In this study, a series of benzotriazole derivatives with various carbon chains (n = 1, 3, 4, 6, 7, 9, 10, 12, 16) were synthesized for the corrosion inhibition of copper in 3.5 wt % (wt %) NaCl solution. The corrosion inhibition efficiencies of these inhibitors in 3.5 wt % NaCl solution for copper were measured by various measurements including the polarization curves, the electrochemical impendence spectroscopy as well as the weight loss method. The inhibition mechanism of these new target molecules were analyzed by the plots of Tafel, Nyquist, and Bode. The corrosion inhibition effect was also evaluated by scanning the copper surface with an electron microscope. The results show that the corrosion of copper in chloride aqueous solution is efficiently inhibited by these new organic inhibitors. Furthermore, the corrosion inhibition efficiencies of the target inhibitors are shown to have much dependence on the carbon chain length attached to the molecular backbone. The inhibitor carrying a 7-carbon chain displays the greatest inhibition efficiency as large as ∼98% at 0.15 mM, while even the poorest inhibitor containing a 2-carbon chain shows ∼60% inhibition efficiency. The adsorption of these new inhibitors on copper was further revealed by analysis of Langmuir isotherms and quantum chemical calculations.

•Synthesis of new conjugated dyes carrying dialkylamino and ketone groups through multi-step routes.•Visible light photoinitiating properties of these dyes using as one-component photoinitiators studied by photo-DSC.•Efficient visible light photoinitiating polymerization of methyl methacrylate by one-component photoinitiators.•Greater visible light photoinitiating efficiencies of one-component photoinitiators than two-component ones.This work presents new conjugated dyes carrying N, N-dialkylamino and ketone groups for using as one-component Norrish type II visible light photoinitiators. The novel dyes without ketone group were also synthesized to compose two-component visible light photoinitiators for comparisons. The target dyes show the remarkable absorption in visible light region. Photo-differential scanning calorimetry was employed to study visible light photoinitiating polymerization kinetics of methyl methacrylate by new one-component photoinitiators and two-component photoinitiators respectively. The results suggest that the one-component photoinitiators showed much more efficient photoinitiating polymerization of methyl methacrylate than the two-component photoinitiating systems under visible light irradiation. The molecular weight of visible light photopolymer produced by the new photoinitiators was determined. The visible light photoinitiating mechanism of the one-component photoinitiators was studied by absorption and emission spectra, electron spin resonance spectra and cyclic voltammograms analysis.

•Synthesis of water soluble corrosion inhibitors for copper in NaCl solution.•Efficient corrosion inhibition nature of the studied inhibitors for copper.•Analyses of adsorption mechanism of the inhibitors on copper surface.In this study, synthesis of water soluble and efficient corrosion inhibitors PBTB carrying single benzotriazole part and PDBTB containing double benzotriazole segments for copper in 3.5 wt% sodium chloride solution was proposed. PDBTB showed greater corrosion inhibition effect than PBTB basing on survey results of polarization curves, impedance spectroscopy and scanning electron microscopy. Adsorption mechanism of the studied inhibitors on copper surface was studied by FT-IR spectra, X-ray photoelectron spectroscopy, X-ray diffraction spectra as well as adsorption isotherm.Download high-res image (106KB)Download full-size image

This study presents a variety of organic dyes with similar molecular structures that could undergo intramolecular proton transfer in excited states via five-, six- and seven-number-membered ring transition states, respectively. In addition, the dyes without proton transfer segments are also synthesized to use as references. X-ray single crystal diffraction, NMR spectra as well as UV/visible spectra suggests the presence of internal hydrogen bond with different strength in the target dyes. The steady and transient fluorescence measurements demonstrate occurrence of excited state intramolecular proton transfer via a six number-membered ring transition state. In contrast, it cannot be processed through five- and seven-number-membered ring transition states of the studied dyes. The molecular geometry optimization of the studied dyes reveals fundamental factors for the difficulties of intramolecular proton transfer in excited states via five- and seven-number-membered ring transition states.

