AgCl/Ti_(3)C_(2)@TiO_(2)ternary composites were prepared to form a heterojunction structure between AgCl and TiO_(2)and introduce Ti3C2 as a cocatalyst.The as-prepared AgCl/Ti_(3)C_(2)@TiO_(2)composites showed higher ...AgCl/Ti_(3)C_(2)@TiO_(2)ternary composites were prepared to form a heterojunction structure between AgCl and TiO_(2)and introduce Ti3C2 as a cocatalyst.The as-prepared AgCl/Ti_(3)C_(2)@TiO_(2)composites showed higher photocatalytic activity than pure AgCl and Ti_(3)C_(2)@TiO_(2)for photooxidation of a 1,4-dihydropyridine derivative(1,4-DHP)and tetracycline hydrochloride(TCH)under visible light irradiation(λ>400 nm).The photocatalytic activity of AgCl/Ti_(3)C_(2)@TiO_(2)composites depended on Ti_(3)C_(2)@TiO_(2)content,and the catalytic activity of the optimized samples were 6.9 times higher than that of pure AgCl for 1,4-DHP photodehydrogenation and 7.3 times higher than that of Ti_(3)C_(2)@TiO_(2)for TCH photooxidation.The increased photocatalytic activity was due to the formation of a heterojunction structure between AgCl and TiO_(2)and the introduction of Ti3C2 as a cocatalyst,which lowered the internal resistance,sped up the charge transfer,and increased the separation efficiency of photogenerated carries.Photogenerated holes and superoxide radical anions were the major active species in the photocatalytic process.展开更多
A Ni–P alloy gradient coating consisting of multiple electroless Ni–P layers with various phosphorus contents was prepared on the aviation aluminum alloy. Several characterization and electrochemical techniques were...A Ni–P alloy gradient coating consisting of multiple electroless Ni–P layers with various phosphorus contents was prepared on the aviation aluminum alloy. Several characterization and electrochemical techniques were used to characterize the different Ni–P coatings’ morphologies, phase structures, elemental compositions, and corrosion protection. The gradient coating showed good adhesion and high corrosion and wear resistance, enabling the application of aluminum alloy in harsh environments. The results showed that the double zinc immersion was vital in obtaining excellent adhesion (81.2 N). The optimal coating was not peeled and shredded even after bending tests with angles higher than 90°and was not corroded visually after 500 h of neutral salt spray test at 35℃. The high corrosion resistance was attributed to the misaligning of these micro defects in the three different nickel alloy layers and the amorphous structure of the high P content in the outer layer. These findings guide the exploration of functional gradient coatings that meet the high application requirement of aluminum alloy parts in complicated and harsh aviation environments.展开更多
The binding characteristics of indigotin with human serum albumin (HSA) and bovine serum albumin (BSA) have been investigated by various spectroscopic techniques.Spectroscopic analysis revealed that the quenching mech...The binding characteristics of indigotin with human serum albumin (HSA) and bovine serum albumin (BSA) have been investigated by various spectroscopic techniques.Spectroscopic analysis revealed that the quenching mechanism between indigotin and HSA/BSA belonged to the static quenching.The displacement experiments suggested that indigotin primarily bound to tryptophan residues on proteins within site I.The thermodynamic parameters indicated that the binding of indigotin-HSA/BSA mainly depended on the hydrophobic interaction.The binding distance of indigotin to HSA/BSA was evaluated.The results by synchronous fluorescence,three-dimensional fluorescence,Fourier Transform Infrared spectroscopy (FT-IR) and circular dichroism (CD) spectra showed that the conformation of proteins altered in the presence of indigotin.展开更多
Owing to the varied mechanisms of ORR/OER,exploiting cost-effective bifunctional catalysts with robust ORR/OER activities and excellent performances in Zn-air batteries is still a challenge.In this work,the Co/CoO@NSC...Owing to the varied mechanisms of ORR/OER,exploiting cost-effective bifunctional catalysts with robust ORR/OER activities and excellent performances in Zn-air batteries is still a challenge.In this work,the Co/CoO@NSC bifunctional catalyst is obtained by using Zn-MOF@Co-MOF as self-template.The Co/CoO@NSC composite has interconnected porous architecture with in tact metal@carb on structure,exhibiting superior electrocatalytic activities toward ORR and OER that can be comparable with the Pt/C and RuO_(2) catalysts,respectively.The Co/CoO@NSC-based aqueous Zn-air battery achieves a high specific capacity(759.7 mAh/g)and energy density(990.5 Wh/kg),and ultra-long rechargeable property(more than 400 h/1200 cycles).The Co/CoO@NSC-based solid-state Zn-air battery also delivers an excellent performance with a long cycle life(more than 143 h/858 cycles).Most importantly,the newly synthesized and recharged Co/CoO@NSC-based solid-state Zn-air battery can be used to light up a 2 V LED lamp for more than 28 h,demonstrating the superior practicability as rechargeable power source.展开更多
Selective hydrogenation of chloronitrobenzene(CNB) to chloroaniline(CAN) catalyzed by water-soluble Ru/Pt bimetallic catalyst in an aqueous-organic biphasic system was studied. It was found that the catalytic activity...Selective hydrogenation of chloronitrobenzene(CNB) to chloroaniline(CAN) catalyzed by water-soluble Ru/Pt bimetallic catalyst in an aqueous-organic biphasic system was studied. It was found that the catalytic activity increased obviously due to the addition of platinum. Ru/Pt bimetallic catalysts exhibited a strong synergistic effect when the molar ratio of Pt was in the range of 5%—80%. Under the mild conditions including a temperature of 25 ℃, a hydrogen pressure of 1.0 MPa and a Pt molar ratio of 20%, the conversion of p-chloronitrobenzene(p-CNB) reached 99.9%, with the selectivity to p-chloroaniline(p-CAN) equating to 99.4%. The Ru/Pt catalyst also showed high activity and selectivity for the hydrogenation of other chloro- and dichloro-nitrobenzenes with different substituted positions. In addition, the catalyst can be recycled five times without significant loss of activity.展开更多
