In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl gro...In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl groups, including 2-(2-methoxyphenoxy)-1-phenylethanone, 2-(2-methoxyphenoxy)-1-phenylethanol, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanol, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanol have been selected and their electrochemical properties have been studied experimentally by cyclic voltammetry, and FT-IR spectroelectrochemistry. Combining with electrolysis products distribution analysis and density functional theory calculations, oxidation mechanisms of all six model dimers have been explored. In particular, a total effect from substituents of both para-methoxy(on the aryl ring closing to Cα) and Cα-OH on the oxidation mechanisms has been clearly observed, showing a significant selectivity on the Cα-Cβbond cleavage induced by electrochemical oxidations.展开更多
The catalyst layers(CLs) electrode is the key component of the membrane electrode assembly(MEA) in proton exchange membrane fuel cells(PEMFCs). Conventional electrodes for PEMFCs are composed of carbon-supported, iono...The catalyst layers(CLs) electrode is the key component of the membrane electrode assembly(MEA) in proton exchange membrane fuel cells(PEMFCs). Conventional electrodes for PEMFCs are composed of carbon-supported, ionomer, and Pt nanoparticles, all immersed together and sprayed with a micron-level thickness of CLs. They have a performance trade-off where increasing the Pt loading leads to higher performance of abundant triple-phase boundary areas but increases the electrode cost. Major challenges must be overcome before realizing its wide commercialization. Literature research revealed that it is impossible to achieve performance and durability targets with only high-performance catalysts, so the controllable design of CLs architecture in MEAs for PEMFCs must now be the top priority to meet industry goals. From this perspective, a 3D ordered electrode circumvents this issue with a support-free architecture and ultrathin thickness while reducing noble metal Pt loadings. Herein, we discuss the motivation in-depth and summarize the necessary CLs structural features for designing ultralow Pt loading electrodes. Critical issues that remain in progress for 3D ordered CLs must be studied and characterized. Furthermore, approaches for 3D ordered CLs architecture electrode development, involving material design, structure optimization, preparation technology, and characterization techniques, are summarized and are expected to be next-generation CLs for PEMFCs. Finally, the review concludes with perspectives on possible research directions of CL architecture to address the significant challenges in the future.展开更多
Acrylic acid(AA)is an important and widely used industrial chemical,but its high toxicity renders its use incompatible with the concept of green development.By leveraging its terminal carboxyl group and unsaturated bo...Acrylic acid(AA)is an important and widely used industrial chemical,but its high toxicity renders its use incompatible with the concept of green development.By leveraging its terminal carboxyl group and unsaturated bond,we designed and explored a new strategy to increase the greenness of AA via its eutectic melting using a quaternary ammonium salt(choline chloride)to form a deep eutectic solvent(DES),followed by polymerisation of the DES to form a polymer(poly(DES)).The greenness of AA,DES,and poly(DES)was evaluated via an in vitro test using MGC80-3 cells and an in vivo test using Kunming mice.The toxicity improved from Grade 2(moderately toxic)for AA to Grade 1(slightly toxic)for DESs and Grade 0(non-toxic)for poly(DES)in the in vitro test.Moreover,the poly(DES)s showed a lower toxicity in mice than the DESs in the in vivo test.Thus,greenness enhancement was successfully achieved,with the greenness following the order AA<DES<poly(DES).Furthermore,the mechanisms underlying the change in toxicity were explored through microscopy and flow cytometry,which revealed that the DES can permeate the MGC80-3 cell membrane during the G_(0)/G_(1) phase to adversely affect DNA synthesis in the S phase,but the poly(DES)cannot.Finally,the green poly(DES),which showed good adsorption properties and flexible functionality,was successfully applied as a carrier or excipient of drugs.Through the novel strategy reported herein,greenness enhancement and the broadening of the application scope of a toxic organic acid were achieved,making such acids applicable for green development.展开更多
