JOURNAL OF CHEMICAL THERMODYNAMICS
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2021
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IF 3.178
Qi-Chao Yang,Dong-Fang Qiu,Yuan-Lin Dang,Zhan-Ping Qiao,Zhi-wei Xu
Two equilibrium diagrams of the ternary system (CsX + MnX 2 + H 2 O, X = Cl, Br) at 298.15 K are reported in this paper. Each system has two double salts (CsMnX 3 ·2H 2 O and Cs 2 MnX 4 ·2H 2 O X = Cl, Br) in it and the elements of all double salts in phase diagrams are confirmed by Schreinemaker method. Equilibrium phase diagrams show that the chloride double salts are congruently soluble compounds in water, however that the bromide double salts are incongruently soluble compounds in water. All the double salts are characterized by titrimetric analysis, powder X-ray diffraction, thermogravimetric and differential thermalanalysis. The enthalpies of formation of these double salts are first calculated by measuring their enthalpies of dissolution.
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高影响因子
Catalysis Science & Technology
·
2020
·Vol. 10
·期 24
·8437-8444
·
IF 5.721
Xiaomei Yang,Liuyong Wang,Tianliang Lu,Beibei Gao,Yunlai Su,Lipeng Zhou
Hydrothermally synthesized Sn-Beta is an excellent catalyst for the conversion of sugars to alkyl lactates. However, its catalytic performance is highly dependent on the synthesis parameters. In this work, the effects of the synthesis parameters such as the water amount of the synthesis gel and the crystallization time on the synthesis and properties and catalytic performance of Sn-Beta in the conversion of glucose to methyl lactate (MLA) were investigated. The crystallization rate was accelerated remarkably by reducing the water amount of the synthesis gel. With the aid of the Si-Beta seed, Sn-Beta was almost fully-crystallized after one day with nH2O/nSiO2 of 4.5, but seven days were needed with nH2O/nSiO2 of 7.5. However, Sn-Beta synthesized with nH2O/nSiO2 of 4.5 has more extraframework SnO2 due to the fast formation of the *BEA structure and the slow incorporation of Sn4+ into the framework sites, which resulted in the lower activity of MLA formation. More Sn4+ species were incorporated into the framework sites and thus more Lewis acid sites were generated with increasing crystallization time. At the same time, the ratio of open to closed Sn sites (RO/C) increased, which led to the decrease in the activity of MLA formation and due to that, the open Sn site with a proximal silanol is unfavorable for the conversion of glucose to MLA. During recycling study, it is surprisingly found that the yield of MLA increased gradually over the fully-crystallized Sn-Beta catalyst. Characterization results of the recovered catalyst from the eighth run indicate that the structure was preserved well, but the value of RO/C reduced due to the change of the state and microenvironment of Sn species.
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高影响因子
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
·
2020
·Vol. 646
·期 20
·1688-1695
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IF 1.24
Shuangsheng Cheng,YuanDong Wu,Dajiang Mei,Shaoguo Wen,Thomas Doert
Four alkali metal bismuth sulfates, NaBi(SO 4 ) 2 · H 2 O ( 1 ) and ABi(SO 4 ) 2 [A = K ( 2 ), Rb ( 3 ), Cs ( 4 )], were successfully synthesized by hydrothermal methods. The crystal structure of 1 features a three-dimensional tunnel framework constructed by BiO 9 tri-capped trigonal prisms and SO 4 tetrahedra interconnected via common corners and edges. Compound 2 exhibits a two-dimensional 2 ∞ [Bi(SO 4 ) 2 ] – double-layered structure, assembled by one-dimensional 1 ∞ [BiS(1)O 4 ] + chains which are linked via S(2)O 4 2– tetrahedra. The isostructural compounds 3 and 4 possess a two-dimensional layered structure, and the layers being composed by BiO 8 square antiprism and SO 4 tetrahedra. The alkali metal cations are located between the layers or in the tunnels of the structures, respectively. The differences in the crystal structures of the title compounds can mainly be attributed to the different sizes of the alkali metal cations and their different coordination environments. Thermogravimetric analysis evidence that compound 1 losses one equivalent of water at 120 °C whereas the anhydrous compounds 2 – 4 are stable up to about 450, 575, and 578 °C, respectively. The solid-state UV/Vis/NIR diffuse reflectance spectra indicate bandgaps of approximately 4.48, 4.43, 3.98, and 3.96 eV for compounds 1 – 4 , respectively.
