Using environment-friendly and low-cost biowaste adsorbents as toxic metal ion removal substrates from aqueous solutions has a great economic advantage. This work evaluated pumpkin and potato peel biowastes for the ad...Using environment-friendly and low-cost biowaste adsorbents as toxic metal ion removal substrates from aqueous solutions has a great economic advantage. This work evaluated pumpkin and potato peel biowastes for the adsorption of cadmium ions. The biowastes were treated with acid or base. Batch experiments were carried out by introducing a known concentration of metal ion solution into the biowaste sorbent at various pH levels. The pH and metal ion concentration was monitored with pH and cadmium ion-selective electrode continuously for two hours, and the final concentration for the metal ion after 24 hours was measured with the cadmium electrode and then confirmed with ICP-OES. L-type isotherms were obtained that fit to Freundlich model. Adsorption isotherms showed chemical adsorption and the kinetics following the second order model. Equilibrium adsorption capacity is higher than 29 mg/g at pH 5.6 when the initial concentration is 220 ppm. Dynamic cadmium adsorption capacity is 17 mg/g from aqueous solution when the feed solution is 220 ppm with pumpkin peel biowaste sorbent. The biowaste materials can be regenerated with acid washing.展开更多
CeO2 nanoparticles with an average diameter of about 30 nm were prepared by sot-gel method at lower temperature. The gel, transformed from the aqueous solution of metal nitrate and citric acid, can be combusted com- p...CeO2 nanoparticles with an average diameter of about 30 nm were prepared by sot-gel method at lower temperature. The gel, transformed from the aqueous solution of metal nitrate and citric acid, can be combusted com- pletely at lower temperature. The redox behavior and the crystallization process of the dried gel were studied by thermogravimetric analysis and infrared spectroscopy. The synthesized powders were characterized by X-ray powder diffraction and transmission electron microscopy. In addition, rare earth elements ion-selective electrodes based on acetyl cellulose were prepared using ultra fine cerium oxide powders.展开更多
Enzyme was immobilized on an ammonium ion-selective electrode by different methods.An ion-selective electrode is not completely ion-specific,and interfering ions react with the ion-selective electrode membrane,alterin...Enzyme was immobilized on an ammonium ion-selective electrode by different methods.An ion-selective electrode is not completely ion-specific,and interfering ions react with the ion-selective electrode membrane,altering the measured potential.Therefore,the characteristics of the effect of other ions on ammonium ion-selective electrode-based urea biosensors are considered.Based on the experimental results,the urea biosensor based on entrapment had a high response voltage of around 189 mV and fast response time of around 16 sec.Moreover,selectivity of the urea biosensor in different interfering ions was considered to elucidate the characteristics of ammonium ion-selective electrode-based biosensors.展开更多
Three new "tailed" porphyrins and their corresponding Mn(Ⅲ) metalloporphyrins were synthesized and characterized. The potentiometric response characteristics of the PVC membrane electrode based on the Mn(Ⅲ...Three new "tailed" porphyrins and their corresponding Mn(Ⅲ) metalloporphyrins were synthesized and characterized. The potentiometric response characteristics of the PVC membrane electrode based on the Mn(Ⅲ) complexes of the three new "tailed" porphyrins toward SCN- have been studied.展开更多
A new ion-selective pH electrode of PVC membrane used formeasuring pH of the upper digestive tract is reported in this paper, which wasprepared with tri-n-octylamine or tris-(2-ehtylhexy)amine sensitive materials,and ...A new ion-selective pH electrode of PVC membrane used formeasuring pH of the upper digestive tract is reported in this paper, which wasprepared with tri-n-octylamine or tris-(2-ehtylhexy)amine sensitive materials,and polyvinylchloride (PVC) as a base. It was shown that the electrode has widelinearity (0.5-8, 3-12), good reproducibility, proper responsible time (【30s),longer life span (15 days). And the measurement was carried out in 50 cases bythe electrode.展开更多
An empirical solution to abnormal potential responses, showing peaks of emf, of commercial Cu2+- and Cd2+-selective electrodes with solid-state membranes was proposed for aqueous solutions of CuCl2 and CdI2. The two-s...An empirical solution to abnormal potential responses, showing peaks of emf, of commercial Cu2+- and Cd2+-selective electrodes with solid-state membranes was proposed for aqueous solutions of CuCl2 and CdI2. The two-step processes of Mn+ + Yn? (s: solid phase) MY(s) and MY(s) + 2X? X2MY2?(s) (n = 1, 2) at a test solution/electrode-interface were considered as a model. Here, Mn+, Yn?, and X? refer to a divalent or univalent cation, functional groups of electrode materials, and a halide ion (X? = Cl?, Br?, I?), respectively. By applying electrochemical potentials to these processes at n = 2, we derived an equation. Regression analyses based on the equation reproduced well the plots of emf versus log 2(*[M]t) for the Cd(II) and Cu(II) systems: *[M]t denotes a total concentration of species relevant to M2+ in a bulk of the aqueous solution. Also, we obtained log Ks(CdBr2) = 4.28 ? 0.22, log Ks(CdI2) = 6.98 ? 0.05, log Ks(CuCl2) = 3.96 ? 0.09, and log Ks(CuBr2) = 11.4 at 25?C. The magnitude in ?log Ks reflected that in the logarithmic solubility product, log {*[M2+](*[X?])2}, for bulk water, where *[M2+] or *[X?] denotes a molar concentration of the bulk solu-tion of M2+ or X? at equilibrium, respectively. Moreover, a mixture of CuSO4 with NaCl at the molar ratio of 1:1 yielded a plot similar to that of CuCl2.展开更多
Robust and easy-to-handle solid-contact ion-selective electrodes (SC-ISEs) based on graphite paste have been developed for the potentiometric detection of NO-3 and NH+4 in environmental samples. Polypyrrole (PPy) has ...Robust and easy-to-handle solid-contact ion-selective electrodes (SC-ISEs) based on graphite paste have been developed for the potentiometric detection of NO-3 and NH+4 in environmental samples. Polypyrrole (PPy) has been used as intermediate layer and solid contact between the electron-conducting graphite paste substrate and the ion-conducting polyvinylchloride (PVC)-containing membrane with the immobilized ionophore. For the nitrate- and ammonium-selective electrodes, tridodecylmethylammonium nitrate (TDMA-NO3) and nonactin have been used as ion-complexing compounds, respectively. Both ISEs show nearly Nernstian response in the linear range from 10-5 mol/L to 10-1 mol/L with average slopes of >58 mV/decade. The ISEs possess short response times (<20 s).展开更多
