Table of Content

10 April 2021, Volume 42 Issue 4

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Cover and Content of Chemical Journal of Chinese Universities Vol.42 No.4(2021)

2021, 42(4):  1-6. 

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Review

Sol-gel Construction of Mesoporous Silica Nanomicrostructures

HAN Yandong, HAN Mingyong, YANG Wensheng

2021, 42(4):  965-977.  doi:10.7503/cjcu20200623

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The hydrolysis/condensation of orthosilicate is the most commonly used chemical method for the preparation of silica materials. During the sol-gel reaction， the addition of mesoporous-directing agent（i.e.， usually a surfactant） results in silica materials with a mesoporous structure. By adjusting the hydrolysis/condensation process in a multiphase interface， different mesoporous nanomicrostructures are constructed. This provides new opportunities for expanding their application fields and enriches the understanding of the sol-gel method. This paper systematically introduces the latest research progress in the sol-gel construction of mesoporous silica nanomicrostructures， including application prospects in biomedicine， catalysis， adsorption separation， and summarizes the problems faced in the fields and the future development direction.



Synthesis of Ordered Mesoporous TiO₂ and Their Application for Hydrogen Production from Photocatalytic Water-splitting

XU Anqi, LI Bin, DU Fanglin

2021, 42(4):  978-996.  doi:10.7503/cjcu20200619

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Titanium dioxide（TiO₂） materials have attracted much attention due to their low cost， high natural abundance， environmental friendliness， good chemical stability and excellent optical properties. Among them， ordered mesoporous TiO₂ materials have been widely used in physics， chemistry， materials science due to their high surface area， large pore volume， adjustable pore structure and morphology etc. In this article， we summarize the synthesis of ordered mesoporous TiO₂ by reasonably controlling the rate of hydrolysis and crosslinking of titanium precursors. Furthermore， the application of mesoporous TiO₂ in the photocatalytic splitting of water to produce hydrogen is also discussed. Finally the challenges in this field are proposed.



Selenium-containing Surface/interface Chemistry

XIA Jiahao, XU Huaping

2021, 42(4):  997-1004.  doi:10.7503/cjcu20200572

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Selenium is an essential element to human body. Our research group has recently revealed many unique features of selenium-containing bonds. For instance， diselenide bond has dual redox response， and it is also a type of dynamic bond which can undergo exchange reaction under visible light irradiation. Combing those interesting properties of selenium-containing bonds with surface/interface chemistry can endow system with unique responsive behaviors. This article reviews the recent progresses we made in the field of selenium-containing surface/interface chemistry. We used single molecule force spectroscopy to study the nature of selenium-containing bonds in the force point of view， and used interface chemistry to modulate the equilibrium of diselenide dynamic exchange reaction. Additionally， we achieved reversible surface modification， two- dimensional material functionalization and layer-by-layer nanocomposite film fabrication based on the redox and light response of diselenide bond， which may find potential applications in fields like biomedical research and liquid transfer.



Recent Development on Surface-interface Chemistry of All-solid-state Lithium Batteries

ZOU Junyan, ZHANG Yanyan, CHEN Shi, SHAO Huaiyu, TANG Yuxin

2021, 42(4):  1005-1016.  doi:10.7503/cjcu20200643

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Owing to the potential safety hazards such as electrolyte leakage and flammability of traditional lithium batteries， nonflammable all-solid-state electrolytes are considered to be ideal electrolyte candidates for lithium batteries. However， how to effectively reduce the interface resistance between the solid-state electrolyte and the electrode is the key to the development of all-solid-state lithium batteries. In this article， we review the research progress in surface modification of all-solid-state lithium battery electrodes and electrolytes. The classic methods of improving the interface contact and reducing the interface resistance are also discussed. Based on the traditional methods， new surface modification technologies will provide new ideas for improving the performance of all-solid-state lithium batteries in the future.