The separation of ethylene glycol(EG)and 1,2-butanediol(1,2-BDO)azeotrope in the synthesis process of EG via coal and biomass is becoming of increasing commercial and environmental importance.Selective adsorption is d...The separation of ethylene glycol(EG)and 1,2-butanediol(1,2-BDO)azeotrope in the synthesis process of EG via coal and biomass is becoming of increasing commercial and environmental importance.Selective adsorption is deemed as the most promising methods because of energy saving and environment favorable.In this paper,NaY zeolite was used to separate 1,2-BDO from EG,and its adsorption properties was then investigated.The isotherms of EG and 1,2-BDO in vapor and liquid phases from 298 to 328 K indicated that they fitted Langmuir model quite well,and the NaY zeolite absorbent favored EG more than 1,2-BDO.The Grand Canonical Monte Carlo(GCMC)and molecular dynamics(MD)simulation techniques were conducted to investigate the competition adsorption and diffusion characteristics in different adsorption regions.It was observed that EG and 1,2-BDO molecules all have the most probable locations of the center of the 12-membered ring near the Na cations.The diffusivities of EG are lower than those of 1,2-BDO at the same adsorption concentration.At last,the breakthrough curves of the binary mixture regressed from the empirical Dose–Response model in fixed-bed column showed that the adsorption selectivity of EG could reach to as high as 2.43,verified that the NaY zeolite could effectively separate EG from 1,2-BDO.This work is also helpful for further separation of other dihydric alcohol mixtures from coal and biomass fermentation.展开更多
The selective dissolution of V and Fe from spent denitrification catalyst(SDC)with oxalic acid was investigated to minimise their environmental effects.The dissolution kinetics of different elements from SDC by using ...The selective dissolution of V and Fe from spent denitrification catalyst(SDC)with oxalic acid was investigated to minimise their environmental effects.The dissolution kinetics of different elements from SDC by using 0.1–1.5 mol L^(-1) oxalic acid concentration was studied at 60℃–90℃.V and Fe were preferentially released(65%and 81%)compared with Al,Ti and W within 5 min due to the redox reactions of oxalic acid.The dissolved fractions of Fe,V,Al,Wand Ti increased with the increase of oxalic acid concentration and reaction temperature.The dissolution kinetic experiments were analysed and controlled diffusion with n<0.5 according to the Avrami dissolve reaction model(R^(2)>0.92).The Arrhenius parameters of the Ea values of Ti,W,V,Fe and Al from SDC with oxalic acid were 30,26,20,19 and 11 kJ mol^(-1),respectively.The obtained Avrami equation of V and Fe was successfully used to predict their leaching behaviour in oxalic acid.Toxicity characteristic leaching procedure revealed that the toxicity risk of Vand Fe metals from SDC after leaching with oxalic acid decreased to below 5 mg kg^(-1) residua.Overall,the leaching residua by oxalic acid indicated its safety for the environment.展开更多
The Ru-catalyzed carbonylation of alkenes with CO_(2)as a C1 surrogate and imidazole chlorides as the promotor is investigated by a combination of computational and experimental study.The conversion rate of CO_(2)to C...The Ru-catalyzed carbonylation of alkenes with CO_(2)as a C1 surrogate and imidazole chlorides as the promotor is investigated by a combination of computational and experimental study.The conversion rate of CO_(2)to CO is positively correlated with the efficiency of both hydroesterification and hydroformylation,which is found facilitated in the presence of chloride additives with a decreasing order of BmimCl~B3MimCl>BmmimCl~LiCl.Taking the hydroesterification with MeOH as a representative example,BmimCl bearing C-H functionality at the C^(2)site of the cation assists the reduction of CO_(2)to CO as a hydrogen donor medium,with the anion and cation acting in a synergistic fashion.Subsequent insertion of CO_(2)into the formed Ru-H bond with the assistance of chloride anion produces the Ru-COOH species,which ultimately accelerates the activation of CO_(2).展开更多
