Loading...

Table of Content

    10 May 2023, Volume 44 Issue 5
    Preface
    电化学能源专辑
    郭少军, 王双印, 余彦, 张强
    2023, 44(5):  1-2. 
    Asbtract ( )   PDF (1361KB) ( )  
    Related Articles | Metrics
    Content
    Cover and Content of Chemical Journal of Chinese Universities Vol.44 No.5(2023)
    2023, 44(5):  1-5. 
    Asbtract ( )   PDF (42226KB) ( )  
    Related Articles | Metrics
    Review
    Research Advances in Transport Mechanism of Lithium Ions in Solid Electrolytes
    FU Zhongheng, CHEN Xiang, YAO Nan, YU Legeng, SHEN Xin, ZHANG Rui, ZHANG Qiang
    2023, 44(5):  20220703.  doi:10.7503/cjcu20220703
    Asbtract ( )   HTML ( )   PDF (9332KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    Global challenges have promoted the rapid development of rechargeable lithium battery technology. Solid-state electrolytes are less flammable than liquid electrolytes. If the ion transport behavior in solid electrolytes is well understood, the lithium dynamic stability and rate performance of solid state batteries can be accurately regulated. With the rapid development of calculation technology, atomic scale simulation technology has become an important method to understand the ion transport of materials. To solve the above problems, this review firstly summarizes the common diffusion mechanisms in solid materials. Then the transport mechanism of lithium ions in solid electrolytes is introduced, and the important factors(crystal structure, electronic structure, external factors, grain boundaries) affecting the transport of lithium ions in solid electrolytes are emphatically included. Finally, the transport mechanism of lithium ion in solid electrolytes is summarized and prospected.

    Recent Process of Carbon-based Catalysts for the Production of H2O2 by Electrocatalytic Oxygen Reduction: Strategies, Calculation and Practical Applications
    ZHANG Xiaoyu, QU Gan, XUE Dongping, YAN Wenfu, ZHANG Jianan
    2023, 44(5):  20220775.  doi:10.7503/cjcu20220775
    Asbtract ( )   HTML ( )   PDF (12402KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    Hydrogen peroxide(H2O2) as a multifunctional and environmentally friendly oxidizer, plays a crucial role in industrial production, bleaching, disinfection, and wastewater treatment, etc. The traditional anthraquinone process is not the ideal choice for batch H2O2 production due to the disadvantages of environmental pollution, insecurity, and complicated process. Typically, H2O2 can be synthesized by the 2-electron(2e) oxygen reduction reaction(ORR) process, which process is a promising alternative to produce the H2O2 at a large scale. Carbon-based materials are considered as one kind of the best catalysts for 2e ORR due to their abundant reserves, low cost, adjustable structure, and good conductivity. Therefore, this paper reviews the research progress of carbon-based catalysts in 2eORR for H2O2. Firstly, the basic principle of 2e ORR is introduced, and the key factors affecting the ORR path are revealed. Then, density functional theory(DFT) employed to reveal the essence of catalytic active sites is introduced. After that, several effective strategies on catalysts for promoting the production of H2O2 are summarized in detail, including optimized single atom catalysts(SACs), defect engineering on catalyst surface, pyrrole nitrogen doping, oxygen-containing functional groups doping, and other heteroatoms(e.g. S, P, F) doping. At last, the deve-lopment of the practical applications in the devices for mass production of H2O2 are discussed. Finally, the potential opportunities and challenges in the future development of electrochemical synthesis of H2O2 are proposed.

