FUEL
·
2022
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IF 8.035
Linjie Guan,Chengming Huang,Dingmei Han,Binbin He,Linhua Zhu,Dedong He,Yi Mei,Yun Zu
A series of HZSM-5 zeolites are fabricated to make it cross-link with an external ultrathin siliceous layer by chemical liquid deposition and the corresponding thickness is measured by TEM and XPS analysis. In situ FTIR experiments disclose that the external surface acidic sites of HZSM-5 zeolite can be covered even by siliceous monolayer (0.7 ∼ 1.3 nm, HZ5-S1). In comparison to parent HZSM-5, the catalytic cracking performance of n-butane over the modified zeolites are evidently enhanced. In particular, the n-butane conversion rate per Brønsted acid site over the HZ5-S2 (16.02 min −1 ) at 550 °C is 2.82 times than that over the HZSM-5 (5.68 min −1 ). Meanwhile, the diffusion properties of n-butane over the zeolites are quantified by in situ FTIR spectroscopic analysis. Negative correlation between steady-state diffusivity and n-butane conversion rate per Brønsted acid site can be found, which unravels the origin of the progressive decrease in the catalytic stability. Under comparable conditions, more advantages can be greatly achieved by HZ5-S1 catalyst in the catalytic activity and the yields to light olefins due to the benign diffusivity and the elimination of external surface acidic sites. This study can provide a guidance for the understanding of diffusion intensification and the rational design of superior catalyst for the catalytic cracking reactions of alkanes.
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高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
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2022
·Vol. 97
·期 7
·1900-1908
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IF 3.709
Yanjie Wu,Huiping Zhang,Ying Yan
BACKGROUND Cu-ZSM-5 was prepared on paper-like sintered stainless steel fibers (PSSF) by ion-exchange method for the catalytic wet peroxide oxidation (CWPO) of phenol in a fixed bed reactor. The prepared Cu-ZSM-5/PSSF catalyst was characterized by scanning electron microscope (SEM), Brunner−Emmet−Teller (BET), X-ray diffraction (XRD), Fourier Transform InfraRed (FT-IR), Ultraviolet–visiblespectroscopy (UV–vis) and X-ray photoelectron spectroscopy (XPS). RESULTS The XRD results showed that the ZSM-5 membrane was loaded well over PSSF with good crystallinity, even after the process of ion-exchange. The UV–vis inferred that isolated copper was the predominant species over ZSM-5 pores of the catalyst. Then, the effects of different catalyst bed heights, reaction temperatures, and feed flow rates on catalytic performance were investigated to obtain optimum reaction conditions. CONCLUSIONS Finally, the catalytic reaction kinetics analysis over Cu-ZSM-5/PSSF catalyst were carried out with the Power-rate Law Kinetic model. The experimental results showed that the reaction order was the first-order reaction, and the activation energy of the oxidation reaction was Ea = 72.9 kJ/mol. The initial oxidation rate equation (−r A0 = 5.36 × 10 8 e −72 994/RT C A ) was obtained for phenol degradation using Cu-ZSM-5/PSSF catalyst. © 2022 Society of Chemical Industry (SCI).
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高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2022
·Vol. 97
·期 7
·1822-1832
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IF 3.709
Yongwei Ma,Xiangxiang Zhao,Hui Shao,Jianfeng Yao
BACKGROUND Fluoride ions can form corresponding complexes with transition metal elements (Co, Ti, V, Cr, Mn, Fe, Ni, Cu, etc.), so it is easier to synthesize heteroatomic molecular sieves in a fluorine-containing system than in a fluorine-free system. RESULTS In this paper, a hierarchical CoAPO-5 molecular sieve was synthesized in a fluorine system, and the effects of different fluorine resources on its synthesis were investigated. The CoAPO-5 samples were characterized by X-ray diffraction, scanning electron microscopy, N 2 adsorption–desorption and temperature-programmed desorption of NH 3 . CONCLUSION The results showed that, compared with other fluorine resources, the sample D-AFI-1 synthesized with HF possessed more acid sites, which appeared to be more attractive for oxidative desulfurization. The central composite design of response surface methodology was applied to design experimental schemes employing D-AFI-1 as catalyst. The volume ratio of oxidant/fuel, extractant/fuel and the mass ratio catalyst/fuel were screened out as the significant factors after the investigation of single factors. The quadratic model of the three significant factors and desulfurization rate was established. On the basis of optimizing the reaction conditions, oxidant/fuel volumetric ratio, catalyst/fuel mass ratio and extractant/fuel were 0.07 mL mL −1 , 0.01 g g −1 and 1.65 mL mL −1 , respectively, the desulfurization rate was 85.0%, which was consistent with the predicted value of the model (83.7%). © 2022 Society of Chemical Industry (SCI).
