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Enhanced photocathodic protection performance of Fe2O3/TiO2 heterojunction for carbon steel under simulated solar light
摘要： Titanium dioxide nano array (TNAs) was successfully modi?ed with Fe2O3 (FTNAs) to enhance the photocathodic protection performance for carbon steel. Fe2O3 as a sensitizer captures large quantities of light photons, resulting in a strong light harvest capability of FTNAs. Meanwhile, the bandgap of FTNAs decreased to 2.26 eV, and the photo-generated current densities were 90 and 400 mA cm?2 for TNAs and FTNAs under simulated solar light illumination, respectively. The narrowed bandgap and the sensitive photoelectric response together contribute to a good photocathodic protection performance of FTNAs, which was con?rmed by the electrochemical impedance spectroscopy and electrochemical noise.
关键词： Photocathodic protection,Titanium,Electrochemistry,Carbon steel,Fe2O3
更新于2025-09-10 09:29:36
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Variable Growth and Characterizations of Monolayer Protected Gold Nanoclusters Based on Molar Ratio of Gold and Capping Ligands
摘要： Controlling the size of nanoscale entities is important because many properties of nanomaterials are directly related to the size of the particles. Gold nanoparticles represent classic materials and are of particular interest due to their potential application in a variety of fields. In this study, hexanethiol-capped gold nanoparticles are synthesized via the Brust-Schiffrin method. Synthesized nanoparticles were characterized by various analytical techniques such as transmission electron microscopy (TEM), scanning tunneling microscopy (STM), UV-Visible absorption spectroscopy (UV-Vis) and electrochemical techniques. We have varied the molar ratio of gold to the protecting agent (hexanethiol) to discover the effect of gold-to-hexanethiol ligand ratio on the size of gold clusters. The clear correlation between cluster size and molar ratio is found that the averaged cluster size decreases from 4.28 ± 0.83 nm to 1.54 ± 0.67 nm as the gold-to-ligand molar ratio changes from 1:1 to 1:9. In contrast to a recent report that thiolated gold nanoparticles are under spontaneous disintegration when they are assembled on a gold substrate, our STM experiments proved that these gold nanoparticles can form a stable monolayer or multiple layers on the platinum electrode without observing disintegration within 72 hours. Therefore, our STM experiments demonstrate that the disintegration behavior of gold nanoparticles is related to the type of ligands and the nature of substrate materials. In electrochemical experiments, these gold nanoparticles displayed an electrochemical quantized charging effect, making these nanoparticles useful in the device applications such as electrochemical or biological sensors.
关键词： particle size,electrochemistry,molar ratio,Gold nanoparticles,STM,disintegration
更新于2025-09-09 09:28:46
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Metal-Ligand Cooperative Synthesis of Benzonitrile via Electrochemical Reduction and Photolytic Splitting of Dinitrogen
摘要： Thermal nitrogen fixation relies on strong reductants to overcome the extraordinarily large N–N bond energy. Photochemical strategies that drive N2 fixation are scarcely developed. Here, the synthesis of a dinuclear N2-bridged complex is presented upon reduction of a rhenium(III) pincer platform. Photochemical splitting into terminal nitride complexes is triggered by visible light. Clean N-transfer with benzoyl chloride to free benzamide and benzonitrile is enabled by cooperative 2H+/2e– transfer of the pincer ligand. A three-step cycle is demonstrated for N2 to nitrile fixation that relies on electrochemical reduction, photochemical N2-splitting and thermal N-transfer.
关键词： Rhenium,Photochemistry,Electrochemistry,Nitrogen Fixation,Pincer Ligand
更新于2025-09-09 09:28:46
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Photo-electrochemical properties of p-type AgCoO2 prepared by low temperature method
摘要： AgCoO2 prepared by co-precipitation at low temperature (~ 80 °C) is characterized by physical and photo-electrochemical techniques. The X-ray diffraction shows broad peaks with a particle size of ~ 20 nm and a specific surface area of ～ 28 m2 g?1. The forbidden band (1.33 eV) is due to Ag+: d → d transition, further transition at 4.50 eV is assigned to the charge transfer. The transport properties, measured up to 650 K, indicate intrinsic conductivity: σ = σo exp{? 0.24 eV/kT (Ω-cm)?1}, supporting a phonon assisted conduction mechanism. An exchange current density of 1.27 mA cm?2 in Na2SO4 (0.1 M) solution is consistent with the electrochemical stability up to 0.8 VSCE. The capacitance measurement (C?2 - E) indicates p type conduction, with a flat band potential (Efb) of 0.26 VSCE and a holes density (NA) of 7.38 × 1019 cm?3 due to the oxygen insertion in the layered lattice. The electrochemical impedance spectroscopy (EIS) data, recorded in the range (1 mHz - Hz), reveals a predominant bulk contribution with a low depletion angle of 3° and a pseudo capacitive behavior. As application, AgCoO2 is tested for the hydrogen production upon visible illumination owing to the potential of its conduction band (?0.83 VSCE), less cathodic than that of H2O/H2 (~ ?0.5 VSCE). H2 evolution rate of 79 μmol g?1 min?1 is determined at neutral pH with a quantum yield of 1.92% in presence of NO2? as hole scavenger; no Ag deposition was observed after photocatalysis.
