Miniaturized electrochemical sensors and their point-of-care applications

Most of the current analytical methods depend largely on laboratory-based analytical techniques that require expensive and bullky equipment,potentially incur costly testing,and involve lengthy detection processes.With increasing requirements for point-of-care testing(POCT),more attention has been paid to miniaturized analytical devices.Miniaturized electrochemical(MEC)sensors,including different material-based MEC sensors(such as DNA-,paper-,and screen electrode-based),have been in strong demand in analytical science due to their easy operation,portability,high sensitivity,as well as their short analysis time.They have been applied for the detection of trace amounts of target through measuring changes in electrochemical signal,such as current,voltage,potential,or impedance,due to the oxidation/reduction of chemical/biological molecules with the help of electrodes and electrochemical units.MEC sensors present great potential for the detection of targets including small organic molecules,metal ions,and biomolecules.In recent years,MEC sensors have been broadly applied to POCT in various fields,including health care,food safety,and environmental monitoring,owing to the excellent advantages of electrochemical(EC)technologies.This review summarized the state-of-the-art advancements on various types of MEC sensors and their applications in POCT.Furthermore,the future perspectives,opportunities,and challenges in this field are also discussed.     

Machine Learning towards Screening Solid-state Lithium Ion Conductors

Machine learning is an emerging method to discover new materials with specific characteristics.An unsupervised machine learning research is highlighted to discover new potential lithium ionic conductors by screening and clustering lithium compounds,providing inspirations for the development of solid-state electrolytes and practical batteries.     

Surface defect-rich ceria quantum dots anchored on sulfur-doped carbon nitride nanotubes with enhanced charge separation for solar hydrogen production

Designing defect-engineered semiconductor heterojunctions can effectively promote the charge carrier separation.Herein,novel ceria(CeO2) quantum dots(QDs) decorated sulfur-doped carbon nitride nanotubes(SCN NTs) were synthesized via a thermal polycondensation coupled in situ depositionprecipitation method without use of template or surfactant.The structure and morphology studies indicate that ultrafine CeO2 QDs are well distributed inside and outside of SCN NTs offering highly dispersed active sites and a large contact interface between two components.This leads to the promoted formation of rich Ce³⁺ ion and oxygen vacancies as confirmed by XPS.The photocatalytic performance can be facilely modulated by the content of CeO2 QDs introduced in SCN matrix while bare CeO2 does not show activity of hydrogen production.The optimal catalyst with 10% of CeO2 loading yields a hydrogen evolution rate of 2923.8 μmol h-1 g-1 under visible light,remarkably higher than that of bare SCN and their physical mixtures.Further studies reveal that the abundant surface defects and the created 0 D/1 D junctions play a critical role in improving the separation and transfer of charge carriers,leading to superior solar hydrogen production and good stability.     

Superfast and solvent-free core-shell assembly of sulfur/carbon active particles by hail-inspired nanostorm technology for high-energy-density Li-S batteries

The demand on low-carbon emission fabrication technologies for energy storage materials is increasing dramatically with the global interest on carbon neutrality.As a promising active material for metal-sulfur batteries,sulfur is of great interest due to its high-energy-density and abundance.However,there is a lack of industry-friendly and low-carbon fabrication strategies for high-performance sulfur-based active particles,which,however,is in critical need by their practical success.Herein,based on a hail-inspired sulfur nano-storm(HSN)technology developed in our lab,we report an energy-saving,solvent-free strategy for producing core-shell sulfur/carbon electrode particles(CNT@AC-S)in minutes.The fabrication of the CNT@AC-S electrode particles only involves low-cost sulfur blocks,commercial carbon nanotubes(CNT)and activated carbon(AC)micro-particles with high specific surface area.Based on the above core-shell CNT@AC-S particles,sulfur cathode with a high sulfur-loading of 9.2 mg cm^-2 delivers a stable area capacity of 6.6 mAh cm^-2 over 100 cycles.Furthermore,even for sulfur cathode with a super-high sulfur content(72 wt%over the whole electrode),it still delivers a high area capacity of 9 mAh cm^-2 over50 cycles in a quasi-lean electrolyte condition.In a nutshell,this study brings a green and industryfriendly fabrication strategy for cost-effective production of rationally designed S-rich electrode particles.     

Unraveling the stabilization mechanism of solid electrolyte interface on ZnSe by rGO in sodium ion battery

Transition metal selenides have been widely studied as anode materials of sodium ion batteries(SIBs),however,the investigation of solid-electrolyte-interface(SEI)on these materials,which is critical to the electrochemical performance of SIBs,remains at its infancy.Here in this paper,ZnSe@C nanoparticles were prepared from ZIF-8 and the SEI layers on these electrodes with and without reduced graphene oxide(rGO)layers were examined in details by X-ray photoelectron spectroscopies at varied charged/discharged states.It is observed that fast and complicated electrolyte decomposition reactions on ZnSe@C leads to quite thick SEI film and intercalation of solvated sodium ions through such thick SEI film results in slow ion diffusion kinetics and unstable electrode structure.However,the presence of rGO could efficiently suppress the decomposition of electrolyte,thus thin and stable SEI film was formed.ZnSe@C electrodes wrapped by rGO demonstrates enhanced interfacial charge transfer kinetics and high electrochemical performance,a capacity retention of 96.4%,after 1000 cycles at 5 A/g.This study might offer a simple avenue for the designing high performance anode materials through manipulation of SEI film.     