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高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2022
·
IF 4.889
He Han,Anfeng Zhang,Limin Ren,Xiaowa Nie,Min Liu,Yi Liu,Chuan Shi,Hong Yang,Chunshan Song,Xinwen Guo
Shape-selective alkylation of toluene with methanol is one of the most attractive promising synthetic routes to para -xylene. To date, modified ZSM-5 zeolites are considered to be one of the best candidate catalysts for this reaction. Although the para -selectivity could be tuned to approaching 100% by modification of the zeolite and optimization of reaction conditions, at present, there is still a lack of effective means to inhibit the rapid deactivation of the catalysts due to coke formation. In this work, a coke-resistant (Pt + Ni)/ZSM-5 zeolite with excellent stability for shape-selective alkylation of toluene with methanol to para -xylene is developed. The pore structure and acid properties of the zeolite are effectively tuned to ensure high para -selectivity. Meanwhile, the co-existence of Pt and Ni species in this catalyst plays the critical role in inhibiting coke formation, as the two species concurrently impede the formation of olefins, the main coking precursors, via two distinctive mechanisms.
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2023
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IF 5.7
Huan Liu,Yu Liu,Xueqing Yu,Minmin Mao,Bing Liu,Hadi Barzegar Bafrooei,Aihua Li,Yuanyuan Zhang,Ehsan Taheri-Nassaj,Kaixin Song,Wenjun Li,Ian.M. Reaney
New ultra-low loss, temperature-stable composite ceramics, (1- x ) Mg 1.99 Ga 0.01 Si 0.99 Al 0.01 O 4 - x CaTiO 3 , have been developed with a view to expanding the portfolio of low-cost, MW dielectrics available for 5 G/6 G telecommunications, currently dominated by 95 wt%MgTiO 3 -5 wt%CaTiO 3 , (Mg,Ca)TiO 3 (relative permittivity, ε r ∼ 21, quality factor, Q × f ∼ 56,000 GHz and temperature coefficient of resonant frequency, τ f ∼ 0 ppm/°C). Compared with (Mg,Ca)TiO 3 , 89 wt%Mg 1.99 Ga 0.01 Si 0.99 Al 0.01 O 4 -11 wt%CaTiO 3 ceramics are also temperature stable ( τ f = −2.72 ppm/°C) but have lower ε r (∼8.55) and a higher Q × f (∼ 72,900 GHz @ 12 GHz and 80,900 GHz @ 26 GHz), better suited to the higher frequencies earmarked for 6 G millimeter-wave (mm-wave) applications. To demonstrate its potential for 5 G/6 G telecommunications, a waveguide filter with novel negative coupling structure was fabricated based on simulated results. The filter had low insertion loss (0.43 dB) at the center frequency (4.8 GHz) and high selectivity with a roll-off rate of 576/375 dB/GHz. The S-parameters matched well at 25 °C and 85 °C, demonstrating that the filter had excellent temperature stability and was therefore suitable for future 5 G/6 G microwave and mm-wave communication devices.
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高影响因子
CHINESE JOURNAL OF STRUCTURAL CHEMISTRY
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2023
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IF 2.2
Ke Wang,Jia Wu,Shuyi Zheng,Shibin Yin
Construction of highly active and stable bifunctional catalysts for 5-hydroxymethylfurfural oxidation reaction (HMFOR) and hydrogen evolution reaction (HER) is meaningful but remains a challenge. Herein, the NiCo–Mo 2 N heterostructure nanosheets catalyst with excellent HMFOR/HER performance is obtained by a simple hydrothermal and calcination method. The heterogeneous interface between NiCo and Mo 2 N induces electron redistribution, regulating the electronic structure of the catalyst and thus optimizing the adsorption/desorption behavior of HMFOR/HER intermediates. Consequently, NiCo–Mo 2 N/NF exhibits superior catalytic activity with a potential of 1.14 V RHE /−17 mV RHE (HMFOR/HER) at ±10 mA cm −2 , and the HMF conversion rate, FDCA yield, and Faradaic efficiency (FE) are ∼100%, 99.98%, and 98.65%, respectively. Besides, it only requires a low voltage of 1.36 V to achieve 100 mA cm −2 for HMFOR-assisted H 2 production. This study provides a strategy for the development of efficient bifunctional catalysts for sustainable production of high value-added products and hydrogen.
