Endowing metal-free graphitic carbon electrodes with high electrocatalytic reactivity is a field of intense research, but remains elusive. Here, we introduce a prototypical edge-plane-site-specific engineering strategy on “herringbone” multi-walled carbon nanotubes by performing an intercalation-exfoliation and truncation process in molten inorganic salts. Controllable synthesis of the target H-MWCNTs-MS with fully exposed edge-plane sites on both the outer surface and inner channels was demonstrated. in-situ infrared spectroscopic study supports the theoretically energetic “edge-state” and identifies the reconstructed ketone/carboxyl-terminated edge sites under oxygen evolution reaction (OER) conditions. These oxygenated edge-plane sites boost charge redistribution and interlayer coupling, which essentially govern the synergistic catalysis, as evidenced by combined theoretical, electrokinetic, and H/D isotopic studies. Benefiting from the dense reactive sites and efficient electron tunneling, the H-MWCNTs-MS demonstrated impressive OER activity with an overpotential of 236 mV at a current density of 10 mA cm−2 in alkaline media, outperforming most state-of-the-art metal-free electrocatalysts reported to date. Furthermore, the catalyst displayed no noticeable degradation during 100 h of operation, indicating its potential for practical applications.

Perovskite solar cells (PSCs) suffer from the presence of non-active and metastable species on the surface of solution-processed perovskite films, and their adverse effects on charge extraction and long-term stability cannot be fully addressed by conventional surface passivation strategies. In this study, a novel concept is proposed to achieve both precise removal of surface impurities and effective passivation of sub-surface defects in a single step, utilizing a functional polymer-based cleaning strategy. The moderate intermolecular force provided by the functional polymer and their inherent robust interchain interactions enable effective surface cleaning without disturbing the active crystal lattice. Following surface cleaning, the electron-donating groups (CO) in the polymer passivate the uncoordinated Pb2+ defects at the sub-surface level. This synergistic effect of surface cleaning and sub-surface defect passivation leads to a drastic reduction in interfacial non-radiative recombination, elimination of ion migration pathways, and prevention of triggers for photodegradation. As a result, the power conversion efficiency (PCE) significantly improved from 22.84% to 25.51%, accompanied by a remarkable enhancement in operational stability. Moreover, the operability and effectiveness of this approach make it highly suitable for scaling up perovskite solar modules in the future. A novel concept is proposed to achieve both precise removal of surface impurities and effective passivation of sub-surface defects in a single step, utilizing a functional polymer-based cleaning strategy. This synergistic effect has significantly boosted power conversion efficiency up to 25.51% by drastically reducing non-radiative recombination and improved operational stability by eliminating ion migration pathways. image

Eliminating surface defects and impurities on metal halide perovskite (MHP) films through chemical reactions represents a novel strategy to improve the performance of perovskite solar cells (PSCs), which can be referred to as "chemical polishing". This approach is anticipated to be more facile, precise, and distinct from the extensively documented surface passivation methods in terms of its underlying mechanism. However, to date, the underlying selective chemical reaction mechanism still requires in-depth study. In this context, we present a novel two-step chemical polishing method that eliminates surface impurities while simultaneously passivating the sub-surface. The core principle of this method involves two primary steps: (1) the creation of two-dimensional (2D) perovskite via selective reactions between polishing agents (n-octylammonium bromide, OABr) and undesired metastable amorphous species, as well as residual PbI2 nanocrystals present on the surface of MHP films. (2) Subsequently, the 2D perovskite and excess polishing agents are efficiently eliminated using a mixed solvent. Following the polishing process, the sub-surface, which is passivated by residual OABr, contains fewer defects and can establish improved electrical contact with the hole transport layer (HTL). As a result, the power conversion efficiency (PCE) of PSCs is enhanced from 21.7% to 23.6%. Moreover, the PSCs processed with chemical polishing exhibit enhanced long-term operational stability, with a capability to retain 80.2% of their original PCE value after 1500 h of illumination.

In response to the weak sense of professional mission and values among students caused by the insufficient integration of ideological and political elements with professional knowledge in chemistry experiment teaching,the Analytical Chemistry Experiment course organically incorporates ideological and political elements into the experimental content.It formulates the"Trinity"educational goals of integrating knowledge,skills,and qualities,establishes a"six-focus"ideological and political case library,implements the"seven-integration"curriculum ideological and political teaching measures,innovates the"five-interaction"ideological and political education design,and creates challenging classrooms with depth and warmth.It engages in dialogues with students on knowledge,thinking,and emotions.

