Infrared reflection-absorption spectra for primary, secondary and tertiary orthophosphate anions on a gold electrode in aqueous solution were studied by in situ FTIR spectroscopy. The spectra show that H2PO4- , HPO io...Infrared reflection-absorption spectra for primary, secondary and tertiary orthophosphate anions on a gold electrode in aqueous solution were studied by in situ FTIR spectroscopy. The spectra show that H2PO4- , HPO ions do not interact with the electrode surface as strong as PO do. According to the surface selection rule, we deduce the modes of adsorption of these anions on the electrode from these spectra. The experiment also confirms the affection to adsorption of ion on the electrode due to ion-migration into thin-layer cavity.展开更多
To fabricate polydopamine-sensitized solar cells with improved solar power conversion efficiency, the effects of pH, buffer, adsorption time and electrode potential for the electrochemical oxidation and polymerization...To fabricate polydopamine-sensitized solar cells with improved solar power conversion efficiency, the effects of pH, buffer, adsorption time and electrode potential for the electrochemical oxidation and polymerization of dopamine on TiO<sub>2</sub> film were investigated. The optimum pH was around 7. It was found that the use of a buffer, especially 2-(N-morpholino)ethanesulfonic acid, significantly deteriorated the electrochemical adsorption of polydopamine, and the highest solar power conversion efficiency was obtained without buffer. With increasing adsorption time, the amount of adsorbed polydopamine increased but the solar power conversion efficiency decreased, suggesting the increased resistivity of polydopamine with a larger degree of polymerization. It was suggested that the reversal of electrode potential from positive to negative would be essential for the electrochemical adsorption of polydopamine.展开更多
An electrochemical method was used to examine Au surface absorption and passivation under the most commonly employed pH conditions in an alkaline Au leaching system.The polarization at different pH values was obtained...An electrochemical method was used to examine Au surface absorption and passivation under the most commonly employed pH conditions in an alkaline Au leaching system.The polarization at different pH values was obtained through the current step curve.At pH 10,no absorption layer was formed.When the pH was increased to 11,an absorption layer was formed through the Au electrode reaction.At pH 12,the entire system could not be stabilized,even after long durations because of the thiourea oxidation and decomposition.The samples were analyzed by scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDS),and atomic force microscopy(AFM).AFM observations of the Au plating surface and SEM-EDS analyses for the Au-coated graphite surface indicated that a passivation membrane was formed on the Au surface after its use in the alkaline thiourea Au leaching system.Two-step leaching was used to confirm the conclusions drawn from the experimental results.The twostage experimental results further confirmed the existence of a passivation membrane.展开更多
Extracts of elephant grass (Penniseturn purpureum) blended with some intensifier halides like ammonium chloride (AMC) and potassium iodide (PTI) were investigated as corrosion inhibitor for mild steel. The corro...Extracts of elephant grass (Penniseturn purpureum) blended with some intensifier halides like ammonium chloride (AMC) and potassium iodide (PTI) were investigated as corrosion inhibitor for mild steel. The corrosion process was monitored in 3.5% HCI by mass loss and electrochemical techniques at 30, 40, 50, 60 and 90 ℃. Addition of AMC and PTI increased the inhibition efficiency with the highest inhibition efficiency obtained with PTI blend- ed extract. The blends behaved as mixed type inhibitors and were spontaneously adsorbed on mild steel surface in exothermic nature. Synergistic parameters of the intensifier ions revealed cooperative effect. Kinetic data treatment indicated increase in energy barrier by intensifier ions. The results demonstrate that elephant grass extract blended with halide ions can act as alternative ecofriendly inhibitor for mild steel at elevated temperatures.展开更多
Electrochemical tests were developed to investigate the electrochemical dissolution behavior of gold and its main coexistent sulfide minerals in acid thiocyanate solutions.The optimal leaching conditions for gold in a...Electrochemical tests were developed to investigate the electrochemical dissolution behavior of gold and its main coexistent sulfide minerals in acid thiocyanate solutions.The optimal leaching conditions for gold in acidic thiocyanate system were pH 2,0.15 mol·L^(-1) thiocyanate and 0.2 g·L^(-1)Fe^(3+).Fe^(3+) addition to the acidic thiocyanate system promoted gold dissolution significantly,arsenopyrite dissolution was inhibited,chalcopyrite dissolution was increased,and the dissolution behavior of other associated minerals remained mostly unchanged.Thiocyanate made gold and associated mineral leaching easier.The galvanic corrosion effect of gold and its main coexistent sulfide minerals in an acidic thiocyanate-free system was that the chalcocite,arsenopyrite and pyrite acted as a cathode to reduce anodic gold dissolution;galena as an anode undergoes oxidation to inhibit anodic gold dissolution.There was almost no galvanic corrosion behavior between stibnite,yellow sphalerite and black sphalerite and gold.Thiocyanate addition changed the galvanic corrosion behavior of stibnite and yellow sphalerite in the thiocyanate system,which inhibited anodic gold dissolution.In the acidic thiocyanate system in the presence of ferric iron,the arsenopyrite promoted anodic gold dissolution,the chalcocite and gold were mostly free of galvanic corrosion,and the remaining minerals inhibited anodic gold dissolution.展开更多
