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Interfacial charge transfer and photocatalytic activity in a reverse designed BiO/TiO core-shell

《能源前沿（英文）》 2021年 第15卷 第3期   页码 732-743 doi: 10.1007/s11708-021-0772-x

摘要： In this study, the electronic and photocatalytic properties of core-shell heterojunctions photocatalysts with reversible configuration of TiO2 and Bi2O3 layers were studied. The core-shell nanostructure, obtained by efficient control of the sol-gel polymerization and impregnation method of variable precursors of semiconductors, makes it possible to study selectively the role of the interfacial charge transfer in each configuration. The morphological, optical, and chemical composition of the core-shell nanostructures were characterized by high-resolution transmission electron microscopy, UV-visible spectroscopy and X-ray photoelectron spectroscopy. The results show the formation of homogenous TiO2 anatase and Bi2O3 layers with a thickness of around 10 and 8 nm, respectively. The interfacial charge carrier dynamic was tracked using time resolved microwave conductivity and transition photocurrent density. The charge transfer, their density, and lifetime were found to rely on the layout layers in the core-shell nanostructure. In optimal core-shell design, Bi2O3 collects holes from TiO2, leaving electrons free to react and increase by 5 times the photocatalytic efficiency toward H2 generation. This study provides new insight into the importance of the design and elaboration of optimal heterojunction based on the photocatalyst system to improve the photocatalytic activity.

关键词： photocatalysis     core-shell     heterojunction     H2     TiO2     Bi2O3    

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Synthesis, spectroscopic, and electrochemical properties of two dyads consisted of tetrathiafulvalene and carbazole

Guoqiao LAI, Yibo LIU, Meijiang LI, Yongjia SHEN

《化学科学与工程前沿（英文）》 2009年 第3卷 第2期   页码 192-195 doi: 10.1007/s11705-009-0015-x

摘要： Two donor-σ-acceptor molecules containing tetrathiafulvalene (TTF) and carbazole moieties were synthesized by the reaction of 9-(4-bromo-butyl)-carbazole ( ) with 2,6-bis(hexylthio)-3-(2-cyanoethylthio)-7-(methylthio)-tetrathiafulvalene ( ) or 2,6-bis(2-cyanoethylthio)-3,7-bis(methylthio)tetrathiafulvalene ( ) in the presence of CsOH·H O, respectively. The structures of the molecules were characterized by H NMR, C NMR, MS, and elemental analyses. They showed negligible intramolecular charge-transfer interaction in their ground states as indicated by their UV-Vis spectroscopics and cyclic voltammetry results. Compared with carbazole, their fluorescence was strongly quenched, which implied that a photo induced electron transfer (PET) interaction between TTF and carbazole moieties occurred.

关键词： donor-σ-acceptor molecule     intramolecular charge transfer interaction     photo induced electron transfer     tetrathiafulvalene     carbazole    

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Generation of enhanced stability of SnO/In(OH)/InP for photocatalytic water splitting by SnO protection layer

《能源前沿（英文）》 2021年 第15卷 第3期   页码 710-720 doi: 10.1007/s11708-021-0764-x

摘要： InP shows a very high efficiency for solar light to electricity conversion in solar cell and may present an expectation property in photocatalytic hydrogen evolution. However, it suffers serious corrosion in water dispersion. In this paper, it is demonstrated that the stability and activity of the InP-based catalyst are effectively enhanced by applying an anti-corrosion SnO layer and In(OH)3 transition layer, which reduces the crystal mismatch between SnO and InP and increases charge transfer. The obtained Pt/SnO/In(OH)3/InP exhibits a hydrogen production rate of 144.42 µmol/g in 3 h under visible light illumination in multi-cycle tests without remarkable decay, 123 times higher than that of naked In(OH)3/InP without any electron donor under visible irradiation.