    Recent Advances in Green C-N Coupling for Urea Synthesis
    ZHANG Xiaoran, ZHENG Jianyun, LYU Yanhong, WANG Shuangyin
    2023, 44(5):  20220717.  doi:10.7503/cjcu20220717
    Asbtract ( )   HTML ( )   PDF (6788KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    The industrial synthesis of chemicals usually operates under harsh conditions with high energy consumption, aggravating energy crisis and environmental concerns. Driven by renewable electricity or/and solar energy, the energy barrier of the reaction could be reduced to achieve the efficient and green synthesis of chemicals under milder conditions. As the main small molecules, carbon dioxide and nitrogen can be used to synthesize various carbon and nitrogen-containing fuels through electrocatalysis, which can alleviate environmental problems while reducing the pressure of energy depletion and achieve the purpose of efficient energy storage. This paper briefly summarizes the recent advances in electrochemical conversion of N2 and CO2, focusing on the improvement of reaction conditions, the adjustment of reaction route, and the investigation of catalytic mechanism. The current challenges and future development for electrocatalytic coupling of C-N are prospected. This mini-review provides a useful guidance for further developing electrochemical conversion of N2 and CO2.

    Research Progresses of in situ Polymerized Electrolytes for Solid-state Lithium Metal Batteries
    XU Pan, KONG Weijin, HUANG Xueyan, SUN Shuo, HUANG Wenze, ZHAO Chenzi
    2023, 44(5):  20220670.  doi:10.7503/cjcu20220670
    Asbtract ( )   HTML ( )   PDF (10238KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    In the next-generation battery systems, solid-state lithium metal batteries possesses high energy density, which are also expected to avoid the potential safety issues such as combustion and explosion faced by current commercial batteries. However, the poor solid-solid contacts between solid-state electrolytes and electrodes are crucial challenges to hinder their practical applications. In recent years, the in situ polymerized electrolytes prepared by the in situ polymerization reactions inside the battery have multiple advantages for solid-state lithium metal batteries, including improved solid-solid interface compatibility via interface integration, Li dendrite suppression, inhibited dissolution/shuttle of cathode transition metal ions/polysulfides/redox mediators and enhanced electro- chemical performances. This review firstly discusses the reaction mechanism of polymerized electrolytes, and then analyzes the state-of-the-art in situ polymerized electrolytes. Furthermore, the recent research progresses of in situ polymerized electrolytes in solid-state lithium metal batteries is summarized, emphasizing the important roles in the battery cycling. Finally, the conclusion and future prospects on the commercial application of in situ polymerized electrolytes are presented.

    Non-precious Metal Catalysts for Electro-oxidation Upgrading of 5-Hydroxymethy Furfural
    DU Lei, LIU Zhaoqing
    2023, 44(5):  20220710.  doi:10.7503/cjcu20220710
    Asbtract ( )   HTML ( )   PDF (13626KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    Hydroxymethylfurfural is a furan compound, which is cheap and widely available, and can be used as a platform chemical to generate value-added products. Traditional thermo-catalytic methods always require high temperature, high pressure, and precious metal catalysts, leading to low economic benefits. By contrast, the electro-catalytic methods do not require harsh conditions including high temperature and high pressure; meanwhile, by using well-designed non-precious metal electrocatalysts, the selective conversion of hydroxymethylfurfural has been achieved, i.e., using precious metal catalysts is not necessary. Reasonably, the upgrading of hydroxymethylfurfural platform compounds via electro-oxidation methods has received extensive attention. Among the various products, 2,5-furandicarboxylic acid was crowned as one of the most valuable twelve biomass-derived chemicals by the department of energy of the united states. In this regard, this paper focuses on the electro-oxidation of hydroxymethyl furfural to generate 2,5-furandicarboxylic acid and review the research progress of non-noble metal catalysts. Finally, prospects for the development of non-precious metal catalysts for the electrooxidation of hydroxymethyl furfural are provided.