As a vital derivative of graphene, graphene oxide (GO) is widely applied in various fields, such as transparent electrodes, solar cells, energy storage, and corrosion protection due to the large specific surface area and abundant active sites. However, compared with graphene, the application of GO has been less reported in metal corrosion protection field. Therefore, in our study, 3-aminobenzenesulfonic acid was selected to combine with oligoanilines to fabricate the GO-based sulfonated oligoanilines coatings for marine corrosion protection application. The obtained composite coatings were covered on the surface of Q235 steel, which is one of the most important structural marine materials. Fourier transform infrared spectra were utilized to prove the existence of different bonds and functional groups of aniline trimer and sulfonated aniline trimer (SAT). Scanning electron microscopy was applied to verify the combination of GO and SAT. What’s more, transmission electron microscopy was applied to observe the surface appearance of the obtained GO–SAT composite material. Besides, the results of electrochemical measurements performed in 3.5 wt % NaCl solution showed excellent corrosion-protective properties of GO/SAT-coated epoxy resin with a dosage of 10 mg of GO compared with the pure epoxy resin. Moreover, the enhancement of surface hydrophobic property, to some extent, is in favor of preventing the absorption of corrosive medium and water molecules revealed by contact angle test. The addition of GO can make the diffusion pathway of the corrosive medium longer and more circuitous, while SAT has displayed excellent solvent solubility while maintaining corrosion-protective properties similar to those of polyanilines so that the corrosion-protective properties of the modified coatings improve significantly due to the synergistically enhanced corrosion protection of GO and SAT.Keywords: corrosion protection; electrochemical measurements; graphene oxide; hydrophobic; sulfonated oligoanilines;

•Three indazole compounds are used as efficient corrosion inhibitors for copper in 3.0 wt% NaCl solution.•The order of inhibition ability obtained from EIS is in perfect agreement with the polarization results.•Theoretical calculations provide favorable support for the experimental results.•The results indicate that the halogenation in IA can improve its inhibitive ability.In this work, three halogeno-indazole compounds were investigated for corrosion inhibition of copper in 3.0 wt% NaCl solution using potentiodynamic polarization measurement, electrochemical impedance spectroscopy, and X-ray diffraction (XRD) analysis. The electrochemical results revealed that all of these organics are mixed-type inhibitors with an inhibitive ability order: 4-CIA > 4-BIA > 4-FIA, which was further confirmed by observations with field emission scanning electron microscope (FE-SEM) and atomic force microscope (AFM). Their favourable performance is ascribed to the formation of inhibitor-adsorption films on copper. Furthermore, theoretical calculations showed the electronic structure of studied compounds and their optimized adsorption configurations on the copper surface.

•Synthesis of new stilbene-benzophenone dyads through multi-step route as well as one-pot method.•Efficient visible light photoinitiating polymerization of methyl methacrylate by the new dyads.•The transient triplet–triplet absorption of the new dyads determined by laser flash photolysis.•The production of free radicals demonstrated by ESR trapping.•The thermal stability of the new dyads demonstrated by differential scanning calorimetry and thermograving.The AB and AB2 trans-stilbene-benzophenone dyads were synthesized through multi-step pathway. The target dyads showed remarkable absorption in visible light region. Visible light photoinitiating polymerization of methyl methacrylate by the new dyads was studied by photo-differential scanning calorimetry. The results suggested that the AB2 dyad showed more efficient photoinitiating polymerization of methyl methacrylate than the AB one under visible light irradiation. Furthermore, the new dyads yielded the greater visible light photoinitiaing polymerization effect than the intermolecular photoinitiating systems and the commercial photoinitiator titanocene respectively. The molecular weights of visible light photopolymers produced by the new dyads were determined by gel permeation chromatography. The visible light photoinitiating mechanism of the new dyads was analyzed by the static and transient absorption and emission spectra, electron spin resonance spectra and cyclic voltammograms. The thermal stabilities of the new dyads were further studied by differential scanning calorimetry and thermograving.