关键词： SnO/In(OH)3/InP photocatalyst     enhanced activity and stability for water splitting     corrosion inhibition     enhancing charge transfer and decreasing crystal mismatch    

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Synthesis and properties of tetrathiafulvalene-fluorescein dyads

Guoqiao LAI, Yibo LIU, Yu ZHANG, Jun RUAN, Meijiang LI, Yongjia SHEN

《化学科学与工程前沿（英文）》 2009年 第3卷 第3期   页码 314-317 doi: 10.1007/s11705-009-0207-4

摘要： Two donor-acceptor molecular systems consisted of tetrathiafulvalene (TTF) and fluorescein were designed and synthesized. The target compounds and their key intermediates were characterized by H NMR, mass spectrography, and infrared spectroscopy, respectively. The UV-vis spectra implied intramolecular interaction in their ground state. Fluorescence spectra and fluorescence lifetimes indicated the photoinduced charge transfer (PET) interaction between the TTF and fluorescein units in their excited states.

关键词： TTF     fluorescein     charge transfer    

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A density functional theory study of methane activation on MgO supported NiM cluster: role of M on C–H activation

《化学科学与工程前沿（英文）》 2022年 第16卷 第10期   页码 1485-1492 doi: 10.1007/s11705-022-2169-8

摘要： Methane activation is a pivotal step in the application of natural gas converting into high-value added chemicals via methane steam/dry reforming reactions. Ni element was found to be the most widely used catalyst. In present work, methane activation on MgO supported Ni–M (M = Fe, Co, Cu, Pd, Pt) cluster was explored through detailed density functional theory calculations, compared to pure Ni cluster. CH4 adsorption on Cu promoted Ni cluster requires overcoming an energy of 0.07 eV, indicating that it is slightly endothermic and unfavored to occur, while the adsorption energies of other promoters M (M = Fe, Co, Pd and Pt) are all higher than that of pure Ni cluster. The role of M on the first C–H bond cleavage of CH4 was investigated. Doping elements of the same period in Ni cluster, such as Fe, Co and Cu, for C–H bond activation follows the trend of the decrease of metal atom radius. As a result, Ni–Fe shows the best ability for C–H bond cleavage. In addition, doping the elements of the same family, like Pd and Pt, for CH4 activation is according to the increase of metal atom radius. Consequently, C–H bond activation demands a lower energy barrier on Ni–Pt cluster. To illustrate the adsorptive dissociation behaviors of CH4 at different Ni–M clusters, the Mulliken atomic charge was analyzed. In general, the electron gain of CH4 binding at different Ni–M clusters follows the sequence of Ni–Cu (–0.02 e) < Ni (–0.04 e) < Ni–Pd (–0.08 e) < Ni–Pt (–0.09 e) < Ni–Co (–0.10 e) < Ni–Fe (–0.12 e), and the binding strength between catalysts and CH 4 raises with the CH4 electron gain increasing. This work provides insights into understanding the role of promoter metal M on thermal-catalytic activation of CH4 over Ni/MgO catalysts, and is useful to interpret the reaction at an atomic scale.

关键词： CH4 dissociation     Ni–M     C–H bond activation     charge transfer    

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Charge-carrier photogeneration and extraction dynamics of polymer solar cells probed by a transient photocurrentnearby the regime of the space charge-limited current

Boa Jin, Hyunmin Park, Yang Liu, Leijing Liu, Jongdeok An, Wenjing Tian, Chan Im

《化学科学与工程前沿（英文）》 2021年 第15卷 第1期   页码 164-179 doi: 10.1007/s11705-020-1976-z

摘要： To understand the complex behaviors of photogenerated charge carriers within polymer-based bulk-heterojunction-type solar cells, the charge-carrier photogeneration and extraction dynamics are simultaneously estimated using a transient photocurrent technique under various external-bias voltages, and a wide range of excitation intensities are analyzed. For this purpose, conventional devices with 80 nm thick active layers consisting of a blend of representative P3HT and PTB7 electron-donating polymers and proper electron-accepting fullerene derivatives were used. After the correction for the saturation behavior at a high excitation-intensity range nearby the regime of the space charge-limited current, the incident-photon-density-dependent maximum photocurrent densities at the initial peaks are discussed as the proportional measures of the charge-carrier-photogeneration facility. By comparing the total number of the extracted charge carriers to the total number of the incident photons and the number of the initially photogenerated charge carriers, the external quantum efficiencies as well as the extraction quantum efficiencies of the charge-carrier collection during a laser-pulse-induced transient photocurrent process were obtained. Subsequently, the charge-carrier concentration-dependent mobility values were obtained, and they are discussed in consideration of the additional influences of the charge-carrier losses from the device during the charge-carrier extraction that also affects the photocurrent-trace shape.