This project introduces an enhanced approach to the experimental preparation of Sodium Ferric Ethylenediaminetetraacetate(NaFeEDTA)as an iron supplement.Bridging theoretical concepts with practical manufacturing,the experimental design is aligned with pharmaceutical production processes.It incorporates a comprehensive set of modules,ranging from experimental design and drug preparation to structural identification and purity analysis.The project transforms the experiment from a validation-based exercise to a holistic,design-oriented experiment.Students are guided to consider quality control,safety protocols,and environmental protection as part of their experimental design.This experimental framework accommodates multiple patent pathways,stimulating students'investigative interests and fostering skills in experimental design and critical thinking.It aims to enhance students'problem-solving capabilities,improve their scientific literacy,and boost their confidence in the field.

Electrochemical surface-enhanced Raman scattering (EC-SERS) spectroscopy is an ultrasensitive spectro-electrochemistry technique that provides mechanistic and dynamic information on electrochemical interfaces at the molecular level. However, the plasmon-mediated photocatalysis hinders the intrinsic electrochemical behavior of molecules at electrochemical interfaces. This work aimed to develop a facile method for constructing a reliable EC-SERS substrate that can be used to study the molecular dynamics at electrochemical interfaces. Herein, a novel Ag-WO3−x electrochromic heterostructure was synthesized for EC-SERS. Especially, the use of electrochromic WO3−x film suppresses the influence of hot-electrons-induced catalysis while offering a reliable SERS effect. Based on this finding, the real electrochemical behavior of p-aminothiophenol (PATP) on Ag nanoparticles (NPs) surface was revealed for the first time. We are confident that metal-semiconductor electrochromic heterostructures could be developed into reliable substrates for EC-SERS analysis. Furthermore, the results obtained in this work provide new insights not only into the chemical mechanism of SERS, but also into the hot-electron transfer mechanism in metal-semiconductor heterostructures.

Plasmonic nanostructures with hot spots are very efficient in generating energetic (hot) electrons to realize light-driven chemical reactions. This effect primarily originates from high electric fields with nonuniform distribution in the hot-spot area. However, charge-transfer (CT) at plasmonic nanostructure interfaces and its effect on hot-electron generation have not been explored in detail. Here, a series of semiconductor/metal interfaces, with continuously adjustable energy-band structures, were constructed by the assembly of CdxZn1-xS supports and Au nanoparticles (NPs) interconnected with p-aminothiophenol (PATP) molecules. The plasmon-mediated oxidation of PATP embedded in CdxZn1-xS/PATP/45 nm-Au NP molecular junctions was systematically investigated using gap-mode-liked surface-enhanced Raman spectroscopy (SERS). Combining in situ SERS studies with energy-level analysis, interfacial CT was found to be a primary determinant of hot-electron-induced oxygen activation on large Au NP surfaces. This study provides a new perspective on the hot-electron generation mechanism to facilitate the rational design of efficient plasmonic photocatalysts.

A simple and highly sensitive photoelectrochemical (PEC) immunoassay sensor was fabricated by using the two forms of polydopamine (PDA), the thin film and nanosphere, to serve as the photoelectrode-modified material and signal reporting label, respectively. The two forms of PDA show similar light absorption behavior but totally different PEC activities. The PDA film can extend the light absorption from the ultraviolet to near infrared light range, transfer a photoelectron to TiO2 nanoparticles and the underlying photoelectrode, and largely amplify the photocurrent response. However, the PDA nanospheres have insignificant photoelectron transport ability. When they are brought close to the PDA film and TiO2 nanocomposite-modified electrode via the sandwich immunoreaction, they function like a black hole to compete with the PDA film for light absorption, resist the access of the electron donor to regenerate the photoactive material, and capture the photoelectron generated from the PDA film. Besides, the heat generated from the PDA nanospheres also contributes to the photocurrent decrease. The PDA nanospheres with multiple quenching effects on the PDA film greatly decrease the photocurrent signal and lead to a highly sensitive PEC immunosensing strategy. Under optimal conditions, a wide linear range from 0.1 to 106 pg·mL-1 is obtained toward carcinoembryonic antigen, with a low limit of detection of 40 fg·mL-1. Besides, the PDA with excellent biosafety can be readily assembled with proteins, which thus simplifies the preparation procedures and decreases the costs. All these features indicate that the whole PDA-based PEC sensing strategy may have great application prospects for the point-of-care assay of various kinds of tumor markers.