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JOURNAL OF CHEMICAL THERMODYNAMICS
·
2020
·
IF 2.888
Kaiyu Zhao,Kangrui Sun,Yafei Guo,Lingzong Meng,Tianlong Deng
The isopiestic equilibria for the systems {Li 2 B 4 O 5 (OH) 4 + H 2 O}, {LiB 5 O 6 (OH) 4 + H 2 O} and {Li 2 B 4 O 5 (OH) 4 + LiB 5 O 6 (OH) 4 + H 2 O} at 288.15 K and ambient pressure were measured by the isopiestic method using a modified gravimetric isopiestic apparatus. The water activities and osmotic coefficients were determined based on the sodium chloride standard reference solution. On the basis of Pitzer model, an extended Pitzer model was developed to describe the thermodynamic properties of the aqueous systems containing different forms of lithium borates, then the Pitzer single salt parameters β (0) , β (1) , β (2) and C ϕ for the binary systems {Li 2 B 4 O 5 (OH) 4 + H 2 O} and {(LiB 5 O 6 (OH) 4 + H 2 O} and mixing ion-interaction parameters θ B 4 O 5 OH 4 , B 5 O 6 OH 4 and ψ Li , B 4 O 5 OH 4 , B 5 O 6 OH 4 for the ternary system {Li 2 B 4 O 5 (OH) 4 + LiB 5 O 6 (OH) 4 + H 2 O} were fitted with the experimental osmotic coefficients using the Fortran 97 program. Meanwhile, the water activities were calculated by the Pitzer parameters, and the good agreement between the calculated water activities and experimental results of this ternary system indicated that the Pitzer parameters obtained in this work were reliable.
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CHEMISTRY OF MATERIALS
·
2021
·
IF 9.811
Da Chen,Shiqiang Hao,Liubing Fan,Yangwu Guo,Jiyong Yao,Christopher Wolverton,Mercouri G. Kanatzidis,Jing Zhao,Quanlin Liu
Recent discoveries in organic−inorganic metal halides reveal superior semiconducting and polarization properties. Herein, we report three organic–inorganic metal halides, (PBA)4BiBr7·H2O, (PBA)4BiI7·H2O, and (PBA)4InBr7·H2O [(PBA)+ = C6H5(CH2)4NH3+], with band gaps of ∼3.52, ∼2.29, and ∼4.05 eV, respectively. They possess zero-dimensional structures containing the inorganic octahedra [MX6]3– (M = Bi, In, X = Br, I) and unbound X– ions and crystallize in the C2 space group. (PBA)4BiI7·H2O shows a second-harmonic-generation (SHG) response in the infrared region, approximately 1.3 times that of AgGaS2; (PBA)4BiBr7·H2O and (PBA)4InBr7·H2O show SHG responses in the ultraviolet region, approximately 0.4 and 0.6 times that of KH2PO4, respectively. The large SHG responses are attributed to the synergistic contribution of the octahedral distortion of [MX6]3– (M = Bi, In, X = Br, I) and the ordered arrangement of the benzene ring-containing organic cation PBA+. Upon ultraviolet and visible-light excitations at room temperature, (PBA)4BiBr7·H2O, (PBA)4BiI7·H2O, and (PBA)4InBr7·H2O exhibit broad red-light luminescence with large Stokes shifts of 290, 237, and 360 nm, respectively, due to self-trapped exciton emission. All of these properties demonstrate that this series of metal halides are potential multifunctional optoelectronic materials.