Advances in Lithium Metal Batteries Based on Surface Interface Reaction and Optimization

WANG Zengqiang, SUN Yiling, QIAN Zhengfang, WANG Renheng

2021, 42(4):  1017-1030.  doi:10.7503/cjcu20200508

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Lithium（Li） metal has high theoretical specific capacity and low reduction potential， so it is one of the ideal materials for the anode of lithium batteries. During the long-term cycling， however， lithium metal has problems such as interface deterioration and serious energy loss due to lithium dendrites growing. The optimization of interface reaction between lithium metal electrodes and electrolytes is a significant research direction. In the paper， the hazards caused by lithium dendrites was outlined， as well as comprehensively reviewing methods adopted to solve this problem from analysis and inhibition of lithium dendritic deposition， including the formation and protection mechanisms of solid electrolyte interface， surface modification， three- dimensional lithium anode， liquid/solid electrolytes， etc. Besides， the advantages and disadvantages of methods above are summarized， and research prospects to lithium metal batteries is expected in the energy field simultaneously.



Status and Prospect of Surface Wettability of Molecular Self-assembled Monolayers

MA Zhuoyuan, WANG Dayang

2021, 42(4):  1031-1042.  doi:10.7503/cjcu20200620

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This article aims to revisit the research of surface wetting on self-assembled monolayers（SAMs） of organic molecules. It starts with a brief overview of the growth mechanism governing the self-assembly of organic molecules， followed by discussion of temperature-induced phase transition of SAMs. In the following sections， the surface wettability of SAMs is discussed in three main aspects on the basis of a collection of studies reported in a time span of 100 years， including （1） the contribution of terminal methyl groups to total surface energy of SAMs； （2） manifestation of the interactions between terminal polar groups and their interactions with water in SAM surface wettability， and the newly-discovered effect of molecular-level roughness of SAMs on their surface wettability. These studies will be put in new prospective in order to shift conventional thermodynamic description of surface wetting phenomena to new molecular-level interpretation and design of surface wettability.



Advanced Progress of Green Textile with Special Wettability

LI Shuhui, HUANG Jianying, LAI Yuekun

2021, 42(4):  1043-1060.  doi:10.7503/cjcu20200646

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We introduced the preparation mechanism of biomimetic superhydrophobic surfaces and the development of hydrophobic finishing chemicals. The research process of multi-functional green textile with special wettability in the last 10 years was systematically reviewed. The preparation technologies and applications in double-superhydrophobic， asymmetric superhydrophobic/superhydrophilic janus surface， patterned/ stimulated responsive surface were discussed. The prospective works were emphasised in this review， including self-cleaning， oil/water separation， durable mechanical surfaces， patterning， self-healing， one-way transportation， especially in some emerging fields such as smart response， wearable electronics， energy- harvesting. The summary and outlook of superhydrophobic and multi-funtional textile were also demonstrated at last.



Research Progress in Droplet Deposition on Superhydrophobic Plant Leaves

CUI Yingtao, WANG Shun, LI Wei, CUI Shumin, HUANG Yanjie, LI He, DUAN Hu, SONG Meirong, DONG Zhichao, WANG Yilin, JIANG Lei

2021, 42(4):  1061-1073.  doi:10.7503/cjcu20200621

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Ubiquitous superhydrophobic plant leaves in nature can easily cause great losses for impinging agrochemical droplets via bouncing and splashing. So， increasing the efficiency of droplet deposition is crucially significant to improve pesticide utilization. Based on the progress scientists have made on enhancing droplet deposition， this paper starts from the analysis of the impact kinetic characteristics of water droplets on the superhydrophobic surface， takes the physical and chemical properties of the droplets after the additives into consideration， systematically summarizes the method and mechanism of the deposition of water droplets on the leaves of superhydrophobic plants. In addition， we conclude that screening additives and exploring mechanisms should consider not only the properties of the additives but also the substrate structure and impact dynamics characteristics. Finally， we propose that future research should focus on the influence of single droplet size， substrate motion and elasticity， and environmental factors on deposition. This work plays significant role not only in pesticide spraying but also in many other fields such as biomedicine， mechanical engineering， coating spraying， ink printing and so on.