    Pyrolysis-free Strategy of Covalent Organic Polymers-based Oxygen Reduction Electrocatalytic Materials
    BAO Chunzhu, XIANG Zhonghua
    2023, 44(5):  20220715.  doi:10.7503/cjcu20220715
    Asbtract ( )   HTML ( )   PDF (16243KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    High-efficient, low-cheap and long-durable cathodic electrocatalysts for oxygen reduction reaction(ORR) play an important role in the global introduction of hydrogen energy technology to assist in achieving carbon neutrality targets. Recent years, great improvements have been witnessed in the ORR catalytic activity and stability of non- noble metal catalysts. Covalent organic polymers(COPs) have leapt to the forefront as an ideal material platform for molecular structure tailoring due to their adjustable porosity, modifiable backbone and periodically arranged ordered structure. However, the unpredictable structural changes and the ambiguous active sites under the commonly adopted pyrolysis strategies have hindered the in-depth exploration of the catalytic mechanism. The pyrolysis-free strategy has arisen to take full advantage of the customizable nature of COPs-based materials. The precisely controllable structure of pyrolysis-free COPs-based materials can provide an ideal model for the study of catalytic mechanisms, which can in turn guide the design of ORR catalysts with better catalytic performance and further facilitate the macro- preparation of materials. Here, this review intended to analyze the ORR mechanism in depth from the source, and gradually generalize the design principles and synthesis strategies of structurally well-defined pyrolysis-free COPs-based materials. Then, combining with representative literatures, the factors influencing the electrocatalytic performance of pyrolysis-free COPs-based materials were analyzed, and the research progress of pyrolysis-free strategies in the ORR field was systematically described. Finally, the research works of our group on pyrolysis-free COPs-based oxygen reduction electrocatalytic materials were summarized, and the development prospects and challenges of pyrolysis-free technologies were discussed in the outlook.

    Progress on the Solvation Structure Regulation of Li Ion for Stable Lithium Metal Anode
    ZHANG Shuo, DING Junfan, XU Rui, HUANG Jiaqi
    2023, 44(5):  20220721.  doi:10.7503/cjcu20220721
    Asbtract ( )   HTML ( )   PDF (12287KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    Owing to the extremely high theoretical specific capacity and low electrode potential, lithium(Li) metal anode is regarded as the ultimate anode option for next-generation secondary batteries. However, the unstable electrode/electrolyte interface results in massive lithium dendrite during cycling, giving rise to a rapid capacity loss and a severe safety problem. Regulating the solvation structure of Li ions and therefore promoting the preferential decomposition of beneficial solid electrolyte interphase(SEI) film-forming components on Li metal surface is an imperative outlet to enable uniform Li deposition, which is strongly considered when designing liquid and quasi solid-state electrolyte for Li metal batteries. In this review, the typical strategies and design principles for regulating the solvation structure of Li ions in liquid and quasi solid-state electrolytes are summarized. Deep insights are afforded into the correlation between Li ion solvation structures and the resulting electrochemical properties. Critical perspectives on the future research in this field are further pointed out.

    Recent Progress of Catalysts in the High Temperature Polymer Electrolyte Membrane Fuel Cells
    WANG Jun, DU Shiqian, TAO Li
    2023, 44(5):  20220722.  doi:10.7503/cjcu20220722
    Asbtract ( )   HTML ( )   PDF (12197KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    High temperature polymer electrolyte membrane fuel cells(HT-PEMFCs) are one form of energy conversion device which have many advantages compared with traditional low temperature PEMFCs. The catalysts in HT-PEMFCs are mainly Pt-based catalysts which have good catalytic activity to the oxygen reduction reaction(ORR) and hydrogen oxidation reaction(HOR). A high loading amount of Pt is used to alleviate the negative effect on activity expression caused by strong absorption of PA on the Pt surface. And Pt catalysts suffer from the issue of inadequate activity, activity loss during long term operation, high cost and support corrosion under harsh conditions. In this review, we summarize recent studies about catalysts in HT-PEMFCs and systematically analyze the further appli- cation of precious and non-precious metal catalysts. Furthermore, we give our perspectives about the problems that the catalysts in HT-PEMFCs currently have.