As one of the important aspects of upgrading coal tar,the ultra-deep removal of metal ions via the complexation method was investigated by screening four complexing agents and performing density functional theory(DFT)...As one of the important aspects of upgrading coal tar,the ultra-deep removal of metal ions via the complexation method was investigated by screening four complexing agents and performing density functional theory(DFT)simulations.Analysis of the compositions and contents of the metallic compounds in the coal tar revealed that the main components were iron and calcium naphthenates.Direct filtration reduced the mechanical impurity content from 0.24%to 0.0752%,indicating that most of the large particles could be easily removed.Among the four complexing agents,namely,acetic acid,oxalic acid,citric acid,and ethylenediaminetetraacetic acid,oxalic acid exhibited the best demetallization performance.The DFT simulations suggested that the high performance of oxalic acid originated from its 1:1 coordination mode,rigid dicarboxyl structure,and greater binding energy.展开更多
N-doped reduced graphene oxide quantum dots(N-rGQDs) have attracted more and more attention in efficient catalytic degradation of aqueous organic pollutants.However,the synthesis of N-rGQDs is generally a complex and ...N-doped reduced graphene oxide quantum dots(N-rGQDs) have attracted more and more attention in efficient catalytic degradation of aqueous organic pollutants.However,the synthesis of N-rGQDs is generally a complex and high energy required process for the reduction and N-doping steps.In this study,a facile and green fabrication approach of N-rGQDs is established,based on a metal-free Fenton reaction without additional energy-input.The N structures of N-rGQDs play a significant role in the promotion of their catalytic performance.The N-rGQDs with relatively high percentage of aromatic nitrogen(NAr-rGQDs) perform excellent catalytic activities,with which the degradation efficiency of pollutant is enhanced by 25 times.Density functional theory(DFT) calculation also indicates aromatic nitrogen structures with electron-rich sites are prone to transfer electron,presenting a key role in the catalytic reaction.This metal-free Fenton process provides a green and costeffective strategy for one-step fabrication of N-rGQDs with controllable features and potential environmental catalytic applications.展开更多
Take after the advantages of lithium-ion battery (LIB) and redox flow battery (RFB), semi-solid flow battery (SSFB) is a promising electrochemical energy storage device in renewable energy utilization. The flowable sl...Take after the advantages of lithium-ion battery (LIB) and redox flow battery (RFB), semi-solid flow battery (SSFB) is a promising electrochemical energy storage device in renewable energy utilization. The flowable slurry electrode realizes decouple of energy and power density, while it also brings about new challenge to SSFBs, electron transport between active material and the out circuit. In this consideration, three types of current collectors (CCs) are applied to study the resistance and electrochemical performances of slurry cathodes within pouch cells for the first time. It proves that the electronic resistance (Re) between slurry electrode and the CC plays a decisive role in SSFB operation, and it is so large when Al foil is adopted that the cell cannot even work. Contact angle between Ketjen black (KB) slurry without active material (AM) and the CC is a preliminarily sign for the Re, the smaller the angle, the lower the resistance, and the better electrochemical performance of the cell.展开更多
The CO_(2)solubilities(including CO_(2)Henry’s constant)in physical-and chemical-based ILs/DESs and the COSMO-RS models describing these properties were comprehensively collected and summarized.The summarized results...The CO_(2)solubilities(including CO_(2)Henry’s constant)in physical-and chemical-based ILs/DESs and the COSMO-RS models describing these properties were comprehensively collected and summarized.The summarized results indicate that chemical-based ILs/DESs are superior to physical-based ILs/DESs for CO_(2)capture,especially those ILs have functionalized cation and anion,and superbase DESs;some of the superbase DESs have higher CO_(2)solubilities than those of ILs;the best physical-and chemical-based ILs,as well as physical-and chemicalbased DESs are[BMIM][BF4](4.20 mol kg^(-1)),[DETAH][Im](11.91 mol kg^(-1)),[L-Arg]-Gly 1:6(4.92 mol kg^(-1))and TBD-EG 1:4(12.90 mol kg^(-1)),respectively.Besides the original COSMO-RS mainly providing qualitative predictions,six corrected COSMO-RS models have