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高影响因子
FUEL
·
2021
·
IF 6.609
Tao Pan,Sida Ge,Mengnan Yu,Yana Ju,Ran Zhang,Pei Wu,Kuanyu Zhou,Zhijie Wu
Zn modified ZSM-5 zeolite supported Ni bifunctional catalysts were prepared by in-situ hydrothermal synthesis (Zn-Ni-ZSM-5), co-impregnation method (Zn-Ni/ZSM-5) as well as combining in-situ hydrothermal synthesis of Zn-ZSM-5 and sequential impregnation of Ni (Ni/Zn-ZSM-5) and used for the selective converting olefin to aromatics applicable for FCC gasoline hydro-upgrading. The Lewis (L) acid sites generated by ZnOH + species and hydrogenation active sites from Ni 0 species were varied with preparation method, in which their locations at the external surface or micropores of zeolite changed the acid properties of catalysts. Comparing to the Zn-Ni/ZSM-5 from the co-impregnation method, direct in-situ hydrothermal method could incorporate Zn and Ni species within zeolite, which makes the strong interaction between the metal species and the framework Al to form medium-strong L acids (ZnOH + /NiOH + ). This leads to the decrease of ratio of Brønsted acid sites to L acid sites (B/L) from 0.40 to 0.12 and the difficulty in reducing of Ni cations to Ni 0 from 57% to 30% Ni 0 percent. Ni/Zn-ZSM-5 sample prepared by incorporating Zn species into micropores and sequential depositing Ni species at the external surface of zeolite possesses a low B/L ratio similar to Zn-Ni-ZSM-5 (0.20 versus 0.12) but a much higher Ni 0 percent (52% versus 30%). Zn-Ni-ZSM-5 shows closer intimacy between Zn and Ni species comparing to Zn-Ni/ZSM-5 and Ni/Zn-ZSM-5. For the 1-hexene aromatization, the formed iso -alkene at acid sites was quickly saturated to iso -alkanes by the adjacent Ni 0 particles over Ni-Zn-ZSM-5 catalyst in hydrogen steam. However, the location of aromatization active sites (ZnOH + , L acid sites) in micropores and hydrogenation active sites (Ni 0 species) on external surface of Ni/Zn-ZSM-5 makes the tandem conversion of n-alkene → iso -alkene → aromatics, rather than the n-alkene → iso -alkene → iso -alkane. Thus, Zn-Ni-ZSM-5 with close intimacy of ZnOH + and Ni 0 particles shows a high iso -alkane selectivity (27.9% iC 4 + ), while Ni/Zn-ZSM-5 exhibits a high aromatics selectivity (39.6 %) in the conversion of 1-hexene in hydrogen steam. Similar results have also found in the conversion of n-heptane. Here, the control of the intimacy of Zn and Ni in ZSM-5 zeolites has been realized to be a good protocol to adjust the selective conversion of olefins/alkanes to aromatics versus iso -alkanes.
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高影响因子
ANALYTICAL CHEMISTRY
·
2021
·
IF 6.986
Jing Chen,Shuying Li,Ying Chen,Jiao Yang,Jianbin Dong,Xiaoquan Lu
5-Hydroxytryptamine (5-HT) is an important neurotransmitter, and its content in the human body is of great significance to human health. In this study, an l-cysteine-terminated triangular silver nanoplate loaded on a MXene (two-dimensional transition metal carbide or nitride) (Tri-AgNP/l-Cys/MXene) electrochemical sensor was used to detect 5-HT. As an electrically active amino acid with a sulfhydryl group, l-cysteine (l-Cys) forms a more stable Ag–S bond with silver nanoparticles, which can selectively substitute trisodium citrate (TSC) in TSC-capped triangular silver nanoplates (Tri-Ag-NP/TSC). Due to the good conductivity, biocompatibility, and large surface area, MXenes provide a good platform for loading Tri-AgNP/l-Cys. Under optimized conditions, the concentration range for detecting 5-HT with the sensor is 0.5–150 μM, and the limit of detection (LOD) is 0.08 μM (S/N = 3). For detecting 5-HT in actual serum samples, the sensor also showed a good recovery rate (95.38–102.3%), and the relative standard deviation was 2.2–3.4%.