    Recent Advances in Amorphous FePO4 for Sodium-Ion Battery Cathodes
    SHENG Xinru, ZHANG Zhuangzhuang, DING Tangjing, LIAO Jiaying, ZHOU Xiaosi
    2023, 44(5):  20220724.  doi:10.7503/cjcu20220724
    Asbtract ( )   HTML ( )   PDF (1386KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    With the increasingly serious energy and environmental problems, the development of green energy storage and conversion technologies becomes more and more crucial. As an environmentally friendly energy storage device, the rapid development of the sodium-ion batteries(SIBs) has stimulated the demand for high-performance cathode materials. Among various kinds of cathode materials, amorphous iron phosphate(FePO4) has attracted enormous attention as a promising cathode material for sodium-ion batteries because of its high theoretical specific capacity and superior electrochemical reversibility. Herein, this review is focused on recent advances in amorphous FePO4 for sodium-ion battery cathodes. First, the common characteristics and applications of amorphous FePO4 are introduced. Next, the synthesis methods are summarized, including template synthesis, hydrothermal synthesis and some other methods. Subsequently, the research progress of strategies to improve sodium-ion storage properties is introduced in detail, with an emphasis on the relationship between structure and performance. Finally, the conclusion and prospects in this field are discussed.

    Construction of Highly Stable Lithium Metal Anode Based on Three Dimensional Lipophilic Materials
    TU Xingchao, GU Xingxing, LAI Chao
    2023, 44(5):  20220727.  doi:10.7503/cjcu20220727
    Asbtract ( )   HTML ( )   PDF (25486KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    With its ultra-high theoretical specific capacity density(3680 mA·h·g-1) and low reduction potential(-3.04 V vs. SHE), lithium metal is considered the “holy grail” of anode for high energy density batteries. However, due to the uncontrolled growth of lithium dendrites and high reactivity to electrolytes, a series of problems, such as low coulomb efficiency, short cycle life and internal short circuit, seriously restrict the practical progress of lithium metal anode. In the practical electrochemical system, the surface properties of the current collector that is employed as the substrate for lithium metal deposition/stripping play an important role in the cyclic stability of the lithium anode. In this review, the modification strategies for constructing three-dimensional(3D) lithiophilic skeleton materials were systematically summarized from the aspects of surface composition and microstructure design for lithium anode and current collector. Utilizing high lithiophilic materials such as metal, metal oxide, doping heteroatoms, polymer materials, and metal-organic frame materials to tune and modify the interface and structure of the collector and anode, can effectively regulate the electrodeposition of lithium metal and promote the practical process of lithium metal anode in high energy density battery system.

    Recent Progress of Hard Carbon Anode Materials for Sodium Ion Batteries
    YANG Cuiyun, YANG Chenghao
    2023, 44(5):  20220728.  doi:10.7503/cjcu20220728
    Asbtract ( )   HTML ( )   PDF (16813KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    Sodium ion batteries(SIBs) have been regarded as the compatible and complementary to lithium ion batteries for energy storage due to abundant sodium resources, low cost and excellent low temperature performance. Therefore, accelerating the commercialization of SIBs can reduce the risk of lithium supply to ensure the long-term stable development of the new energy industry. As the host material for intercalation of large-radius sodium ions, the related design and development requirements of anode material are more demanding. Currently, hard carbon(HC) has been considered one of the most suitable anode materials for sodium ion batteries and large-scale commercialization. This paper reviews the bottleneck of high performance SIBs development, the materials characteristics, sodium storage mechanism and functionalized design strategies of hard carbon materials. Moreover, the advantages and disadvantages of various optimization strategies are discussed. Finally, future developments and challenges relating to ideal HCs are also proposed on the basis of recent progress.