In the recent years,biological nanostructures coatings have been incorporated into orthopedic and dental implants in order to accelerate osseointegration and reducing surgical restrictions.In the present work,chemical...In the recent years,biological nanostructures coatings have been incorporated into orthopedic and dental implants in order to accelerate osseointegration and reducing surgical restrictions.In the present work,chemical etching,anodization and metal doping surface modification methods were integrated in one strategy to fabricate innovative titanium surfaces denominated by titanium nanoporous,anodized titanium nanoporous,silver-anodized titanium nanoporous and gold-anodized titanium nanoporous.The stability properties of nanostructures-coated surfaces were elucidated using electrochemical impedance spectroscopy(EIS) after 7 days of immersion in simulated biological fluids.Morphology and chemical compositions of new surfaces were characterized by scanning electron microscope and energy-dispersive X-ray analysis.The EIS results and data fitting to the electrical equivalent circuit model demonstrated the influence of adsorption of bovine serum albumin on new surfaces as a function of protein concentration.Adsorption process was described by the very well-known model of the Langmuir adsorption isotherm.The thermodynamic parameter DGADS(-50 to 59 kJ mol^(-1)) is calculated,which supports the instantaneous adsorption of protein from biological fluids to new surfaces and refers to their good biocompatibility.Ultimately,this study explores new surface strategy to gain new implants as a means of improving clinical outcomes of patients undergoing orthopedic surgery.展开更多
氨是一种很有前途的能源载体,由于其高氢含量和无碳的特点,可用于燃料电池,并可作为电解水制氢装置中水的替代氧化底物.然而,人们对氨电氧化反应(AOR)的机理认识不足,且缺乏廉价、高效的AOR催化剂,因而阻碍了氨基能源系统的发展.在这项...氨是一种很有前途的能源载体,由于其高氢含量和无碳的特点,可用于燃料电池,并可作为电解水制氢装置中水的替代氧化底物.然而,人们对氨电氧化反应(AOR)的机理认识不足,且缺乏廉价、高效的AOR催化剂,因而阻碍了氨基能源系统的发展.在这项工作中,我们通过光诱导化学沉淀法合成的新型Ni和Cu共掺杂的多孔FeOOH纳米棒(NiCu-FeOOH)可以作为AOR催化剂,其具有高效的催化活性(阳极电流密度达到10 mA cm^(-2)时执行电压为1.41 V)和在氨碱溶液中优异的稳定性.实验数据和理论计算结果表明,异质的Ni和Cu原子的协同作用使得NiCu-FeOOH表面的Ni和Fe位点表现出更合适的电子结构,他们可以共同吸附含氮中间产物和羟基,并使其吸附自由能位于火山形曲线的顶部,从而加速AOR脱氢.决速步骤的后移(*NH_(2)+*OH形成步骤移至*N_(2)H_(3)+*OH形成步骤)和决速步骤较低的能垒(0.86 eV)揭示了Ni和Cu的共掺策略使FeOOH晶体对催化AOR更具活性.本文创新地提出了涉及含氮中间物和羟基的共吸附反应途径,以更好地描述和模拟AOR过程,这为设计低成本和稳定的AOR催化剂开辟了新的路径.展开更多
Anodic oxidation electrodeposition is the primary way to prepare lead dioxide anode. The regulation of the external circuit for the reaction is a unique advantage of electrocatalytic reaction, which can regulate cryst...Anodic oxidation electrodeposition is the primary way to prepare lead dioxide anode. The regulation of the external circuit for the reaction is a unique advantage of electrocatalytic reaction, which can regulate crystallization and accelerate the reaction process. In this study, lead dioxide coatings with uniform pore size distribution were quickly prepared on three different substrates by potential linear increase electrodeposition(PLIED). Morphology and structure analysis shows that the prepared electrodes have uniform porous morphology, and Ti/SnO_(2)/PLIED has the smallest grain size. Three electrodes all display well degradation performance to azophloxine and diclofenac sodium. Ti/PLIED, and Ti/SnO_(2)/PLIED are appreciated for degrading organics with a simple structure in low concentrations. At the same time,Ti/SnO_(2)/PLIED is more suitable for complex organics in high concentrations. Electrochemical activity tests indicate the different mechanisms of the PLIED electrodes that build the other degradation performance.Three PLIED electrodes show excellent electrical and electrochemical stability during the cycle degradation process. The results provide a reference for the subsequent anodic oxidation electrodeposition research and the regulating effect of the external circuit on coating properties.展开更多
文摘Infrared reflection-absorption spectra for primary, secondary and tertiary orthophosphate anions on a gold electrode in aqueous solution were studied by in situ FTIR spectroscopy. The spectra show that H2PO4- , HPO ions do not interact with the electrode surface as strong as PO do. According to the surface selection rule, we deduce the modes of adsorption of these anions on the electrode from these spectra. The experiment also confirms the affection to adsorption of ion on the electrode due to ion-migration into thin-layer cavity.