Surface and Interface Chemistry in Flexible Electronics

JI Shaobo, CHEN Xiaodong

2021, 42(4):  1074-1092.  doi:10.7503/cjcu20200644

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Flexible electronics is an emerging research hotspot， which involves chemistry， physics， mate- rials， etc.. As an interdisciplinary topic， flexible electronics have been used in various fields， such as wea-rable devices， bio-medical applications， artificial intelligence. The fabrication of flexible devices requires the integration of different materials including flexible substrates， conductive materials， and functional components. Their integration is limited by their surface properties and interfacial interactions， their function and reliability are also influenced by the stability of their interfacial bindings. Thus surface and interface treatments， including chemical treatments， are important for fabrication and functionalization of flexible electronic devi-ces. In this review， the application of surface/interface chemistry in flexible electronics will be cataloged into 3 types. Firstly， electrochemical reactions on surface， which are the bases for flexible chemical sensors and can be used to control the loading/release of chemicals on device surfaces. Secondly， surface modification， which can improve the processability of materials by varying their surface properties， and endow the devices with specific properties， functions， or protections. Lastly， interfacial connections， which link different materials and layers through covalent bonding or chemical process assisted physical entanglement， to improve the stability of the whole device. Summary and examples for each type will be given， followed by discussion of existing problems， possible future developments， and application potentials.



Highly Adhesive and Stretchable Polymers for the Interface of Cyber-human Interaction

ZHANG Jun, LIU Yixuan, DU Xiaohui, YANG Hui

2021, 42(4):  1093-1113.  doi:10.7503/cjcu20200597

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With the rapid developments of flexible electronics and artificial intelligence， flexible sensors can be organically combined with artificial intelligence， big data and 5G communication to build a cyber-human interaction system， which plays an important role in the fields of intelligent e-healthcare and biomedical. As the interface between the cyber system and human， the mechanical properties of on-skin electrodes directly affect the sensitivity and stability of human monitoring signals. From the point of view of materials， how to realize high stretchability and adhesion of the electrode has become a scientific problem and technical challenge to be solved urgently for the further application of on-skin electrodes. In this review， we summarize the recent developments of highly adhesive and stretchable polymers， and discuss the various applications of stable interface of cyber-human interaction in monitoring various human electrophysiological signals. Meanwhile， the development of the next generation flexible electronic devices is prospected.



Progress on the Design and Fabrication of High Performance Piezoelectric Flexible Materials Based on Polyvinylidene Fluoride

ZHANG Shuting, AN Qi

2021, 42(4):  1114-1145.  doi:10.7503/cjcu20200636

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Piezoelectricity presents important applications in the fields of energy conversion， sensor， medical materials， wearable electronics and so forth， and receives widespread scientific attentions. Among all types of piezoelectrical materials， poly（vinylidene fluoride）（PVDF） and its copolymers have the unique merits of being flexible， easily processable， stable， and biocompatible. Thus they have received a lot of research efforts. This article reviews the progresses on enhancing the piezoelectricity of PVDF from two dimensions which are the fabrication method and the compositing strategy. Based on the discussion of the piezoelectrical mechanism of PVDF， a series of strategies including casting， electrospinning， wire drawing， and nanocomfinement are introduced. In addition， piezoelectricity promoting strategies via compositing with fillers including small molecules， polymers， graphene-based particles， and inorganic nanoparticles are also reviewed. These strategies all benefit the formation of the piezoelectrically active β phase in PVDF. Lastly， the article discusses the remaining challenges and prospects in the design and preparation of high-performance piezoelectric PVDF-based materials. We expect that the article benefits the development of PVDF-based piezoelectrical materials， and inspires the design of materials in the fields of energy， environments， medicine and healthcare.