在基础化学实验课程中以"统筹规划、共建共享"为原则,在实验教学过程中深入挖掘各实验课程和实验项目中蕴含的思政教育资源,凝练成涵盖"家国情怀""科学家/大国工匠""科技创新（理论/技术和方法创新）""安全环保""社会责任/职业素养""朋辈榜样"六大主题的化学实验课程思政案例库,并结合多形态呈现的"智能+教学"实验教学模式,多途径强化教师"育德"能力,充分发挥化学实验课程育人功能。

为了实施个性化、互动化、智慧化的分析化学实验教学,使学生学会学习、学会探究、学会创新,本研究对分析化学实验进行了智慧教学模式改革实践.通过智能化的教学模式提高了学生自主学习的效率和信息素养,激发了学生的学习内驱力,有效提高了课堂的热烈度、达成度和学生的参与度、专注度.

Sensitive detection of H2O2 in the nano- to micromolar range is critical for health monitoring and disease diagnosis. Two-dimensional transition metal carbides or/and nitrides (called MXenes, MXs) have excellent potential applications in the electrochemical field due to their outstanding electrical conductivity and catalytic properties. In this work, Ti3C2Tx (MX) was employed for the construction of a sensitive and enzyme-free electrochemical sensing interface for the detection of hydrogen peroxide (H2O2) through a simple and effective method. Prussian blue (PB) was electrochemically deposited on the surface of a glassy carbon electrode (GCE). Chitosan (CS) and MX were sequentially dripped onto the PB modified GCE surface. The reasonable fabrication of the MX/CS/PB/GCE sensing interface presented good electrochemical sensing performance towards H2O2 with a low limit of detection (4 nM), a wide linear range from 50 nM to 667 μM and good selectivity. The proposed MX/CS/PB/GCE has been proven to monitor H2O2 in food samples and biological samples with recoveries between 94.7% and 100.3%. This work has made a beneficial attempt and research for exploring and expanding the application of MXs in the field of electrochemical sensing.

This work demonstrates that the photoelectrochemical response of the CdS/Bi2O2.33 direct Z-scheme heterojunction, synthesized by in situ deposition of CdS nanocrystals on the defect engineered Bi2O2.33, can be modulated by oxygen defect concentration. The appropriate oxygen defects not only increase the visible light absorption, provide active reaction sites to enhance PEC activity, but also promote the separation of carriers. The formation of CdS/Bi2O2.33 direct Z-scheme heterojunction further improves these properties by extending the visible light absorption and promoting separation and transport of carriers, but avoids the usage of noble metal nanoparticles as electron transfer mediators, thus has a low cost and easy fabrication technology. The CdS/Bi2O2.33 direct Z-scheme junction shows significantly improved photocurrent response as compared with those containing less oxygen defects, and is applied as a photoelectrochemical assay platform for Hg2+. The specific interaction between Hg2+ and the S2- in CdS significantly quenches the photocurrent response of the CdS/Bi2O2.33 due to the formation of HgS. The photocurrent decrease is linear to the concentration of Hg2+ in the range from 10(-11) to 10(-6) g/mL, with the limit of detection of 3.2 pg/mL. High accuracy and good reproducibility are realized in the real sample analysis of urine, river water, and sea water. The integration of oxygen defect engineering and direct Z-scheme electron transport principle provides a new avenue for fabricating high performance photoelectrochemical materials, which can be further combined with bio-recognition strategy for the ultrasensitive detection of biological molecules.

A simple and easy-operation electrode modification strategy was proposed using Cu-MOF/GO nanohybrids for physiologists and pathologists for the feasible and reliable simultaneous electrochemical detections of DNA bases, namely guanine and adenine. The nanohybrids were prepared via a simple ultrasonic method and were employed for the fabrication of a sensing interface. SEM, TEM, XRD, FT-IR, and electrochemical characterizations were used to characterize the general morphology and structure of the nonohybrids. The proposed Cu-MOF/ERGO/GCE exhibited ultra-stable and high-sensitivity performance in the simultaneous electrochemical detection of guanine and adenine. The recorded DPV curves revealed a linear increase in the faradaic signals with increase in the concentrations of guanine and adenine in the range of 0.02-10 µM and 20-100 µM for guanine, and 0.005-20 µM and 40-200 µM for adenine. The relative standard deviation of guanine and adenine for 50 consecutive detections is 1.37% and 1.92%, respectively. It was proved that the proposed Cu-MOF/ERGO/GCE can be performed for the detection of guanine and adenine in real samples, such as Herring sperm DNA, and satisfactory results were obtained. This strategy does not require complicated modification procedures, professional modification techniques, or sophisticated instruments, but it can provide a highly sensitive and stable detection method, which is expected to expand and deepen the applications of electrochemical detection in life science research.

