electrochemical

摘要： Objective To develop effective alternatives to natural enzymes,it is crucial to develop nanozymes that are economical,resource efficient,and environmentally conscious.Carbon nanomaterials that have enzyme-like activities have been extensively developed as substitutes for traditional enzymes.Methods Carbide-derived carbons(CDCs)were directly synthesized via a one-step electrochemical method from a MAX precursor using an ammonium bifluoride electrolyte at ambient conditions.The CDCs were characterized by systematic techniques.Results CDCs showed bienzyme-like activities similar to that of peroxidase and superoxide dismutase.We systematically studied the dependence of CDC enzyme-like activity on different electrolytes and electrolysis times to confirm activity dependence on CDC content.Additionally,the synthesis mechanism and CDC applicability were elaborated and demonstrated,respectively.Conclusion The demonstrated synthesis strategy eliminates tedious intercalation and delamination centrifugation steps and avoids using high concentrations of HF,high temperatures,and halogen gases.This study paves the way for designing two-dimensional material-based nanocatalysts for nanoenzyme and other applications.

摘要： A novel and effective water-soluble aldehydes(β-HA)as corrosion inhibitor was synthesized for N80 steel corro-sion in 15%HCl solution,and the corrosion inhibition performance was evaluated by using weight loss,electro-chemical measurements,scanning electron microscope(SEM),quantum chemical calculation and molecular dynamics simulation(MDS).The results show that synthesizedβ-HA showed excellent corrosion performance compared with MHB and PE for carbon steel in 15%HCl solution compared with MHB and PE,and the inhibi-tion efficiency increased with increasing concentration of the inhibitor.The inhibition efficiency of β-HA at 8 mmol/L reached the maximum value 94.08%.The inhibitor acted as mixed-type inhibitor via blocking both the anodic and cathodic reaction.The adsorption of inhibitors on N80 steel surface obeyed Langmuir adsorption isotherm,and the process contained chemisorption and physisorption.TheΔG ads of β-HA was−28.81 kJ·mol^(-1)der the standard atmospheric pressure.Moreover,the theoretical calculation parameters revealed stronger combination and higher interaction energy for inhibitor β-HA comparing with MHB and PE,further demonstrat-ing the correlation between the theoretical and experimental results.

摘要： The low cell voltage during electrolytic Mn from the MnCl2 system can effectively reduce the power consumption.In this work,the Ti/Sn−Ru−Co−Zr modified anodes were obtained by using thermal decomposition oxidation.The physical parameters of coatings were observed by SEM(scanning electron microscope).Based on the electrochemical performance and SEM/XRD(X-ray diffraction)of the coatings,the influence of Zr on electrode performance was studied and analyzed.When the mole ratio of Sn−Ru−Co−Zr is 6:1:0.8:0.3,the cracks on the surface of coatings were the smallest,and the compactness was the best due to the excellent filling effect of ZrO_(2)nanoparticles.Moreover,the electrode prepared under this condition had the lowest mass transfer resistance and high chloride evolution activity in the 1mol%NH4Cl and 1.5mol%HCl system.The service life of 3102 h was achieved according to the empirical formula of accelerated-life-test of the new type anode.

摘要： As one of the most common cathode materials for aqueous zinc-ion batteries(AZIBs),manganese oxides have the advantages of abundant reserves,low cost,and low toxicity.However,the electrochemical mechanism at the cathode of aqueous zinc-manganese batteries(AZMBs) is complicated due to different electrode materials,electrolytes and working conditions.These complicated mechanisms severely limit the research progress of AZMBs system and the design of cells with better performance.Hence,the mechanism of AZMBs currently recognized by most researchers according to the classification of the main ions involved in the faradaic reaction is introduced in the review.Then a series of reasons that affect the electrochemical behavior of the battery are summarized.Finally,the failure mechanisms of AZMBs over prolonged cycling are discussed,and the current insufficient research areas of the system are explained,along with the direction of further research being prospected.