Application of Conductive Polymer in Nerve Interface Electrode

FAN Wenqian, ZHONG Zhengxiang, TIAN Gongwei, WANG Yu, GONG Guifen, QI Dianpeng

2021, 42(4):  1146-1155.  doi:10.7503/cjcu20200583

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As a medium of information communication between human body and external devices， neural interface electrode provides an effective tool for people to further explore the working mechanism of nervous system. Most of the traditional nerve electrodes are made from metal or semiconductor materials. These materials have become the main preparation materials of early nerve electrode because of their inert material characteristics and excellent electrical conductivity. However， due to the mechanical mismatch caused by excessive rigidity and smooth surface， and the high electrochemical impedance with biological tissues， these materials limit the further development of nerve electrode. As an organic conductive material， conductive polymer has the characteristics of softness（Young’s modulus is about 0.01—10 GPa） and conductivity（the conductivity of highly doped conductive polymer is in the metal range of 10⁰—10⁵ S/cm）， which is an effective material for nerve electrode preparation. In recent years， conductive polymers have been used to modify or even replace the traditional electrode materials to reduce the interface impedance and improve the sensitivity of electrode detection； At the same time， it can increase the stability of electrode implanted in vivo for a long time by reducing the strain mismatch between the electrode and tissue， the inflammatory reaction， and further introducing functional biomacromolecules into the conductive polymer to reduce the rejection of biological tissue to the electrode. In this paper， we will discuss and summarize the application of conductive polymer materials in neural electrode. Herein， three aspects of conducting polymer， including polymer coating nerve electrode， all polymer neural electrode and conductive polymer composite material neural electrode， are discussed respectively. The application prospect and existing problems of conductive polymer in neural interface electrode are analyzed， which can provide reference for the further development of neural interface electrode in brain science， bioelectronic medicine and other frontier fields.



Improving the Detection Performance of Surface-assisted Laser Desorption/ionization Mass Spectrometry by Silicon Nanostructures

DOU Shuzhen, WANG Zhongshun, LYU Nan

2021, 42(4):  1156-1166.  doi:10.7503/cjcu20200506

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Various technologies of constructing silicon nanostructures are summarized. Recent research progress on improving the performance of surface assisted laser desorption/ionization mass spectrometry（SALDI-MS） by silicon-based nanostructures is reviewed， and the functionalized silicon nanostructure surfaces to promote laser desorption/ionization（LDI） is prospected.



Research Progress of Metal-organic Frameworks in the Field of Chemical Separation and Analysis

WANG Longjie, FAN Hongchuan, QIN Yu, CAO Qiue, ZHENG Liyan

2021, 42(4):  1167-1176.  doi:10.7503/cjcu20200494

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Metal-organic frameworks（MOFs） are known as a class of porous materials which are formed by metal ions and organic ligands through coordination bonds. Extensive attentions have been attracted due to their large surface area， adjustable pores and controllable surface properties and so forth. The surface properties of MOFs can be regulated through selection of organic ligands and metal ions， as well as post-modification. Thus， many applications of MOFs were expanded in separation and analysis field according to improving selective adsorption， specific recognition and other properties. In this review， we focuse on the relationship between the surface properties and separation performance of MOFs， and summarize some relative works in separation and analysis field of MOFs in recent years， and look forward to the future research of MOFs.



Research Progress of Graphene-based Hemostatic Sponges

DU Fanglin, WU Bingxin, LIU Jiao, XU Congcong, LI Guofeng, WANG Xing

2021, 42(4):  1177-1187.  doi:10.7503/cjcu20200496

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Graphene-based sponge， constructed by two-dimensional carbon nanosheets， is a new type of trauma hemostatic material. It has features of hierarchical porous structures， ultrafast liquid absorption capacity， and versatile surface functionalization. Therefore， it has been used as a platform to achieve multifunctional composites， showing the great applications in the field of trauma hemostasis. This review summaries the research progress focusing on the applications and mechanism researches of graphene-based hemostatic sponges， and suggests its prospects for its development.