关键词： charge-carrier photogeneration     transient photocurrent     polymer solar cells     charge-carrier extraction     space charge-limited current    

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Design and mechanism insight on SiC quantum dots sensitized inverse opal TiO with superior photocatalytic activities under sunlight

《化学科学与工程前沿（英文）》 2023年 第17卷 第12期   页码 1913-1924 doi: 10.1007/s11705-023-2350-8

摘要： The combination of SiC quantum dots sensitized inverse opal TiO2 photocatalyst is designed in this work and then applied in wastewater purification under simulated sunlight. From various spectroscopic techniques, it is found that electrons transfer directionally from SiC quantum dots to inverse opal TiO2, and the energy difference between their conduction/valence bands can reduce the recombination rate of photogenerated carriers and provide a pathway with low interfacial resistance for charge transfer inside the composite. As a result, a typical type-II mechanism is proved to dominate the photoinduced charge transfer process. Meanwhile, the composite achieves excellent photocatalytic performances (the highest apparent kinetic constant of 0.037 min–1), which is 6.2 times (0.006 min–1) and 2.1 times (0.018 min–1) of the bare inverse opal TiO2 and commercial P25 photocatalysts. Therefore, the stability and non-toxicity of SiC quantum dots sensitized inverse opal TiO2 composite enables it with great potential in practical photocatalytic applications.

关键词： inverse opal TiO2     silicon carbide quantum dots     quantum dot sensitized photocatalyst     type-II charge transfer route    

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Charge and separation characteristics of nanofiltration membrane embracing dissociated functional groups

Zhun MA,Meng WANG,Xueli GAO,Congjie GAO

《环境科学与工程前沿（英文）》 2014年 第8卷 第5期   页码 650-658 doi: 10.1007/s11783-013-0605-1

摘要： The current work focused on the investigation of charge and separation characteristics of nanofiltration (NF) membrane embracing dissociated functional groups under different electrolyte solutions. The electro-kinetic method was carried out to assess the membrane volume charge density ( ) with different salt concentrations ranging from 0.1 to 10 mol·m and different electrolyte species, such as type 1–1, type 2–1 and type 3–1. The Donnan steric pore model-dielectric exclusion (DSPM-DE) model was employed to evaluate the separation characteristics of the NF membrane for wide range of electrolyte concentration (from 25.7 to 598.9 mol·m ). The results indicated that the dissociation of the hydrophilic functional groups and the specific adsorption contributed to charge formation on membrane surface. The former played a dominant role in type 1–1 and type 2–1 electrolytes at dilute aqueous solutions (0.1–0.5 mol·m ). However, for type 3–1 electrolyte, specific adsorption should contribute to the charge effect to a large extent. Moreover, the correlation between the volume charge density and feed concentration was in accordance with Freundlich isotherm. Furthermore, it was found that the separation characteristic of NF membrane could be evaluated well by DSPM-DE model coupling with electro-kinetic method in a whole concentration range.

关键词： Sulfonated polyethersulfone nanofiltration membrane     charge characteristics     electro-kinetic method     volume charge density     separation behavior    

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Visible-light-driven heterostructured g-CN/Bi-TiO floating photocatalyst with enhanced charge carrier

《环境科学与工程前沿（英文）》 2021年 第15卷 第6期 doi: 10.1007/s11783-021-1417-3

摘要：

• Bi doping in TiO2 enhanced the separation of photo-generated electron-hole.

关键词： Bi doping     Visible light     Algal removal     Charge carrier separation    

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Numerical simulation of charge stratifications to improve combustion and NO formation of lean-burn SI

Zhijun PENG ,

《能源前沿（英文）》 2009年 第3卷 第3期   页码 353-358 doi: 10.1007/s11708-009-0035-8

摘要： The influences of charge stratification on spark ignition (SI) engine combustion and NO emission were analyzed using a phenomenological model. The mixture in the cylinder was divided spherically into three parts: a central core with a stoichiometric air-fuel charge, a dilution region without any combustible charge, and a mixing region lying between the core and the dilution region. Three mixture stratification parameters such as the extent of dilution in the mixing region, the extent of combustible charge in the mixing region, and the gradient of stratification in the mixing region were investigated. The results indicate that the extent of combustible charge in the mixing region could reduce in-cylinder NO formation significantly, compared with the extent of dilution in the mixing region. As long as the degree of dilution in the mixing region is within the dilution limit of the combustible charge, the gradient of dilution has little effect on combustion and NO formation.

