查看更多>>摘要：Though there are numerous intrinsic merits of metal-organic frameworks(MOFs),low charge separation efficiency has imposed heavy restrictions on their photo-catalytic application.Herein,in situ porphyrin ligand sub-stitution,as a strategy for improving the charge separation efficiency and increasing the amounts of active sites,has been designed and realized in a Hf-biphenyl dicarboxylic acid(BPDC)MOF.Specifically,a size and geometry matched meso-tetra(4-carboxyphenyl)porphyrin(TCPP)ligand was selected and doped into Hf-BPDC MOF by forming coordinating bonds with Hf centers,forming dual-ligand Hf-BPDC-TCPP MOF.The resultant Hf-BPDC-TCPP MOF showed significantly improved activity and chemical stability in the photocatalytic H2 generation(261 μmol·g-1·h-1)and tetracycline(TC)degradation reactions(95.8％),which was 48 and 1.47 folds higher than that of the Hf-BPDC MOF.Photophysical and electro-chemical studies revealed that the introduction of por-phyrin ligand could generate a stronger internal electric field for boosting the charge separation and transfer,increase the specific surface area for providing more active sites,and narrow the band gap to enhance the visible light absorption.This in situ ligand substitution method provides a promising approach to build a tunable platform for con-structing high-performance MOF photocatalysts.
查看更多>>摘要：The abused ciprofloxacin antibiotics have caused significant environmental damage.Although oxidative degradation of ciprofloxacin exhibits promising efficacy,it often entails excessive energy consumption.Hence,it is necessary to explore an effective and ecolog-ically sustainable degradation strategy.Herein,we demonstrated that g-C3N4 decorated with the coordinated CeO2 and Co3O4(CeO2-Co3O4/CN)exhibited effective ciprofloxacin photodegradation via in situ H2O2 production and activation mechanism.Results indicate that the intro-duced CeO2 enhances the transference of photogenerated electrons to O2 by adjusting the oxygen vacancy of pho-tocatalyst,thereby increasing the generation of superoxide radicals,which in turn generate H2O2,resulting in a 22.4-fold increase in H2O2 generation over g-C3N4.Moreover,the in situ H2O2 generation facilitated by CeO2 is con-firmed to be essential for ciprofloxacin degradation via CeO2-Co3O4/CN,as it provides enough oxidant for Co3O4 to activate into hydroxyl radicals for the pollutants degradation.Ultimately,CeO2-Co3O4/CN achieves a ciprofloxacin degradation ratio of 97.7％within 80 min.This study introduces a novel approach that combines H2O2 generation and activation,offering an innovative perspective for achieving clean and efficient purification of antibiotic-contaminated water.
查看更多>>摘要：Zeolite imidazole skeleton(ZIF-8)is a promising option for self-cleaning of building exterior walls due to its large specific surface area,high antibac-terial activity and low biotoxicity.However,it suffers from low antibacterial efficiency and yield under visible light irradiation.To address the issues,we developed the pho-tocatalytic materials T-ZIF-8-TDI(thermally treated-ZIF-8-toluene 2,4-diisocyanate)by modifying ZIF-8 with thermal oxygen sensitization and chemical bonding.The results show that the yield of T-ZIF-8-TDI photocatalytic antibacterial agent is increased to 11.5 times of that of T-ZIF-8,while maintaining the crystal structure of T-ZIF-8 and thermal stability up to 60 ℃.Furthermore,T-ZIF-8-TDI exhibits extended optical response range to the near-infrared region,significantly narrowed band gap,improved photogenerated electron-hole separation efficiency,reduced recombination rate,and excellent photocatalytic performance.When the concentration of antibacterial agent is 600 mg·L-1,the antibacterial rate of Escherichia coli(E.coli)reaches 99.99％irradiated by visible light for 30 min,and when the concentration of antibacterial agent is 200 mg·L-1,the antibacterial rate of Staphylococcus aureus(S.aureus)reaches 99.99％irradiated by visible light for 25 min.We also analyzed the reasons in detail from the aspects of bacterial species and antibacterial mechanism,and proposed the antibacterial mechanism of·O2-and h+as the main active species.These findings suggest that T-ZIF-8-TDI photocatalytic antibacterial agent has potential for use in self-cleaning of building exterior walls.
