共查询到20条相似文献,搜索用时 114 毫秒
1.
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. 相似文献
2.
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. 相似文献
3.
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. 相似文献
4.
Mengru Li Changfeng Chen Liping Xu Yushuai Jia Yan Liu Xin Liu 《Journal of Energy Chemistry》2021,(1)
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. 相似文献
5.
Lanxiang Feng Zhiwei Zhu Yan He Yuan Ji Xuewe He Lei Jing Mingbo Yang Wei Yang Yu Wang 《Journal of Energy Chemistry》2022,(2):565-573
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. 相似文献
6.
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. 相似文献
7.
CXN天然沸石的研究2: 吸附性质 总被引:3,自引:0,他引:3
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。 相似文献
8.
常温常湿条件下Au/MeO~x催化剂上CO氧化性能 总被引:12,自引:0,他引:12
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。 相似文献
9.
Zhixin Jin Bin-Bin Yu Min Liao Di Liu Jingwei Xiu Zheng Zhang Efrat Lifshitz Jiang Tang Haisheng Song Zhubing He 《Journal of Energy Chemistry》2021,(3)
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. 相似文献
10.
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 FexP particles.The ORR rate of the atomically dispersed Fe sites is three orders of magnitude higher than it of FexP 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. 相似文献
11.
12.
According to the latest requirements of engineering education professional certification of chemical engineering and technology specialty on organic chemistry laboratory, current situation and problems of organic chemistry laboratory in Jianghan University are discussed from the perspective of teaching mode, teaching content, teachers and students. This paper has explored the blended teaching mode combining the online teaching with the traditional teaching. This teaching mode is successfully applied to the course of organic chemistry laboratory. It has been proved that this teaching mode improved the teaching quality, enhanced the classroom efficiency, achieved the teaching objectives, as well as met the requirements in the engineering education professional certification. 相似文献
13.
14.
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。 相似文献
15.
有机化学实验是制药工程专业的一门必修课,旨在训练学生有机合成基本实验技能。本文以三苯甲醇的制备和重结晶实验为例,讲述了笔者在多年教学中获得的一点感悟和经验:1)将实验步骤分解成片断讲解可以使学生更好地理解和记忆实验过程和操作目的;2)重要的基本操作应反复练习,即"学习、复习、提高",通过三次重复练习来实现巩固和熟练掌握该操作的目的。 相似文献
16.
有机化学实验是化学、化工、制药及其他近化学类专业学生必修的一门基础实验课程,对增强学生动手能力、培育创新思维有不可替代的作用。本文以八个具体的实验为实例,介绍了随着时代变迁和人才培养规格的变化,有机化学实验课程建设、教学内容改革的情况,从早期简单的过程模仿、性质鉴定、基本操作实验,发展为现有的“基础规范性实验–综合设计性实验–研究探索性实验”三层次实验,并经实践检验行之有效,使实验教学形式更丰富、内容更充实、手段更新颖,更加有利于学生的多样化成才,教学质量和教师的教研水平得到极大提高。 相似文献
17.
18.
19.
有机化学涉及的有机反应类型繁多,反应机理复杂,理论性强,难以理解和掌握。而大学有机化学的教学模式基本以教师为中心,以课堂讲授为主,这在某种程度上束缚了学生的创造思维和积极性。融入科研的有机化学教学法的尝试,可以破解有机化学授课的困惑,调动了学生对有机化学的兴趣及精准掌握。科研渗透的教学可以拓宽学生知识视野,激发学习兴趣,实现理论联系科研、实际生产,能够加强学生对有机化学知识的掌握。 相似文献
20.
针对有机化学教学改革现状,利用现有网络教学资源及化学资料,将问题式教学法和翻转课堂教学理念融入传统教学方法中,构建了一种简易型混合式教学法,并应用于生物学专业拔尖学生试验班有机化学小班教学实践。结果表明,简易型混合式教学法能够培养学生学习兴趣,提高化学文献查阅、交流沟通、团队协作等综合能力,因而有助于提高有机化学的教学质量,促进拔尖人才的培养。 相似文献