu,Yanna Lv,Haisong Wang
To develop an industrial zeolite-based catalyst for efficient furfural production, the acidity, pore structure, and electronic properties of H-β zeolite were modulated by synergistic deatomization and atomic implantation treatments. The dealumination effectively decreased the intrinsic aluminum-related Lewis and Brosted acid sites, thus decreasing the occurrence of unwanted side reactions. Meanwhile, the removed skeleton aluminum can create voids for the following atomic implantation of introducing higher valent-state niobium species, which would provide new kinds of catalytic active sites, increase the average pore size by distorting the zeolite skeleton, and enhance the interaction with reactant molecules by acting as more electron deficient centers. In a single-phase water/γ-valerolactone reaction system, the optimum catalyst can efficiently convert both xylan and xylose with a conversion of 100 % at a medium temperature of 130 ℃ within 3 hours. Compared with the furfural yield over untreated H-β (12.7%), the yield over deAlβ/Nb(20%) catalyst was greatly enhanced by 54% with xylose as raw material. The catalyst can be recovered by simple cleaning and thermal regeneration and then reused. The proposed post-treatment strategy could maintain the integrity of the zeolite structure, ensure uniform and stable metal dispersion under harsh conditions, manage the complexity and cost of the preparation process, and most importantly, optimize the catalytic performance. Addressing these issues is essential for improving the efficiency and practical application of industrial zeolite catalysts by this general approach and benefiting industrial furfural production.
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