been proposed to improve the prediction performance based on the experimental data,but only one model is with universal parameters.The newly determined experimental results were further used to verify the perditions of original and corrected COSMO-RS models.The comparison indicates that the original COSMO-RS qualitatively predicts CO_(2)solubility for some but not all ILs/DESs,while the quantitative prediction is incapable at all.The original COSMO-RS is capable to predict CO_(2)Henry’s constant qualitatively for both physical-based ILs and DESs,and quantitative prediction is only available for DESs.For the corrected COSMO-RS models,only the model with universal parameters provides quantitative predictions for CO_(2)solubility in physical-based DESs,while other corrected models always show large deviations(>83%)compared with the experimental CO_(2)Henry’s constants.展开更多
A novel hybrid material consisted of carbon covered Fe_(3)O_(4)nanoparticles and MoS_(2)nanoflower(FCM)was designed and prepared by micelle-assisted hydrothermal methods.Multiple techniques,including X-Ray diffraction...A novel hybrid material consisted of carbon covered Fe_(3)O_(4)nanoparticles and MoS_(2)nanoflower(FCM)was designed and prepared by micelle-assisted hydrothermal methods.Multiple techniques,including X-Ray diffraction(XRD),high-resolution transmission electron microscopy(HRTEM)and X-ray photoelectron spectroscopy(XPS)were employed to characterize it.The results show that FCM has a flower-like morphology with a 330 nm Fe_(3)O_(4)core as well as 70 nm highly crystalline MoS_(2)shell.FCM is superparamagnetic with a saturation magnetization of 35 emu g-1.Then hydrocracking of Canadian bitumen residue(CBR)was applied to estimate its catalytic activity.The results show that FCM exhibits superior catalytic hydrocracking activity compared to bulk MoS_(2)and commercial oil-dispersed Mo(CO)6 by the same Mo loading.Further measurement by elemental analysis,XPS and XRD reveals that the MoS_(2)nanoflower with abundant catalytic active sites and covered carbon layer with anti-coke ability donate to the superior upgrading performance.Besides,the catalysts can be easily recovered by the external magnetic field.This work provides a novel kind magnetic nanocatalyst which is potential for slurry-phase hydrocracking applications.■2020,Institute of Process Engineering,Chinese Academy of Sciences.Publishing services by Elsevier B.V.on behalf of KeAi Communications Co.,Ltd.This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).展开更多
The surface species transformation of oxidized carrollite processing with NaHS and KBX was investigated.Flotation and contact angle tests indicate that the combination of NaHS and KBX takes a better flotation performa...The surface species transformation of oxidized carrollite processing with NaHS and KBX was investigated.Flotation and contact angle tests indicate that the combination of NaHS and KBX takes a better flotation performance than adding NaHS or KBX alone.Thermodynamic analysis,X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared(FTIR) results confirm the stronger chemisorption of KBX occurs on the oxidized carrollite surface with NaHS,which is beneficial to remove the cobalt oxides,thus contributing to the superior floatability.Interestingly,less elemental sulfur was observed on the carrollite surface as the interaction of NaHS and KBX than adding NaHS alone.It suggests that elemental sulfur is not the main contributor to the restored floatability of oxidized carrollite through sulfidisation.This study provided a new perspective to correlate the surface species with xanthate adsorption and oxidized carrollite flotation through determining the various intermediate products.展开更多
Since Israelachvili and co-workers in 1970s first developed apparatuses to detect van der Waals forces of molecularly smooth mica surfaces confined down to 1.5 nm, these advanced surface techniques have been vastly ex...Since Israelachvili and co-workers in 1970s first developed apparatuses to detect van der Waals forces of molecularly smooth mica surfaces confined down to 1.5 nm, these advanced surface techniques have been vastly explored and extended to detect a variety of intermolecular forces in fluids and biomolecular systems [1]. The Surface Forces Apparatus(SFA) is one representative, which has been widely applied in the cutting-edge fields. The most fascinating advantage of SFA is on its capability to detect the force at atomic level。展开更多