A K^+-selective electrode and a Na^+-selective electrode were used to construct a measuring cell without liquid-junction for the determination of the ion activity ratio of K^+ to Na^+ in soil suspensions.The measured...A K^+-selective electrode and a Na^+-selective electrode were used to construct a measuring cell without liquid-junction for the determination of the ion activity ratio of K^+ to Na^+ in soil suspensions.The measured cell potential was not affected by the total electrolyte concentration when the total cation concentration was 10^-1-10^-3 mol L^-1 and the concentration ratio Ck+/CNa+ was 10:1 to 1:50.When the concentration ratios were equal to 1 and the total electrolyte concentrations were 10^-2 and 10^-3 mol L^-1,the ion activity ratio measurenent would not be affected by pH in the pH range of 3.5 to 11.5 and 4.4 to 11 respectively.Ions other than H^+ have no remarkable influence on the measurement.The ion activity ratio of K^+ to Na^+ measured directly in soil suspension agree well with those in centrifuged supernant solution.The relative deviation was within 4%.From the measured ion activity ratio,the difference of the bonding energies of K^+ and Na^+ ions was calculated.展开更多
A PVC membrane enoxacin ion-selective electrode based on a needle-shaped inner reference electrode was prepared. A Ag/AgCl wire was used as the substrate of this electrode. It was previously coated with a thin sheet o...A PVC membrane enoxacin ion-selective electrode based on a needle-shaped inner reference electrode was prepared. A Ag/AgCl wire was used as the substrate of this electrode. It was previously coated with a thin sheet of urea-formaldehyde resin containing Cl - ions to form a needle-shaped inner reference electrode, then the inner reference electrode was coated with a thin sheet of a PVC membrane containing an enoxacin tetraphenylborate ion-pair complex. The influences of various ion-pair complexes, concentrations of the active components in the membrane and the plasticizers on the performance of the electrode were studied by orthogonal design. The linear response range of the electrode was 7.9×10 -5 -1.0×10 -2 mol/L. The detection limit was 2.0×10 -5 mol/L. The slope was 30.4 mV/decade(25 ℃). The electrode can be used for the potentiometric determination of enoxacin tablets directly. The average recovery was 100.4%, and the RSD was 0.9%. The results agreed with those determined by the method in Chinese Pharmacopoeia.展开更多
The authors developed a nitrate ion-selective electrode(ISE) based on poly(vinyl chloride)(PVC) membrane with methyltrioctylammonium nitrate as a carrier and 1-decanol as a plasticizer.The performance of the nitrate-s...The authors developed a nitrate ion-selective electrode(ISE) based on poly(vinyl chloride)(PVC) membrane with methyltrioctylammonium nitrate as a carrier and 1-decanol as a plasticizer.The performance of the nitrate-sensitive membranes was optimized by tuning the composition of components.The electrode exhibits a linear response with a Nernstian slope of(52±1.0) mV per decade for the nitrate ion concentration ranging from 5.8×10-5 mol/L to 1.0 mol/L.The electrode can be used to detect a low concentration of nitrate ions down to 3×10-5 mol/L in a pH range of 2.1―11.5 without any compensation.The advantage of the electrode includes simple preparation,short response time and good repeatability.The detection performance of the novel electrode on nitrate ions has been tested for water samples.展开更多
The analytical performance of H+-selective solid-contact ion-selective electrodes(SCISEs)based on solid contact polyaniline doped with chloride(PANI(Cl))and poly(3,4-ethylenedioxythiophene)doped with poly(styrene sulf...The analytical performance of H+-selective solid-contact ion-selective electrodes(SCISEs)based on solid contact polyaniline doped with chloride(PANI(Cl))and poly(3,4-ethylenedioxythiophene)doped with poly(styrene sulfonate)(PEDOT(PSS))was characterized by a developed coulometric signal transduction method.PEDOT(PSS)solid contact is covered by PVC based H+-selective membrane.The obtained coulometric signal demonstrates that the cumulated charge can be amplified by increasing the capacitance of solid contact.SCISEs covered with spin-coated membrane behave faster amperometric response than electrodes with drop-cast mem-brane.In contrast to earlier works,the amperometric response and impedance spectrum demonstrates H+transfer through SCISEs is independent from the thickness of membrane.The exceptional behavior of PANI(Cl)H+-SCISEs shows that the capacitance estimated from impedance spectrum at low frequency 10 mHz and coulometric signal of PANI(Cl)based SCISEs is influenced by the applied po-tentials,whereas PEDOT(PSS)solid contact is independent from the chosen applied potentials.Furthermore,preliminary investiga-tions of coulometric signal transduction on flexible pH sensor implies its potential applications in wearable sensors for sweat ion concentration detection.展开更多
Ion-selective electrode(ISE)is a quick and low-cost method of soil nitrate nitrogen(N)detection.The measurement models of soil nitrate-N based on ISEs includes the linear regression model,multiple linear regression mo...Ion-selective electrode(ISE)is a quick and low-cost method of soil nitrate nitrogen(N)detection.The measurement models of soil nitrate-N based on ISEs includes the linear regression model,multiple linear regression model and BP neural network model,and so on.Three models were analyzed in theory,measurement experiments of validation samples and soil nitrate-N concentrations were carried out in this study,and the measurement accuracies of the three models were compared.The results showed that,in the measurement experiments of validation samples and soil nitrate-N concentrations,BP neural network model had the highest accuracy(the average relative errors between results of the BP neural network model and the reference values were 5.07%and 8.81%,respectively)among the three models,multiple linear regression model had the second highest accuracy(the average relative errors between results of the multiple linear regression model and the reference values were 7.70%and 10.51%,respectively),linear regression model couldn’t exclude the interference of chloride ions so that it had the lowest accuracy(the average relative errors between results of the linear regression model and the reference values were 11.16%and 12.28%,respectively)among the three models.The BP neural network model can effectively restrain the interference of chloride ions,and it has a high accuracy for the measurement of soil nitrate-N concentration,so that the BP neural network model can be used to measure soil nitrate-N concentration accurately.展开更多