Hyper-cross-linked microporous organic polymers(MOP) with controlled skeleton structure and pore distribution were prepared by Friedel-Crafts alkylation reaction. The hyper-cross-linked polymers(HCPs) produced by knit...Hyper-cross-linked microporous organic polymers(MOP) with controlled skeleton structure and pore distribution were prepared by Friedel-Crafts alkylation reaction. The hyper-cross-linked polymers(HCPs) produced by knitting aromatic functional groups posses the typical micro-and meso-porous composite structure and specific surface areas of up to 957 m^2·g^(-1). The obtained materials were evaluated as adsorbents for methylene blue(MB) and subjected to several batch adsorption tests to investigate the effects of adsorbent dosage, concentration of MB, temperature, and pH on MB removal. The maximum adsorbed capacity(q_m) of KAPs-Ph(381 mg·g^(-1), knitted using benzene) exceeded those of less mesoporous KAPs-PhPh_3(310 mg·g^(-1) knitted using 1,3,5-triphenylbenzene) and chloromethyl polystyrene resin(58 mg·g^(-1)). Moreover, KAPs-Ph could be regenerated by Soxhlet extraction with ethanol and reused for up to 15 times with minimal loss of adsorption capacity. The results illustrate that adsorption performance can be improved by controlling the pore structure of the adsorbing materials, and KAPs-Ph has a potential application values for the industrial removal of organic dyes from wastewater.展开更多
8-Oxoguanine(8-oxoG), a critical mutagenic DNA lesion induced by reactive oxygen species, gives rise to a G·C→T·A transversion during replication and thereby must be repaired. The effects of explicit and im...8-Oxoguanine(8-oxoG), a critical mutagenic DNA lesion induced by reactive oxygen species, gives rise to a G·C→T·A transversion during replication and thereby must be repaired. The effects of explicit and implicit solvent molecules on the hydrolysis cleavage of N-Glycosidic bond in 8-oxo-7,8-dihydro-2'-deoxyguanosine(8-oxo-dG) have been systematically clarified in the present work based upon two types of computational models. Detailed potential energy surface(PES) scans and full unconstraint optimizations for all the representative points on PESs were carried out at the B3LYP/6-31+G(d) level of theory. The effect of implicit solvent was tested by single-point calculation at the SCRF/IEF-PCM model. The results illustrate that the direct hydrolysis model involving one explicit water molecule can't provide a complete depiction of the hydrolysis process of 8-oxo-dG, attributed to the insufficiency of nucleophile activation and leaving group stabilization. The expansion hydrolysis model involving four explicit water molecules, however, facilitates discrete proton transfer and therefore produces smooth reaction surfaces for both the dissociative(SN1) and concerted(SN2) pathways. The presence of the implicit solvent substantially lowers all activation energies and the SN1 process is more favorable than the SN2 process. The data and insights present here agree well with the experimental results and have given out a baseline for the enzymatic deglycosylation reaction of 8-oxo-dG.展开更多
Polyimide(PI) is an organic polymer material with good stability and diverse sources that has attracted widespread attention in the field of photocatalysis. In this study, a series of PI photocatalysts were synthesize...Polyimide(PI) is an organic polymer material with good stability and diverse sources that has attracted widespread attention in the field of photocatalysis. In this study, a series of PI photocatalysts were synthesized by a thermal polymerization approach using pyromellitic dianhydride(PMDA) and various diamine monomers(melamine(MA), 4,4′-oxydianiline, and melem) as the precursors as well as different heating rates. The effects of the diamine precursor and heating rate on the structure, composition, morphology, and optical properties of the as-prepared PI materials were systematically investigated by various characterization techniques. The selective photo-oxidation of benzylamine was used as a model reaction to evaluate the photocatalytic activities of the resulting PI samples for the oxidation of amines to imines. The results revealed that the PI sample prepared using MA and PMDA as the precursors and a heating rate of 7 ℃/min(MA-PI-7) exhibited the best catalytic performance, with 98% benzylamine conversion and 98% selectivity for N-benzylidene benzylamine after 4 h of irradiation. Several benzylamine derivatives and heterocyclic amines also underwent the photo-oxidation reaction over the MA-PI-7 catalyst to afford the corresponding imines with good activity. In addition, MA-PI-7 exhibited good stability over four successive photocatalytic cycles.展开更多
A decorated ruthenium catalyst was prepared by the coprecipitation method and used for the selective hydrogenation of maleic anhydride(MA) to γ-butyrolactone(GBL). The as-prepared catalyst was characterized by XRD, T...A decorated ruthenium catalyst was prepared by the coprecipitation method and used for the selective hydrogenation of maleic anhydride(MA) to γ-butyrolactone(GBL). The as-prepared catalyst was characterized by XRD, TGDTG and N2 adsorption techniques. The characterization tests revealed that the catalyst carrier was composed of monoclinic zirconia(m-ZrO2) and hydroxyl cobalt oxide(CoO(OH)). The hydrogenation results showed that the content of CoO(OH), the reaction temperature, the hydrogen pressure and the reaction time significantly affected the catalytic selectivity to GBL. The promotional effect of CoO(OH) was remarkable, which led to an obvious increase in GBL selectivity. An 100% MA conversion and 92.0% selectivity to GBL were achieved over the Ru/ZrO2-CoO(OH)(35%) catalyst in water solvent under the conditions involving a reaction temperature of 180 ℃, a hydrogen pressure of 3.0 MPa, and a reaction time of 6 h.展开更多