CXN天然沸石的研究2: 吸附性质

采用N~2,NH~3,CO~2,乙烯,丙烯,水,甲醇,乙醇,丙醇等作为吸附剂,研究了由我国CXN天然沸石改性制得的H-STI和Na-STI沸石的吸附性质,H-STI和Na-STI沸石的BET表面积及微孔孔体积约为420m^2/g和0.20m^3/g。根据NH~3和CO~2在H-STI沸石上的吸附等温线计算得到它们的吸附热分别为44.8和26.5kJ/mol。乙烯,丙烯,甲醇,乙醇,丙醇等在Na-STI沸石上的吸附等温线表明该沸石对有机分子的吸附具有链长选择性。在低分压下水相对于甲醇的吸附量表明沸石具有一定的疏水性质。     

常温常湿条件下Au/MeO~x催化剂上CO氧化性能

利用共沉淀法制备了Au/MeO~x催化剂(Me=Al,Co,Cr,Cu,Fe,Mn,Ni,Zn)。在常温常湿条件下,考察了不同氧化物负载的金基催化剂的CO氧化性能。结果表明,氧化物种类对催化剂的活性和稳定性均有较大的影响。Cu,Mn,Cr等氧化物负载的金基催化剂的活性较差,而Zn,Fe,Co,Ni,Al等金属氧化物负载的金基催化剂可将CO完全氧化,又具有一定的稳定性,在相同反应条件下,CO完全转化时的稳定性顺序为Au/ZnO>Au/α-Fe~2O~3>Au/Co~3O~4>Au/γ-Al~2O~3≈Au/NiO。还发现水对Au/MnO~x催化剂的活性和稳定性有负作用,而对180℃焙烧制备的Au/ZnO-180催化剂的活性和稳定性均有明显的湿度增强作用。     

Boost oxygen reduction reaction performance by tuning the active sites in Fe-N-P-C catalysts

Cost-effective atomically dispersed Fe-N-P-C complex catalysts are promising to catalyze the oxygen reduction reaction(ORR)and replace Pt catalysts in fuel cells and metal-air batteries.However,it remains a challenge to increase the number of atomically dispersed active sites on these catalysts.Here we report a highly efficient impregnation-pyrolysis method to prepare effective ORR electrocatalysts with large amount of atomically dispersed Fe active sites from biomass.Two types of active catalyst centers were identified,namely atomically dispersed Fe sites and Fe_xP particles.The ORR rate of the atomically dispersed Fe sites is three orders of magnitude higher than it of Fe_xP particles.A linear correlation between the amount of the atomically dispersed Fe and the ORR activity was obtained,revealing the major contribution of the atomically dispersed Fe to the ORR activity.The number of atomically dispersed Fe increases as the Fe loading increased and reaching the maximum at 1.86 wt%Fe,resulting in the maximum ORR rate.Optimized Fe-N-P-C complex catalyst was used as the cathode catalyst in a homemade Zn-air battery and good performance of an energy density of 771 Wh kgZn^-1,a power density of 92.9 m W cm^-2 at 137 m A cm^-2 and an excellent durability were exhibited.     

Regulation of carbon distribution to construct high-sulfur-content cathode in lithium-sulfur batteries

Lithium-sulfur(Li-S)battery is regarded as one of the most promising next-generation energy storage systems due to the ultra-high theoretical energy density of 2600 Wh kg^-1.To address the insulation nature of sulfur,nanocarbon composition is essential to afford acceptable cycling capacity but inevitably sacrifices the actual energy density under working conditions.Therefore,rational structural design of the carbon/sulfur composite cathode is of great significance to realize satisfactory electrochemical performances with limited carbon content.Herein,the cathode carbon distribution is rationally regulated to construct high-sulfur-content and high-performance Li-S batteries.Concretely,a double-layer carbon(DLC)cathode is prepared by fabricating a surface carbon layer on the carbon/sulfur composite.The surface carbon layer not only provides more electrochemically active surfaces,but also blocks the polysulfide shuttle.Consequently,the DLC configuration with an increased sulfur content by nearly 10 wt%renders an initial areal capacity of 3.40 mAh cm^-2 and capacity retention of 83.8%during 50 cycles,which is about two times than that of the low-sulfur-content cathode.The strategy of carbon distribution regulation affords an effective pathway to construct advanced high-sulfur-content cathodes for practical high-energy-density Li-S batteries.     