Damage to the spinal cord disrupts the electrically active nerve cells which normally transmit afferent and efferent signals,resulting in loss of motor,sensory,and autonomic functions.Potential treatments for spinal c...Damage to the spinal cord disrupts the electrically active nerve cells which normally transmit afferent and efferent signals,resulting in loss of motor,sensory,and autonomic functions.Potential treatments for spinal cord injury utilizing implanted spinal electrodes can be broadly classified into three different categories.The first of these approaches is“spinal stimulation”where electrodes,usually positioned above the level of injury,provide electrical stimulation to target and disrupt pain signals before they reach the brain.The second approach uses“activity-dependent neuro-technologies”,in which electrodes positioned below the level of injury initiate a complex spatiotemporal pattern of stimulation at the lumbar spinal cord to generate a walking gait in the limbs(Minev et al.,2015;Wagner et al.,2018).展开更多
Black phosphorus with a superior theoretical capacity(2596 mAh g^(-1))and high conductivity is regarded as one of the powerful candidates for lithium-ion battery(LIB)anode materials,whereas the severe volume expansion...Black phosphorus with a superior theoretical capacity(2596 mAh g^(-1))and high conductivity is regarded as one of the powerful candidates for lithium-ion battery(LIB)anode materials,whereas the severe volume expansion and sluggish kinetics still impede its applications in LIBs.By contrast,the exfoliated two-dimensional phosphorene owns negligible volume variation,and its intrinsic piezoelectricity is considered to be beneficial to the Li-ion transfer kinetics,while its positive influence has not been discussed yet.Herein,a phosphorene/MXene heterostructure-textured nanopiezocomposite is proposed with even phosphorene distribution and enhanced piezo-electrochemical coupling as an applicable free-standing asymmetric membrane electrode beyond the skin effect for enhanced Li-ion storage.The experimental and simulation analysis reveals that the embedded phosphorene nanosheets not only provide abundant active sites for Li-ions,but also endow the nanocomposite with favorable piezoelectricity,thus promoting the Li-ion transfer kinetics by generating the piezoelectric field serving as an extra accelerator.By waltzing with the MXene framework,the optimized electrode exhibits enhanced kinetics and stability,achieving stable cycling performances for 1,000 cycles at 2 A g^(-1),and delivering a high reversible capacity of 524 m Ah g^(-1)at-20℃,indicating the positive influence of the structural merits of self-assembled nanopiezocomposites on promoting stability and kinetics.展开更多
Sluggish storage kinetics is considered as the main bottleneck of cathode materials for fast-charging aqueous zinc-ion batteries(AZIBs).In this report,we propose a novel in-situ self-etching strategy to unlock the Pal...Sluggish storage kinetics is considered as the main bottleneck of cathode materials for fast-charging aqueous zinc-ion batteries(AZIBs).In this report,we propose a novel in-situ self-etching strategy to unlock the Palm tree-like vanadium oxide/carbon nanofiber membrane(P-VO/C)as a robust freestanding electrode.Comprehensive investigations including the finite element simulation,in-situ X-ray diffraction,and in-situ electrochemical impedance spectroscopy disclosed it an electrochemically induced phase transformation mechanism from VO to layered Zn_(x)V_(2)O_5·nH_(2)O,as well as superior storage kinetics with ultrahigh pseudocapacitive contribution.As demonstrated,such electrode can remain a specific capacity of 285 mA h g^(-1)after 100 cycles at 1 A g^(-1),144.4 mA h g^(-1)after 1500 cycles at 30 A g^(-1),and even 97 mA h g^(-1)after 3000 cycles at 60 A g^(-1),respectively.Unexpectedly,an impressive power density of 78.9 kW kg^(-1)at the super-high current density of 100 A g^(-1)also can be achieved.Such design concept of in-situ self-etching free-standing electrode can provide a brand-new insight into extending the pseudocapacitive storage limit,so as to promote the development of high-power energy storage devices including but not limited to AZIBs.展开更多
Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stab...Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial application.Herein,aflexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is pro-posed.The porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and NaHCO3.Due to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aflat pressure sensor without a porous MNA structure.Finite-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the sen-sor.In addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode structure.Most importantly,it was found that the sensor could accurately monitor the motion of afinger,wrist joint,arm,face,abdomen,eye,and Adam’s apple.Furthermore,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s apple.Finally,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×tion.Compared to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.展开更多
The electrochemical CO_(2) reduction reaction(CO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped c...The electrochemical CO_(2) reduction reaction(CO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(Cu-N-C) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient CO_(2)RR. The electrocatalytic performance of Cu-N-C materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for CO_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized Cu-NC catalysts are found to be active and highly CO selective at low overpotentials(from -0.6 to -0.8 V vs.RHE) in 0.1 M KHCO_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing Cu-N_(4) moieties exhibits a CO_(2)-to-CO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/CO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from CO_(2)RR.展开更多