The preparation of pH-responsive nanocontainers by typical silane modification of the mesoporous silica nanoparticle(MSN)surface is usually high-cost,complex,and time-consuming,which remains a great challenge for effe...The preparation of pH-responsive nanocontainers by typical silane modification of the mesoporous silica nanoparticle(MSN)surface is usually high-cost,complex,and time-consuming,which remains a great challenge for effective corrosion protection of magnesium alloy.Here,a new strategy to construct pH-responsive nanocontainers(MSN-MBT@LDH)is demonstrated.The nanocontainers consist of corrosion inhibitor(2-mercaptobenzothiazole,MBT)loaded MSN core and layered double hydroxide(LDH)nanosheet shell serving as gatekeepers.The successful loading of MBT and encapsulation by LDH nanosheets were confirmed by a series of characterization such as scanning transmission electron microscopy coupled with energy dispersive X-ray spectroscopy(STEM-EDS)and N2 adsorption/desorption isotherms.The pH-responsive feature of the nanocontainers was demonstrated by determination of the MBT concentration in buffer solutions with different pH values.A smart corrosion protection system on Mg alloy is obtained by incorporating the synthesized nanocontainers into a self-assembled nanophase particle(SNAP)coating.The electrochemical tests and visual observations show that the hybrid coating has the best barrier properties and robustness in corrosion protection in NaCl corrosive solutions in comparison with the control coatings.The present method simplifies the synthesis processes of nanocontainers and eliminates the potential detrimental effect of excess gatekeepers on the coating.The findings provide new insights into the preparation of scalable nanocontainers.The self-healing coatings are expected to have widespread applications for corrosion protection of Mg alloy and other metals.展开更多
The colloidal carbon microspheres(CMS)were prepared by the hydrothermal method.The nickel catalysts supported on carbon microspheres(Ni/CMS)were further prepared and were characterized by the Fourier transform infrare...The colloidal carbon microspheres(CMS)were prepared by the hydrothermal method.The nickel catalysts supported on carbon microspheres(Ni/CMS)were further prepared and were characterized by the Fourier transform infrared spectroscopy(FTIR),the X-ray diffraction(XRD),the scanning electron microscopy(SEM),the transmission electron microscopy(TEM),and the N_(2)adsorption technique.The selective hydrogenation of maleic anhydride(MA)to succinic anhydride(SA)over the Ni/CMS catalysts was investigated.The results indicated that the Ni/CMS catalyst,which was prepared with glucose as carbon source and calcined at 500℃,exhibited the best performance.The hydrogen pressure,reaction temperature,and reaction time could significantly affect the conversion of maleic anhydride during the hydrogenation reaction.A 98.4%conversion of MA and an 100%selectivity to SA were achieved over the Ni/CMS catalyst in acetic anhydride solvent under mild conditions covering a temperature of 90℃,a H2 pressure of 1.0 MPa,and a reaction time of 3 h.展开更多
Reduced graphene oxide(RGO) supported ruthenium(Ru) catalyst was prepared by an impregnation method using RuCl_3 as a precursor and RGO as a support.The catalyst Ru/RGO was used for the selective hydrogenation of p-ch...Reduced graphene oxide(RGO) supported ruthenium(Ru) catalyst was prepared by an impregnation method using RuCl_3 as a precursor and RGO as a support.The catalyst Ru/RGO was used for the selective hydrogenation of p-chloronitrobenzene(p-CNB) to p-chloroaniline(p-CAN),showing a selectivity of 96%at complete conversion of p-CNB at 60 ℃ and 3.0 MPa H_2.The Ru/RGO catalyst was extremely active for the hydrogenation of a series of nitroarenes,which can be attributed to the small sized and the fine dispersity of the Ru nanoparticles on the RGO sheets characterized by TEM.Moreover,the catalyst also can be recycled five times without the loss of activity.展开更多
Coating technologies are a commonly used way to protect metals against corrosion.However,with more and more severe service environments of materials,many protective coating systems often are not environmentally friend...Coating technologies are a commonly used way to protect metals against corrosion.However,with more and more severe service environments of materials,many protective coating systems often are not environmentally friendly or toxic as in the case of chromates.Based on the world’s abundant ideal magnesium(Mg)and its alloy,the smart self-healing anticorrosive coating can autonomously restore the damaged part of the coating according to the environmental changes,strengthen the corrosion protection ability,and prolong its service life.This paper reviews the research progress of smart self-healing coatings on Mg alloys.These coatings mostly contain suitable corrosion inhibitors encapsulated into micro/nano containers.Moreover,the different self-healing mechanisms and functionalities of micro/nano containers are discussed.The micro/nano containers range from inorganic nanocontainers such as mesoporous nanoparticles(silica(SiO_(2)),titanium dioxide(TiO_(2)),etc.),over inorganic clays(halloysite,hydrotalcite-like,zeolite),to organic nanocontainers such as polymer microcapsules,nanofibers,chitosan(CS)and cyclodextrin(CD),as well as,carbon materials such as graphene and carbon nanotubes and hybrids such as metal organic frameworks.The functioning of micro/nano containers can be divided in two principal groups:autonomous(based on defect filling and corrosion inhibition)and non-autonomous(based on dynamic bonds and shape memory polymers).Moreover,multi functionalities and composite applications of various micro/nano containers are summarized.At present,significant progress has been made in the preparation methods and technologies of micro/nano containers.Achieving long-term self-healing properties of coatings sensing of coating failure and early warning after self-healing function failure can be expected as the main development direction of self-healing corrosion protection coatings in the future.展开更多