    Research Progress of Organosulfur in Rechargeable Batteries
    REN Siyuan, GUO Wei, FU Yongzhu
    2023, 44(5):  20220729.  doi:10.7503/cjcu20220729
    Asbtract ( )   HTML ( )   PDF (17204KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    Organosulfur has been widely used in the field of energy storage in recent years due to their flexible and diverse structure, resourcefulness and environmental friendliness, showing great promise for development. During the charge and discharge, sulfur-sulfur(S—S) bonds can be reversibly broken and formed. The number of S—S bonds in the molecule determines the amount of electron transfer, and organic groups can affect the electrochemical behavior of the batteries. In this review, we introduced the research progress of organosulfur in rechargeable batteries including the application of organosulfur small molecules and polymer-based cathode materials in rechargeable lithium batteries, the influence of organosulfur electrolyte additives on the performance of lithium-sulfur(Li-S) and lithium-selenium(Li-Se) batteries, and the application of organosulfur materials in other rechargeable batteries. These organosulfur with adjustable structures show excellent cycle stability, change the redox pathways of traditional Li-S and Li-Se batteries, participate in the formation of solid electrolyte interfaces in cathode and anode, inhibit the shuttle effect of polysulfides, and prevent the growth of lithium dendrites. Finally, the challenges faced by organosulfur in the future research and development of rechargeable batteries were discussed.

    Research Progress on Hollow Precious Metal-based Nanostructures for Oxygen Reduction Reaction
    LI Ruisong, MIAO Zhengpei, LI Jing, TIAN Xinlong
    2023, 44(5):  20220730.  doi:10.7503/cjcu20220730
    Asbtract ( )   HTML ( )   PDF (30708KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    Hollow nanostructures have been receiving great attention for structural design and electrocatalytic applications in energy conversion and storage due to their large specific area, tunable mass transfer rates, and well-defined active sites. Especially when hollow precious metal-based nanostructures are used as oxygen reduction reaction(ORR) electrocatalysts, the introduction of interior cavity in hollow precious metal-based nanostructures(HPMs) can expose more active sites and reduce the amount of costly precious metals, which will provide a desirable platform to achieve their large-scale applications. Herein, recent progress on synthesis and ORR application of the HPMs is summarized. First, a brief review of the advantages and significance for developing HPMs towards ORR is given. Further, four main strategies to synthesize HPMs, including hard-, soft- and self-template methods, as well as template-free methods, are explicitly described in terms of recent advances and their advantages. Finally, the remaining challenges and promising solutions are summarized to provide some useful clues for the future development of the HPMs in ORR field.

    Recent Progress of Lithium-based Semi-solid Flow Batteries
    XIN Benjian, WANG Rui, LIU Lili, NIU Zhiqiang
    2023, 44(5):  20220731.  doi:10.7503/cjcu20220731
    Asbtract ( )   HTML ( )   PDF (7902KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    Semi-solid flow battery(SSFBs) is a critical technology for large-scale energy storage due to their promising characteristics of high energy density and design flexibility. Recently, tremendous research efforts have been made to design lithium-based SSFBs(Li-SSFBs). In this review, the working principle and characteristics of Li-SSFBs are presented. The recent development of Li-SSFBs is also highlighted, in particular focusing on the active materials of cathodes and anodes. Finally, the challenges and future perspectives of Li-SSFBs are discussed. This will shed light on the research and development of Li-SSFBs.

    Recent Progress on Strategies for Electrochemical Hydrogen Production Coupling with Oxidation of Inorganic Chemicals
    YAN Dafeng, XIE Chao, CHEN Chen
    2023, 44(5):  20220732.  doi:10.7503/cjcu20220732
    Asbtract ( )   HTML ( )   PDF (6580KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    Electrochemical water splitting to produce H2 has drawn much attention for inherent advantages. However, the sluggish reaction kinetics of anodic oxygen evolution reaction(OER) and high energy consumption greatly limited its application. In contrast to OER, the electrooxidation of some inorganic chemicals is more thermo-dynamically and kinetically favorable. Therefore, coupling hydrogen evolution reaction(HER) with inorganic alternatives oxidization shows great potential to enhance the efficiency of H2 production. It can obviously lower the anodic overpotential compared with OER. Simultaneously, some pollutants can be removed or some valuable chemicals can be produced on the anode. In this review, we will summarize the recent progress on the strategy of H2 production coupling with the electrooxidation of inorganic chemicals. Firstly, some representative inorganic alternatives are introduced and discussed, including nitrogenous N2H4 and NO and sulfureted H2S and SO2, which can assist to produce H2 at very low cell voltage and radically avoid the generation of O2. And then introducing electrochemical neutralization energy to further decrease the cell voltage of electrochemical H2 production or even achieve H2 production together with electricity output are further discussed. Finally, the remaining challenges and perspectives are also provided for future development.