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PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2023
·
IF 4.7
Jiaxing Zhang,Ajuan Zhou,Limin Ren,Min Yang,Guangjin Hou,Anfeng Zhang,Chunshan Song,Xinwen Guo
A clear understanding of the acidity-activity relationship is an important prerequisite for designing functional materials in alkylation of benzene with methanol. Herein, a series of b -axis-oriented [Fe/Al]-MFI nanosheets with similar thickness but varied acidities were prepared by tuning Fe incorporation to systematically study the effect of acidity on their alkylation performance. Comprehensive physiochemical studies demonstrate that tetrahedral framework type Fe species are dominated. The incorporation of Fe significantly weakens the strong acid strength of zeolite thus endowing the samples with proper acidity, consequently showing a strong inhibition effect on the by-product ethylbenzene. Moreover, a long-term stable operation (>300 h) is further achieved over the [Fe]-S-1 nanosheets by optimizing the content of framework Fe. This work elucidates the important relationship between acidity and alkylation activity.
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高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2023
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IF 4.5
Jing Chen,Jiao Yang,Ying Chen,Jianbin Dong,Rong Deng,Lianqin Zhu
5-hydroxytryptamine (5-HT) is an important neurotransmitter that plays an important role in regulating mood, sleep, vomiting, cardiovascular function, libido and appetite. When its concentration level changes or exceeds a certain range, it can lead to a variety of diseases. In this study, bis (dithiophen-dibenzoic acid) nickel, [Ni(C 2 S 2 (C 6 H 4 COOH) 2 ) 2 ], was successfully synthesized and self-assembled with Zn(NO 3 ) 2 ·4H 2 O to form a oxidation–reduction active three-dimensional MOFs with a nickel-zinc bimetallic center. Multi-walled carbon nanotubes (MWCNTS) have good electrical conductivity, and the composite of 3D Ni Zn-MOF materials with unsaturated coordination and oxidation–reduction activity can improve the electrical conductivity and catalytic performance of the composite. The prepared Ni Zn-MOF/MWCNTs/GCE electrochemical sensor can be used for detecting 5-HT. Under the optimized conditions, the concentration range of 5-HT was 0.5–115 μM, and the detection limit (LOD) was 0.03 μM (S/N = 3). The recovery of 5-HT in urine samples was 99.94 % ∼ 102.02 %, which proved that the sensor has excellent practical application value.
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高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
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IF 9.9
Yiyuan Tao,Shiying Fan,Xinyong Li,Jing Yang,Jingang Wang,Guohua Chen
Owing to the sluggish reaction kinetics, it is a promising yet challenging task to achieve the adequate electricity-driven catalytic oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) in neutral conditions. Herein, we have prepared an elelctrocatalyst with interfacial coupling effect through in-situ growth of Cu phthalocyanine (CuPc) on Co 3 O 4 spinel (Co 3 O 4 /CuPc), which constructs an effective electrocatalytic system of HMF oxidation with overall oxidation value-added products yield and total Faraday efficiency up to 80% and 70%, respectively. The interfacial coupling effect between CuPc and Co 3 O 4 spinel improve catalytic activity by effectively boosting the interfacial charge transfer and reducing the formation energy of key *C 6 H 3 O 4 in the catalytic pathway according to the in situ Raman spectroscopy and DFT simulation. This work illustrates the significance of interfacial coupling effect for developing highly efficient electrocatalysts applied for neutral system of biomass oxidation.
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PubMed
高影响因子
JOURNAL OF LUMINESCENCE
·
2023
·
IF 3.6
Chuncheng Zhang,Chaomin Zhang,Chao Yun
In this paper, Er 3+ /Ho 3+ co-doped fluoride glasses were prepared by the high temperature melt-quenching technique. Pumped by the 980 nm LD , as a result of the emission spectra overlapping of Er 3+ and Ho 3+ ions, a broadband mid-infrared emission band from 2530 to 2950 nm with a full width at half maximum of the synthetic fluoride glasses near 231 nm was obtained, which exist latent application in wide band tunable mid-infrared fiber laser. Furthermore, the intense 4.1 μm mid-infrared fluorescence (3600–4400 nm) was obtained and the FWHM was 320 nm. The up-conversion emission peaks around 525, 546 and 660 nm, near-infrared emissions at 1.2 and 1.5 μm together with mid-infrared fluorescence around 2.0 μm was observed in Er 3+ /Ho 3+ co-doped fluoride glass. Moreover, the relevant energy transfer processes were discussed in detail based on the emission spectrum and the energy level transition processes. The results indicate that the fabricated Er 3+ /Ho 3+ co-doped fluoride glasses exist prominent emission features for fiber laser gain medium.
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高影响因子
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