Pt–Au alloy nanowires have been controllably electrodeposited on microelectrodes by applying an alternating current and were used as the electrocatalyst for formic acid oxidation. The frequency and voltage of the alt...Pt–Au alloy nanowires have been controllably electrodeposited on microelectrodes by applying an alternating current and were used as the electrocatalyst for formic acid oxidation. The frequency and voltage of the alternating current and the electrolyte composition were adjusted to precisely control the morphologies, alloying structures and composition. The characteristics of Pt–Au alloy nanowires were analyzed by scanning electron microscopy, X-ray diffraction and transmission electron spectroscopy. Electrocatalytic performance of formic acid oxidation at Pt–Au alloy nanowires electrode was investigated by cyclic voltammetry and chronoamperometry. The results showed that the Pt–Au alloy nanowires possessed highlycrystalline morphologies, the controllable bimetallic composition and single-phase alloy structures, which mainly grow in the <111> crystal orientation. The electrocatalytic activity of formic acid oxidation strongly depended on the bimetallic Pt/Au composition. The Pt35Au65 alloy nanowires displayed superior electrocatalytic performance and high stability toward the electrooxidation of formic acid in acidic solution, owing to the ensemble effect of the Pt and Au components. These ?ndings provided insights into the design of the Pt–Au bimetallic nanomaterials as electrocatalysts for formic acid oxidation.展开更多
The utilization of readily available amino acids,which is not only an oxygen nucleophile but also a nitrogen nucleophile,in palladium-catalyzed allylic substitution is realized under mild conditions.The chemoselectivi...The utilization of readily available amino acids,which is not only an oxygen nucleophile but also a nitrogen nucleophile,in palladium-catalyzed allylic substitution is realized under mild conditions.The chemoselectivity and multiple allylation are controlled by adjusting the reaction conditions.This represents the first example of this convenient access to valuable N,O-diallylated amino acids.Under the title conditions,a range of amino acids(α-,β-,γ-)and dipeptides can be readily converted in to the corresponding allylic products with excellent yields(67 examples,up to 99%yield)as well as good functional group tolerance.展开更多
TiO_2 nanocrystals/graphene hybrids(TiO_2-G) with ultrafine TiO_2 nanocrystals(~7 nm in size) conformally coated on ultrathin graphene nanosheets(~ 2 layers thick) were successfully prepared via a facile one-pot solvo...TiO_2 nanocrystals/graphene hybrids(TiO_2-G) with ultrafine TiO_2 nanocrystals(~7 nm in size) conformally coated on ultrathin graphene nanosheets(~ 2 layers thick) were successfully prepared via a facile one-pot solvothermal route under mediated conditions.With the feature of large surface area,abundant mesopores and high thermal stability,the TiOi-G nanohybrids exhibited large reversible Li-ion storage capacity with excellent cycling stability(629 mAh·g^(-1) after 400 cycles at a current of 60 mA·g^(-1)) and good rate capability(184 mAh·g^(-1) at a current density of 3 A·g^(-1)) due to the synergetic effects and strong interactions between the components,showing great promise in applications for advanced energy storage devices.展开更多
Designing single-atom nanozymes with densely exposed metal atom active sites and enhancing catalytic activity to detect pollutants remain a serious challenge.Herein,we reported a single-atom nanozyme with layered stac...Designing single-atom nanozymes with densely exposed metal atom active sites and enhancing catalytic activity to detect pollutants remain a serious challenge.Herein,we reported a single-atom nanozyme with layered stacked Fe/Cu dual active sites(Fe/Cu-NC SAzyme)synthesized via hydrothermal and hightemperature pyrolysis using folic acid as a template.Compared with Fe-NC and Cu-NC SAzyme,Fe/Cu-NC SAzyme has higher peroxidase-like activity,which indicates that the doping of synthesized Fe/Cu bimetals can improve the catalytic activity and that the atomic loading of Fe and Cu in Fe/Cu-NC is 5.5 wt%and 2.27 wt%,respectively.When S^(2-)is added to the Fe/Cu-NC catalytic system,a high-sensitivity and high-selectivity S^(2-)colorimetric sensing platform can be established,with a wide linear range(0.09-6μmol/L)and a low detection limit(30 nmol/L),which can be used to detect S^(2-)in environmental water samples.What’s more,the Fe/Cu-NC SAzyme can activate peroxymonosulfate(PMS)to degrade 99.9%of rhodamine B(Rh B)within 10 min with a degradation kinetics of 0.5943 min^(-1).This work details attractive applications in Fe/Cu-NC SAzyme colorimetric sensing and dye degradation.展开更多
Electrocoagulation(EC)has been widely used to treat the heavymetal wastewater in industry.A novel process of sinusoidal alternating current electrocoagulation(SACC)is adopted to remove Ni2+in wastewater in this study....Electrocoagulation(EC)has been widely used to treat the heavymetal wastewater in industry.A novel process of sinusoidal alternating current electrocoagulation(SACC)is adopted to remove Ni2+in wastewater in this study.The morphology of precipitates and the distribution of the main functional iron configurations were investigated.Ferron timed complex spectroscopy can identify the monomeric iron configurations[Fe(a)],oligomeric iron configurations[Fe(b)]and polymeric iron configurations[Fe(c)].The optimal operating conditions of SACC process were determined through single-factor experiments.The maximum Ni2+removal efficiency[Re(Ni^(2+))]was achieved under the conditions of pH0=7,current density(j)=7 A/m^(2),electrolysis time(t)=25 min,c0(Ni^(2+))=100 mg/L.At pH=7,the proportion of Fe(b)and Fe(c)in the system was 50.4 at.% and 23.1 at.%,respectively.In the SACC process,Fe(b)and Fe(c)are themain iron configurations in solution,while Fe(c)are the vastmajority of the iron configurations in the direct current electrocoagulation(DCC)process.Re(Ni2+)is 99.56% for SACC and 98.75% for DCC under the same optimum conditions,respectively.The precipitates produced by SACC have a high proportion of Fe(b)configurations with sphericalα-FeOOH andγ-FeOOH structures which contain abundant hydroxyl groups.Moreover,it is demonstrated that Fe(b)has better adsorption capacity than Fe(c)through adsorption experiments of methyl orange(MO)dye.Fe(a)configurations in the homogeneous solution had no effect on the removal of nickel.展开更多
基金This work was supported by the Opening Project of the Key Laboratory of Green Chemistry of Sichuan Institutes of Higher Education(LZJ2002)the Open Project of Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province(CSPC2016-3-2).