    Recent Progress on Carbon Dots Preparation and Electrochemical Energy Application
    WANG Siyang, JING Wen, CHANG Jiangwei, LU Siyu
    2023, 44(5):  20220733.  doi:10.7503/cjcu20220733
    Asbtract ( )   HTML ( )   PDF (10511KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    As a typical zero-dimensional carbon material, carbon dots (CDs) with particle size smaller than 10 nm are composed by sp2/ sp3 hybridization of carbon atoms. Owing to their unique physicochemical structures, CDs have many features, such as rich edge sites and accessibility for functional modification, which endow themselves wide applications in electrocatalysis and energy storage/conversion. Based on this, it is of great significance to reveal the formation mechanism of CDs and clarify the structure-property relationship, which is helpful in guiding the synthesis of CDs and then obtain excellent catalytic performance. Therefore, based on the introduction of preparation and regulation strategies of CDs, this paper analyzes the activity origin of CDs-based catalytic materials by combining with theoretical investigations and more importantly, reviews the recent progress of CDs applications in electro- chemistry and discusses the opportunities and challenges for the future development of functional CDs materials.

    Recent Progress in Intercalation Chemistry of Transition Metal Oxides for Electrocatalytic Applications
    CHI Liping, NIU Zhuangzhuang, LIAO Jie, TANG Kaibin, GAO Minrui
    2023, 44(5):  20220740.  doi:10.7503/cjcu20220740
    Asbtract ( )   HTML ( )   PDF (14231KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    Intercalation chemistry describes the process by which a guest is intercalated into a host to form an intercalated compound. Intercalation chemistry, as an effective method to modify structures, has been intensively studied in recent centuries for electrocatalysis-based energy storage and conversion devices. Particularly, research on transition metal oxides(TMOs) has become an emerging frontier in intercalation chemistry because of their tunability in structure and composition. Nonetheless, confusions remain in the discovery of indefinable intercalation mechanism and unexplained properties change. In this paper, a first-ever in-depth description of the intercalation mechanism, which directly determines the potential of properties and applications, will be presented. We discuss the major synthesis strategies for TMOs intercalation compounds. We summarize the recent advances for electrocatalytic applications of intercalated TMOs. Moreover, this review will be concluded with a section on the future opportunities and challenges for intercalation of TMOs.

    Design of Electrolyte for High Specific Energy Lithium Ion Batteries Working at High Voltage
    SUN Zhaoyu, ZHAO Jingwei, LIU Jun
    2023, 44(5):  20220743.  doi:10.7503/cjcu20220743
    Asbtract ( )   HTML ( )   PDF (8447KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    The current energy storage devices of lithium ion batteries can hardly satisfy people’s work and living since the advent of portable electronics and electric vehicles. Lithium ion batteries, with their market superiority of commercial energy storage devices, are being researched and developed in the aspects of higher specific energy, longer cycle life and safer performance. The gravimetric and volumetric energy densities of lithium ion batteries can be increased at high-voltage conditions on which the battery systems are unstable. This will attenuate the batteries’ capacity rapidly. Simultaneously, the interface impedance of batteries rises when amounts of decomposition products accumulate. In addition, the generation of harmful gas threatens the safety of the batteries. This paper reviews the development of high voltage electrolyte in allusion to the design of solvent and additive of electrolyte for working at high voltage. Based on the current theoretical researches, this paper also indicates the design focus and future research directions of multifunctional electrolyte for high specific energy lithium ion batteries.