文摘To fabricate polydopamine-sensitized solar cells with improved solar power conversion efficiency, the effects of pH, buffer, adsorption time and electrode potential for the electrochemical oxidation and polymerization of dopamine on TiO<sub>2</sub> film were investigated. The optimum pH was around 7. It was found that the use of a buffer, especially 2-(N-morpholino)ethanesulfonic acid, significantly deteriorated the electrochemical adsorption of polydopamine, and the highest solar power conversion efficiency was obtained without buffer. With increasing adsorption time, the amount of adsorbed polydopamine increased but the solar power conversion efficiency decreased, suggesting the increased resistivity of polydopamine with a larger degree of polymerization. It was suggested that the reversal of electrode potential from positive to negative would be essential for the electrochemical adsorption of polydopamine.
基金financially supported by the National Key Research and Development Project(No.2018YFC1900301)Young Scientists Fund of the National Natural Science Foundation of China(Nos.51704028 and 51504031)the Innovation Fund of the GRIMAT Engineering Institute Co.,Ltd.(GRIMAT)(Nos.53319 and 533801)。
文摘An electrochemical method was used to examine Au surface absorption and passivation under the most commonly employed pH conditions in an alkaline Au leaching system.The polarization at different pH values was obtained through the current step curve.At pH 10,no absorption layer was formed.When the pH was increased to 11,an absorption layer was formed through the Au electrode reaction.At pH 12,the entire system could not be stabilized,even after long durations because of the thiourea oxidation and decomposition.The samples were analyzed by scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDS),and atomic force microscopy(AFM).AFM observations of the Au plating surface and SEM-EDS analyses for the Au-coated graphite surface indicated that a passivation membrane was formed on the Au surface after its use in the alkaline thiourea Au leaching system.Two-step leaching was used to confirm the conclusions drawn from the experimental results.The twostage experimental results further confirmed the existence of a passivation membrane.
基金financial support provided by World Bank Robert S.Mc Namara Fellowship Program 2015 to carry out this research abroad
文摘Extracts of elephant grass (Penniseturn purpureum) blended with some intensifier halides like ammonium chloride (AMC) and potassium iodide (PTI) were investigated as corrosion inhibitor for mild steel. The corrosion process was monitored in 3.5% HCI by mass loss and electrochemical techniques at 30, 40, 50, 60 and 90 ℃. Addition of AMC and PTI increased the inhibition efficiency with the highest inhibition efficiency obtained with PTI blend- ed extract. The blends behaved as mixed type inhibitors and were spontaneously adsorbed on mild steel surface in exothermic nature. Synergistic parameters of the intensifier ions revealed cooperative effect. Kinetic data treatment indicated increase in energy barrier by intensifier ions. The results demonstrate that elephant grass extract blended with halide ions can act as alternative ecofriendly inhibitor for mild steel at elevated temperatures.
基金This study was financially supported by the National Key Research and Development Project(No.2018YFC1900301)the National Natural Science Foundation of China(No.51504031)the Innovation Fund of the General Research Institute for Nonferrous Metals(No.53319,533801).
文摘Electrochemical tests were developed to investigate the electrochemical dissolution behavior of gold and its main coexistent sulfide minerals in acid thiocyanate solutions.The optimal leaching conditions for gold in acidic thiocyanate system were pH 2,0.15 mol·L^(-1) thiocyanate and 0.2 g·L^(-1)Fe^(3+).Fe^(3+) addition to the acidic thiocyanate system promoted gold dissolution significantly,arsenopyrite dissolution was inhibited,chalcopyrite dissolution was increased,and the dissolution behavior of other associated minerals remained mostly unchanged.Thiocyanate made gold and associated mineral leaching easier.The galvanic corrosion effect of gold and its main coexistent sulfide minerals in an acidic thiocyanate-free system was that the chalcocite,arsenopyrite and pyrite acted as a cathode to reduce anodic gold dissolution;galena as an anode undergoes oxidation to inhibit anodic gold dissolution.There was almost no galvanic corrosion behavior between stibnite,yellow sphalerite and black sphalerite and gold.Thiocyanate addition changed the galvanic corrosion behavior of stibnite and yellow sphalerite in the thiocyanate system,which inhibited anodic gold dissolution.In the acidic thiocyanate system in the presence of ferric iron,the arsenopyrite promoted anodic gold dissolution,the chalcocite and gold were mostly free of galvanic corrosion,and the remaining minerals inhibited anodic gold dissolution.