文摘AgCl/Ti_(3)C_(2)@TiO_(2)ternary composites were prepared to form a heterojunction structure between AgCl and TiO_(2)and introduce Ti3C2 as a cocatalyst.The as-prepared AgCl/Ti_(3)C_(2)@TiO_(2)composites showed higher photocatalytic activity than pure AgCl and Ti_(3)C_(2)@TiO_(2)for photooxidation of a 1,4-dihydropyridine derivative(1,4-DHP)and tetracycline hydrochloride(TCH)under visible light irradiation(λ>400 nm).The photocatalytic activity of AgCl/Ti_(3)C_(2)@TiO_(2)composites depended on Ti_(3)C_(2)@TiO_(2)content,and the catalytic activity of the optimized samples were 6.9 times higher than that of pure AgCl for 1,4-DHP photodehydrogenation and 7.3 times higher than that of Ti_(3)C_(2)@TiO_(2)for TCH photooxidation.The increased photocatalytic activity was due to the formation of a heterojunction structure between AgCl and TiO_(2)and the introduction of Ti3C2 as a cocatalyst,which lowered the internal resistance,sped up the charge transfer,and increased the separation efficiency of photogenerated carries.Photogenerated holes and superoxide radical anions were the major active species in the photocatalytic process.
基金financially supported by the National Natural Science Foundation of China (No.52271073)。
文摘A Ni–P alloy gradient coating consisting of multiple electroless Ni–P layers with various phosphorus contents was prepared on the aviation aluminum alloy. Several characterization and electrochemical techniques were used to characterize the different Ni–P coatings’ morphologies, phase structures, elemental compositions, and corrosion protection. The gradient coating showed good adhesion and high corrosion and wear resistance, enabling the application of aluminum alloy in harsh environments. The results showed that the double zinc immersion was vital in obtaining excellent adhesion (81.2 N). The optimal coating was not peeled and shredded even after bending tests with angles higher than 90°and was not corroded visually after 500 h of neutral salt spray test at 35℃. The high corrosion resistance was attributed to the misaligning of these micro defects in the three different nickel alloy layers and the amorphous structure of the high P content in the outer layer. These findings guide the exploration of functional gradient coatings that meet the high application requirement of aluminum alloy parts in complicated and harsh aviation environments.
基金support by the Education Department of Sichuan Province (12ZA171)
文摘The binding characteristics of indigotin with human serum albumin (HSA) and bovine serum albumin (BSA) have been investigated by various spectroscopic techniques.Spectroscopic analysis revealed that the quenching mechanism between indigotin and HSA/BSA belonged to the static quenching.The displacement experiments suggested that indigotin primarily bound to tryptophan residues on proteins within site I.The thermodynamic parameters indicated that the binding of indigotin-HSA/BSA mainly depended on the hydrophobic interaction.The binding distance of indigotin to HSA/BSA was evaluated.The results by synchronous fluorescence,three-dimensional fluorescence,Fourier Transform Infrared spectroscopy (FT-IR) and circular dichroism (CD) spectra showed that the conformation of proteins altered in the presence of indigotin.
基金supported by the National Natural Science Foundation of China (21706217)the Fundamental Research Funds of China West Normal University (CXTD2020-1,17C035)+1 种基金the Scientific Research Fund of Science & Technology of Sichuan (2021YJ0410)the Province and Scientific Research Fund of Sichuan Provincial Education Department (17ZA0382).
文摘Owing to the varied mechanisms of ORR/OER,exploiting cost-effective bifunctional catalysts with robust ORR/OER activities and excellent performances in Zn-air batteries is still a challenge.In this work,the Co/CoO@NSC bifunctional catalyst is obtained by using Zn-MOF@Co-MOF as self-template.The Co/CoO@NSC composite has interconnected porous architecture with in tact metal@carb on structure,exhibiting superior electrocatalytic activities toward ORR and OER that can be comparable with the Pt/C and RuO_(2) catalysts,respectively.The Co/CoO@NSC-based aqueous Zn-air battery achieves a high specific capacity(759.7 mAh/g)and energy density(990.5 Wh/kg),and ultra-long rechargeable property(more than 400 h/1200 cycles).The Co/CoO@NSC-based solid-state Zn-air battery also delivers an excellent performance with a long cycle life(more than 143 h/858 cycles).Most importantly,the newly synthesized and recharged Co/CoO@NSC-based solid-state Zn-air battery can be used to light up a 2 V LED lamp for more than 28 h,demonstrating the superior practicability as rechargeable power source.
基金the financial supports of the Natural Science Foundation of China(No.21303139)the Open Project of Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province(No.CSPC2013-1)+1 种基金the Key Fund Project of Educational Department of Sichuan Province(No.14ZA0126)the Doctoral Initiating Fund of China West Normal University(No.10B010)
文摘Selective hydrogenation of chloronitrobenzene(CNB) to chloroaniline(CAN) catalyzed by water-soluble Ru/Pt bimetallic catalyst in an aqueous-organic biphasic system was studied. It was found that the catalytic activity increased obviously due to the addition of platinum. Ru/Pt bimetallic catalysts exhibited a strong synergistic effect when the molar ratio of Pt was in the range of 5%—80%. Under the mild conditions including a temperature of 25 ℃, a hydrogen pressure of 1.0 MPa and a Pt molar ratio of 20%, the conversion of p-chloronitrobenzene(p-CNB) reached 99.9%, with the selectivity to p-chloroaniline(p-CAN) equating to 99.4%. The Ru/Pt catalyst also showed high activity and selectivity for the hydrogenation of other chloro- and dichloro-nitrobenzenes with different substituted positions. In addition, the catalyst can be recycled five times without significant loss of activity.