Thick electrodes can increase incorporation of active electrode materials by diminishing the proportion of inactive constituents,improving the overall energy density of batteries.However,thick electrodes fabricated us...Thick electrodes can increase incorporation of active electrode materials by diminishing the proportion of inactive constituents,improving the overall energy density of batteries.However,thick electrodes fabricated using the conventional slurry casting approach frequently exhibit an exacerbated accumulation of carbon additives and binders on their surfaces,invariably leading to compromised electrochemical properties.In this study,we introduce a designed conductive agent/binder composite synthesized from carbon nanotube and polytetrafluoroethylene.This agent/binder composite facilitates production of dry-process-prepared ultra-thick electrodes endowed with a three-dimensional and uniformly distributed percolative architecture,ensuring superior electronic conductivity and remarkable mechanical resilience.Using this approach,ultra-thick LiCoO_(2)(LCO) electrodes demonstrated superior cycling performance and rate capabilities,registering an impressive loading capacity of up to 101.4 mg/cm^(2),signifying a 242% increase in battery energy density.In another analytical endeavor,time-of-flight secondary ion mass spectroscopy was used to clarify the distribution of cathode electrolyte interphase(CEI) in cycled LCO electrodes.The results provide unprecedented evidence explaining the intricate correlation between CEI generation and carbon distribution,highlighting the intrinsic advantages of the proposed dry-process approach in fine-tu ning the CEI,with excellent cycling performance in batteries equipped with ultra-thick electrodes.展开更多
Smart wearable devices are regarded to be the next prevailing technology product after smartphones and smart homes,and thus there has recently been rapid development in flexible electronic energy storage devices.Among...Smart wearable devices are regarded to be the next prevailing technology product after smartphones and smart homes,and thus there has recently been rapid development in flexible electronic energy storage devices.Among them,flexible solid-state zinc-air batteries have received widespread attention because of their high energy density,good safety,and stability.Efficient bifunctional oxygen electrocatalysts are the primary consideration in the development of flexible solid-state zinc-air batteries,and self-supported air cathodes are strong candidates because of their advantages including simplified fabrication process,reduced interfacial resistance,accelerated electron transfer,and good flexibility.This review outlines the research progress in the design and construction of nanoarray bifunctional oxygen electrocatalysts.Starting from the configuration and basic principles of zinc-air batteries and the strategies for the design of bifunctional oxygen electrocatalysts,a detailed discussion of self-supported air cathodes on carbon and metal substrates and their uses in flexible zinc-air batteries will follow.Finally,the challenges and opportunities in the development of flexible zinc-air batteries will be discussed.展开更多
The unique characteristics of nanofibers in rational electrode design enable effec-tive utilization and maximizing material properties for achieving highly efficient and sustainable CO_(2) reduction reactions( CO_(2)R...The unique characteristics of nanofibers in rational electrode design enable effec-tive utilization and maximizing material properties for achieving highly efficient and sustainable CO_(2) reduction reactions( CO_(2)RRs)in solid oxide elec-trolysis cells(SOECs).However,practical appli-cation of nanofiber-based electrodes faces chal-lenges in establishing sufficient interfacial contact and adhesion with the dense electrolyte.To tackle this challenge,a novel hybrid nanofiber electrode,La_(0.6)Sr_(0.4)Co_(0.15)Fe_(0.8)Pd_(0.05)O_(3-δ)(H-LSCFP),is developed by strategically incorporating low aspect ratio crushed LSCFP nanofibers into the excess porous interspace of a high aspect ratio LSCFP nanofiber framework synthesized via electrospinning technique.After consecutive treatment in 100% H_(2) and CO_(2) at 700°C,LSCFP nanofibers form a perovskite phase with in situ exsolved Co metal nanocatalysts and a high concentration of oxygen species on the surface,enhancing CO_(2) adsorption.The SOEC with the H-LSCFP electrode yielded an outstanding current density of 2.2 A cm^(-2) in CO_(2) at 800°C and 1.5 V,setting a new benchmark among reported nanofiber-based electrodes.Digital twinning of the H-LSCFP reveals improved contact adhesion and increased reaction sites for CO_(2)RR.The present work demonstrates a highly catalytically active and robust nanofiber-based fuel electrode with a hybrid structure,paving the way for further advancements and nanofiber applications in CO_(2)-SOECs.展开更多
文摘Using environment-friendly and low-cost biowaste adsorbents as toxic metal ion removal substrates from aqueous solutions has a great economic advantage. This work evaluated pumpkin and potato peel biowastes for the adsorption of cadmium ions. The biowastes were treated with acid or base. Batch experiments were carried out by introducing a known concentration of metal ion solution into the biowaste sorbent at various pH levels. The pH and metal ion concentration was monitored with pH and cadmium ion-selective electrode continuously for two hours, and the final concentration for the metal ion after 24 hours was measured with the cadmium electrode and then confirmed with ICP-OES. L-type isotherms were obtained that fit to Freundlich model. Adsorption isotherms showed chemical adsorption and the kinetics following the second order model. Equilibrium adsorption capacity is higher than 29 mg/g at pH 5.6 when the initial concentration is 220 ppm. Dynamic cadmium adsorption capacity is 17 mg/g from aqueous solution when the feed solution is 220 ppm with pumpkin peel biowaste sorbent. The biowaste materials can be regenerated with acid washing.