Silicon nanowires(SiNWs)have been used in a wide variety of applications over the past few decades due to their excellent material properties.The only drawback is the high production cost of SiNWs.The preparation of S...Silicon nanowires(SiNWs)have been used in a wide variety of applications over the past few decades due to their excellent material properties.The only drawback is the high production cost of SiNWs.The preparation of SiNWs from photovoltaic waste silicon(WSi)powders,which are high-volume industrial wastes,not only avoids the secondary energy consumption and environmental pollution caused by complicated recycling methods,but also realizes its high-value utilization.Herein,we present a method to rapidly convert photovoltaic WSi powders into SiNWs products.The flash heating and quenching provided by carbothermal shock induce the production of free silicon atoms from the WSi powders,which are rapidly reorganized and assembled into SiNWs during the vapor-phase process.This method allows for the one-step composite of SiNWs and carbon cloth(CC)and the formation of SiC at the interface of the silicon(Si)and carbon(C)contact to create a stable chemical connection.The obtained SiNWs-CC(SiNWs@CC)composites can be directly used as lithium anodes,exhibiting high initial coulombic efficiency(86.4%)and stable cycling specific capacity(2437.4 mA h g^(-1)at 0.5 A g^(-1)after 165 cycles).In addition,various SiNWs@C composite electrodes are easily prepared using this method.展开更多
Lithium battery with high energy density and enhanced safety is undoubtedly the ideal choice for consumer electronics and electric vehicles.Metal anode such as lithium has been considered as the most effective way to ...Lithium battery with high energy density and enhanced safety is undoubtedly the ideal choice for consumer electronics and electric vehicles.Metal anode such as lithium has been considered as the most effective way to enhance the energy density as it provides ultra-high theoretical capacity and the lowest redox potential.However,due to the low coulombic efficiency as well as safety concerns originated from dendrite issue of lithium,its further commercial utilization is hindered.Dendrite growth is a common phenomenon in metal electrodeposition while the plating process of Li is more complicated than other metals for its high reactivity nature.As a matter of fact,the Li plating process is accompanied with the generation of solid electrolyte interphase(SEI)in which the electrolyte plays a vital role.In this paper,recent advances of electrolytes for Li protect application are reviewed,from liquid to gel polymer and solid state,on which we find that although tremendous progress has been accomplished,there are still great challenges before Li metal anode could be commercially used.展开更多
The cycloaddition of CO2 with epoxides catalyzed by ionic liquids(ILs)has been a widely ongoing studied hot topic over the years.Recent experimental research has shown that the protic ionic liquids(PILs)behave stronge...The cycloaddition of CO2 with epoxides catalyzed by ionic liquids(ILs)has been a widely ongoing studied hot topic over the years.Recent experimental research has shown that the protic ionic liquids(PILs)behave stronger hydrogen proton donating ability than aprotic ionic liquids(APILs),and can effectively catalyze the cycloaddition of CO2.Unfortunately,the mechanistic explanation remains primarily unraveled.Herein,a detailed simulation study on the cycloaddition reaction catalyzed by PIL([HDBU][Mim])in comparison with APIL([MeDBU][Mim])re-action catalysts was conducted,including the three-step route(ring-opening of PO(propylene oxide),insertion of CO2 and ring-closure of propylene carbonate(PC))and two-step route(simultaneously ring-opening of PO and addition of CO2,and then ring-closure of PC).Based on the activation energy barrier of the rate-determining step,PIL preferentially activates PO as the optimal route for the reaction with the energy barrier of 23.2 kcal mol-1,while that of APIL is 31.2 kcal mol-1.The role of[HDBU]+in the reaction was also explored and found that the direct formation of intermolecular hydrogen bond(H-bond)between[HDBU]+and the reactants(PO+CO2)was unfavorable for the reaction,while the cooperation with the anion[Mim]-to assist indirectly was more conducive.To fully consider the reaction microenvironment of ILs,ONIOM calculation was used to study the solvent effect.At last,the above conclusions were further verified by the analysis of intermediates with charge,non-covalent interaction(NCI),and atoms in molecules(AIM)methods.The computational findings show that ILs studied in this work have dual functions of catalyst and solvent,enabling a microscopic understanding of the ILs catalyst for CO2 utilization as well as providing guidance for the rational design of more efficient ILs-based catalysts.展开更多