Research Progress of Noble Metal⁃based Nanozymes

CAI Rui, LIU Jianbo, WU Xiaochun

2021, 42(4):  1188-1201.  doi:10.7503/cjcu20200591

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Noble metal nanomaterials are a kind of special nanomaterials with unique optical， electrical， and catalytic properties. The noble metal-based nanozymes are a new research frontier of noble metal nanomaterials in biomedical field. Noble metal-based nanozymes possess good stability， controllable enzyme-like activity， multiple enzyme-like activities， and excellent biocompatibility and hold great potential in biomedical applications. In this review， we summarized the enzyme mimic types， enzyme catalytic mechanisms， activity regulation， and potential biomedical applications of noble metal-based nanozymes.



Surface Functionalized Gold Nanomaterials in Tumor Diagnosis and Treatment

GE Haoying, DU Jianjun, LONG Saran, SUN Wen, FAN Jiangli, PENG Xiaojun

2021, 42(4):  1202-1212.  doi:10.7503/cjcu20200639

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As an important noble metal， gold exhibits unique surface plasmon resonance characteristics and has been widely applied in materials， catalysis， medical diagnosis and treatment and so forth. In this review， the surface functionalization of gold nanomaterials and their applications in imaging?based diagnosis and treatment of tumors are reviewed， and the problems that need to be solved in the future for clinical applications are summarized.



Multiplex Structures of Plasmonic Metal Nanoparticles and Their Applications

WANG Yawen, LI Dong, LIANG Wenkai, SUN Yinghui, JIANG Lin

2021, 42(4):  1213-1224.  doi:10.7503/cjcu20200666

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Currently， metal nanoparticle structure with single structural design or component has been difficult to meet the requirements of interdisciplinary development. Therefore， the integration of multiplex metal nanoparticles（such as different sizes， shapes， components or spacing） onto one substrate can fully show the properties and advantages coming from different metal nanoparticles simultaneously， which have significant research and application value. This review introduces the methods of fabricating multiplex plasmonic nanoparticle structures， as well as their potential applications in surface encoding， optoelectronic devices and photo- catalysis. Finally， we put forward the challenges in the structural construction and the prospects in the performance improvement using multiplex structures.



Progress of MXenes Composites： Interface Modification and Structure Design

BA Zhichen, LIANG Daxin, XIE Yanjun

2021, 42(4):  1225-1240.  doi:10.7503/cjcu20200716

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As an emerging type of two-dimensional material， MXenes have become a research focus because of their unique advantages including hydrophilicity， excellent mechanical properties， abundant surface functional groups， high conductivity， photothermal and photoelectric effects. As a result， they have been widely used in electromagnetic shielding， electrochemical energy storage， biomedicine， separation， sensor and seawater desalination. Although MXenes have these excellent properties， their drawbacks such as poor compati- bility with hydrophobic polymers， the impediment of electrolyte transport by negative charged functional groups and the ease of oxidation， all limit their practical application. Recently， efforts have been made by interface modification of MXenes to solve their inherent defects. Subsequently， targeted structural design of MXenes is carried out to improve the interface stability and further enhance their performance. In this paper， the research progress of interface modification and structure design of MXenes composites is summarized， in which the structure and properties of MXenes， the interface modification methods of MXenes and the structure strategies of MXenes composite are discussed followed by a brief prospect of MXenes composite materials.



Article

Break of Metal-organic Chains Induced by 4，4′-Dihydroxybiphenyl on Surfaces

XU Zhichao, LI Xuechao, TANG Yanning, ZHANG Haiming, CHI Lifeng

2021, 42(4):  1241-1245.  doi:10.7503/cjcu20200661

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Metal-organic hybrid structures are common intermediates in on-surface reactions. To break metal-organic bonds of the hybrid structures needs to overcome a higher activation barrier， which often leads to a series of competitive side reactions and even desorption of target products. Scanning tunneling microscope（STM） has been used to show that the oxygen terminal of 4，4′-dihydroxybiphenyl can effectively reduce the bond breaking barrier of the metal-organic hybridization system， so that the transfer of metal-organic hybrids can be carried out at a lower temperature. This result provides a new method to regulate the intermediates of on-surface reactions.