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APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Xiaoyan Feng,Qiong Wu,Li Li,Ping Wang,Qiang Wang,Jun Liang
Simulating natural photosynthesis to convert CO 2 and H 2 O into fuels achieving overall reaction is a promising solution for addressing environmental problems and energy crises. Constructing an S-scheme catalyst of two or more catalytic sites with rapid electron transfer and strong redox capability may be an effective strategy for coupling photocatalytic CO 2 reduction and H 2 O oxidation. Here, an oxygen vacancies-rich S-scheme semiconductor photocatalyst composed of monoclinic lead chromate oxide (Pb 2 (CrO 4 )O) coupled with Mn 3 O 4 quantum dots (QDs) (Pb 2 (CrO 4 )O@Mn 3 O 4 QDs) are synthesized and tested for photoconversion of CO 2 with H 2 O under visible light. Through the integration of Pb 2 (CrO 4 )O with Mn 3 O 4 QDs, the photocatalytic C1-evolution rate on Pb 2 (CrO 4 )O@Mn 3 O 4 QDs is radically increased by 6.0 and 8.1 times, which is much faster than that of pristine Pb 2 (CrO 4 )O and Mn 3 O 4 . The origin of the greatly raised activity is revealed by advanced characterizations, and in situ X-ray photoelectron spectroscopy (XPS) confirms the electron transport pathway in Pb 2 (CrO 4 )O@Mn 3 O 4 QDs with light illumination, unveiling the efficient spatial separation/transfer of charge carriers in oxygen vacancies-rich Pb 2 (CrO 4 )O@Mn 3 O 4 QDs S-scheme heterojunction. Consequently, powerful photoelectrons and holes accumulate in the Mn 3 O 4 conduction band and Pb 2 (CrO 4 )O valence band, respectively, exhibiting prolonged long lifetimes and facilitating their involvement in CO 2 photoreduction and H 2 O photooxidation through altering the interfacial charge dynamics.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Bingyan Han,Yajun Chen,Qingdong Liu,Yuncong Gao,Jiao Wang,Haiyan Liu,Gaohong He
Aggregation-induced emission enhancement is one of the main methods for designing copper clusters (CuNCs) with high fluorescence intensity. In this study, H 2 O can rapidly construct stable hydrogen bonds with 2-thiobarbituric acid ligands of CuNCs, leading to denser aggregation between CuNCs. This process can occur at a level of intensity visible to the naked eye and can be completed within 30 s. As a result, the fluorescence turns to yellow with emission wavelength at 573 nm from red with emission wavelength at 638 nm, and the quantum yield has been increased to 50.03 %. The noticeable “turn on” phenomenon can be utilized for detecting alcohol content in low-alcohol liquor quality control. Additionally, bright luminous make Y-CuNCs can be employed for accurate identification of human latent fingerprints (LFPs), which can accurately identify the third level structure of the LFPs.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yu Zhang,Rui Wang
NH 3 ‑selective catalytic reduction as the fascinating technology for complete NO x removal, the key in practical applications is to explore advanced catalysts with high catalytic reactivity and stability at low temperature. Herein, a series of hollow spherical AMnO x (A = Ce, Cu, Ni) catalysts was fabricated by using carbon nanospheres as sacrificial template. Characterization analysis including XRD, ICP, BET, SEM, TEM, H 2 -TPR, NH 3 -TPD, XPS, in situ DRIFTS together with kinetic studies were applied to acquire knowledge of the morphological structure and surface features of the catalysts as-prepared. We also performed a comparative study on three samples with regard to their SCR activity at low temperatures. Notable, the catalytic activity of the NiMnO x catalyst (95.9 %) was vastly superior to that of the CeMnO x (85.4 %) and CuMnO x (30.5 %) at 100 °C. This enhanced low-temperature activity of NiMnO x are correlated against hollow structure with more active sites, wider pore distribution, higher surface Mn content and the enhancement in surface acidity and reducibility. Even with 5 vol% H 2 O in the reaction gas fraction, the catalytic performance of NiMnO x hollow spheres was superior to the other two catalysts. Besides, it can be used for six consecutive runs without suffering a substantial activity loss. Additionally, the impact of various crucial process variables, including space velocity, H 2 O, SO 2 , and metal poisons, on the denitrification efficiency of NH 3 -SCR was examined. The current researches have a positive guiding role in the development of high-efficiency low-temperature NH 3 -SCR denitrification catalysts to boost NO x degradation.
