JOURNAL OF CATALYSIS
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2023
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IF 7.3
Jin Yuan,Zhiwei He,Hongbo Zhang
Selective C–H bond oxidation of cyclohexane into KA oil (ketone-alcohol) is of vital importance in both fundamental research and industrial applications while limited by complex reaction network and suffering from low efficiency. In this study, Ce(OH)SO 4 · x H 2 O was chosen as a probe to systematically investigate the C–H bond activation and C–C bond rupture as a function of various reaction parameters, including the reactant/product concentrations, catalyst applied, reaction temperatures, acidic concentrations etc, and found that bi-molecule of C 6 H 12 was probably involved in both C–H bond rupture and C–C bond cleavage and both were controlled by one deprotonation elementary step with ·O 2 – and h + as the key active components, which were supported by parity fittings and primary KIEs determined. In addition, the C–C bond rupture was found to be mainly following C 6 H 10 O to ε-caprolactone and further to linear acids reaction path. Hopefully, this study could help people find/optimize reaction systems in selective hydrocarbon upgradings.
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Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Pei Nian,Xiaojuan Wang,Shuming Li,Zheng Wang,Yibin Wei
There remains a great challenge to develop a switchable and feasible membrane for integrate reversible separation of oil/water mixtures. Herein, a highly-quality CAU-10-H mesh membrane with switchable superwettability was fabricated via solvothermal synthesis for on-demand oil/water separation. The CAU-10-H membrane exhibited under-liquid dual superlyophobicity due to the hierarchical micro-/nanostructures constructed by interpenetrating CAU-10-H crystals grown on the mesh. Meanwhile, the secondary growth time affecting the wetting behavior of the membrane is studied. More importantly, the membrane can achieve both immiscible oil/water separation and emulsion separation with high separation flux and high efficiency (>99.9%). Moreover, the membrane shows an excellent anti-corrosive property in various harsh environment. The present development would provide novel insights into the rational fabrication of MOF-based membranes for on-demand oil/water separation.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2022
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IF 4.326
Wei Li,Ting Luo,Changxu Zhu,Bin Zhang,Bingqiang Cao
Graphene/hexagonal boron nitride nanocomposites with different dimensions have great application prospects in the field of lubrication due to their unique layered structure and excellent mechanical properties. However, due to their complex synthesis process, easy agglomeration, and poor stability, graphene/hexagonal boron nitride nanocomposites have not yet been applied in lubricating applications. Herein, a simple and green in situ laser irradiation method is proposed to construct two-dimensional (2D) reduced graphene oxide (rGO) nanosheets and zero-dimensional (0D) hexagonal boron nitride nanosphere 2D/0D nanocomposite (L-rGO/h-BN). During the one-step laser irradiation in liquid, the GO nanosheets were reduced to rGO nanosheets. Meanwhile, the hexagonal boron nitride (h-BN) transformed from nanoflakes to nanospheres via a pulsed laser heating and reshaping process and embedded into the multilayer graphene nanosheets. The spherical h-BN nanoparticles as interlayer support can maintain the 2D graphene with a more stable layered structure, while the insertion of graphene sheets also effectively inhibits the agglomeration of the spherical h-BN nanoparticles. Therefore, a hierarchical 2D/0D layered rGO/h-BN nanocomposite was formed. Importantly, such composite nanoparticles can well disperse in the lubricating oil without significant precipitation for over 30 days and show remarkably improved tribological performance. This is due to the synergistic lubricant effect of the deposition repair effect from rGO nanosheets reducing wear and micro-bearing effect from h-BN nanospheres reducing friction by changing sliding friction into rolling friction.
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JOURNAL OF MASS SPECTROMETRY
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2019
·Vol. 54
·期 3
·239-249
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IF 2.267
Hua-Ming Xiao,Xian Wang,Xing Yang,Feng Zheng,Yu-Qi Feng
Hydralazine has been widely employed in the development of drugs, derivatization reagents, and ligands. In the present work, we reported a new type of dehydrogenated ion [M − H] + that was produced from the hydralazine derivative of hexanal in electrospray ionization mass spectrometry (ESI-MS). The formation of [M − H] + ions in the ESI-MS was found to be independent on the mobile phase composition of the liquid chromatography and ESI source parameters. A series of hydralazine derivatives of aldehyde were investigated to confirm this phenomenon. The results showed that hydralazine derivatives of aldehydes that contained an sp 3 hybridization carbon with a hydrogen at the α-position of aldehydes could form the unexpected [M − H] + ions, whereas hydralazine derivative of acetone could only generate [M + H] + ion in the ESI-MS. We proposed the possible formation mechanism of [M − H] + ion for the hydralazine derivatives of aldehydes: the [M − H] + ion was possibly formed by the loss a hydrogen molecule (H 2 ) from the protonated ion [M + H] + . The results obtained from density functional theory (DFT) calculations supported this proposed formation mechanism of [M − H] + ion.