关键词： Delafossite AgCoO2,Co-precipitation,Nano sized,Hydrogen,Photo electrochemistry
更新于2025-09-09 09:28:46
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Hemoglobin Immobilization on Multiporous Nanofibers of SnO <sub/>2</sub> and Chitosan Composite for Hydrogen Peroxide Sensing
摘要： A multiporous nanofiber (MPNFs) of SnO2 and chitosan has been used for the immobilization of a redox protein, hemoglobin (Hb), onto the surface of glassy carbon electrode (GCE). The multiporous nanofiber of SnO2 that has very high surface area is synthesized by using electrospinning technique through controlling the tin precursor concentration. Since the constructed MPNFs of SnO2 exposes very high surface area, it increases the efficiency for biomolecule-loading. The morphology of fabricated electrodes is examined by SEM observation and the absorbance spectra of Hb/(MPNFs) of SnO2 are studied by UV-Vis analysis. Cyclic Voltammetry and amperometry are employed to study and optimize the performance of the resulting fabricated electrode. After fabrication of the electrode with the Hb and MPNFs of SnO2, a direct electron transfer between the protein’s redox centre and the glassy carbon electrode was established. The modified electrode has showed a couple of redox peak located at ?0.29 V and ?0.18 V and found to be sensitive to H2O2. The fabricated electrode also exhibited an excellent electrocatalytic activity towards the reduction of H2O2. The catalysis currents increased linearly to the H2O2 concentration in a wide range of 5.0 × 10?6–1.5 × 10?4 M. Overall experimental results show that MPNFs of SnO2 has a role towards the enhancement of the electroactivity of Hb at the electrode surface. Thus the MPNFs of SnO2 is a very promising candidate for future biosensor applications.
关键词： Multiporous SnO2 Nanofiber,Hemoglobin,Electrical Contact,H2O2 Sensing,Direct Electrochemistry
更新于2025-09-09 09:28:46
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A novel functionalized black phosphorus nanocomposite for biosensing
摘要： A novel functionalized black phosphorus (BP) nanocomposite was synthesized through a facile strategy by non-covalently and ionic combining liquid poly(diallyldimethylammonium chloride) (PDDA) with BP. The resultant nanocomposite exhibited good biocompatibility, favorable the solubility and enhanced electric conductivity facilitate to the immobilization of hemoglobin (Hb) and realize fast direct electron transfer with a rate constant (kET) of 15.36 s-1. The immobilized Hb displayed desirable electro-catalytic activity toward nitrite reduction in the range of 80 μM to 3.8 mM with a detection limit of 3.65 μM. The present work advances a new way to construct novel bio-friendly BP-based biosensors, biofuel cells and bioelectronics with excellent sensitivity and stability.
关键词： poly(diallyldimethylammonium chloride),electrochemistry,black phosphorus,biosensor,ionic liquid
更新于2025-09-09 09:28:46
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Synthesis and electrochemical properties of peripheral, non-peripheral tetra [2-(3,5-diphenyl-1H-1,2,4-triazol-1-yl)ethoxy] substituted cobalt(II), manganese(III) phthalocyanines
摘要： In this study, 4-[2-(3,5-diphenyl-1H-1,2,4-triazol-1-yl)ethoxy]phthalonitrile ET-CN, 3-[2-(3,5-diphenyl-1H-1,2,4-triazol-1-yl)ethoxy]phthalonitrile n-ET-CN and cobalt(II), manganese(III) phthalocyanines bearing [2-(3,5-diphenyl-1H-1,2,4-triazol-1-yl)ethoxy] group at peripheral, non-peripheral positions were synthesized for the first time. The new compounds have been characterized by FT-IR, NMR (only for ET-CN, n-ET-CN), mass and UV–Vis spectroscopy (except ET-CN, n-ET-CN) techniques. Electrochemistry of cobalt(II), manganese(III) phthalocyanines bearing [2-(3,5-diphenyl-1H-1,2,4-triazol-1-yl)ethoxy] group at peripheral, non-peripheral positions were examined by using cyclic voltammetry.