查看更多>>摘要：To address the challenge of achieving both high sensitivity and a high quality factor in quartz crystal microbalance(QCM)humidity sensors,a nanodiamond(ND)/Ti3C2 MXene composite-coated QCM humidity sensor was fabricated.The material characteristics of ND,Ti3C2 MXene,and ND/Ti3C2 MXene composite were analyzed by transmission electron microscopy(TEM)and Fourier trans-form infrared(FTIR)spectroscopy.The experimental results demonstrated that the hydrophilic ND nanoparticles coated on Ti3C2 MXene nanosheet prevented the self-stacking of Ti3C2 MXene and enhanced the sensitivity of Ti3C2 MXene-based QCM humidity sensor.Moreover,the high mechanical modulus of Ti3C2 MXene material helped ND/Ti3C2 MXene composite-coated QCM humidity sensor to achieve a high quality factor(＞20,000).ND/Ti3C2 MXene composite-coated QCM humidity sensor exhibited a sensitivity of 82.45 Hz/％RH,a humidity hysteresis of 1.1％RH,fast response/recovery times,acceptable repeatability,and good stability from 11.3％RH to 97.3％RH.The response mechanism of ND/Ti3C2 MXene composite-coated QCM humidity sensor was analyzed in combination with a bi-ex-ponential kinetic adsorption model.Finally,the potential application of ND/Ti3C2 MXene composite-coated QCM humidity sensor was demonstrated through its frequency response to wooden blocks with different moisture contents.
查看更多>>摘要：Meeting the continuous glucose monitoring requirements of individuals necessitates the research and development of sensors with high sensitivity and stability.In this study,a straightforward strategy was proposed for synthesizing ultra-thin oxygen-rich graphitized carbon nanosheets(denoted as GCS-O).These nanosheets are obtained by calcining a topologically two-dimensional indium-based coordination polymer.Subsequently,the growth of FeNi Prussian blue analogue(PBA)on GCS-O effectively introduces active sites and increases the nitro-gen content within the carbonaceous matrix.The resulting FeNi-PBA/GCS-O composite exhibits excellent glucose sensing performance with a broad linear range of 1 to 1300μmol·L-1.Meanwhile,it also achieves a high sensitivity of 2496 μA·mmol-1·L·cm-2,a limit of detection of 100 nmol·L-1(S/N=3),and commendable long-term dura-bility.The relatively simple synthesis process,exceptional sensitivity,and satisfactory electrochemical sensing per-formance of FeNi-PBA/GCS-O open up new directions for biosensor applications.
查看更多>>摘要：Based on the fact that it is challenging for the polymer flexible circuit substrates to meet the requirements of serving in high-temperature environments,this work proposed the idea of using printable ceramic fiber paper as a high-temperature flexible circuit substrate.A ceramic fiber paper with all ceramic components had been devel-oped via electrospinning,solving the problems of low strength and severe strength drop at high temperatures of traditional ceramic fiber paper.The tensile strength of the prepared ceramic fiber paper is 2.63 MPa,and the reliable service temperature is 1200 ℃.Its bulk density is about 1.5 times that of traditional ceramic fiber paper.It can be printed with patterns by commercial inkjet printers like ordinary printing paper and has excellent printability.The feasibility of ceramic fiber paper as a flexible circuit sub-strate was verified by constructing a simple circuit.When the fiber paper is significantly bent,the circuit still forms a complete path,which proves that it has a strong application potential for high-temperature flexible circuit substrate and is expected to promote the development of flexible elec-tronic devices serving at extreme high-temperature envi-ronments.