It is very difficult to directly spin the lignocellulose without pretreatment.Ionic liquids(ILs)are promising solvent to dissolve lignocellulose to prepare cellulose fiber.However,the degree of cellulose polymerizatio...It is very difficult to directly spin the lignocellulose without pretreatment.Ionic liquids(ILs)are promising solvent to dissolve lignocellulose to prepare cellulose fiber.However,the degree of cellulose polymerization(DP)is reduced when lignocellulose is dissolved in ILs,and the lignin removal rate is low.The elongation at break and tensile strength of the fibers obtained by spinning the lignocellulose dissolved in ILs are poor.In this paper,preparing cellulose fiber directly from lignocellulose based on dissolving corn stalk via[C4mim]Cl-L-arginine binary system is achieved.It shows that the removal rate of lignin can reach 92.35%and the purity of cellulose can reach 85.32%after corn stalk was dissolved at 150℃C for 11.5 h when the mass fraction of arginine is 2.5%.The elongation at break of fiber reached 10.12%and the tensile strength reached 420 MPa.It is mainly due to the fact that L-arginine not only inhibits the degradation of cellulose but also promotes the delignination.Without any pulping or pretreatment,preparing cellulose fibers via direct dissolution and extrusion may provide a simple and effective way to prepare many novel cellulose materials.展开更多
In this paper,we propose“The Infinite Separation Principle”.This principle contains two implications:firstly,even exhausting all separation approaches,including chemical techniques,it is impossible to achieve 100%pu...In this paper,we propose“The Infinite Separation Principle”.This principle contains two implications:firstly,even exhausting all separation approaches,including chemical techniques,it is impossible to achieve 100%purity for separating a mixture;secondly,separation can continue infinitely without an endpoint.展开更多
Deep eutectic solvents(DESs) are now considered a new class of ionic liquid analogs that have been generously used in various fields.Herein, vanadium phosphorus oxide(VPO) catalysts are synthesized in combination with...Deep eutectic solvents(DESs) are now considered a new class of ionic liquid analogs that have been generously used in various fields.Herein, vanadium phosphorus oxide(VPO) catalysts are synthesized in combination with a deep eutectic solvent containing rare earth metal(rE-DES), and their catalytic performance in n-butane selective oxidation to produce maleic anhydride(MA) is evaluated. The rE-DES is produced from the interaction of choline chloride(ChCl) and rare earth metal salts(Cerium, Europium, Lanthanum, and Samarium metal salt)(ChCl:rE = 1:0.5–1:3) under mild conditions. It was found that DESs served as structural modifiers and electronic promoters during VPO synthesis. It regulated the chemical state of the catalyst surface, such as the vanadium valence state, acid-base properties, and ratios of V^(4+)/V^(5+),Lat–O/Sur–O and P/V. Various characterization techniques, such as FT-IR, DSC, XRD, SEM, EDS, TEM, Raman, TGA, NH3-TPD, and XPS,were used to examine its physical and chemical characteristics. These characteristics were correlated with the catalytic performance. The VPO catalyst modified by rE-DES showed a significant enhancement of n-butane conversion and MA selectivity while suppressing the selectivity of CO and CO_(2)as well as the CO/CO_(2)ratio compared to the unpromoted VPO catalyst. Especially for Ce-DES-VPO, it increased the n-butane conversion and MA mass yield up to approximately 11% and 10%, respectively. In addition, we evaluated the catalytic performance under different activation atmospheres.展开更多
基金The authors gratefully acknowledge the financial support of the Natural Science Foundation of China,China(Grant No.21975082 and 21736003)the Guangdong Basic and Applied Basic Research Foundation(Grant Number:2019A1515011472 and 2022A1515011341)the Science and Technology Program of Guangzhou(Grant Number:202102080479).