基金National Undergraduate Training Program for Innovation and Enterpreneurship,China(No.201710638031)Fundamental Research Funds of China West Normal University,China(No.17C038)M eritiocracy Research Funds of China West Normal University,China(No.17Y031)
文摘Hyper-cross-linked microporous organic polymers(MOP) with controlled skeleton structure and pore distribution were prepared by Friedel-Crafts alkylation reaction. The hyper-cross-linked polymers(HCPs) produced by knitting aromatic functional groups posses the typical micro-and meso-porous composite structure and specific surface areas of up to 957 m^2·g^(-1). The obtained materials were evaluated as adsorbents for methylene blue(MB) and subjected to several batch adsorption tests to investigate the effects of adsorbent dosage, concentration of MB, temperature, and pH on MB removal. The maximum adsorbed capacity(q_m) of KAPs-Ph(381 mg·g^(-1), knitted using benzene) exceeded those of less mesoporous KAPs-PhPh_3(310 mg·g^(-1) knitted using 1,3,5-triphenylbenzene) and chloromethyl polystyrene resin(58 mg·g^(-1)). Moreover, KAPs-Ph could be regenerated by Soxhlet extraction with ethanol and reused for up to 15 times with minimal loss of adsorption capacity. The results illustrate that adsorption performance can be improved by controlling the pore structure of the adsorbing materials, and KAPs-Ph has a potential application values for the industrial removal of organic dyes from wastewater.
基金supported by the National Natural Science Foundation of China(21203153 and 21173151)Science&Technology Department(2011JY0136)+1 种基金Department of Education(12ZA174)of Sichuan ProvinceChina West Normal University(11B002)
文摘8-Oxoguanine(8-oxoG), a critical mutagenic DNA lesion induced by reactive oxygen species, gives rise to a G·C→T·A transversion during replication and thereby must be repaired. The effects of explicit and implicit solvent molecules on the hydrolysis cleavage of N-Glycosidic bond in 8-oxo-7,8-dihydro-2'-deoxyguanosine(8-oxo-dG) have been systematically clarified in the present work based upon two types of computational models. Detailed potential energy surface(PES) scans and full unconstraint optimizations for all the representative points on PESs were carried out at the B3LYP/6-31+G(d) level of theory. The effect of implicit solvent was tested by single-point calculation at the SCRF/IEF-PCM model. The results illustrate that the direct hydrolysis model involving one explicit water molecule can't provide a complete depiction of the hydrolysis process of 8-oxo-dG, attributed to the insufficiency of nucleophile activation and leaving group stabilization. The expansion hydrolysis model involving four explicit water molecules, however, facilitates discrete proton transfer and therefore produces smooth reaction surfaces for both the dissociative(SN1) and concerted(SN2) pathways. The presence of the implicit solvent substantially lowers all activation energies and the SN1 process is more favorable than the SN2 process. The data and insights present here agree well with the experimental results and have given out a baseline for the enzymatic deglycosylation reaction of 8-oxo-dG.
基金the Opening Project of Key Laboratory of Green Catalysis of Higher Education Institutes of Sichuan(Grant number:LZJ2101)the Fundamental Research Funds of China West Normal University(Grant number:19D038).
文摘Polyimide(PI) is an organic polymer material with good stability and diverse sources that has attracted widespread attention in the field of photocatalysis. In this study, a series of PI photocatalysts were synthesized by a thermal polymerization approach using pyromellitic dianhydride(PMDA) and various diamine monomers(melamine(MA), 4,4′-oxydianiline, and melem) as the precursors as well as different heating rates. The effects of the diamine precursor and heating rate on the structure, composition, morphology, and optical properties of the as-prepared PI materials were systematically investigated by various characterization techniques. The selective photo-oxidation of benzylamine was used as a model reaction to evaluate the photocatalytic activities of the resulting PI samples for the oxidation of amines to imines. The results revealed that the PI sample prepared using MA and PMDA as the precursors and a heating rate of 7 ℃/min(MA-PI-7) exhibited the best catalytic performance, with 98% benzylamine conversion and 98% selectivity for N-benzylidene benzylamine after 4 h of irradiation. Several benzylamine derivatives and heterocyclic amines also underwent the photo-oxidation reaction over the MA-PI-7 catalyst to afford the corresponding imines with good activity. In addition, MA-PI-7 exhibited good stability over four successive photocatalytic cycles.
基金the financial support from the Natural Science Foundation of China(No.21303139)the Key Fund Project of Educational Department of Sichuan Province(No.14ZA0126)the Open Project of Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province(No.CSPC2013-1)
文摘A decorated ruthenium catalyst was prepared by the coprecipitation method and used for the selective hydrogenation of maleic anhydride(MA) to γ-butyrolactone(GBL). The as-prepared catalyst was characterized by XRD, TGDTG and N2 adsorption techniques. The characterization tests revealed that the catalyst carrier was composed of monoclinic zirconia(m-ZrO2) and hydroxyl cobalt oxide(CoO(OH)). The hydrogenation results showed that the content of CoO(OH), the reaction temperature, the hydrogen pressure and the reaction time significantly affected the catalytic selectivity to GBL. The promotional effect of CoO(OH) was remarkable, which led to an obvious increase in GBL selectivity. An 100% MA conversion and 92.0% selectivity to GBL were achieved over the Ru/ZrO2-CoO(OH)(35%) catalyst in water solvent under the conditions involving a reaction temperature of 180 ℃, a hydrogen pressure of 3.0 MPa, and a reaction time of 6 h.