Preparation of Carboxyl-betaine Polyurethane Hydrogel and Study on Its Underwater Anti-crude-oil-adhesion Property

WANG Aqiang, ZHU Yuzhang, JIN Jian

2021, 42(4):  1246-1252.  doi:10.7503/cjcu20200697

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Quaternary ammonium ionic diol was synthesized by nucleophilic substitution reaction between ethyl 4-bromobutyrate and N-Methyldiethanolamine. Then， polyurethane prepolymer was prepared via the polymerization of the quaternary ammonium ionic diol and hexamethylene diisocyanate（HDI） trimer. By the process of alkaline hydrolysis， carboxyl-betaine polyurethane hydrogel with different hydrolysis time was finally obtained. The result shows the underwater oil contact angles of hydrolyzing-for-60-min carboxyl-betaine polyurethane hydrogel for cetane， kerosene， petroleum ether， isooctane and even crude oil are all above 160° and the corresponding underwater oil-adhesion forces are all 0. Carboxyl-betaine polyurethane hydrogel with excellent underwater anti-crude-oil-adhesion was successfully prepared.



Helical Structure and Circularly Polarized Luminescence of Naphthalene Derived Amphiphilic Molecules Through Air/water Interface Assembly

MENG Yan, WANG Xiufeng, ZHANG Li, LIU Minghua

2021, 42(4):  1253-1259.  doi:10.7503/cjcu20200560

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Langmuir-Blodgett（LB） technology precisely control the arrangement and stacking of molecules to construct ordered ultrathin films and assemblies on the two-dimensional air/water interface. Meanwhile， the asymmetric environment of the interface can also effectively amplify chirality of the assembly. In this paper， two chiral amphiphilic molecules with different substitution positions of naphthalene ring were studied. N，N′-bisoctadecyl-α-naphthalene-L-amino-glutamic acid diamide（1NLG） and N，N′-bisoctadecyl-β-naphthalene-L-amino-glutamic acid diamide（2NLG） were spread and assembled at air/water interface. It was showed that the substitution position affected the arrangement of amphiphilic molecules at the air/water interface. 1NLG formed uniform nanobelt structure， while 2NLG formed left-handed helix structures. Also， 2NLG LB films exhibited circularly polarized luminescence（CPL）， and its dissymmetry factor（g_lum） was significantly enhanced than that of three-dimensional assemblies（supramolecular gel）， indicating that the interface promoted the amplification of supramolecular chirality.



Controllable Liquid Transfer for Preparing Oriented Polymer Thin Films： Toward the Enhanced Performance of PLED

MENG Lili, CHEN Linlin, ZHANG Xiaoliang, XIE Linghai, LIU Huan

2021, 42(4):  1260-1267.  doi:10.7503/cjcu20200478

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We demonstrated a facile solution process guided by the conical fibers array（CFA）， based on which bulky polydiarylfluorene（PODPF） were oriented on substrate. After thermal annealing at ca. 240 ℃， PODPF changed from the amorphous-phase to compact π-π stacking β-phase， leading to a PODPF film with higher orientations and larger crystallized sizes. It is proposed that the CFA enables finely controlling the wetting and dewetting processes under directional stress， guiding the disorganized polymer transform into orientation. Using the as-prepared PODPF films as the active layer， a polymer light-emitting diodes（PLEDs） device was developed， which exhibited higher current efficiency of 1.53 cd/A（5.6 V） and more stable electroluminescence compared with that of the spin-coating one. We envision that the as-developed approach offers new inspiration for fabricating high-performance polymer films.