The simultaneous and sensitive detection of metabolites of DNA ( uric acid ( UA) , xanthine ( XA) and hypoxanthine ( HX) ) is of great significance for the early diagnosis and prevention of related diseases caused by abnormal metabolism. In this study , hydroxyl functionalized metal-organic framework ( OH-MOFs) and electrochemically reduced graphene oxide ( ERGO ) nano-functional interface was designed and constructed based on the synergic effect of Fe(III) terephthalate OH-MOFs ( OH-MIL-101 ( Fe ) and ERGO for simultaneous detection of UA, XA and HX in blood. Nano-composites were prepared by ultrasonic mixing method , and were characterized by X-ray diffraction ( XRD) , Fourier transform infrared ( FT-IR) and UV-Vis spectroscopic methods. By casting the surface of glassy carbon electrode ( GCE ) with the composite and electrochemical reduction of the modified electrode, OH-MOFs-ERGO/GCE was obtained. Under the optimum conditions , the oxidation peak currents of UA , XA and HX were linearly correlated to their concentrations in the ranges of 0. 20-1150 mu mol/L , 0. 15 -800 mu mol/L , and 0. 40-600 mu mol/L , respectively. The detection limits for UA , XA and HX were 0. 12 , 0. 10 and 0. 20 mu mol/L ( S/N= 3) , respectively. The recoveries of UA, XA and HX in real serum samples were between 99. 5% and 105. 8%. The proposed electrode was expected to provide a simple and easy detection method for the physiological and pathological study of purine metabolism.

This paper reports the covalent functionalization of graphene oxide (GO) by a presynthesized metal-organic framework NH2-MIL-101(Fe) via ultrasonication of the two components. The formation of Fe-O covalent bonding in the NH2-MIL-101(Fe)-GO nanohybrid is clearly evidenced, and the covalent bonding still remains after electrochemical reduction. The morphology and structure of the nanohybrid are characterized via scanning electron microscopy, transmission electron microscopy, UV-vis spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and Raman spectroscopy. The electrode based on electrochemically reduced NH2-MIL-101(Fe)-GO shows ultrastable and high-sensitive performance in simultaneous electrochemical sensing of three purine metabolic derivatives (uric acid, xanthine, and hypoxanthine); in particular, no signal fading is seen even after running for 120 times. The covalent bonding within the nanohybrid is obviously the key to maintain such a stability.

A ruthenium(II) bipyridyl derivative photoelectrochemical probe, Ru-1, is synthesized and coupled with TiO2 nanoparticles (Ru-1/TiO2) for the specific recognition and highly sensitive photoelectrochemical (PEC) detection of Hg2+ in a series of biofluids. The probe is designed with a chromophore, a thiocyanate recognition unit, a π-conjugated photoelectron-transfer pathway, and a phosphonate anchor. TiO2 nanoparticles with strong affinity to phosphonate and suitable conduction band energy are used as intermediate layers to increase the Ru-1 adsorption amount and amplify the photocurrent response. Under irradiation, the Ru-1/TiO2/fluorine-doped tin oxide (FTO), with strong visible light-harvesting capacity, aqueous stability, and efficient photoelectron transfer, shows a high and stable photocurrent response. In the presence of Hg2+, however, the specific Hg2+ and NCS coordination changes the photophysical properties of Ru-1, imposing the probe with a wider band gap, a weaker absorbance, and a poorer photoelectron and hole separation efficiency, thus resulting in a significant photocurrent decrease. On the basis of the Hg2+-induced photocurrent change, the Ru-1/TiO2/FTO shows good selectivity and high sensitivity toward the PEC detection of Hg2+, with wide linear ranges from 10-12 to 10-7 and 10-7 to 10-3 g/mL, and a low limit of detection of 0.63 pg/mL. The PEC probe is recyclable and accurate for selective detection of Hg2+ in urine, serum, and cell extracts. The whole analysis can be completed within 15 min. These good analytical performances indicate that the PEC method might have great potential for the onsite detection of small molecules in biosystems.