基金Sichuan Science and Technology Program(2018JY0483)Young Elite Scientists Sponsorship Program by China Association for Science and Technology(YESS,2018QNRC001)+4 种基金Natural Science Foundation of Hunan Province(2020JJ4073)Open Project of Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province(CSPC202004)Foundation of Huaihua University Double First-rate Applied Characteristic Discipline Construction Projects of Materials Science and Engineering(19CKA002)the Fundamental Research Funds of China West Normal University(CXTD2020-1)the support from the National Science Foundation(CHE 1566283)。
文摘The preparation of pH-responsive nanocontainers by typical silane modification of the mesoporous silica nanoparticle(MSN)surface is usually high-cost,complex,and time-consuming,which remains a great challenge for effective corrosion protection of magnesium alloy.Here,a new strategy to construct pH-responsive nanocontainers(MSN-MBT@LDH)is demonstrated.The nanocontainers consist of corrosion inhibitor(2-mercaptobenzothiazole,MBT)loaded MSN core and layered double hydroxide(LDH)nanosheet shell serving as gatekeepers.The successful loading of MBT and encapsulation by LDH nanosheets were confirmed by a series of characterization such as scanning transmission electron microscopy coupled with energy dispersive X-ray spectroscopy(STEM-EDS)and N2 adsorption/desorption isotherms.The pH-responsive feature of the nanocontainers was demonstrated by determination of the MBT concentration in buffer solutions with different pH values.A smart corrosion protection system on Mg alloy is obtained by incorporating the synthesized nanocontainers into a self-assembled nanophase particle(SNAP)coating.The electrochemical tests and visual observations show that the hybrid coating has the best barrier properties and robustness in corrosion protection in NaCl corrosive solutions in comparison with the control coatings.The present method simplifies the synthesis processes of nanocontainers and eliminates the potential detrimental effect of excess gatekeepers on the coating.The findings provide new insights into the preparation of scalable nanocontainers.The self-healing coatings are expected to have widespread applications for corrosion protection of Mg alloy and other metals.
基金The authors are grateful for the financial supports of the Project of Research and Development Fund of Nanchong City(19YFZJ0107,18YFZJ0041)the Meritocracy Research Funds of China West Normal University(17YC041)the Undergraduate Training Program for Innovation of China West Normal University.(cxcy2020186).
文摘The colloidal carbon microspheres(CMS)were prepared by the hydrothermal method.The nickel catalysts supported on carbon microspheres(Ni/CMS)were further prepared and were characterized by the Fourier transform infrared spectroscopy(FTIR),the X-ray diffraction(XRD),the scanning electron microscopy(SEM),the transmission electron microscopy(TEM),and the N_(2)adsorption technique.The selective hydrogenation of maleic anhydride(MA)to succinic anhydride(SA)over the Ni/CMS catalysts was investigated.The results indicated that the Ni/CMS catalyst,which was prepared with glucose as carbon source and calcined at 500℃,exhibited the best performance.The hydrogen pressure,reaction temperature,and reaction time could significantly affect the conversion of maleic anhydride during the hydrogenation reaction.A 98.4%conversion of MA and an 100%selectivity to SA were achieved over the Ni/CMS catalyst in acetic anhydride solvent under mild conditions covering a temperature of 90℃,a H2 pressure of 1.0 MPa,and a reaction time of 3 h.
基金financially supported by the National Natural Science Foundation of China(No.21207109)Scientific Research Fund of Sichuan Provincial Education Department(No.11ZA034)the Opening Project of Key Laboratory of Green Catalysis of Sichuan Institutes of High Education(No.LZJ1205)
文摘Reduced graphene oxide(RGO) supported ruthenium(Ru) catalyst was prepared by an impregnation method using RuCl_3 as a precursor and RGO as a support.The catalyst Ru/RGO was used for the selective hydrogenation of p-chloronitrobenzene(p-CNB) to p-chloroaniline(p-CAN),showing a selectivity of 96%at complete conversion of p-CNB at 60 ℃ and 3.0 MPa H_2.The Ru/RGO catalyst was extremely active for the hydrogenation of a series of nitroarenes,which can be attributed to the small sized and the fine dispersity of the Ru nanoparticles on the RGO sheets characterized by TEM.Moreover,the catalyst also can be recycled five times without the loss of activity.
基金supported by the National Natural Science Foundation of China(51971040,52171101)the Natural Science Foundation of Chongqing(cstc2021jcyj-msxmX0613)+1 种基金the National Natural Science Foundation of China(52001036,51971044)the Independent Research Project of State Key Laboratory of Mechanical Transmissions(SKLMT-ZZKT-2022M12).
文摘Coating technologies are a commonly used way to protect metals against corrosion.However,with more and more severe service environments of materials,many protective coating systems often are not environmentally friendly or toxic as in the case of chromates.Based on the world’s abundant ideal magnesium(Mg)and its alloy,the smart self-healing anticorrosive coating can autonomously restore the damaged part of the coating according to the environmental changes,strengthen the corrosion protection ability,and prolong its service life.This paper reviews the research progress of smart self-healing coatings on Mg alloys.These coatings mostly contain suitable corrosion inhibitors encapsulated into micro/nano containers.Moreover,the different self-healing mechanisms and functionalities of micro/nano containers are discussed.The micro/nano containers range from inorganic nanocontainers such as mesoporous nanoparticles(silica(SiO_(2)),titanium dioxide(TiO_(2)),etc.),over inorganic clays(halloysite,hydrotalcite-like,zeolite),to organic nanocontainers such as polymer microcapsules,nanofibers,chitosan(CS)and cyclodextrin(CD),as well as,carbon materials such as graphene and carbon nanotubes and hybrids such as metal organic frameworks.The functioning of micro/nano containers can be divided in two principal groups:autonomous(based on defect filling and corrosion inhibition)and non-autonomous(based on dynamic bonds and shape memory polymers).Moreover,multi functionalities and composite applications of various micro/nano containers are summarized.At present,significant progress has been made in the preparation methods and technologies of micro/nano containers.Achieving long-term self-healing properties of coatings sensing of coating failure and early warning after self-healing function failure can be expected as the main development direction of self-healing corrosion protection coatings in the future.