基金The work was financially supported by the Project KJCXGC-O1 of Northwest Normal University, Lanzhou and theExcellent Young Te
文摘CeO2 nanoparticles with an average diameter of about 30 nm were prepared by sot-gel method at lower temperature. The gel, transformed from the aqueous solution of metal nitrate and citric acid, can be combusted com- pletely at lower temperature. The redox behavior and the crystallization process of the dried gel were studied by thermogravimetric analysis and infrared spectroscopy. The synthesized powders were characterized by X-ray powder diffraction and transmission electron microscopy. In addition, rare earth elements ion-selective electrodes based on acetyl cellulose were prepared using ultra fine cerium oxide powders.
文摘Enzyme was immobilized on an ammonium ion-selective electrode by different methods.An ion-selective electrode is not completely ion-specific,and interfering ions react with the ion-selective electrode membrane,altering the measured potential.Therefore,the characteristics of the effect of other ions on ammonium ion-selective electrode-based urea biosensors are considered.Based on the experimental results,the urea biosensor based on entrapment had a high response voltage of around 189 mV and fast response time of around 16 sec.Moreover,selectivity of the urea biosensor in different interfering ions was considered to elucidate the characteristics of ammonium ion-selective electrode-based biosensors.
文摘Three new "tailed" porphyrins and their corresponding Mn(Ⅲ) metalloporphyrins were synthesized and characterized. The potentiometric response characteristics of the PVC membrane electrode based on the Mn(Ⅲ) complexes of the three new "tailed" porphyrins toward SCN- have been studied.
文摘A new ion-selective pH electrode of PVC membrane used formeasuring pH of the upper digestive tract is reported in this paper, which wasprepared with tri-n-octylamine or tris-(2-ehtylhexy)amine sensitive materials,and polyvinylchloride (PVC) as a base. It was shown that the electrode has widelinearity (0.5-8, 3-12), good reproducibility, proper responsible time (【30s),longer life span (15 days). And the measurement was carried out in 50 cases bythe electrode.
文摘An empirical solution to abnormal potential responses, showing peaks of emf, of commercial Cu2+- and Cd2+-selective electrodes with solid-state membranes was proposed for aqueous solutions of CuCl2 and CdI2. The two-step processes of Mn+ + Yn? (s: solid phase) MY(s) and MY(s) + 2X? X2MY2?(s) (n = 1, 2) at a test solution/electrode-interface were considered as a model. Here, Mn+, Yn?, and X? refer to a divalent or univalent cation, functional groups of electrode materials, and a halide ion (X? = Cl?, Br?, I?), respectively. By applying electrochemical potentials to these processes at n = 2, we derived an equation. Regression analyses based on the equation reproduced well the plots of emf versus log 2(*[M]t) for the Cd(II) and Cu(II) systems: *[M]t denotes a total concentration of species relevant to M2+ in a bulk of the aqueous solution. Also, we obtained log Ks(CdBr2) = 4.28 ? 0.22, log Ks(CdI2) = 6.98 ? 0.05, log Ks(CuCl2) = 3.96 ? 0.09, and log Ks(CuBr2) = 11.4 at 25?C. The magnitude in ?log Ks reflected that in the logarithmic solubility product, log {*[M2+](*[X?])2}, for bulk water, where *[M2+] or *[X?] denotes a molar concentration of the bulk solu-tion of M2+ or X? at equilibrium, respectively. Moreover, a mixture of CuSO4 with NaCl at the molar ratio of 1:1 yielded a plot similar to that of CuCl2.
文摘Robust and easy-to-handle solid-contact ion-selective electrodes (SC-ISEs) based on graphite paste have been developed for the potentiometric detection of NO-3 and NH+4 in environmental samples. Polypyrrole (PPy) has been used as intermediate layer and solid contact between the electron-conducting graphite paste substrate and the ion-conducting polyvinylchloride (PVC)-containing membrane with the immobilized ionophore. For the nitrate- and ammonium-selective electrodes, tridodecylmethylammonium nitrate (TDMA-NO3) and nonactin have been used as ion-complexing compounds, respectively. Both ISEs show nearly Nernstian response in the linear range from 10-5 mol/L to 10-1 mol/L with average slopes of >58 mV/decade. The ISEs possess short response times (<20 s).
文摘A K^+-selective electrode and a Na^+-selective electrode were used to construct a measuring cell without liquid-junction for the determination of the ion activity ratio of K^+ to Na^+ in soil suspensions.The measured cell potential was not affected by the total electrolyte concentration when the total cation concentration was 10^-1-10^-3 mol L^-1 and the concentration ratio Ck+/CNa+ was 10:1 to 1:50.When the concentration ratios were equal to 1 and the total electrolyte concentrations were 10^-2 and 10^-3 mol L^-1,the ion activity ratio measurenent would not be affected by pH in the pH range of 3.5 to 11.5 and 4.4 to 11 respectively.Ions other than H^+ have no remarkable influence on the measurement.The ion activity ratio of K^+ to Na^+ measured directly in soil suspension agree well with those in centrifuged supernant solution.The relative deviation was within 4%.From the measured ion activity ratio,the difference of the bonding energies of K^+ and Na^+ ions was calculated.