关键词： Phthalocyanine,Synthesis,Electrochemistry,1,2,4-triazol
更新于2025-09-09 09:28:46
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Electrochromism of novel triphenylamine-containing polyamide polymers
摘要： A series of novel polymers (coded as BCT-1 to BCT-6 (BTC is block triphenylamine)) based on N1-(4-aminophenyl)-N1-phenyl benzene-1,4-diamine, pyridine-2,6-dicarboxylic acid, 4,40-(phenyl azanediyl)dibenzoic acid (PDA), and different diamine compounds were synthesized successfully through a polymer condensation reaction. For comparison, model polymers, BCT–2,6-pyridine dicarboxylic acid (PA) and BCT–PDA, were synthesized as well. The electrochromic properties of the BCTs were determined via an electrochemical workstation and a UV–visible spectrophotometer. Through electrooxidation, the polymer ?lms showed reversible redox processes and steady color changes. In a comparision of the electrochromic characteristics of the BCTs, almost all the novel polymer ?lms showed a better electrochromism stability, a higher electrochromic coloration ef?ciency (CE), and a more rapid switching time than BCT–PA and BCT–PDA. Among these polymers, BCT-1 exhibited the highest CE of 266.7 cm2/C, and BCT-4 showed the most rapid switching time (color switching time = 3.08 s and bleaching time = 2.01 s). ? 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 136, 47264.
关键词： electrochemistry,copolymers,polyamides,optical properties
更新于2025-09-04 15:30:14
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Spectro-electrochemical Studies on [Ru(TAP) <sub/>2</sub> (dppz)] <sup>2+</sup> —Insights into the Mechanism of its Photosensitized Oxidation of Oligonucleotides
摘要： [Ru(TAP)2(dppz)]2+ (TAP = 1,4,5,8-tetraazaphenanthrene; dppz = dipyrido[3,2-a:2′,3′-c]phenazine) is known to photo-oxidize guanine in DNA. Whether this oxidation proceeds by direct photoelectron transfer or by proton-coupled electron transfer is still unknown. To help distinguish between these mechanisms, spectro-electrochemical experiments have been carried out with [Ru(TAP)2(dppz)]2+ in acetonitrile. The UV?vis and mid-IR spectra obtained for the one-electron reduced product were compared to those obtained by picosecond transient absorption and time-resolved infrared experiments of [Ru(TAP)2(dppz)]2+ bound to guanine-containing DNA. An interesting feature of the singly reduced species is an electronic transition in the near-IR region (with λmax at 1970 and 2820 nm). Density functional and time-dependent density functional theory simulations of the vibrational and electronic spectra of [Ru(TAP)2(dppz)]2+, the reduced complex [Ru(TAP)2(dppz)]+, and four isomers of [Ru(TAP)(TAPH)(dppz)]2+ (a possible product of proton-coupled electron transfer) were performed. Significantly, these predict absorption bands at λ > 1900 nm (attributed to a ligand-to-metal charge-transfer transition) for [Ru(TAP)2(dppz)]+ but not for [Ru(TAP)(TAPH)(dppz)]2+. Both the UV?vis and mid-IR difference absorption spectra of the electrochemically generated singly reduced species [Ru(TAP)2(dppz)]+ agree well with the transient absorption and time-resolved infrared spectra previously determined for the transient species formed by photoexcitation of [Ru(TAP)2(dppz)]2+ intercalated in guanine-containing DNA. This suggests that the photochemical process in DNA proceeds by photoelectron transfer and not by a proton-coupled electron transfer process involving formation of [Ru(TAP)(TAPH)(dppz)]2+, as is proposed for the reaction with 5′-guanosine monophosphate. Additional infrared spectro-electrochemical measurements and density functional calculations have also been carried out on the free TAP ligand. These show that the TAP radical anion in acetonitrile also exhibits strong broad near-IR electronic absorption (λmax at 1750 and 2360 nm).
关键词： proton-coupled electron transfer,DNA oxidation,photoelectron transfer,Ruthenium complexes,spectro-electrochemistry
更新于2025-09-04 15:30:14