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高影响因子
CELLULOSE
·
2019
·Vol. 26
·期 4
·2729-2741
·
IF 3.917
Zheng Chenmin,Wen Sili,Teng Ziling,Ye Chunlu,Chen Qiaoling,Zhuang Yuanhong,Zhang Guoguang,Cai Jie,Fei Peng
Abstract In this study, H 2 Ti 2 O 5 ·H 2 O nanotubes (TNTs) prepared through hydrothermal synthesis and TiO 2 used as a raw material were deposited on the surface of bamboo fibre materials through a layer-by-layer (LBL) self-assembly technique to reduce flammability. Scanning electron microscopy indicated that the TNTs were successfully loaded onto the bamboo surface, and their content was dependent on the number of assembled bilayers. Cone calorimetry results showed that the flame retardant performance of the coated bamboo fibre materials improved significantly. As the number of the assembled bilayers increased, performance was further enhanced. When the number of TNTs bilayers was 9, the time to ignition of the bamboo fibre materials was extended from 29.5 s for raw bamboo fibre (RBF) materials to 36.8 s for LBL9. The average heat release rate, total heat release and peak specific extinction area of the fibre materials decreased from 55.67 MJ/m 2 (RBF) to 35.28 MJ/m 2 (LBL9), and their fire performance index increased from 0.123 m 2 s/kW (RBF) to 0.161 m 2 s/kW (LBL9). Differential scanning calorimetry and thermogravimetry results demonstrated that the thermal oxidation and decomposition temperatures of bamboo fibre materials increased from 241.4 °C and 217 °C (RBF) to 311.3 °C and 274 °C (LBL9), respectively. Graphical abstract
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高影响因子
TALANTA
·
2017
·
IF 4.162
Fei Wang,Fan Yang,Yang Tian,Jiawei Liu,Jiwei Shen,Quan Bai
A stoichiometric displacement model for retention (SDM-R) of small solutes and proteins based on hydrophilic interaction chromatography (HILIC) was presented. A linear equation that related the logarithm of the capacity factor of the solute to the logarithm of the concentration of water in the mobile phase was derived. The stoichiometric displacement parameters, Z (the number of water molecules required to displace a solute from ligands) and lg I (containing a number of constants that relate to the affinity of solute to the ligands) could be obtained from the slope and the intercept of the linear plots of lg k' vs. lg[H 2 O]. The retention behaviors and retention mechanism of 15 kinds of small solutes and 6 kinds of proteins on 5 kinds HILIC columns with different ligands were investigated with SDM-R in typical range of water concentration in mobile phase. A good linear relationship between lg k' and lg[H 2 O] demonstrated that the most rational retention mechanism of solute in HILIC was a stoichiometric displacement process between solute and solvent molecules with water as displacing agents, which was not only valid for small solutes, but also could be used to explain the retention mechanism of biopolymers in HILIC. Comparing with the partition and adsorption models in HILIC, SDM-R was superior to them.