文摘A PVC membrane enoxacin ion-selective electrode based on a needle-shaped inner reference electrode was prepared. A Ag/AgCl wire was used as the substrate of this electrode. It was previously coated with a thin sheet of urea-formaldehyde resin containing Cl - ions to form a needle-shaped inner reference electrode, then the inner reference electrode was coated with a thin sheet of a PVC membrane containing an enoxacin tetraphenylborate ion-pair complex. The influences of various ion-pair complexes, concentrations of the active components in the membrane and the plasticizers on the performance of the electrode were studied by orthogonal design. The linear response range of the electrode was 7.9×10 -5 -1.0×10 -2 mol/L. The detection limit was 2.0×10 -5 mol/L. The slope was 30.4 mV/decade(25 ℃). The electrode can be used for the potentiometric determination of enoxacin tablets directly. The average recovery was 100.4%, and the RSD was 0.9%. The results agreed with those determined by the method in Chinese Pharmacopoeia.
基金Supported by the Project of Wuxi Pollution Prevention Funding Agency,China(No.2008-1)
文摘The authors developed a nitrate ion-selective electrode(ISE) based on poly(vinyl chloride)(PVC) membrane with methyltrioctylammonium nitrate as a carrier and 1-decanol as a plasticizer.The performance of the nitrate-sensitive membranes was optimized by tuning the composition of components.The electrode exhibits a linear response with a Nernstian slope of(52±1.0) mV per decade for the nitrate ion concentration ranging from 5.8×10-5 mol/L to 1.0 mol/L.The electrode can be used to detect a low concentration of nitrate ions down to 3×10-5 mol/L in a pH range of 2.1―11.5 without any compensation.The advantage of the electrode includes simple preparation,short response time and good repeatability.The detection performance of the novel electrode on nitrate ions has been tested for water samples.
基金We are grateful to the National Natural Science Foundation of China(22172040,21974031 and 22204026)the Project Funded by China Postdoctoral Science Foundation(2022M710859)+2 种基金the Department of Science and Techniques of Guangdong Province(2021A1515010180,2019B010933001)Guangzhou Municipal Science and Technology Bureau(202102010449)the Department of Guangdong Provincial Public Security(GZQC20-PZ11-FD084)fortheirfinancial support of thiswork.
文摘The analytical performance of H+-selective solid-contact ion-selective electrodes(SCISEs)based on solid contact polyaniline doped with chloride(PANI(Cl))and poly(3,4-ethylenedioxythiophene)doped with poly(styrene sulfonate)(PEDOT(PSS))was characterized by a developed coulometric signal transduction method.PEDOT(PSS)solid contact is covered by PVC based H+-selective membrane.The obtained coulometric signal demonstrates that the cumulated charge can be amplified by increasing the capacitance of solid contact.SCISEs covered with spin-coated membrane behave faster amperometric response than electrodes with drop-cast mem-brane.In contrast to earlier works,the amperometric response and impedance spectrum demonstrates H+transfer through SCISEs is independent from the thickness of membrane.The exceptional behavior of PANI(Cl)H+-SCISEs shows that the capacitance estimated from impedance spectrum at low frequency 10 mHz and coulometric signal of PANI(Cl)based SCISEs is influenced by the applied po-tentials,whereas PEDOT(PSS)solid contact is independent from the chosen applied potentials.Furthermore,preliminary investiga-tions of coulometric signal transduction on flexible pH sensor implies its potential applications in wearable sensors for sweat ion concentration detection.
基金The research was supported by the key project of the National Natural Science Foundation of China(61134011).
文摘Ion-selective electrode(ISE)is a quick and low-cost method of soil nitrate nitrogen(N)detection.The measurement models of soil nitrate-N based on ISEs includes the linear regression model,multiple linear regression model and BP neural network model,and so on.Three models were analyzed in theory,measurement experiments of validation samples and soil nitrate-N concentrations were carried out in this study,and the measurement accuracies of the three models were compared.The results showed that,in the measurement experiments of validation samples and soil nitrate-N concentrations,BP neural network model had the highest accuracy(the average relative errors between results of the BP neural network model and the reference values were 5.07%and 8.81%,respectively)among the three models,multiple linear regression model had the second highest accuracy(the average relative errors between results of the multiple linear regression model and the reference values were 7.70%and 10.51%,respectively),linear regression model couldn’t exclude the interference of chloride ions so that it had the lowest accuracy(the average relative errors between results of the linear regression model and the reference values were 11.16%and 12.28%,respectively)among the three models.The BP neural network model can effectively restrain the interference of chloride ions,and it has a high accuracy for the measurement of soil nitrate-N concentration,so that the BP neural network model can be used to measure soil nitrate-N concentration accurately.
基金supported by the CatWalk Spinal Cord Injury Trust and the Health Research Council of New Zealand(Project grant and HRC/Catwalk Partnership 19/895)(to DS).
文摘Damage to the spinal cord disrupts the electrically active nerve cells which normally transmit afferent and efferent signals,resulting in loss of motor,sensory,and autonomic functions.Potential treatments for spinal cord injury utilizing implanted spinal electrodes can be broadly classified into three different categories.The first of these approaches is“spinal stimulation”where electrodes,usually positioned above the level of injury,provide electrical stimulation to target and disrupt pain signals before they reach the brain.The second approach uses“activity-dependent neuro-technologies”,in which electrodes positioned below the level of injury initiate a complex spatiotemporal pattern of stimulation at the lumbar spinal cord to generate a walking gait in the limbs(Minev et al.,2015;Wagner et al.,2018).