基金supported by the National Natural Science Foundation of China(No.51271074)the Key Project of Hunan provincial Education Department of China(No.15A146)
文摘Pt–Au alloy nanowires have been controllably electrodeposited on microelectrodes by applying an alternating current and were used as the electrocatalyst for formic acid oxidation. The frequency and voltage of the alternating current and the electrolyte composition were adjusted to precisely control the morphologies, alloying structures and composition. The characteristics of Pt–Au alloy nanowires were analyzed by scanning electron microscopy, X-ray diffraction and transmission electron spectroscopy. Electrocatalytic performance of formic acid oxidation at Pt–Au alloy nanowires electrode was investigated by cyclic voltammetry and chronoamperometry. The results showed that the Pt–Au alloy nanowires possessed highlycrystalline morphologies, the controllable bimetallic composition and single-phase alloy structures, which mainly grow in the <111> crystal orientation. The electrocatalytic activity of formic acid oxidation strongly depended on the bimetallic Pt/Au composition. The Pt35Au65 alloy nanowires displayed superior electrocatalytic performance and high stability toward the electrooxidation of formic acid in acidic solution, owing to the ensemble effect of the Pt and Au components. These ?ndings provided insights into the design of the Pt–Au bimetallic nanomaterials as electrocatalysts for formic acid oxidation.
基金financial support from the National Natural Science Foundation of China(No.21602144)the Science and Technology Program of Sichuan Province(No.2018JY0485)Scientific Research Project of Education Department of Hubei Province(Nos.Q20211503,B2020057)。
文摘The utilization of readily available amino acids,which is not only an oxygen nucleophile but also a nitrogen nucleophile,in palladium-catalyzed allylic substitution is realized under mild conditions.The chemoselectivity and multiple allylation are controlled by adjusting the reaction conditions.This represents the first example of this convenient access to valuable N,O-diallylated amino acids.Under the title conditions,a range of amino acids(α-,β-,γ-)and dipeptides can be readily converted in to the corresponding allylic products with excellent yields(67 examples,up to 99%yield)as well as good functional group tolerance.
基金supported by the National Natural Science Foundation of China(51071131)the Program for New Century Excellent Talents in University(NCET-10-0890)
文摘TiO_2 nanocrystals/graphene hybrids(TiO_2-G) with ultrafine TiO_2 nanocrystals(~7 nm in size) conformally coated on ultrathin graphene nanosheets(~ 2 layers thick) were successfully prepared via a facile one-pot solvothermal route under mediated conditions.With the feature of large surface area,abundant mesopores and high thermal stability,the TiOi-G nanohybrids exhibited large reversible Li-ion storage capacity with excellent cycling stability(629 mAh·g^(-1) after 400 cycles at a current of 60 mA·g^(-1)) and good rate capability(184 mAh·g^(-1) at a current density of 3 A·g^(-1)) due to the synergetic effects and strong interactions between the components,showing great promise in applications for advanced energy storage devices.
基金Acknowledgement The project is supported by the National Basic Research Program of China （973 Program, No. 2015CB856600）, the National Natural Science Foundation of China （Grant 21472004, 21332002） and the China Postdoctoral Science Foundation Funded Project （2015M5B0911）.
基金supported by the National Natural Science Foundation of China(Nos.22276150,21906129)the Natural Science Foundation of Sichuan Province of China(No.2019YJ0522)the Innovation Team of Research at China West Normal University(No.KCXTD2022–2)。
文摘Designing single-atom nanozymes with densely exposed metal atom active sites and enhancing catalytic activity to detect pollutants remain a serious challenge.Herein,we reported a single-atom nanozyme with layered stacked Fe/Cu dual active sites(Fe/Cu-NC SAzyme)synthesized via hydrothermal and hightemperature pyrolysis using folic acid as a template.Compared with Fe-NC and Cu-NC SAzyme,Fe/Cu-NC SAzyme has higher peroxidase-like activity,which indicates that the doping of synthesized Fe/Cu bimetals can improve the catalytic activity and that the atomic loading of Fe and Cu in Fe/Cu-NC is 5.5 wt%and 2.27 wt%,respectively.When S^(2-)is added to the Fe/Cu-NC catalytic system,a high-sensitivity and high-selectivity S^(2-)colorimetric sensing platform can be established,with a wide linear range(0.09-6μmol/L)and a low detection limit(30 nmol/L),which can be used to detect S^(2-)in environmental water samples.What’s more,the Fe/Cu-NC SAzyme can activate peroxymonosulfate(PMS)to degrade 99.9%of rhodamine B(Rh B)within 10 min with a degradation kinetics of 0.5943 min^(-1).This work details attractive applications in Fe/Cu-NC SAzyme colorimetric sensing and dye degradation.
基金supported by the National Natural Science Foundation of China (No. 51974115)the National Natural Science Foundation of Hunan Province of China (No. 2020JJ4145)the Key R & D Plan Project of Changsha (No. 2021-440)
文摘Electrocoagulation(EC)has been widely used to treat the heavymetal wastewater in industry.A novel process of sinusoidal alternating current electrocoagulation(SACC)is adopted to remove Ni2+in wastewater in this study.The morphology of precipitates and the distribution of the main functional iron configurations were investigated.Ferron timed complex spectroscopy can identify the monomeric iron configurations[Fe(a)],oligomeric iron configurations[Fe(b)]and polymeric iron configurations[Fe(c)].The optimal operating conditions of SACC process were determined through single-factor experiments.The maximum Ni2+removal efficiency[Re(Ni^(2+))]was achieved under the conditions of pH0=7,current density(j)=7 A/m^(2),electrolysis time(t)=25 min,c0(Ni^(2+))=100 mg/L.At pH=7,the proportion of Fe(b)and Fe(c)in the system was 50.4 at.% and 23.1 at.%,respectively.In the SACC process,Fe(b)and Fe(c)are themain iron configurations in solution,while Fe(c)are the vastmajority of the iron configurations in the direct current electrocoagulation(DCC)process.Re(Ni2+)is 99.56% for SACC and 98.75% for DCC under the same optimum conditions,respectively.The precipitates produced by SACC have a high proportion of Fe(b)configurations with sphericalα-FeOOH andγ-FeOOH structures which contain abundant hydroxyl groups.Moreover,it is demonstrated that Fe(b)has better adsorption capacity than Fe(c)through adsorption experiments of methyl orange(MO)dye.Fe(a)configurations in the homogeneous solution had no effect on the removal of nickel.
