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.     

等浓度的氯化铵和硫酸铵溶液哪个pH高

有中学化学参考资料题:0.10 mol/L的NH4Cl和(NH4)2SO4溶液哪个pH值高?这似乎是个中学生可做的简单题目,仔细考虑不是如此.如果简单地认为盐酸和硫酸都是强酸,而硫酸是二元酸,硫酸铵溶液中铵盐浓度为0.20 mol/L,那么NH4Cl溶液pH高,那是不妥的.硫酸是二元酸,第一个氢离子能完全电离,第二个氢离子部分电离,如此考虑情况怎么样呢?是不是答案发生变化?这要通过计算来说明.     

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。     

Enhanced efficiency and stability in Sn-based perovskite solar cells with secondary crystallization growth

The conversion efficiencies reported for Tin(Sn)halide-based perovskite solar cells(PSCs)fall a large gap behind those of lead halide-based PSCs,mainly because of poor film quality of the former.Here we report an efficient strategy based on a simple secondary crystallization growth(SCG)technique to improve film quality for tin halide-based PSCs by applying a series of functional amine chlorides on the perovskite surface.They were discovered to enhance the film crystallinity and suppress the oxidation of Sn²⁺remarkably,hence reduce trap state density and non-irradiative recombination in the absorber films.Furthermore,the SCG film holds the band levels matching better with carrier transport layers and herein favoring charge extraction at the device interfaces.Consequently,a champion device efficiency of 8.07% was achieved alo ng with significant enhancements in VOC and JSC,in contrast to 5.35% of the control device value.Moreover,the SCG film-based devices also exhibit superior stability comparing with the control one.This work explicitly paves a novel and general strategy for developing high performance lead-free PSCs.     

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.     

课程专业相映衬赋予教学生命力——当无机化学遇上能源化学工程专业

This paper introduces the exploration of inorganic chemistry course teaching based on the energy chemical engineering major. The sense of professional mission of students is inspired, the sense of responsibility for curriculum learning is strengthened, and the curriculum knowledge is integrated into the professional connotation. The teaching of inorganic chemistry course is full of vitality due to some teaching methods including mutual inquiry, case discussion, expanding extracurricular knowledge and communication and online learning. Thus, the learning capability and professionalism of the students are improved.     

形象化教学方法在药学专业化学类课程中的应用

In view of the complex knowledge points and some abstract theories of pharmaceutical chemistry courses, the application of visualized teaching methods to present important knowledge points in a vivid way can enhance the teaching effect and stimulate students' interest in learning. Based on the authors' teaching and research work, this article summarizes the application of figurative teaching methods such as metaphor and analogy in inorganic chemistry and medicinal chemistry courses.     

专业学习共同体对化学全日制教育硕士课堂教学的影响

收集3位化学全日制教育硕士在中学实践过程中文本、视频等资料,采用个案研究、文本分析、课堂观察的质化方法,利用化学课堂教学系统构造模型对专业学习共同体多元成员的干预以及实践过程中化学全日制教育硕士的课堂教学进行分析和比较。结果表明:化学全日制教育硕士的课堂教学在专业学习共同体的干预下,发生了显著的变化,构造模型中的各个教学要素均有不同程度的提升,专业学习共同体中不同成员对全日制教育硕士教学的干预内容、作用效果、影响程度有所差异,并在此基础上建立教学变化模型。多元成员的专业学习共同体可以促进全日制教育硕士的教学发展,为教育硕士的培养改革提供了一种可供参考的实践干预范式。     

在《高分子化学》课程中开展互动式教学的实践与探索

通过在"高分子化学"课程中开展师生互动式教学,探讨了运用互联网网站、网上论坛和学生上讲台作学术报告等方式对提高学生学习积极性、促进专业课程教学改革、提高教学质量的作用.介绍了所采用的具体做法,并就互动式教学的开展总结了个人的体会.     

"课程思政"背景下有机化学教学模式探索

有机化学是化学化工及相关专业的重要基础课程,复杂的反应与深奥的理论使其成为理工科院校中较难掌握的课程之一。在当今高校青年学生成长的时代特征与大的社会背景下,只重视专业讲授、轻思想教育的课堂模式,已经跟不上时代的要求。理工科专业课程教师在教授专业内容的同时,把思想引领与价值观塑造融入专业教学中,将教学与育才有机地融合,能极大提升课堂教学效果与质量,有利于培养素质过硬的专业人才。本文从化学史与化学热点问题分析两个角度,阐述了开展有机化学课程思政的具体方法举措,并对实际效果进行了研究分析。     

建构主义知识论在《高分子流变学》课程教学中的运用

随着国家对应用型和创新型人才的需求不断增加,大学教育特别是研究生的人才培养模式势必也要做出相应的调整,而教学方法改革是人才培养模式改革的重要环节。课程的学习很大程度上影响着学生的科研能力,如何通过专业课程的教学培养学生扎实的专业理论基础与一定的实践能力,显得非常重要。本文旨在以《高分子流变学》课程为例,将建构主义知识论与课程教学实践相结合,以学生的学习为本,对具体教学方法进行改革,摸索抛锚式教学模式在教学中的应用。     

基于“1+2”模式的结构化学课程在线教学实践

Since the outbreak of novel coronavirus pneumonia (NCP) at the beginning of this year, Chinese government acted immediately and made some regulations to control the epidemic NCP and promote the recovery of society and industry including education. Chinese universities stayed on the online courses without suspension on teaching and learning. Herein, we report online teaching of structural chemistry course based on the teaching mode of online live broadcast platform, online course resources and management platforms ("1 + 2" mode). This may promote online teaching, and take advantage of online live broadcast and massive open online courses, which achieves good teaching and learning experiences on structural chemistry course.     

高分子化学理论课与实验课的融合教学模式探索*

以“乙酸乙烯酯的乳液聚合”理论课和实验课为例,探索了将高分子化学理论和实验课程进行融合的创新教学模式。将理论教学和实验教学进行互动和融合的整体安排,克服了传统教学中理论课和实验课相互分离、缺乏相互支撑的缺点。在融合教学模式中,理论课和实验课实行团队协同教学;在同一个实验中设置必修内容和扩展性内容,更好地培养学有余力的学生;将理论课和实验课进行综合考核;对比了实验课前置、实验课居中和实验课后置教学方式,其中实验课居中的融合教学适合于大部分学生,有助于提高学生学习质量。     

新工科背景下通识教育类课程的教学模式探索*——以材料导论课程为例

通识教育类课程是新工科背景下推进大类招生与专业分流的重要组成部分。针对高校通识教育类课程教学过程中存在的弊端,从课程定位、教学方式、资源配置和评价体系等4个方面进行统筹规划、整体推进,以最大程度地提升学生的学习效果和人才的培养质量,旨为通识教育类课程的教学改革提供一定的参考。     

基于“超星泛雅平台+学习通”快速完善课程的技巧和实践

Due to COVID-19, all the universities in China has postponed their spring semester. The Ministry of Education issued a call "suspending classes without stopping learning" to require universities to carry out online teaching actively. Up to now, Online teaching has been implemented for nearly eight weeks, and teachers are familiar with online teaching methods. Then, how to hold online courses efficiently and refine course resources have become the main tasks for teachers. This paper elaborates on the practice and skills of rapid improvement of online course and interactive teaching based on "Chaoxing fanya platform and Xuexitong". Using these skills can not only reduce the workload of teachers, but also build high-quality online courses to ensure teaching quality and objectives. This paper could provide a reference for college teachers to implement online teaching efficiently.