关键词： charge stratification     SI engine     lean-burn combustion     NO emission    

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membranes using SPES as a hydrophilic polymer for the effective removal of dyes via steric hindrance and charge

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1555-1567 doi: 10.1007/s11705-023-2338-4

摘要： Herein, polyethersulfone (PES) and sulfonated polysulfone (SPSf) blend membranes were prepared with addition of sulfonated polyethersulfone (SPES) as a hydrophilic polymer and adipic acid as a porogen via non-solvent induced phase separation method for effective fractionation of dyes based on the influence of steric hindrance and charge effect. Raman spectroscopy and molecular dynamic simulation modeling confirmed that hydrogen bonds between PES, SPSf, SPES, and adipic acid were crucial to membrane formation and spatial arrangement. Further addition of hydrophilic SPES resulted in a membrane with reduced pore size and molecular weight cut-off as well as amplified negative charge and pure water permeance. During separation, the blend membranes exhibited higher rejection rates for nine types of small molecular weight (269.3–800 Da) dyes than for neutral polyethylene glycol molecules (200–1000 Da). This was attributed to the size effect and the synergistic effect between steric hindrance and charge repulsion. Notably, the synergistic impact decreased with dye molecular weight, while greater membrane negative charge enhanced small molecular dye rejection. Ideal operational stability and anti-fouling performance were best observed in M2 (PES/SPSf/SPES, 3.1 wt %). Summarily, this study demonstrates that SPES with –SO3‒ functional groups can be applied to control the microstructure and separation of membranes.

关键词： adipic acid     loose nanofiltration membrane     dye/salt selective separation     steric hindrance     charge effect    

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真实空气中TNT装药爆炸近区冲击波传播特性研究

周丰峻,郑磊,孙云厚,张鏖,夏明

《中国工程科学》 2017年 第19卷 第6期   页码 18-26 doi: 10.15302/J-SSCAE-2017.06.004

摘要：

本文基于点源爆炸理论，建立了面源、线源和点源TNT装药强爆炸解，填补了面源与线源强爆炸解的空白；采用真实空气状态方程进行分析计算，研究了真实空气条件下球形TNT装药爆炸近区冲击波的传播特性。通过算例分析，计算结果与已有文献资料数据吻合较好。本文的研究成果对爆炸力学和防护工程研究起到了重要的参考作用。

关键词： TNT装药爆炸     真实空气状态方程     面源装药     线源装药     点源装药     抗爆防护    

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Effects of operating conditions on membrane charge property and nanofiltration

Li XU, Li-Shun DU, Jing HE

《化学科学与工程前沿（英文）》 2011年 第5卷 第4期   页码 492-499 doi: 10.1007/s11705-011-1143-7

摘要： The effects of the operating pressure, cross flow velocity, feed concentration, and temperature on the streaming and Zeta potential of the membranes were studied. The permeate flux and the retention rate under different nanofiltration operating conditions were also investigated. The results show that the higher pressure, feed concentration, temperature, and lower cross flow velocity lead to the higher absolute value of streaming and Zeta potential. The permeate flux of the nanofiltration decreases with the feed concentration and increases with not only the pressure but also the cross flow velocity and temperature. The higher the pressure and the cross flow velocity, the higher the retention rate. The lower feed concentration and higher temperature leads to lower retention rate. The effects of the operating conditions on the permeate flux and the retention rate were explained by the variation of the membrane charge property.

