JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
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2021
·
IF 8.067
Yunwei Liu,Zelin Chen,Chang Liu,Jinfeng Zhang,Wenbin Hu,Yida Deng
We have developed an efficient strategy to synthesize an active and durable electrocatalyst of Pd hydride nanocubes (NCs). Instead of the traditional chemical method, the PdH 0.43 NCs are firstly prepared via a hydrogen diffusion procedure, followed by hydrothermal synthesis of an amorphous CuO layer encapsulating the PdH 0.43 NCs to prevent the hydrogen atoms from escaping. Obvious lattice expansion is demonstrated playing a pivotal role in the enhancement of their oxygen reduction reaction (ORR) activity and durability. The obtained PdH 0.43 @CuO NCs catalysts exhibit an ORR mass activity of 0.18 A mg −1 at 0.90 V versus reversible hydrogen electrode in an alkaline medium, which is about five times higher than that of commercial Pt/C. Accelerated durability tests show that there is only a 32 mV decay in half-wave potential even after 10,000 potential cycles, indicating the excellent stability of PdH 0.43 @CuO NCs. Density functional theory (DFT) calculations also indicate that, compared to Pd, PdH 0.43 has a lower limiting barrier to form OH − during the ORR process. The present study illustrates the importance of lattice expansion caused by hydrogen and offers an available strategy to design highly efficient and durable Pd-based electrocatalysts for alkaline fuel cells.
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JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2021
·
IF 5.302
Fuhai Liu,Maozhong Yi,Liping Ran,Yicheng Ge,Zhe Zhou,Ke Peng
C/C-BN-SiC composite was prepared by ceramic slurry infiltration combined with resin impregnation and carbonization, and the matrix with continuous distributed self-healing phase was obtained. In this study, the kinetic characteristics and oxidation behavior of the composites with various h-BN/SiC ratios in the temperature range of 600∼1300°C were studied by combining the isothermal oxidation test with the kinetic model. The optimal h-BN/SiC ratio balances the thermal stability and fluidity of the oxidized product, which not only has high thermal stability and low oxygen permeability to acts as an oxygen diffusion barrier but also has a certain fluidity to seal defects.
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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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高影响因子
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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BIOMETALS
·
2019
·Vol. 32
·期 2
·251-264
·
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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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2019
·
IF 4.084
Liangfeng Luo,Yidi Wang,Siping Huo,Peng Lv,Jun Fang,Yang Yang,Bin Fei
CuS/CdS(H)/CdS(C) photocatalysts were synthesized via the hydrothermal method by employing thiourea , Cd(CH 3 COO) 2 ·3H 2 O and copper 1,4-benzenedicarboxylate MOF (CuBDC). The photocatalysts were characterized by XRD , XPS , BET, TEM and UV–vis diffuse reflectance spectra. Interestingly, hexagonal CdS (CdS(H)) and cubic CdS (CdS(C)) were formed with phase junctions in one step when CuBDC was introduced in the synthesis process, in addition, CuS nanoparticles were deposited on CdS. However, only hexagonal CdS was obtained without CuBDC. It demonstrated that CuBDC was not only the precursor of CuS but also the structural modifier for CdS. With the reduction of re-combination of photo-induced electrons and holes caused by phase junctions and the enhancement of visible-light absorptions due to the loading of CuS, all CuS/CdS(H)/CdS(C) photocatalysts had higher photocurrent densities under visible-light irradiation, and consequently the higher rates of H 2 production than pure CdS(H). Typically, the catalyst with 2.89 wt% of Cu showed a highest rate of H 2 evolution at 2042 μmol/g/h.
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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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RSC Advances
·
2018
·Vol. 8
·期 73
·42109-42115
·
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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高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2018
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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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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
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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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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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高影响因子
CEMENT AND CONCRETE RESEARCH
·
2025
·
IF 13.1
Minghui Jiang,Xiao Liu,Shiyu Li,Yurui Xu,Simai Wang,Lei Lu,Xinxin Li,Xinru Sun,Chunlei Xia,Ziming Wang,Suping Cui
The internal water migration within calcium silicate hydrate (C-S-H) in dry environments is considered to be the primary factor affecting the volume stability of cementitious materials. In this research, the in-situ polymerization product of plant polyphenol tannic acid (TA) was applied to modify C-S-H based on an organic-inorganic composite modification method. The chemical structure, microstructure, composition, dimensional changes and water migration characteristics of modified C-S-H were analyzed. Experimental results showed that TA improved the polymerization degree of siloxane chains in the C-S-H nanostructure, with a maximum improvement of 80.70%, and increased the interlayer spacing in the C-S-H structure, confirming the modification of C-S-H at the nanoscale, exhibited by 29 Si Nuclear Magnetic Resonance (NMR), X-ray diffraction (XRD) and Transmission Electron Microscopy (TEM). This modification by TA optimized the C-S-H nanostructure and microscopic pores, and increased the interlayer and gel pore water content, especially gel pore water increased by 56.53% compared to that of the unmodified C-S-H, revealed by nitrogen adsorption and 1 H LF-NMR. In the dry environment, the blocking and cladding effects of TA on C-S-H effectively inhibited the gel water loss and reduced the drying shrinkage, especially at low TA concentration. This research aims to improve the volume stability of C-S-H by in-situ polymerization product of plant polyphenol, which provides new insights into improving the volume stability of cementitious materials.
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