Nature Communications
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2023
·Vol. 14
·期 1
·1-12
·
IF 16.6
Meng Hao,Yang Yusen,Shen Tianyao,Yin Zhiming,Wang Lei,Liu Wei,Yin Pan,Ren Zhen,Zheng Lirong,Zhang Jian,Xiao Feng-Shou,Wei Min
Copper-based catalysts serve as the predominant methanol steam reforming material although several fundamental issues remain ambiguous such as the identity of active center and the aspects of reaction mechanism. Herein, we prepare Cu/Cu(Al)O x catalysts with amorphous alumina-stabilized Cu 2 O adjoining Cu nanoparticle to provide Cu 0 −Cu + sites. The optimized catalyst exhibits 99.5% CH 3 OH conversion with a corresponding H 2 production rate of 110.8 μmol s −1 g cat −1 with stability over 300 h at 240 °C. A binary function correlation between the CH 3 OH reaction rate and surface concentrations of Cu 0 and Cu + is established based on kinetic studies. Intrinsic active sites in the catalyst are investigated with in situ spectroscopy characterization and theoretical calculations. Namely, we find that important oxygen-containing intermediates (CH 3 O* and HCOO*) adsorb at Cu 0 −Cu + sites with a moderate adsorption strength, which promotes electron transfer from the catalyst to surface species and significantly reduces the reaction barrier of the C−H bond cleavage in CH 3 O* and HCOO* intermediates.
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JACS Au
·
2023
·
IF 8
Qi Yang,Xiujuan Gao,Faen Song,Xiaoxing Wang,Tao Zhang,Pan Xiong,Yunxing Bai,Xingchen Liu,Xiaoyan Liu,Junfeng Zhang,Gang Fu,Yisheng Tan,Yizhuo Han,Qingde Zhang
Selective oxidation of C–H bonds under mild conditions is one of the most important and challenging issues in utilization of energy-related molecules. Molybdenum oxide nanostructures containing Mo5+ species are effective for these reactions, but the accurate identification of the structure of active Mo5+ species and the catalytic mechanism remain unclear. Herein, unsaturated penta-coordinated Mo5c5+ with a high fraction in MoOx fabricated by the hydrothermal method were identified as the active sites for low-temperature oxidation of dimethyl ether (DME) by the deep correlation of characterizations, density functional theory calculations, and activity results, giving a methyl formate selectivity of 96.3% and DME conversion of 12.5% at unreported 110 °C. Low-temperature electron spin resonance (ESR) and quasi in situ X-ray photoelectron spectra (XPS) with the designed experiments confirm that the Mo5c5+ species can be formed in situ. Molybdenum located at the pentachronic site is preferable to significantly promote the oxidation of the C–H bond in CH3O* at lower temperatures.
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Nature Communications
·
2023
·Vol. 14
·期 1
·1-12
·
IF 16.6
Li Guowei,Jiang Shihui,Liu Aijun,Ye Lixiang,Ke Jianxi,Liu Caiping,Chen Lian,Liu Yongsheng,Hong Maochun
Crystal-field perturbation is theoretically the most direct and effective method of achieving highly efficient photoluminescence from trivalent lanthanide (Ln 3+ ) ions through breaking the parity-forbidden nature of their 4 f -transitions. However, exerting such crystal-field perturbation remains an arduous task even in well-developed Ln 3+ -doped luminescent nanocrystals (NCs). Herein, we report crystal-field perturbation through interstitial H + -doping in orthorhombic-phase NaMgF 3 :Ln 3+ NCs and achieve a three-orders-of-magnitude emission amplification without a distinct lattice distortion. Mechanistic studies reveal that the interstitial H + ions perturb the local charge density distribution, leading to anisotropic polarization of the F − ligand, which affects the highly symmetric Ln 3+ -substituted [MgF 6 ] 4− octahedral clusters. This effectively alleviates the parity-forbidden selective rule to enhance the 4 f –4 f radiative transition rate of the Ln 3+ emitter and is directly corroborated by the apparent shortening of the radiative recombination lifetime. The interstitially H + -doped NaMgF 3 :Yb/Er NCs are successfully used as bioimaging agents for real-time vascular imaging. These findings provide concrete evidence for crystal-field perturbation effects and promote the design of Ln 3+ -doped luminescent NCs with high brightness.