    Research Progresses on Interface Engineering of Si-Based Anodes for Lithium-ion Batteries
    HE Ruhan, LI Hao, HAN Fang, CHEN Aoyuan, MAI Liqiang, ZHOU Liang
    2023, 44(5):  20220748.  doi:10.7503/cjcu20220748
    Asbtract ( )   HTML ( )   PDF (21055KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    Si-based anode material is regarded as a key material for improving the energy density of lithium-ion batteries due to its high specific capacity and low lithium-ion intercalation potential. However, its large volume expansion and side reactions with electrolyte will cause serious interfacial problems. This reviewer article starts from the definition of the Si anode interface, and then summarizes its interface problems, the corresponding causes and the formation mechanism. After that, the present development status of interface engineering of the Si-based anode is described. At last, the future research directions towards tackling the Si-based anode interface problems are concluded and proposed.

    Electrocatalytic Oxidative Cleavage of Lignin: Facile and Efficient Biomass Valorization Strategy
    XU Jianing, BAI Wenjing, LOU Yuhan, YU Haipeng, DOU Shuo
    2023, 44(5):  20220749.  doi:10.7503/cjcu20220749
    Asbtract ( )   HTML ( )   PDF (5356KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    Lignin, as an intriguing native renewable aromatic polymer, can be depolymerized into aromatic platform chemicals by catalysis procedures, and its high-value conversion is of great significance for realizing the green and sustainable production of biofuels, fine chemicals, and bulk chemicals. With this regard, catalytic oxidation of lignin through electrochemistry offers an economized energy nature with tunable potential or current to determine the products selectivity and conversion rate. However, to realize the controllable degradation of lignin, the electrocatalytic system, including the catalysts, electrolyte, reaction cell, etc., should be rationally designed based on the well-understanding of the depolymerization mechanism. In this review, we focused on the bond cleavage mechanism of C—C bond and C—O bond, respectively, in the depolymerization of lignin. Research works based on the different bond cleavage mechanisms in the electrochemical oxidation of lignin and its model compounds to aromatic monomers in recent years were reviewed here, including the different types of catalytic systems, electrocatalysts, and free radical initiators. Of which the free radical intermediates play decisive role in the highly selective cleavage of C—O and C—C bonds. Finally, the challenges and development perspectives in the future of electrocatalytic lignin depolymerization are also provided.

    Advances in Nanofiber-based Electrocatalysts for Oxygen Reduction Reaction
    LI Xuan, QI Shuai, ZHOU Weiliang, LI Xiaojie, JING Lingyan, FENG Chao, JIANG Xingxing, YANG Hengpan, HU Qi, HE Chuanxin
    2023, 44(5):  20220770.  doi:10.7503/cjcu20220770
    Asbtract ( )   HTML ( )   PDF (17599KB) ( )  
    Figures and Tables | References | Related Articles | Metrics

    The excessive usage of fossil fuels is accompanied by the environmental pollution problems. Positively explore and develop green and sustainable energy conversion and storage technologies is of great significance to alleviate the environmental problems. Proton exchange membrane fuel cells(PEMFC) and metal air battery(MAB) stand out among many energy technologies. The oxygen reduction reaction(ORR), as critical part of PEMFC and MAB, seriously restrict the widespread use of PEMFC and MAB due to the multistep proton-electron coupling process and high energy barrier. The advantages of fiber structure, including high specific surface area, adjustable geometric structure, simple and convenient preparation, make it a new emerging architecture for the fabrication of electrocatalyst toward oxygen reduction reaction. In this review, the preparation of nanofibers and adjustable metal site in nanofiber-based electrocatalysts are summerized, and the latest progresses of nanofiber-based electrocatalyst toward ORR are discussed. Moreover, the structure-activity relationship of nanofiber-based electrocatalysts toward ORR is revealed. Finally, the challenges and opportunities of nanofiber-based electrocatalyst for ORR electro- catalysis are discussed.