•The mild acid-free one-pot reaction strategy for efficient synthesis of phenanthridines dyes.•A large scope of the substrates well used for this approach.•The chemical structures of the yielded phenanthridines well identified by various characterizations.•The roles of alcoholic solvents well demonstrated by the experiments.A series of new phenylphenanthridin dyes have been synthesized in the yields of 52–75% by a mild strategy in one-pot reaction. This is the first successful attempt to perform efficient soft acid-free reaction for phenanthridine ring construction. A large substrate scope was well demonstrated.

A variety of AB2 type new target dyes containing two proton transfer segments (o-hydroxy-phenyl-imino) are presented in this study. Furthermore, the corresponding reference molecules absent of hydroxy or imino groups are provided as well. Dual intramolecular hydrogen bonds in the target dyes are demonstrated by 1H NMR spectra, X-ray single crystal analysis as well as one-photon absorption spectra. Linear emission properties (static and transient emission nature) and two-photon absorption optical properties of these target and reference dyes are determined in various media such as organic solvents, solid phase state as well as PMMA substrate. The results show that the new AB2 type target dyes can efficiently undergo internal proton transfer in the excited states under one-photon irradiation and near-infrared femtosecond laser two-photon irradiation, respectively, and thus they exhibit well-separated dual-emission. The molecular geometry optimization is performed for the analysis of the occurrence of internal proton transfer in the excited states of the target AB2 chromophores.

•OMIMBr and [AOIM]Br are modest cathodic inhibitors for mild steel in 0.5 M H2SO4.•AOIMBr shows better corrosion inhibition due to the allyl electron-donating group.•Inhibitor mainly physically adsorbs on steel surface via positively charged N atom.•The adsorption of inhibitor molecules obeys El-Awady thermodynamic–kinetic model.The inhibition performance and mechanism of 1-octyl-3-methylimidazolium bromide ([OMIM]Br) and 1-allyl-3-octylimidazolium bromide ([AOIM]Br) for the corrosion of mild steel in 0.5 M H2SO4 were investigated using weight loss method, electrochemical measurements, scanning electron microscope (SEM) and quantum chemical calculation. The results revealed that [OMIM]Br and [AOIM]Br acted as modest cathodic inhibitors, and due to the electron-donating effect of allyl group, [AOIM]Br showed better inhibitive performance. The adsorption of both inhibitors on steel surface obeyed El-Awady thermodynamic–kinetic model, thus the thermodynamic and kinetic parameters were calculated and discussed. Moreover, theoretical calculation was used to investigate inhibition mechanism of studied inhibitors.

The inhibition performance and mechanism of triisopropanolamine (TIPA) for the corrosion of aluminum alloy in 3% NaCl solution were investigated using weight loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). The electrochemical results revealed that TIPA was an effective inhibitor and the inhibition efficiency increased with the increasing concentrations of TIPA, which was further confirmed by SEM observation. Potentiodynamic polarization studies revealed that TIPA acted as a mixed-type inhibitor. The adsorption of TIPA on the aluminum surface obeyed a Langmuir thermodynamic–kinetic model, and the thermodynamic and kinetic parameters meant that the interaction between the inhibitor and the surface of aluminum alloy involved both physisorption and chemisorption. Moreover, theoretical calculations were used to investigate inhibition mechanism of the studied inhibitor. The results showed that TIPA molecule could adsorbed on Al substrate spontaneously and chelated with Al atom due to the hydroxyl group.

•Binding kinetics of lectin–dye conjugates with glycoproteins on cells was determined.•Charge property of fluorescent dye greatly alters the binding kinetics of lectin.•Positively-charged fluorescent label promotes the association of lectin onto cells.•This effect arises from electrostatic interaction of charged dye with cell membrane.Fluorescent labeling is a mainstream technology for detecting molecular binding. Despite the importance, few studies have been devoted to quantitatively examine the effect of labeling on the molecular binding processes. Here we present a quantitative study on the binding kinetics of fluorescent-labeled and un-labeled molecules (lectin proteins) with glycoproteins on the membrane of cells using surface plasmon resonance imaging (SPRi) technique. The study shows that fluorescent labeling has a significant influence on the binding behaviors of proteins, especially the association processes, and the influence depends sensitively on the charge of fluorescent labels. It further shows that the labels also affect the local distribution of probe proteins, due to the inhomogeneous surface charge distribution of the cell membrane. Our work indicates that fluorescent labeling in general affects the binding behaviors, but proper design of the label will help to minimize its effect.