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高影响因子
Chemical Engineering Journal Advances
·
2020
·
IF 0
Jiuhu Zhao,Zhengzhong Wen,Rongshu Zhu,Zhi Li,Ran Ding,Yongji Zhu,Tingkun Gu,Rong Yang,Zhenye Zhu
In this paper, In-metal oxide/H-Beta catalysts were synthesized by ion exchange method and In-Co 3 O 4 /H-Beta exhibited the highest catalytic activity for the selective catalytic reduction of NO x with CH 4 in presence of H 2 O and SO 2 . Thus, the synthesis conditions of In-Co 3 O 4 /H-Beta were optimized. The results showed that In-Co 3 O 4 /H-Beta exhibited excellent catalytic performance and high CH 4 selectively when the synthesis was carried out by ion exchange method, the ratio of Si and Al in H-Beta was 25, the ratio of Co 3 O 4 and H-Beta was 5:40, the concentration of ion exchange liquid was 0.033 M and calcination temperature was 500 °C. The NO x removal efficiency was about 87.6 % and N 2 selectivity could reach 96.3% in the presence of H 2 O and SO 2 . Through a series of characterizations, it was concluded that In-Co 3 O 4 /H-Beta owned stable catalyst structure, abundant Brønsted acid sites and the highest ratio of InO + /In 2 O 3 under the optimal synthesis conditions. In addition, the doped of Co 3 O 4 could inhibit the adsorption of sulfate species on the surface of In/H-Beta catalyst, leading to the excellent H 2 O and SO 2 resistance property.
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JOURNAL OF PHYSICAL CHEMISTRY B
·
2026
·
IF 3.2
Xiaonan Li,Xirong Huang
Abstract An oil-in-water microemulsion is an excellent candidate medium for the electrochemical regeneration of the coenzyme NADH and its subsequent coupled conversion application due to its good electrical conductivity and solubilization capacity for hydrophobic substrates. In this work, the reduced methyl viologen (MV+•)-mediated electrochemical reduction of coenzyme NAD+ was studied in a Triton X-100 (TX-100)-stabilized methyl tert-butyl ether (MTBE)-in-water microemulsion. The effects of the surfactant concentration and the oil content on the electrochemical behavior of the MV2+/MV+• couple and the activity of diaphorase (DH) were systematically investigated. The results show that in the microemulsion, the couple exhibits excellent reversibility. Compared with the aqueous buffer system, the couple in the microemulsion system has a more positive formal potential and a lower redox peak current, depending on the levels of both the surfactant and the oil. The positive shift of the formal potential is attributed to the stabilizing effect of the surfactant aggregates on the relatively hydrophobic MV+• species, and the decrease of the redox currents is ascribed to the decrease of the electroactive area of the electrode due to the adsorption of the surfactant and the oil as well as the decrease of the diffusion coefficients of MV species associated with or solubilized in the surfactant aggregates. The activity of DH in the microemulsion system also depends on the TX-100 concentration and the MTBE content. Increases in both [TX-100] and [MTBE] result in a decrease in DH activity. This phenomenon could be explained based on the [TX-100]/[MTBE]-dependent changes in the local acidity and the local concentration of the substrate DCPIP in the microemulsions. Based on cyclic voltammetry, the MV+•-mediated electroreduction of NAD+ in the TX-100-stabilized MTBE/H2O (0.1 M PB, pH = 7.0) microemulsion was studied. For the microemulsion system containing 0.5 mM MV2+, 5 mM NAD+, and 26.6 μM DH, when a scan rate of 2 mV s–1 was applied, a typical steady-state S-shaped CV curve was obtained. UV–vis spectroscopy confirms that the NADH generated by the mediated reaction is bioactive. By coupling the MV+•-mediated NADH electrochemical regeneration reaction with the horse liver alcohol dehydrogenase (HLADH)-catalyzed reduction of the hydrophobic substrate 4-phenyl-2-butanone, the enantiomerically pure (S)-4-phenyl-2-butanol can be selectively obtained. After 12 h, the yield of the product in the microemulsion is approximately 10 times that in the DMSO-buffer mixed homogeneous system. This difference in yield is caused by the differences in enzyme activity and stability, as well as in the substrate local concentration and reactivity in the two systems. The present study indicates that the TX-100-stabilized MTBE-in-water microemulsion is a suitable medium for the electrochemical regeneration of NADH and the electroenzymatic conversion of water-insoluble substrates catalyzed by NADH-dependent oxidoreductases.
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