文摘In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl groups, including 2-(2-methoxyphenoxy)-1-phenylethanone, 2-(2-methoxyphenoxy)-1-phenylethanol, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanol, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanol have been selected and their electrochemical properties have been studied experimentally by cyclic voltammetry, and FT-IR spectroelectrochemistry. Combining with electrolysis products distribution analysis and density functional theory calculations, oxidation mechanisms of all six model dimers have been explored. In particular, a total effect from substituents of both para-methoxy(on the aryl ring closing to Cα) and Cα-OH on the oxidation mechanisms has been clearly observed, showing a significant selectivity on the Cα-Cβbond cleavage induced by electrochemical oxidations.
基金funded by the Natural Science Foundation of Shandong Province, China (ZR2023MB049)the China Postdoctoral Science Foundation (2020M670483)the Science Foundation of Weifang University (2023BS11)。
文摘The catalyst layers(CLs) electrode is the key component of the membrane electrode assembly(MEA) in proton exchange membrane fuel cells(PEMFCs). Conventional electrodes for PEMFCs are composed of carbon-supported, ionomer, and Pt nanoparticles, all immersed together and sprayed with a micron-level thickness of CLs. They have a performance trade-off where increasing the Pt loading leads to higher performance of abundant triple-phase boundary areas but increases the electrode cost. Major challenges must be overcome before realizing its wide commercialization. Literature research revealed that it is impossible to achieve performance and durability targets with only high-performance catalysts, so the controllable design of CLs architecture in MEAs for PEMFCs must now be the top priority to meet industry goals. From this perspective, a 3D ordered electrode circumvents this issue with a support-free architecture and ultrathin thickness while reducing noble metal Pt loadings. Herein, we discuss the motivation in-depth and summarize the necessary CLs structural features for designing ultralow Pt loading electrodes. Critical issues that remain in progress for 3D ordered CLs must be studied and characterized. Furthermore, approaches for 3D ordered CLs architecture electrode development, involving material design, structure optimization, preparation technology, and characterization techniques, are summarized and are expected to be next-generation CLs for PEMFCs. Finally, the review concludes with perspectives on possible research directions of CL architecture to address the significant challenges in the future.
基金supported by National Natural Science Foundation of China(22178081)Interdisciplinary Research Program of Natural Science of Hebei University(No.DXK202116)+1 种基金Functional Pharmaceutical Chromatographic Materials Innovation Team(605020521006)High-level Talents Introduction Program of Hebei University。
文摘Acrylic acid(AA)is an important and widely used industrial chemical,but its high toxicity renders its use incompatible with the concept of green development.By leveraging its terminal carboxyl group and unsaturated bond,we designed and explored a new strategy to increase the greenness of AA via its eutectic melting using a quaternary ammonium salt(choline chloride)to form a deep eutectic solvent(DES),followed by polymerisation of the DES to form a polymer(poly(DES)).The greenness of AA,DES,and poly(DES)was evaluated via an in vitro test using MGC80-3 cells and an in vivo test using Kunming mice.The toxicity improved from Grade 2(moderately toxic)for AA to Grade 1(slightly toxic)for DESs and Grade 0(non-toxic)for poly(DES)in the in vitro test.Moreover,the poly(DES)s showed a lower toxicity in mice than the DESs in the in vivo test.Thus,greenness enhancement was successfully achieved,with the greenness following the order AA<DES<poly(DES).Furthermore,the mechanisms underlying the change in toxicity were explored through microscopy and flow cytometry,which revealed that the DES can permeate the MGC80-3 cell membrane during the G_(0)/G_(1) phase to adversely affect DNA synthesis in the S phase,but the poly(DES)cannot.Finally,the green poly(DES),which showed good adsorption properties and flexible functionality,was successfully applied as a carrier or excipient of drugs.Through the novel strategy reported herein,greenness enhancement and the broadening of the application scope of a toxic organic acid were achieved,making such acids applicable for green development.