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INTERNATIONAL JOURNAL OF PHARMACEUTICS
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2023
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IF 5.8
Shuai Zhang,Quanzhi Zhang,Runmei Xu,Junyao Ma,Liang Fang
Transdermal drug delivery system (TDDS) was an effective way to realize controlled drug delivery. However, realizing zero-order controlled drug skin delivery was still challenging in the drug-in-adhesive patch. This study provided a strategy to accomplish this delivery form by stabilizing the drug concentration in adhesive through concentration-dependent competitive interaction. Clonidine (CLO) and Granisetron (GRA) were chosen as the model drugs which were of high skin permeability, and polydimethylaminoethyl acrylate (EA) as an excipient to interact with hydroxyphenyl adhesive (HP). Drug release, permeation and pharmacokinetic study were conducted to evaluate the controlled effect of HP-EA. The molecular interaction was characterized by FT-IR, 1 H NMR and XPS. Dynamic simulation and molecular docking further clarified the competitive interaction involved in the release process. Both the drug skin permeation study of CLO and GRA patch based on the HP-EA adhesive showed good zero-order fitting with r of 0.994 and 0.998, compared with non-functional adhesive (0-PSA). Furthermore, the pharmacokinetic study of the CLO patch showed a plateau phase for around 52 h without influencing the area under concentration–time curve ( AUC ), indicating that the HP-EA could realize zero-order drug skin delivery. The mechanism study revealed that EA serving as a ‘buffer component’ promoted the conversion of the ionic CLO to the neutrals the as the neutrals released, which stabilized ‘1% neutrals CLO concentration’. In conclusion, the drug delivery system based on the concentration-dependent competitive interaction broadened our understanding of the molecular mechanisms involved in zero-order controlled release in transdermal patches which would promote the development of zero-order drug delivery in TDDS.
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ChemCatChem
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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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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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PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY
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2019
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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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PROGRESS IN ORGANIC COATINGS
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2019
·
IF 3.42
Bingjie Zou,Xijiang Chang,Jingxia Yang,Shuchuan Wang,Jingli Xu,Shirong Wang,Seiji Samukawa,Lidong Wang
h-BN nanoflakes were treated in three plasma gases (Ar、Ar+H 2 (4:1)、Ar + NH 3 (4:1)) for surface modification. The structure characterization (XRD, IR, XPS etc.) of h-BN indicated that the plasma treatment not only enlarged the interlayer distance of h-BN, but also increased the NH/OH surface groups and the ratio of exfoliated h-BN planes. The plasma treated h-BN exhibited better dispersion and stronger Fe 2+ holding ability in acrylic resin than the pristine h-BN, resulting in smaller corrosion current density (i corr ) and larger charge transfer resistance for the acrylic coating on low carbon steel, especially treated in Ar + NH 3 (4:1).
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Journal of Chemistry
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2019
·
IF 1.727
Song-qi Hu,Yin Wang,Lin-lin Liu
Hexagonal boron nitride (h-BN) powders were fabricated by the combustion synthesis with B/KNO3/HMX (octogen) mixtures as reactants. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were adopted to investigate the phase composition and the chemical composition of the products, respectively. The morphology and resistance to oxidation were studied by scanning electron microscopy (SEM) and thermogravimetry (TGA), respectively. The characterization results showed that the h-BN which was produced through this method has high purity and exhibits excellent resistance to oxidation. The purity of h-BN is improved with the increasing content of HMX in reactants with boron carbide (B4C) and boron oxide (B2O3) as main impurity, but conversely, the yields are obviously decreased. Taking the comprehensive consideration of the purity and the yields together, the optimal molar ratio of B/KNO3/HMX is 10 : 1 : 4. In addition, the experimental results indicated that the crystalline grain size grows with the increasing content of HMX. The method explored in this study does not need expensive processing facilities and equipment, which is a preferable approach for the laboratory to prepare h-BN of high purity.