基金financially supported by the National Key Research and Development Program of China(No.2017YFB1002900)the National Natural Science Foundation of China(No.51661145021)+5 种基金the Key Natural Science Program of Jiangsu Province(Nos.BE2022118,BE2021643 and BE2016772)the Traction Project of Key Laboratory of Advanced Carbon Materials and Wearable Energy Technologies of Jiangsu Province(No.Q816000217)the Scholarship from Key Laboratory of Modern Optical Technologies of Ministry of Education of Chinathe Priority Academic Program Development(PAPD)of Jiangsu Higher Education InstitutionsChina Prosperity Green Industry Foundation of Ministry of Industry and Information Technologysupported by the open project of synchrotron radiation characterization of chain oriented/stacked polar topology and energy modulation of supramolecules(No.2100982)。
文摘Black phosphorus with a superior theoretical capacity(2596 mAh g^(-1))and high conductivity is regarded as one of the powerful candidates for lithium-ion battery(LIB)anode materials,whereas the severe volume expansion and sluggish kinetics still impede its applications in LIBs.By contrast,the exfoliated two-dimensional phosphorene owns negligible volume variation,and its intrinsic piezoelectricity is considered to be beneficial to the Li-ion transfer kinetics,while its positive influence has not been discussed yet.Herein,a phosphorene/MXene heterostructure-textured nanopiezocomposite is proposed with even phosphorene distribution and enhanced piezo-electrochemical coupling as an applicable free-standing asymmetric membrane electrode beyond the skin effect for enhanced Li-ion storage.The experimental and simulation analysis reveals that the embedded phosphorene nanosheets not only provide abundant active sites for Li-ions,but also endow the nanocomposite with favorable piezoelectricity,thus promoting the Li-ion transfer kinetics by generating the piezoelectric field serving as an extra accelerator.By waltzing with the MXene framework,the optimized electrode exhibits enhanced kinetics and stability,achieving stable cycling performances for 1,000 cycles at 2 A g^(-1),and delivering a high reversible capacity of 524 m Ah g^(-1)at-20℃,indicating the positive influence of the structural merits of self-assembled nanopiezocomposites on promoting stability and kinetics.
基金financially supported by the Shenzhen Science and Technology Program (JCYJ20200109105805902,JCYJ20220818095805012)the National Natural Science Foundation of China (22208221,22178221,42377487)+2 种基金the Scientific and Technological Plan of Guangdong Province (2019B090905005,2019B090911004)the Natural Science Foundation of Guangdong Province (2021A1515110751)the Guangdong Basic and Applied Basic Research Foundation (2022A1515110477,2021B1515120004)。
文摘Sluggish storage kinetics is considered as the main bottleneck of cathode materials for fast-charging aqueous zinc-ion batteries(AZIBs).In this report,we propose a novel in-situ self-etching strategy to unlock the Palm tree-like vanadium oxide/carbon nanofiber membrane(P-VO/C)as a robust freestanding electrode.Comprehensive investigations including the finite element simulation,in-situ X-ray diffraction,and in-situ electrochemical impedance spectroscopy disclosed it an electrochemically induced phase transformation mechanism from VO to layered Zn_(x)V_(2)O_5·nH_(2)O,as well as superior storage kinetics with ultrahigh pseudocapacitive contribution.As demonstrated,such electrode can remain a specific capacity of 285 mA h g^(-1)after 100 cycles at 1 A g^(-1),144.4 mA h g^(-1)after 1500 cycles at 30 A g^(-1),and even 97 mA h g^(-1)after 3000 cycles at 60 A g^(-1),respectively.Unexpectedly,an impressive power density of 78.9 kW kg^(-1)at the super-high current density of 100 A g^(-1)also can be achieved.Such design concept of in-situ self-etching free-standing electrode can provide a brand-new insight into extending the pseudocapacitive storage limit,so as to promote the development of high-power energy storage devices including but not limited to AZIBs.
基金supported in part by the National Natural Science Foundation of China(Grant No.62104056)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ21F010010)+4 种基金the National Natural Science Foundation of China(Grant Nos.62141409 and 62204204)the National Key R&D Program of China(Grant No.2022ZD0208602)the Zhejiang Provincial Key Research&Development Fund(Grant Nos.2019C04003 and 2021C01041)the Shanghai Sailing Program(Grant No.21YF1451000)the Key Research and Development Program of Shaanxi(Grant No.2022GY-001).
文摘Flexible pressure sensors have many potential applications in the monitoring of physiological signals because of their good biocompatibil-ity and wearability.However,their relatively low sensitivity,linearity,and stability have hindered their large-scale commercial application.Herein,aflexible capacitive pressure sensor based on an interdigital electrode structure with two porous microneedle arrays(MNAs)is pro-posed.The porous substrate that constitutes the MNA is a mixed product of polydimethylsiloxane and NaHCO3.Due to its porous and interdigital structure,the maximum sensitivity(0.07 kPa-1)of a porous MNA-based pressure sensor was found to be seven times higher than that of an imporous MNA pressure sensor,and it was much greater than that of aflat pressure sensor without a porous MNA structure.Finite-element analysis showed that the interdigital MNA structure can greatly increase the strain and improve the sensitivity of the sen-sor.In addition,the porous MNA-based pressure sensor was found to have good stability over 1500 loading cycles as a result of its bilayer parylene-enhanced conductive electrode structure.Most importantly,it was found that the sensor could accurately monitor the motion of afinger,wrist joint,arm,face,abdomen,eye,and Adam’s apple.Furthermore,preliminary semantic recognition was achieved by monitoring the movement of the Adam’s apple.Finally,multiple pressure sensors were integrated into a 33 array to detect a spatial pressure distribu-×tion.Compared to the sensors reported in previous works,the interdigital electrode structure presented in this work improves sensitivity and stability by modifying the electrode layer rather than the dielectric layer.