Density Functional Theoretical Studies on the Promising Electrocatalyst of M-BHT（M=Co or Cu） for CO₂ Reduction to CH₄

YANG Tao, YAO Huiying, LI Qing, HAO Wei, CHI Lifeng, ZHU Jia

2021, 42(4):  1268-1275.  doi:10.7503/cjcu20200729

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Two-dimensional metal organic frame materials show excellent electrocatalytic activity for CO₂ reduction reaction because of their unique electronic structures and abundant catalytic sites. Herein， based on density functional theory calculations， we found that monolayer Co-BHT（BHT=benzenehexathiol） exhibits promising electrocatalytic activity in CO₂ reduction to CH₄. The Gibbs free energy change calculations reveal that the optimal reaction path of CO₂ reduction to CH₄ on Co-BHT is CO₂→^*COOH→^*CO→^*CHO→ ^*CHOH→^*CH→^*CH₂→^*CH₃→CH₄， with the rate-limiting step of ^*CO→^*CHO. The Gibbs free energy change of the rate-limiting step（ΔG_L） is 0.66 eV， lower than that on both 2D Cu-C₃N₄（ΔG_L=0.75 eV） and traditional Cu（211）（ΔG_L=0.74 eV）. Furthermore， the studies for monolayer Cu-BHT were also carried out， where the optimal reaction path is different， and the rate-limiting step is CO₂→^*COOH with the ΔG_L of 0.76 eV. The lower ΔG_L of CO₂ reduction on Co-BHT than that on Cu-BHT may be attributed to its higher d-band center compared with that of Cu-BHT， which leads to stronger interactions with the intermediates. Our work predicts the promi-sing electrocatalytic activity of Co-BHT and provides useful insights into the catalytic mechanism and performance of Metal-BHT for CO₂ reduction to CH₄.



Intelligent Controllable Microreactor Based on Superhydrophilic Nanochannel

WANG Can, WANG Dianyu, MIAO Weining, TIAN Ye

2021, 42(4):  1276-1283.  doi:10.7503/cjcu20200650

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The anodic alumina oxide（AAO） porous membrane was treated with low-temperature air plasma to obtain superhydrophilic nanochannels. An oil-soluble ferrofluid was introduced on the AAO membrane， and an intelligent and controllable microreactor was constructed by adjusting the direction and strength of the external magnetic field. The intelligent microreactor has the characteristics of multilevel gating， high current-gating ratio， and long-term cycle stability. It was used in homogeneous and heterogeneous reactions and characterized by fluorescence spectrophotometer and scanning electron microscope. The results showed that the reaction products have different yields and structures under different gated states， and have good application prospects in the controllable reaction of microreactors.



Carbon-doped Oxygen-deficient TiO₂ Fibers Synthesized without Adding External Carbon Sources and Their Photocatalytic Activity

ZHOU Shuai, WANG Juan

2021, 42(4):  1284-1291.  doi:10.7503/cjcu20200625

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The carbon-doped oxygen-deficient TiO₂（C-TiO_2-n） fiber photocatalysts were prepared by sol-gel method combined with centrifugal spinning technology and heat treatment under steam. The structure， component and properties of the C-TiO_2-n fibers as well as the effect of carbon doping on the photocatalytic activity of C-TiO_2-n fibers were investigated. The results confirm that the introduction of carbon into TiO₂ can be realized using the organic components in the fiber precursor as carbon sources without the introduction of external carbon sources. The introduction of carbon components effectively improved the light harvesting ability of photocatalysts and inhibited the recombination of photoinduced carriers. In the photocatalytic degradation experiment with azo dye reactive brilliant red（X-3B） as the target pollutant， C-TiO_2-n fibers showed excellent photocatalytic activity and cycling stability. After visible light irradiation of 60 min， the degradation rate of X-3B over C-TiO_2-n fibers reached 96.99%， and the kinetic constant was 0.0556 min^-1， 19.86 times higher than that of TiO_2-n fibers.