摘要： LiNi_(0.8)Co_(0.15)Al_(0.05)O_(2)@Cr_(2)O_(5)composite electrode combines the high rate-capability characteristics of NCA with the stability of Cr_(2)O_(5),playing a synergistic role in improving the cyclic stability,initial discharge capacity and the security of low cut-off voltage(2.0 V).When the mass ratio of Cr_(2)O_(5)in NCA is 45%(mass),the capacity retention rate increases from 58.5% without Cr_(2)O_(5)to 69.3% in the range of 2.0-4.3 V.The initial discharge capacity of NCA@Cr_(2)O_(5)composite material is 211.4 mA·h·g^(-1),its first coulombic efficiency is 94.2%,and the charging capacity remains approximately constant when mixed with 15%(mass)Cr_(2)O_(5).The reason for the improvement of the initial charge-discharge efficiency(ICDE)was explained.Impedance and cyclic voltammetry analysis reveal more detailed reasons of the observed improvements.Compared with NCA cathode material,the NCA@Cr_(2)O_(5)composite material can provide not only additional stable sites and channels for Li^(+)insertion/extraction to make up for the loss of active Li^(+)sites and prevent the accumulation of Li+in the circulation process,but also protect the NCA electrode from the corrosion of the electrolyte decomposition by the Cr_(2)O_(5)nanoparticles adhering to NCA interface.

摘要： The involvement between electron transfer(ET)and catalytic reaction at the electrocatalyst surface makes the electrochemical process challenging to understand and control.How to experimentally determine ET process occurring at the nanoscale is important to understanding the overall electrochemical reaction process at active sites.

摘要： Nano-emulsion,a kinetically stable system of nanosized oil droplets in water has been numerously used as a medium for biological and medicinal processes.It is also used as a solubilizing medium for compounds or molecules that are insoluble or poorly soluble in aqueous medium in addition to its use as a penetration enhancer in dermatological processes.Ferrocene,a metallocene that is known to be quite insoluble in aqueous medium is liberally soluble in the prepared oil-in-water nano-emulsion.In this medium,ferrocene undergoes a quasi-reversible reaction process and its relevant electrochemical kinetic parameters such as the heterogeneous rate constant,ko,the formal redox potential,Eo,the half-wave potential,E1/2,the electron transfer coefficient,α,and its diffusion coefficient,D,are determined in this medium.These important electrochemical parameters including the observed current function have been used to formulate a plausible mechanism for the oxidation of ferrocene in the formulated nano-emulsion.

摘要： Electrochemical carbon dioxide reduction reaction (CO2RR) powered by renewable electricity offers an attractive approach to reduce carbon emission and at the same time produce valuable chemicals/fuels.To design efficient CO2 reduction electrocatalyst,it is important to understand the structure-activity relationship.Herein,we design a series of single Co atoms electrocatalysts with well-defined active sites electronic structures,which exhibit outstanding CO2RR activity with controllable selectivity to CO.Experimental and density functional theory (DFT) calculation studies show that introducing nitro (amino) ligand next to single Co atom catalytic center with electron-withdrawing (electron-donating) capability favors (hinders) CO2 reduction catalysis.This work provides an in-depth understanding of how functional ligand affects the splitting of transition metal 3d electron orbital,thereby changing the electron transfer from transition metal active site to CO2,which is closely related to the Gibbs free energy of the rate-determining step (CO2+e^-+*→*CO2^-).

摘要： Electrochemical carbon dioxide(CO2)reduction is considered to be an efficient strategy to produce usable fuels and overcome the concerns regarding global warming.For this purpose,an efficient,earth abundant,and a low cost catalyst has to be designed.It has been found that graphene-based materials could be promising candidates for CO2 conversion because of their unique physical,mechanical,and electronic properties.In addition,the surface of graphenebased materials can be modified by using different strategies,including doping,defect engineering,producing composite structures,and wrapping shapes.In this review,the fundamentals of electrochemical CO2 reduction and recent progress of graphene-based catalysts are investigated.Furthermore,recent studies on graphene-based materials for CO2 reduction are summarized.

摘要： Corrosion of reinforced concrete is the most important cause of concrete structure deterioration. In the present study, the protective effect of the reinforcement mortars against corrosion is examined. In particular, the chloride penetration resistance on reinforced cement mortars using organic coating as additive containing was studied. The aforementioned additive consists of corrosion inhibitor for protection of steel rebars against pitting corrosion. For the experimental procedure, four (4) different types of reinforced mortars were prepared. The corrosion protection of the additive was evaluated by electrochemical methods, (linear polarization resistance, Half-cell Potential Resistance and Electrochemical Impedance Spectroscopy). In addition, the mass loss of steel rebars against time of partially immersed in NaCl solution was carried out in the lab. The experimental results showed that in all examined cases the organic coating provides anticorrosion protection on steel rebars against chlorides.