基金Grant PID2020-115848RB-C21 "STORELEC" projectTED2021-129694B-C22 "DEFY-CO2" project funded by MCIN/AEI/10.13039/501100011033+3 种基金LMP253_ (2)1 project funded by Gobierno de AragónGrant IJC2019-041874-I funded by the MCIN/AEI/10.13039/501100011033CSIC for her JAE Intro ICU 2021-ICB-04 grantthe Y2020/EMT-6419 "CEOTRES" project funded by the Comunidad Autonoma de Madrid。
文摘The electrochemical CO_(2) reduction reaction(CO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(Cu-N-C) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient CO_(2)RR. The electrocatalytic performance of Cu-N-C materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for CO_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized Cu-NC catalysts are found to be active and highly CO selective at low overpotentials(from -0.6 to -0.8 V vs.RHE) in 0.1 M KHCO_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing Cu-N_(4) moieties exhibits a CO_(2)-to-CO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/CO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from CO_(2)RR.
基金supported by the National Key Research and Development Program of China,China(2019YFA0705102)the National Natural Science Foundation of China,China(22179144,22005332)。
文摘Thick electrodes can increase incorporation of active electrode materials by diminishing the proportion of inactive constituents,improving the overall energy density of batteries.However,thick electrodes fabricated using the conventional slurry casting approach frequently exhibit an exacerbated accumulation of carbon additives and binders on their surfaces,invariably leading to compromised electrochemical properties.In this study,we introduce a designed conductive agent/binder composite synthesized from carbon nanotube and polytetrafluoroethylene.This agent/binder composite facilitates production of dry-process-prepared ultra-thick electrodes endowed with a three-dimensional and uniformly distributed percolative architecture,ensuring superior electronic conductivity and remarkable mechanical resilience.Using this approach,ultra-thick LiCoO_(2)(LCO) electrodes demonstrated superior cycling performance and rate capabilities,registering an impressive loading capacity of up to 101.4 mg/cm^(2),signifying a 242% increase in battery energy density.In another analytical endeavor,time-of-flight secondary ion mass spectroscopy was used to clarify the distribution of cathode electrolyte interphase(CEI) in cycled LCO electrodes.The results provide unprecedented evidence explaining the intricate correlation between CEI generation and carbon distribution,highlighting the intrinsic advantages of the proposed dry-process approach in fine-tu ning the CEI,with excellent cycling performance in batteries equipped with ultra-thick electrodes.
基金supported by the National Natural Science Foundation of China(22072107,21872105)the Natural Science Foundation of Shanghai(23ZR1464800)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Science&Technology Commission of Shanghai Municipality(19DZ2271500)。
文摘Smart wearable devices are regarded to be the next prevailing technology product after smartphones and smart homes,and thus there has recently been rapid development in flexible electronic energy storage devices.Among them,flexible solid-state zinc-air batteries have received widespread attention because of their high energy density,good safety,and stability.Efficient bifunctional oxygen electrocatalysts are the primary consideration in the development of flexible solid-state zinc-air batteries,and self-supported air cathodes are strong candidates because of their advantages including simplified fabrication process,reduced interfacial resistance,accelerated electron transfer,and good flexibility.This review outlines the research progress in the design and construction of nanoarray bifunctional oxygen electrocatalysts.Starting from the configuration and basic principles of zinc-air batteries and the strategies for the design of bifunctional oxygen electrocatalysts,a detailed discussion of self-supported air cathodes on carbon and metal substrates and their uses in flexible zinc-air batteries will follow.Finally,the challenges and opportunities in the development of flexible zinc-air batteries will be discussed.
基金This work was supported by the National Research Foundation of Korea(NRF)grant funded by the Korean Government(MSIT)(2019M3E6A1103944,2020R1A2C2010690).
文摘The unique characteristics of nanofibers in rational electrode design enable effec-tive utilization and maximizing material properties for achieving highly efficient and sustainable CO_(2) reduction reactions( CO_(2)RRs)in solid oxide elec-trolysis cells(SOECs).However,practical appli-cation of nanofiber-based electrodes faces chal-lenges in establishing sufficient interfacial contact and adhesion with the dense electrolyte.To tackle this challenge,a novel hybrid nanofiber electrode,La_(0.6)Sr_(0.4)Co_(0.15)Fe_(0.8)Pd_(0.05)O_(3-δ)(H-LSCFP),is developed by strategically incorporating low aspect ratio crushed LSCFP nanofibers into the excess porous interspace of a high aspect ratio LSCFP nanofiber framework synthesized via electrospinning technique.After consecutive treatment in 100% H_(2) and CO_(2) at 700°C,LSCFP nanofibers form a perovskite phase with in situ exsolved Co metal nanocatalysts and a high concentration of oxygen species on the surface,enhancing CO_(2) adsorption.The SOEC with the H-LSCFP electrode yielded an outstanding current density of 2.2 A cm^(-2) in CO_(2) at 800°C and 1.5 V,setting a new benchmark among reported nanofiber-based electrodes.Digital twinning of the H-LSCFP reveals improved contact adhesion and increased reaction sites for CO_(2)RR.The present work demonstrates a highly catalytically active and robust nanofiber-based fuel electrode with a hybrid structure,paving the way for further advancements and nanofiber applications in CO_(2)-SOECs.