Synthesis and Enhanced Photocatalytic Activity of Ni₅P₄/g-C₃N₄

LI Dongping, LI Bin, LI Changheng, YU Xuegang, SHAN Yan, CHEN Kezheng

2021, 42(4):  1292-1298.  doi:10.7503/cjcu20200615

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Ni₅P₄/g-C₃N₄ photocatalysts were synthesized by a simple calcination method with urea， phosphorus and nickel chloride. The formed heterojunction can decrease the interface resistance and photogenerate electron-hole pair recombination rate. These lead to an increase in the catalytic performance of the photocatalyst. In the photocatalytic degradation of RhB， 3NPC（mass fraction of Ni₅P₄： 3%） has the highest reaction rate constant， which is almost 7 times that of g-C₃N₄. And 3NPC also exhibits the highest photocatalytic hydrogen activity of 1013.88 μmol·g^-1·h^-1， which is higher than that of g-C₃N₄（664.38 μmol·g^-1·h^-1）.



Synthesis of Li₂FeP₂O₇ Cathode Material at Different Temperatures and Its Electrochemical Performance for Lithium Ion Batteries

WANG Renheng, XIAO Zhe, LI Yan, SUN Yiling, FAN Shuting, ZHENG Junchao, QIAN Zhengfang, HE Zhenjiang

2021, 42(4):  1299-1306.  doi:10.7503/cjcu20200630

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The cathode material Li₂FeP₂O₇ was synthesized via freeze-drying and followed by solid state sintering method. X-ray diffraction（XRD）， scanning electron microscopy（SEM）， transmission electron microscopy（TEM） and Fourier transform infrared spectroscopy（FTIR） were used to characterize the structure， composition and morphology of the material. In addition， the electrochemical performance of the Li₂FeP₂O₇ material was investigated by cyclic voltammetry（CV） and electrochemical impedance spectroscopy（EIS）. It was found that the greatest particle quality could be acquired when the synthesis temperature of Li₂FeP₂O₇ was 590 ℃. The discharge specific capacity reached 55.0 mA·h·g^?1 at 1.6C， which was much higher than that of the samples synthesized at other temperatures. The Li₂FeP₂O₇ synthesized at 590 ℃ had a low impedance and a large exchange current density， which facilitated the diffusion of lithium ions and improved the electrochemical performance.



Core-shell Heterostructure Construction Between Thiospinel CuCo₂S₄ and MoS₂ for Improved Hydrogen Evolution Electrocatalytic Performance

ZHANG Nan, HAN Kuo, LI Yue, WANG Chunru, ZHAO Feng, HAN Dongxue, NIU Li

2021, 42(4):  1307-1314.  doi:10.7503/cjcu20210098

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The heterostructure construction between thiospinel transition metal sulfide CuCo₂S₄ and MoS₂ was achieved by a simple three-step hydrothermal process. Ni foam（NF） was employed as the substrate and the self-supported MoS₂@ CuCo₂S₄-Ni₃S₂/NF electrode was obtained. The high resolution transmission electron microscopy（HRTEM）， X-ray diffraction（XRD）， X-ray photoelectron spectroscopy（XPS）， scanning electron microscopy（SEM） and transmission electron microscopy（TEM） verified that MoS₂ nanosheets grown onto the surface of CuCo₂S₄-Ni₃S₂ nanorods densely and uniformly， which formed a hierarchical core-shell structure. The electrocatalytic performance of MoS₂@CuCo₂S₄-Ni₃S₂/NF for hydrogen evolution reaction（HER） in 1 mol/L KOH verified that the rational hybridization between MoS₂ and CuCo₂S₄ as well as the construction of the speci-fic nanostructure significantly increased the electrochemical surface area and efficiently improved the electron transfer. Therefore， MoS₂@CuCo₂S₄-Ni₃S₂/NF only needed overpotential of 116， 231， 282 mV， respectively， to reach the current density of 10， 100， 300 mA/cm². The overpotential corresponded to 100 mA/cm² only increased 6% after 2000 cycles of CV measurement. Therefore， outstanding HER catalytic activity and stability have been achieved by this MoS₂@CuCo₂S₄-Ni₃S₂/NF self-supported electrode.