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RSC Advances
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2018
·Vol. 8
·期 73
·42109-42115
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IF 2.936
Myonghak Ri,Kwanghak Choe,Kumchol Kim,Yan Gao,Zhiyong Tang
BCN (boron carbon nitride) nanosheets are promising photocatalyst materials for solar fuel production by visible light-driven water splitting and CO2 reduction due to their tunable band gap and unique properties. C-doping into h-BN by thermal annealing makes possible the preparation of BCN nanosheets with photocatalytic activity under visible light irradiation, but it generally requires a very high temperature (>1250 °C) from the thermodynamic viewpoint. Here, we report a new method to prepare BCN nanosheets with visible light-photocatalytic activity at lower annealing temperature (1000 °C) than equilibrium by adding alkaline earth metal compounds. BCN nanosheets formed in borate melt show a clear layered structure, tunable bandgap and photocatalytic activity for water splitting and CO2 reduction under visible light illumination. This provides a direction for doping other elements into h-BN at low annealing temperature by alkaline earth metal borates.
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BIOMETALS
·
2019
·Vol. 32
·期 2
·251-264
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IF 2.455
Liu Xiao-Li,Ye Sen,Li Hua-Wei,Lu Bo,Yu Yan-Qin,Fan Yu-Peng,Yang Wei-Jun,Yang Jin-Shu
Rimicaris exoculata (Decapoda: Bresiliidae) is one of the dominant species among hydrothermal vent communities along the Mid-Atlantic Ridge. This shrimp can tolerate high concentrations of heavy metals such as iron, but the mechanisms used for detoxification and utilization of excess metals remain largely unknown. Ferritin is a major iron storage protein in most living organisms. The central heavy subunit of ferritin (H-ferritin) possesses ferroxidase activity and converts iron from Fe 2+ to Fe 3+ , the non-toxic form used for storage. In the present study, the H-ferritin RexFrtH was identified in the hydrothermal vent shrimp R. exoculata , and found to be highly expressed in the gill, the main organ involved in bioaccumulation of metals, at both RNA and protein levels. Accumulation of RexFrtH decreased from efferent to afferent vessels, coinciding with the direction of water flow through the gills. Fe 3+ was localized with RexFrtH, and in vitro iron-binding and ferroxidase assays using recombinant RexFrtH confirmed the high affinity for iron. Based on these results, we propose a model of iron metabolism in R. exoculata gills; ferrous iron from ambient hydrothermal water accumulates and is converted and stored in ferric form by RexFrtH as an iron reservoir when needed for metabolism, or excreted as an intermediate to prevent iron overload. The findings expand our understanding of the adaptation strategies used by shrimps inhabiting extreme hydrothermal vents to cope with extremely high heavy metal concentrations.
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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2018
·Vol. 135
·期 6
·3005-3013
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IF 2.209
Luo Liqiong,Jin Bo,Peng Rufang,Shang Yu,Xiao Lipengcheng,Chu Shijin
A new nitrogen-rich energetic salt of bis-1-methylimidazole 1 H ,1′ H -5,5′-bistetrazole-1,1′-diolate salt, (1- M ) 2 BTO, was synthesized and characterized (FT-IR, 1 H NMR, 13 C NMR, elemental analysis, and X-ray single-crystal diffraction). Results indicated that (1- M ) 2 BTO crystallizes in the triclinic space group P -1. The thermal decomposition behavior of (1- M ) 2 BTO was determined by differential scanning calorimetry (DSC) and thermogravimetric tandem infrared spectroscopy. The decomposition peak temperature of (1- M ) 2 BTO was 530 K, which suggested that the salt is strong heat resistance. The apparent activation energies were 130.56 kJ mol −1 (Kissinger’s method) and 132.50 kJ mol −1 (Ozawa’s method), respectively. The enthalpy of formation for the salt was calculated as 917.3 kJ mol −1 . The detonation velocity and detonation pressure of (1- M ) 2 BTO were 7448 m s −1 and 20.7 GPa, respectively, using the Kamlet-Jacobs equation. Furthermore, the sensitivity test results showed that its impact sensitivity is greater than 50 J and friction sensitivity is 180 N, indicating that it has a lower sensitivity.