A new 3D V2O5@PPy network built from numerous ultrathin, flexible and single-crystalline nanoribbons was successfully fabricated by a combined hydrothermal, freeze-drying and nanocasting process. Such a unique network can not only provide a high surface area for enhancement of electrolyte/electrode interactions, and reduce the diffusion length of ions, but also efficiently maintain the high electrical conductivity. As a result, this network exhibits high capacitance, excellent rate capability and good charge–discharge stability for energy storage. An asymmetric supercapacitor based on a 3D V2O5@PPy network as the cathode material further delivers high energy density and high power density. We expect that our work presents an efficient approach to design and produce various 3D architectures built from nanoribbons or nanosheets for energy storage and other applications.

By using cyclic voltammetry, eosin Y film was electrodeposited on the surface of glassy carbon electrode (GCE) to obtain the modified electrode (denoted as eosin Y/GCE). Scanning electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry techniques were used for the characterization of the morphological and electrochemical properties of eosin Y/GCE. The electrocatalysis capability of eosin Y/GCE to hydroquinone (HQ) and catechol (CC) was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. Compared with the bare GCE, eosin Y/GCE exhibited outstanding electrocatalytic activity and reversibility towards the oxidation of HQ and CC. The oxidation and reduction peak separation was decreased from 386 to 60 mV for HQ and from 340 to 56 mV for CC at eosin Y/GCE. The differential pulse voltammetry results showed that the oxidation peaks of the two isomers in acetate buffer solution could be clearly discriminated with a peak potential separation of ca. 106 mV, which was sufficiently wide to discriminate the two dihydroxybenzene isomers. Under optimal conditions, the oxidation peak currents were linear to HQ/CC concentration in the range from 1 μM to 130 μM with a detection limit of 0.14 μM (3σ) for HQ and 0.12 μM (3σ) for CC. Moreover, eosin Y/GCE exhibited excellent anti-interference ability, and was successfully applied to the simultaneous determination of HQ and CC in spiked water samples with reliable recovery.

In this report, a novel voltammetric sensor based on a glassy carbon electrode modified with L-cysteine/glycine composite film (L-cysteine/glycine/GCE) was developed for the quantitative detection of catechol. The as-fabricated electrode exhibited good electrochemical performance with low electron transfer resistance. The results of electrochemical impedance spectroscopy revealed that electron transfer through the L-cysteine/glycine film was more facile than that for the bare GCE. The electrochemical behavior of catechol at the prepared electrode was also investigated by cyclic voltammetry and differential pulse voltammetry . The modified electrode showed excellent electrocatalytic activity towards the oxidation of catechol in NaOH–KH2PO4 buffer solution (pH = 6.0). Under optimum conditions, a linear relationship between the oxidation peak current and concentration of catechol was obtained in the range from 3 μM to 280 μM with a detection limit of 0.32 μM (3σ). An interference and stability study showed that satisfactory detection results were achieved using this electrode. In addition, the proposed method was successfully applied in the determination of catechol in water samples with satisfactory results.

An energetic salt, sodium nitroformate (NaNF), was synthesized and characterized by elemental analysis, IR and UV spectra, and its crystal structure was first determined by single crystal X-ray diffraction. The structure exhibits two types of π-π stacking interactions between the nitroformate anions, i e, the parallel-displaced and T-shaped configurations. Furthermore, the thermal decomposition mechanism was investigated by DSC, TG-DTG and FTIR techniques. The kinetic parameters of the thermal decomposition were also calculated by using Kissinger’s and Ozawa-Doyle’s methods. The results show that NaNF has a good thermal stability, which is attributed to the π-π stacking interactions.