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Energies
·
2019
·Vol. 12
·期 15
·2966
·
IF 2.707
Pijian Gong,Xinxue Li
In this study, NaClO2was selected as a denitration oxidant. In order to clarify the mechanism of NaClO2as an oxidation agent for NO removal efficiency, the effects of H+and other factors (NaClO2concentration, temperature, and the other gas) on the NO removal efficiency were investigated. NaClO2showed a promotional ability on NO removal, whose efficiency increased with the increase of NaClO2concentration. One hundred percent removal efficiency of NO could be achieved when the NaClO2concentration was 0.014 mol/L. Furthermore, raising the reaction temperature benefited the removal of NO. The lower the pH, the better the NO removal efficiency. The promoting effect of H+on the NO removal was studied by the Nernst equation, ionic polarization, and the generation of ClO2. Under the optimal conditions, the best removal efficiency of NO was 100%. Based on the experimental results, the reaction mechanism was finally speculated.Keywords:sodium chlorite (NaClO2);wet scrubbing;removal efficiency;NO reaction mechanism
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JOURNAL OF HAZARDOUS MATERIALS
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2018
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IF 6.434
Tian Liu,Jinming Luo,Xiaoyang Meng,Liming Yang,Bin Liang,Meijun Liu,Chengbin Liu,Aijie Wang,Xia Liu,Yong Pei,Jili Yuan,John Crittenden
Although noble metal electrocatalysts are highly efficient in the dehalogenation of halogenated antibiotics, the prohibitive cost hinders their practical applications. In this study, a cobalt-phosphorous/oxide (Co P/O) composite prepared via a one-step electrodeposition was for the first time applied in electroreductive dechlorination of halogenated antibiotics (HA), including chloramphenicol (CAP), florfenicol (FLO) and thiamphenicol (TAP). Co P/O had a higher FLO dechlorination efficiency (91%) than Pd/C (69.3%) (t = 60 min, C 0 = 20 mg L −1 , applied voltage of −1.2 V vs. saturated calomel electrode (SCE)). Furthermore, the dechlorination efficiencies of Co P/O for CAP and TAP reached to 98.7 and 74.2%, respectively. The electron spin resonance and in situ Raman characterizations confirmed that atomic H* was produced via the Co P and the formation of Co Cl bonds occurred on the Co O in Co P/O. The Co Cl bond formation could trap HA molecules onto Co P/O and weaken the C Cl bond strength. The synergistic effect of H* attack and Co Cl bond was responsible for the high dechlorination efficiency. This study offers new insights into the interface mechanism of electroreductive dehalogenation process, and shows a great potential for the remediation of halogenated antibiotics contaminated wastewater.
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CATALYSIS TODAY
·
2018
·
IF 4.667
Lingcong Li,Xiaojun Liu,Hong He,Ningqiang Zhang,Ziwen Liu,Guizhen Zhang
The MgO-doped hexagonal boron nitride (MgO-h-BN) nanomaterials were designed as a support for Palladium (Pd) catalysts for CO oxidation reaction. The catalytic properties of Pd/MgO(5)-h-BN catalyst was investigated and compared with Pd/h-BN catalyst. Transmission electron microscopy (TEM) results suggested that the PdO nanoparticles with small grain sizes (ca. 8 nm) were effectively dispersed on the surface of MgO, and the MgO were deposited on the h-BN nanosheets in the Pd/MgO(5)-h-BN catalyst. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses revealed that a small amount of Mg 2+ embedded into the B vacancies of h-BN nanosheets in the Pd/MgO(5)-h-BN catalyst. More significantly, a large amount of adsorbed oxygen appeared near the B vacancies of Pd/MgO(5)-h-BN catalyst. The experiments outcomes of diffuse reflectance fourier transform spectra analysis of CO (CO-DRIFT) indicated that the carbonate/formate species were easily decomposed to CO 2 on the Pd/MgO(5)-h-BN catalyst than Pd/h-BN catalyst, which might be a reason why the Pd/MgO(5)-h-BN catalyst had high CO oxidation activity. According to above analyses, we provide a new insight for the MgO-h-BN nanomaterials for Pd catalysts for application in CO oxidation reaction.
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