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Journal of Physical Chemistry C
·
2018
·
IF 4.484
Zhiqiang Xie,Congbiao Chen,Bo Hou,Dekui Sun,Heqin Guo,Jungang Wang,Debao Li,Litao Jia
The nature of high-silica H–Y acid sites in dimethoxymethane carbonylation is investigated by NH3 poisoning with a combination of reaction results, diffuse reflection infrared Fourier transform spectra, and NH3 temperature-programmed desorption. After NH3 poisoning of H–Y, ammonia desorption of zeolites NH4–Y was conducted at different temperatures to obtain catalysts HNH4–Y that gradually exposed different acid sites. The zeolites thus produced catalyzed dimethoxymethane carbonylation with a linear dependence of the conversion on the ammonia desorption temperature before the plateau stage. It was observed that strong Brønsted acids in zeolite Y catalyzed the reaction more selectively toward the main product methyl methoxyacetate, and weak Brønsted acids catalyzed the reaction more selectively toward the byproduct methyl formate. Furthermore, the turnover frequency of Brønsted acids varied significantly among the Brønsted acids and decreased with acid strength. This finding suggested that only 10.1–18.3% of the total Al in zeolite Y with Si/Al ratios of 15, 30, and 40 contributed to the total framework Brønsted acids.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2018
·
IF 3.235
Qing Zheng,Huibo Shao
We have explored the intermolecular interactions within a two-component self-assembled monolayer, a model system to develop our understanding of interfacial chemistry in molecular level. The redox signal of 11-ferrocenyl-1-undecanethiol (FcC11) reversibly responded to the formation of intermolecular H-bonding: The intermolecular H-bonding between the terminal carboxyl groups of MSA promoted the formation of MSA assemblies, which increased the influence of MSA on the neighboring molecules (FcC11). Meanwhile, the disordered FcC11 appeared within the locally ordered FcC11 patches, resulting in the presence of a new couple of redox peaks in the cyclic voltammograms. The surface coverage that corresponding to the H-bonding affected FcC11 increased exponentially from 0 to 3.49 × 10 −10 mol cm −2 as a function of the time of MSA assembly. The pK 1/2 value (the pH when half of the –COOH groups are ionized) that determined for the FcC11/MSA modified gold substrate was obviously higher than the alkanoic acids in aqueous solution. The results show that the intermolecular H-bonding between MSA molecules plays a key role in controlling the molecular assembly within the two-component self-assembled monolayer, which provides an approach for regulating the structural changes of the model membrane in molecular level.
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Nanomaterials
·
2019
·Vol. 9
·期 7
·1051
·
IF 4.034
Xiu Wang,Zhihuai Yu,Liang Jiao,Huiyang Bian,Weisheng Yang,Weibing Wu,Huining Xiao,Hongqi Dai
Hexagonal boron nitride (h-BN)-based heat-spreading materials have drawn considerable attention in electronic diaphragm and packaging fields because of their high thermal conductivity and desired electrical insulation properties. However, the traditional approach to fabricate thermally conductive composites usually suffers from low thermal conductivity, and cannot meet the requirement of thermal management. In this work, novel h-BN/cellulose-nano fiber (CNF) composite films with excellent thermal conductivity in through plane and electrical insulation properties are fabricated via an innovative process, i.e., the perfusion of h-BN into porous three dimensional (3D) CNF aerogel skeleton to form the h-BN thermally conductive pathways by filling the CNF aerogel voids. When at an h-BN loading of 9.51 vol %, the thermal conductivity of h-BN/CNF aerogel perfusion composite film is 1.488 W·m−1·K−1at through plane, an increase by 260.3%. The volume resistivity is 3.83 × 1014Ω·cm, superior to that of synthetic polymer materials (about 109~1013Ω·cm). Therefore, the resulting h-BN/CNF film is very promising to replace the traditional synthetic polymer materials for a broad spectrum of applications, including the field of electronics.Keywords:CNF aerogel;perfusion;h-BN;thermal conductivity;electrical insulation
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RSC Advances
·
2017
·Vol. 7
·期 82
·51831-51837
·
IF 3.108
Yunrui Zhang,Haihong Niu,Xiangjie Zhang,Junxiu Pan,Yang Dong,Haijun Wang,Yongjun Gao
A kind of magnetic N-containing carbon material was synthesized by a simple method using sustainable N-acetyl-D-glucosamine (NAG) and iron nitrate as the raw materials. In C–H oxidation reactions such as the epoxidation of stilbene and styrene, and the oxidation of ethylbenzene, the carbon catalyst exhibited excellent catalytic activity and selectivity for the target products. The superparamagnetic properties at room temperature facilitated catalyst recycling and reusability when it was used as a catalyst. The relationship between the catalytic results and the N 1s XPS analysis indicated that the graphitic N species located in the carbon skeleton was the key accelerating factor which promoted the catalytic C–H oxidation. Density functional theory (DFT) calculations further indicated that the iron species were not an essential factor but they acted as promoters for the catalytic performance of the catalyst. This study will expand the application of biomass-based heteroatom-containing compounds.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Nanqi Shi,Zhike Li,Xin Li,Hongxin Luo,Shuzhen Dong,Haiyan Li
Hexagonal boron nitride (h-BN), as a two-dimensional lamellar material, has been paid more and more attention in the field of corrosion protection because of its excellent thermal stability, chemical stability and insulation. In order to solve the problem that h-BN is difficult to disperse in resin, inspired by the adhesion ability of mussel secretions, the surface of h-BN was modified with polydopamine (PDA) to improve the dispersion of the fillers in epoxy resin, and the prepared corrosion inhibition CeO 2 nanoparticles were loaded on the surface. A functional filler CeO 2 &PDA/h-BN with corrosion inhibition effect was prepared. The surface morphology , chemical structure and thermal stability of functional fillers were analyzed by SEM, FTIR, XRD and thermogravimetric analysis . The test results show that after 40 days of testing, the low-frequency impedance modulus of the epoxy composite coating is 15 times that of the pure epoxy resin, and the wear resistance properties also significantly improved. The anti-corrosion mechanism of the composite coating is analyzed, and the synergistic effect of h-BN's barrier ability and CeO 2 's corrosion inhibition ability is revealed. This paper provides an idea for the preparation of multifunctional h-BN composite anticorrosive filler.
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