关键词： nanofiltration membrane     streaming potential     Zeta potential     permeate flux     retention rate    

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一种新型聚能破甲战斗部及其发展趋势探讨

安二峰,沈兆武,周听清,王德润

《中国工程科学》 2004年 第6卷 第6期   页码 85-90

摘要：

针对当前以单罩聚能效应为主的聚能破甲战斗部，提出一种新型多罩复合聚能装药结构，探讨了其成型机理和联合破甲原理，系统研究了主要装药结构参数对破甲效果的影响。实验结果表明，该聚能装药结构比EFP装药结构，在保持穿孔孔径相当和同等装药条件下，可以提高穿深50%左右。在此基础上，进一步提出反反应装甲目标新型聚能装药结构，深化了聚能效应的内涵，丰富了打击目标的手段。

关键词： 聚能战斗部     爆炸成型弹丸     聚能射流     反应装甲     侵彻    

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Effect of ligand chain length on hydrophobic charge induction chromatography revealed by molecular dynamics

Lin ZHANG, Yan SUN

《化学科学与工程前沿（英文）》 2013年 第7卷 第4期   页码 456-463 doi: 10.1007/s11705-013-1357-y

摘要： Hydrophobic charge induction chromatography (HCIC) is a mixed-mode chromatography which is advantageous for high adsorption capacity and facile elution. The effect of the ligand chain length on protein behavior in HCIC was studied. A coarse-grain adsorbent pore model established in an earlier work was modified to construct adsorbents with different chain lengths, including one with shorter ligands (CL2) and one with longer ligands (CL4). The adsorption, desorption, and conformational transition of the proteins with CL2 and CL4 were examined using molecular dynamics simulations. The ligand chain length has a significant effect on both the probability and the irreversibility of the adsorption/desorption. Longer ligands reduced the energy barrier of adsorption, leading to stronger and more irreversible adsorption, as well as a little more unfolding of the protein. The simulation results elucidated the effect of the ligand chain length, which is beneficial for the rational design of adsorbents and parameter optimization for high-performance HCIC.

关键词： adsorption     desorption     irreversibility     protein conformational transition     molecular dynamics simulation    

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标题 作者 时间 类型 操作

Interfacial charge transfer and photocatalytic activity in a reverse designed BiO/TiO core-shell

期刊论文

Synthesis, spectroscopic, and electrochemical properties of two dyads consisted of tetrathiafulvalene and carbazole

Guoqiao LAI, Yibo LIU, Meijiang LI, Yongjia SHEN

期刊论文

Generation of enhanced stability of SnO/In(OH)/InP for photocatalytic water splitting by SnO protection layer

期刊论文

Synthesis and properties of tetrathiafulvalene-fluorescein dyads

Guoqiao LAI, Yibo LIU, Yu ZHANG, Jun RUAN, Meijiang LI, Yongjia SHEN

期刊论文

A density functional theory study of methane activation on MgO supported NiM cluster: role of M on C–H activation

期刊论文

Charge-carrier photogeneration and extraction dynamics of polymer solar cells probed by a transient photocurrentnearby the regime of the space charge-limited current

Boa Jin, Hyunmin Park, Yang Liu, Leijing Liu, Jongdeok An, Wenjing Tian, Chan Im

期刊论文

Design and mechanism insight on SiC quantum dots sensitized inverse opal TiO with superior photocatalytic activities under sunlight

期刊论文

Charge and separation characteristics of nanofiltration membrane embracing dissociated functional groups

Zhun MA,Meng WANG,Xueli GAO,Congjie GAO

期刊论文

Visible-light-driven heterostructured g-CN/Bi-TiO floating photocatalyst with enhanced charge carrier

期刊论文

Numerical simulation of charge stratifications to improve combustion and NO formation of lean-burn SI

Zhijun PENG ,

期刊论文

membranes using SPES as a hydrophilic polymer for the effective removal of dyes via steric hindrance and charge

期刊论文

真实空气中TNT装药爆炸近区冲击波传播特性研究

周丰峻,郑磊,孙云厚,张鏖,夏明

期刊论文

Effects of operating conditions on membrane charge property and nanofiltration

Li XU, Li-Shun DU, Jing HE

期刊论文

一种新型聚能破甲战斗部及其发展趋势探讨

安二峰,沈兆武,周听清,王德润

期刊论文

Effect of ligand chain length on hydrophobic charge induction chromatography revealed by molecular dynamics

Lin ZHANG, Yan SUN

期刊论文