查看更多>>摘要：Stretchable electronics that monitor joint activity and treat diseases based on liquid metal could be used in the development of healthcare applications.Such devices can be seamlessly integrated with human skin.However,most high-precision microstructures and com-plex patterns are difficult to fabricate due to the limitations of conventional fabrication solutions,resulting in subopti-mal performance under practical conditions.Here,a liq-uid-metal stretchable system utilizing natural leaf veins was reported as microstructures,which was based on a biomimetic concept and utilized an all-solution process for the preparation of complex microstructures.The systems are ultra-high tensile(800％tensile strain),environmen-tally stable(20 days)and mechanically durable(300-cy-cle).The system can accurately recognize the wearer's finger bending level as well as simple gesture signals.At the same time,the system acts as a wearable heater,which can realize the fast heating behavior of heating up to 50 ℃ in 3 min under the human body-safe voltage(1.5 V).The tensile stability is demonstrated by the heterogeneous integration of lasers(405 nm)with the system intercon-nects for a stretchable and wearable light source.
查看更多>>摘要：Although inorganic pigments in common spec-tral tuning materials show good weatherability and heat resistance,the limited color choices,weak coloring power,poor dispersibility,and a possibility of toxicity limit their development.On the basis of organic pigments which possess a wide range of colors,high coloring power,good transparency,and high safety,herein,the modified pigment and biomimetic coating with improved weatherability,especially ultraviolet(UV)resistance(from 2 to 6 days),was achieved by intercalating acid green 25(AG25)pig-ment into Mg/Al-layered double hydroxides(Mg/Al-LDH).Furthermore,the heat resistance of AG25 was also signif-icantly increased.Moreover,the spectral stability of pig-ments after heat treatment is superior with almost unchanged spectral profile and green reflection peak.The formation of strong N-H bonds and the S-M(Mg,Al)bonds between Mg/Al-LDH laminates and AG25 molecules contributes to the improvement.This work shows potential for biomimetic leaf materials in respect of reflective spectra stability.
查看更多>>摘要：As a lot of electromagnetic pollution and interference issues have emerged,to overcome electro-magnetic interference,prevent electromagnetic hazards,and develop new high-performance electromagnetic wave(EMW)absorbers have become a significant task in the field of materials science.In this paper,a three-dimensional(3D)carbon nanofibers network with core-shell structure,embedded with varied molar ratios of iron and cobalt(4∶0,3∶1,2∶2,1∶3,0∶4),was effectively synthesized(Fe/Co@C-CNFs)via electrospinning.The phase,microstructure,magnetic and EMW absorption properties were studied.It is discovered that Fe/Co@C-CNFs doped with iron:cobalt=1∶1 have excellent EMW absorption capacity.When the matching thickness is 1.08 mm,the minimum reflection loss(RL)value is-18.66 dB,while the maxi-mum effective absorption bandwidth(EAB)reaches 4.2 GHz(13.9-18 GHz)at a thickness of 1.22 mm.This is owing to the absorbers'superior impedance matching and multiple reflections as well as the conductivity,dielectric,and magnetic losses of carbon nanofibers embedded with Fe-Co alloy particles.In addition,the radar cross section(RCS)of the absorbers has been calculated by CST Studio Suite,showing that the absorbing coating can effectively reduce the RCS at various angles,especially for Fe/Co@C-CNFs doped with iron:cobalt=1∶1.These findings not only provide new insights for the preparation of light-weight and high-performance electromagnetic wave absorbers,but also contribute to energy storage and conversion.
查看更多>>摘要：The Ⅳ-Ⅵ compound GeTe is considered as a promising alternative to the toxic PbTe for high-efficiency mid-temperature thermoelectric applications.However,pristine GeTe suffers from a high concentration of Ge vacancies,resulting in an excessively high hole concen-tration(＞1 × 1021 cm-3),which greatly limits its thermoelectric enhancement.To address this issue,CuBiTe2 alloying is introduced to increase the formation energy of Ge vacancies in GeTe,thereby inhibiting the high carrier concentration.The carrier scattering caused by the electronegativity difference between different elements is suppressed due to the similar electronegativity of Cu and Ge atoms.A relatively high hole mobility is obtained,which ultimately leads to a high power factor.Addition-ally,by introducing Se as an alloying element at the anionic site in GeTe,dense point defects with mass/strain-field fluctuations are induced.This contributes to the strengthening of phonon scattering,thereby reducing the lattice thermal conductivity from 1.44 W·m-1·K-1 for pristine GeTe to 0.28 W·m-1·K-1 for Ge0.95Cu0.05Bi0.05-Te0.9Se0.15 compound at 623 K.
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