文摘In the recent years,biological nanostructures coatings have been incorporated into orthopedic and dental implants in order to accelerate osseointegration and reducing surgical restrictions.In the present work,chemical etching,anodization and metal doping surface modification methods were integrated in one strategy to fabricate innovative titanium surfaces denominated by titanium nanoporous,anodized titanium nanoporous,silver-anodized titanium nanoporous and gold-anodized titanium nanoporous.The stability properties of nanostructures-coated surfaces were elucidated using electrochemical impedance spectroscopy(EIS) after 7 days of immersion in simulated biological fluids.Morphology and chemical compositions of new surfaces were characterized by scanning electron microscope and energy-dispersive X-ray analysis.The EIS results and data fitting to the electrical equivalent circuit model demonstrated the influence of adsorption of bovine serum albumin on new surfaces as a function of protein concentration.Adsorption process was described by the very well-known model of the Langmuir adsorption isotherm.The thermodynamic parameter DGADS(-50 to 59 kJ mol^(-1)) is calculated,which supports the instantaneous adsorption of protein from biological fluids to new surfaces and refers to their good biocompatibility.Ultimately,this study explores new surface strategy to gain new implants as a means of improving clinical outcomes of patients undergoing orthopedic surgery.
基金supported by the National Natural Science Foundation of China(21975286)Shandong Provincial Natural Science Foundation(ZR2020QE058)+1 种基金the Colleges and Universities Twenty Terms Foundation of Jinan(202228053)the QLUT Special Funding for Distinguished Scholars(2419010420)。
文摘氨是一种很有前途的能源载体,由于其高氢含量和无碳的特点,可用于燃料电池,并可作为电解水制氢装置中水的替代氧化底物.然而,人们对氨电氧化反应(AOR)的机理认识不足,且缺乏廉价、高效的AOR催化剂,因而阻碍了氨基能源系统的发展.在这项工作中,我们通过光诱导化学沉淀法合成的新型Ni和Cu共掺杂的多孔FeOOH纳米棒(NiCu-FeOOH)可以作为AOR催化剂,其具有高效的催化活性(阳极电流密度达到10 mA cm^(-2)时执行电压为1.41 V)和在氨碱溶液中优异的稳定性.实验数据和理论计算结果表明,异质的Ni和Cu原子的协同作用使得NiCu-FeOOH表面的Ni和Fe位点表现出更合适的电子结构,他们可以共同吸附含氮中间产物和羟基,并使其吸附自由能位于火山形曲线的顶部,从而加速AOR脱氢.决速步骤的后移(*NH_(2)+*OH形成步骤移至*N_(2)H_(3)+*OH形成步骤)和决速步骤较低的能垒(0.86 eV)揭示了Ni和Cu的共掺策略使FeOOH晶体对催化AOR更具活性.本文创新地提出了涉及含氮中间物和羟基的共吸附反应途径,以更好地描述和模拟AOR过程,这为设计低成本和稳定的AOR催化剂开辟了新的路径.
基金the financial supports from the National Natural Science Foundation of China (No. 52270078)the Natural Science Basic Research Plan in Shaanxi Province of China (No. 2021JM-012)+1 种基金the Welfare Technology Research Plan of Zhejiang Province (No. LZY21E080003)the Fundamental Research Funds for the Central Universities (No. xjh012020037)。
文摘Anodic oxidation electrodeposition is the primary way to prepare lead dioxide anode. The regulation of the external circuit for the reaction is a unique advantage of electrocatalytic reaction, which can regulate crystallization and accelerate the reaction process. In this study, lead dioxide coatings with uniform pore size distribution were quickly prepared on three different substrates by potential linear increase electrodeposition(PLIED). Morphology and structure analysis shows that the prepared electrodes have uniform porous morphology, and Ti/SnO_(2)/PLIED has the smallest grain size. Three electrodes all display well degradation performance to azophloxine and diclofenac sodium. Ti/PLIED, and Ti/SnO_(2)/PLIED are appreciated for degrading organics with a simple structure in low concentrations. At the same time,Ti/SnO_(2)/PLIED is more suitable for complex organics in high concentrations. Electrochemical activity tests indicate the different mechanisms of the PLIED electrodes that build the other degradation performance.Three PLIED electrodes show excellent electrical and electrochemical stability during the cycle degradation process. The results provide a reference for the subsequent anodic oxidation electrodeposition research and the regulating effect of the external circuit on coating properties.