Confined Ni-In intermetallic alloy nanocatalyst with excellent coking resistance for methane dry reforming

Carbon dioxide and methane are two main greenhouse gases which are contributed to serious global warming.Fortunately,dry reforming of methane(DRM),a very important reaction developed decades ago,can convert these two major greenhouse gases into value-added syngas or hydrogen.The main problem retarding its industrialization is the seriously coking formation upon the nickel-based catalysts.Herein,a series of confined indium-nickel(In-Ni)intermetallic alloy nanocatalysts(In_xNi@SiO₂)have been prepared and displayed superior coking resistance for DRM reaction.The sample containing 0.5 wt.%of In loading(In_0.5Ni@SiO₂)shows the best balance of carbon deposition resistance and DRM reactivity even after 430 h long term stability test.The boosted carbon resistance can be ascribed to the confinement of core–shell structure and to the transfer of electrons from Indium to Nickel in In-Ni intermetallic alloys due to the smaller electronegativity of In.Both the silica shell and the increase of electron cloud density on metallic Ni can weaken the ability of Ni to activate C–H bond and decrease the deep cracking process of methane.The reaction over the confined InNi intermetallic alloy nanocatalyst was conformed to the Langmuir-Hinshelwood(L-H)mechanism revealed by in situ diffuse reflectance infrared Fourier transform spectroscopy(in-situ DRIFTS).This work provides a guidance to design high performance coking resistance catalysts for methane dry reforming to efficiently utilize these two main greenhouse gases.     

"基础学科拔尖学生培养试验计划"中的有机模块化实验探索

In recent years, some innovations have been explored in laboratory teaching of basic organic chemistry based on program of "Top Talent Training Program". This paper discussed and reflected moduling experiment of organic chemistry for this Top Talent Training Program, including experiment objectives, moduling experiment design, conduct of moduling experiment, lessons and prospects.     

南开大学化学本科拔尖人才培养模式探索与实践

南开大学化学学科从2009年起实施"基础学科拔尖学生培养试验计划"。经过十年的探索和改革,取得了一些成绩。本文从培养目标、教学计划、科研创新能力培养、国际化等几个方面,分享南开化学拔尖人才培养模式的探索与实践。     

基于科研引导的化学类拔尖人才全过程培养模式的探索与实践

从课堂教学和第二课堂两个方面详细地阐述了四川大学化学学院基于科研引导的拔尖人才全过程培养模式,重点梳理了拔尖班学生在校成果、毕业去向、人才培养满意度等方面内容,明确了学院拔尖计划2.0的工作目标。     

关于为拔尖人才培养开设的"学科前沿"类课程的探讨

With the implementation of the basic discipline of "Top Talent Training Program" (the "East Ever Project"), more and more new reforms and attempts are being made in various universities. In the process of innovation and exploration, a new curriculum is being implemented, that is, the "the frontier aspects of disciplines" course. Through investigation and research, we found that many colleges and universities in China are carrying out or trying to carry out such courses, and the students who participated have different benefits. This paper mainly discusses the current situation of the development of the frontier courses of many universities in China, and gives suggestions based on the two courses of Tang Aoqing Honors Program in Science of chemistry in Jilin University. This paper provides reference for other colleges and universities to open such courses.     

化学专业拔尖学生实验教学体系的探索与实践

介绍了山东大学化学学科拔尖学生实验教学体系的探索与实践,在实验教学体系、教学内容、教学方法、师资建设四个方面总结了近十年来课程改革及实施成效,探索适应化学拔尖人才培养的实验课程体系和运行机制。     

厦门大学"化学学科拔尖学生培养试验计划"的探索与实践

全面介绍了厦门大学化学学科拔尖学生培养试验计划的探索与实施,包括:目标定位、生源遴选、导师配备、课程体系、科研训练、管理机制和实施成效等。     

"化学拔尖计划""强化实验"课程平台建设与实践

This paper mainly introduces the laboratory course platform "Enhanced Experiments in Basic Chemistry" of its basic framework, experimental content design, dynamic textbook construction and teaching practice, which is particularly designed for top talented chemistry-majored students in Xiamen University. In order to provide the reference experience for the reform of chemistry laboratory teaching in colleges and universities, and to provide reference for the implementation of "Top Talent Training Program of Chemistry" 2.0 in the future.     

“双一流”建设背景下化学拔尖班学生的国际化培养模式探索与实践

四川大学化学学院于2009年开始实施"化学拔尖学生培养试验计划",致力于培养化学领域领军人才。在化学学科入选教育部"双一流"学科建设的背景下,学院立足本专业特点、依托校院两级资源,从师资、课程、学生、办学等多方面构建拔尖学生国际化培养体系,做出了诸多尝试并取得了良好的成效。本文在对现有国际化建设策略讨论的基础上,进一步对加强拔尖学生全球胜任力进行思考、提出建议。     

中山大学化学"拔尖计划"人才培养探索

介绍了中山大学化学学院"基础学科拔尖学生培养试验计划"项目的开展情况,从培养目标、实施探索和实施成效三个方面对近年来中山大学化学学院拔尖学生人才培养模式进行了系统全面的总结,为今后"拔尖计划"的实施和改进提供了有益的借鉴。     

厦门大学"化学学科拔尖学生培养试验计划"学生科研能力培养的探索与思考

介绍了厦门大学化学拔尖学生培养试验计划学生科研训练开展情况,并结合问卷调查,通过数据对比分析,探索如何培养高层次创新人才的科研兴趣、素养和能力。