Nanoscale Pt3Ni/functionalized multiwalled carbon nanotubes (FMWCNTs) catalysts, successfully synthesized by anchoring nickel–platinum alloy nanoparticles on FMWCNTs, are presented in this paper. Compared with conventional commercial Pt/C catalysts, the preliminary results revealed that the Pt3Ni/FMWCNTs catalysts demonstrated not only higher specific activity for oxygen reduction reaction (ORR) but also outstanding stability. The enhancement in the stability of the Pt3Ni/FMWCNTs catalysts is believed to be due to the anchor effects in Pt3Ni alloy structure, the stronger interaction between Pt3Ni alloy nanoparticles and FMWCNTs, and the “π sites” anchoring centers for metal nanoparticles from CNTs with high graphite.

The geometric and electronic structures of crystalline potassium and silver salts of nitroform are comparatively investigated using density functional theory. The results show that the geometric structures optimized by local density functional compare well with experimental data. The nature of the anion–cation interactions of the two salts and the bonding mechanism of the nitroformate anions are quite different, but their geometrical structural characteristics are similar. Furthermore, the anion–cation interactions influence the energy of the conduction band formed by the unoccupied states of the nitroformate anion, and so are correlated with the impact sensitivity.Graphical abstractHighlights► The nature of the anion–cation interactions of the two salts is quite different. ► The anions have similar structural features, but their bonding mechanisms are different. ► The anion–cation interactions influence the energy of the conduction band. ► The anion–cation interactions are correlated with their impact sensitivity.

The triazole-acetate derivative TMCA was synthesized and its inhibiting action on the corrosion of mild steel in sulphuric acid was investigated by means of weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and scanning electronic microscope (SEM). The potentiodynamic polarization measurements show that the TMCA acts essentially as a mixed-type inhibitor, and EIS confirmed that changes in the impedance parameters were due to surface adsorption. The inhibition efficiencies (IE%) obtained from weight loss measurement and electrochemical tests were in good agreement. Substitutional inhibition mechanism of mild steel was established according to the fitted results at different temperatures. The number of water molecules (X) replaced by a molecule of organic adsorbate was determined from the different substitutional adsorption isotherms applied to the data obtained from weight loss experiments.

This paper presents the investigation of diniconzole and triadimefon as chemical corrosion inhibitors for freshly polished copper in synthetic seawater (3.5% NaCl solution). Determination of weight loss, polarization curves, electrochemical impedance spectroscopy (EIS), and SEM, were performed to analyze the inhibiting performance of these compounds. Polarization curves show that they act as mixed-type inhibitors. EIS indicates that an adsorption film of the inhibitors is formed on copper surface. The highest values of inhibition efficiency are respectively, 99.2% and 97.3% at 100 mg/L concentration. Thermodynamic calculation suggests that chemisorptions between the compounds and copper are accordance with Langmuir adsorption isotherm.

A newly synthesized benzoic−triazole derivative 3,5-dimethylbenzoic acid [1,2,4]triazol-1-ylmethyl ester (DBT) was investigated as a corrosion inhibitor of mild steel in 1 M HCl solution using weight loss measurements, potentiodynamic polarization, SEM, and EIS methods. The results revealed that DBT was an excellent inhibitor, and the inhibition efficiencies obtained from weight loss and electrochemical experiments were in good agreement. Using the potentiodynamic polarization technique, the inhibitor was proved to have a mixed-type character for mild steel by suppressing both anodic and cathodic reactions on the metal surface. The number of water molecules (X) replaced by a molecule of organic adsorbate was determined from the Flory−Huggins, Dhar−Flory−Huggins, and Bockris−Swinkels substitutional adsorption isotherms applied to the data obtained from the gravimetric experiments performed on a mild steel specimen in 1 M HCl solution at 298 K.

The oxo-triazole derivative (DTP) was synthesized and its inhibiting action on the corrosion of mild steel in sulphuric acid was investigated by means of weight loss, potentiodynamic polarization, EIS and SEM. The results revealed that DTP was an excellent inhibitor and the inhibition efficiencies obtained from weight loss experiment and electrochemical experiment were in good agreement. Potentiodynamic polarization studies clearly revealed that DTP acted essentially as the mixed-type inhibitor. Thermodynamic and kinetic parameters were obtained from weight loss of the different experimental temperatures, which suggested that at different temperatures (298–333 K) the adsorption of DTP on metal surface obeyed Langmuir adsorption isotherm model.