A facile label-free sensing method is developed for the one-step and highly sensitive fluorescent detection of DNA, which couples the specific C-C mismatch bonding and fluorescent quenching property of a trimethyl-substituted naphthyridine dye (ATMND) with the exonuclease III (Exo III) assisted cascade target recycling amplification strategy. In the absence of target DNA, the DNA hairpin probe with a C-C mismatch in the stem and more than 4 bases overhung at the 3' terminus could entrap and quench the fluorescence of ATMND and resist the digestion of Exo III, thus showing a low fluorescence background. In the presence of the target, however, the hybridization event between the two protruding segments and the target triggers the digestion reaction of Exo III, recycles the initial target, and simultaneously releases both the secondary target analogue and the ATMND caged in the stem. The released initial and secondary targets take part in another cycle of digestion, thus leading to the release of a huge amount of free ATMND for signal transducing. Based on the fluorescence recovery, the as-proposed label-free fluorescent sensing strategy shows very good analytical performances towards DNA detection, such as a wide linear range from 10pM to 1μM, a low limit of detection of 6pM, good selectivity, and a facile one-step operation at room temperature. Practical sample analysis in serum samples indicates the method has good precision and accuracy, which may thus have application potentials for point-of-care screening of DNA in complex clinical and environmental samples.

This study demonstrates a new strategy to develop in vivo electrochemical biosensors through rational design and simple formation of bioelectrochemically multifunctional film (BMF). The BMF is rationally designed by first efficiently incorporating oxidase, ferrocene mediator, and graphene oxide into polymaleimidostyrene/polystyrene (PMS/PS) matrix to form a homogeneous mixture and then simply formed by drop-coating the mixture onto solid conducting substrate. By using the as-formed BMF, electrochemical biosensors could be constructed with a technical simplicity and high reproducibility. To illustrate the BMF-based biosensors for in vivo applications, we directly couple the biosensors to in vivo microdialysis to establish an online electrochemical system (OECS) for in vivo monitoring of glucose in rat auditory cortex during salicylate-induced tinnitus model. The OECS with the BMF-based biosensor as the detector shows a linear response toward glucose within a concentration range from 50 to 500 μM with a detection limit of 10 μM (S/N = 3). Additionally, the OECS is stable and does not suffer from the interference from the electroactive species endogenously coexisting in the brain microdialysate. With the BMF-based OECS, the basal level of glucose in the microdialysate continuously sampled from rat auditory cortex is determined to be 120 ± 10 μM (n = 5). After the rats were administrated with salicylate to induce transient tinnitus, the microdialysate glucose concentration in the rat auditory cortex remarkably increased to 433 ± 190 μM (n = 5) at the time point of 1.5 h. This study essentially offers a new, technically simple and reproducible approach to development of in vivo electrochemical biosensors, which is envisaged to be relatively useful for understanding of the molecular basis of brain functions.

A label-free ratiometric fluorescence aptasensor has been developed for the rapid and sensitive detection of cocaine in complex biofluids. The fluorescent aptasensor is composed of a non-labeled GC-38 cocaine aptamer which serves as a basic sensing unit and two fluorophores, 2-amino-5,6,7-trimethyl-1,8-naphthyridine (ATMND) and SYBR Green I (SGI) which serves as a signal reporter and a build-in reference, respectively. The detection principle is based on a specific cocaine mediated ATMND displacement reaction and the corresponding change in the fluorescence ratio of ATMND to SGI. Due to the high affinity of the non-labeled aptamer, the good precision originated from the ratiometric method, and the good fluorescence quantum yield of the fluorophore, the aptasensor shows good analytical performance with respect to cocaine detection. Under optimal conditions, the aptasensor shows a linear range of 0.10-10μM and a low limit of detection of 56nM, with a fast response of 20s. The low limit of detection is comparable to most of the fluorescent aptasensors with signal amplification strategies and much lower than all of the unamplified cocaine aptasensors. Practical sample analysis in a series of complex biofluids, including urine, saliva and serum, also indicates the good precision, stability, and high sensitivity of the aptasensor, which may have great potential for the point-of-care screening of cocaine in complex biofluids.