•Synthesis of dibenzotriazoles as corrosion inhibitors for copper in NaCl solution.•Survey of corrosion inhibiting properties of new inhibitors for copper.•Analysis of adsorption mechanism with Langmuir isotherm, FT-IR and XPS.•Structural-property relationship of inhibitors revealed by theoretical calculation.A variety of new dibenzotriazoles bearing alkylene linker as well as corresponding monobenzotriazoles using as corrosion inhibitors for copper in 3.5 wt% sodium chloride solution at 298 K were prepared. The corrosion inhibition efficiencies of these benzotriazoles were determined by electrochemical methods and weight loss experiments. Furthermore, scanning electron microscopy was utilized to compare corrosion inhibition effect. The results showed that corrosion of copper in NaCl solution could be inhibited more efficiently by dibenzotriazole derivatives comparing to monobenzotriazole ones. The inhibition mechanism of dibenzotriazoles on copper was analyzed by Langmuir isotherm, Fourier transform infrared spectra and X-ray photoelectron spectroscopy.

In this report, a novel voltammetric sensor based on a glassy carbon electrode modified with L-cysteine/glycine composite film (L-cysteine/glycine/GCE) was developed for the quantitative detection of catechol. The as-fabricated electrode exhibited good electrochemical performance with low electron transfer resistance. The results of electrochemical impedance spectroscopy revealed that electron transfer through the L-cysteine/glycine film was more facile than that for the bare GCE. The electrochemical behavior of catechol at the prepared electrode was also investigated by cyclic voltammetry and differential pulse voltammetry . The modified electrode showed excellent electrocatalytic activity towards the oxidation of catechol in NaOH–KH2PO4 buffer solution (pH = 6.0). Under optimum conditions, a linear relationship between the oxidation peak current and concentration of catechol was obtained in the range from 3 μM to 280 μM with a detection limit of 0.32 μM (3σ). An interference and stability study showed that satisfactory detection results were achieved using this electrode. In addition, the proposed method was successfully applied in the determination of catechol in water samples with satisfactory results.

By using cyclic voltammetry, eosin Y film was electrodeposited on the surface of glassy carbon electrode (GCE) to obtain the modified electrode (denoted as eosin Y/GCE). Scanning electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry techniques were used for the characterization of the morphological and electrochemical properties of eosin Y/GCE. The electrocatalysis capability of eosin Y/GCE to hydroquinone (HQ) and catechol (CC) was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. Compared with the bare GCE, eosin Y/GCE exhibited outstanding electrocatalytic activity and reversibility towards the oxidation of HQ and CC. The oxidation and reduction peak separation was decreased from 386 to 60 mV for HQ and from 340 to 56 mV for CC at eosin Y/GCE. The differential pulse voltammetry results showed that the oxidation peaks of the two isomers in acetate buffer solution could be clearly discriminated with a peak potential separation of ca. 106 mV, which was sufficiently wide to discriminate the two dihydroxybenzene isomers. Under optimal conditions, the oxidation peak currents were linear to HQ/CC concentration in the range from 1 μM to 130 μM with a detection limit of 0.14 μM (3σ) for HQ and 0.12 μM (3σ) for CC. Moreover, eosin Y/GCE exhibited excellent anti-interference ability, and was successfully applied to the simultaneous determination of HQ and CC in spiked water samples with reliable recovery.

A new 3D V2O5@PPy network built from numerous ultrathin, flexible and single-crystalline nanoribbons was successfully fabricated by a combined hydrothermal, freeze-drying and nanocasting process. Such a unique network can not only provide a high surface area for enhancement of electrolyte/electrode interactions, and reduce the diffusion length of ions, but also efficiently maintain the high electrical conductivity. As a result, this network exhibits high capacitance, excellent rate capability and good charge–discharge stability for energy storage. An asymmetric supercapacitor based on a 3D V2O5@PPy network as the cathode material further delivers high energy density and high power density. We expect that our work presents an efficient approach to design and produce various 3D architectures built from nanoribbons or nanosheets for energy storage and other applications.