基金the National Natural Science Foundation of China(21576272)“Transformational Technologies for Clean Energy and Demonstration”Strategic Priority Research Program of Chinese Academy of Sciences,Grant No.XDA 21030600,Science and Technology Service Network Initiative,Chinese Academy of Sciences(KFJ-STS-QYZD-138).
文摘The separation of ethylene glycol(EG)and 1,2-butanediol(1,2-BDO)azeotrope in the synthesis process of EG via coal and biomass is becoming of increasing commercial and environmental importance.Selective adsorption is deemed as the most promising methods because of energy saving and environment favorable.In this paper,NaY zeolite was used to separate 1,2-BDO from EG,and its adsorption properties was then investigated.The isotherms of EG and 1,2-BDO in vapor and liquid phases from 298 to 328 K indicated that they fitted Langmuir model quite well,and the NaY zeolite absorbent favored EG more than 1,2-BDO.The Grand Canonical Monte Carlo(GCMC)and molecular dynamics(MD)simulation techniques were conducted to investigate the competition adsorption and diffusion characteristics in different adsorption regions.It was observed that EG and 1,2-BDO molecules all have the most probable locations of the center of the 12-membered ring near the Na cations.The diffusivities of EG are lower than those of 1,2-BDO at the same adsorption concentration.At last,the breakthrough curves of the binary mixture regressed from the empirical Dose–Response model in fixed-bed column showed that the adsorption selectivity of EG could reach to as high as 2.43,verified that the NaY zeolite could effectively separate EG from 1,2-BDO.This work is also helpful for further separation of other dihydric alcohol mixtures from coal and biomass fermentation.
基金The authors are grateful for the financial support of the National Natural Science Foundation of China(No.51574214).
文摘The selective dissolution of V and Fe from spent denitrification catalyst(SDC)with oxalic acid was investigated to minimise their environmental effects.The dissolution kinetics of different elements from SDC by using 0.1–1.5 mol L^(-1) oxalic acid concentration was studied at 60℃–90℃.V and Fe were preferentially released(65%and 81%)compared with Al,Ti and W within 5 min due to the redox reactions of oxalic acid.The dissolved fractions of Fe,V,Al,Wand Ti increased with the increase of oxalic acid concentration and reaction temperature.The dissolution kinetic experiments were analysed and controlled diffusion with n<0.5 according to the Avrami dissolve reaction model(R^(2)>0.92).The Arrhenius parameters of the Ea values of Ti,W,V,Fe and Al from SDC with oxalic acid were 30,26,20,19 and 11 kJ mol^(-1),respectively.The obtained Avrami equation of V and Fe was successfully used to predict their leaching behaviour in oxalic acid.Toxicity characteristic leaching procedure revealed that the toxicity risk of Vand Fe metals from SDC after leaching with oxalic acid decreased to below 5 mg kg^(-1) residua.Overall,the leaching residua by oxalic acid indicated its safety for the environment.
基金Financial support from National Natural Science Foundation of China (22078336, U1662133, 21773158, 22008238)Innovation Academy for Green Manufacture, CAS (IAGM2020C13) is gratefully acknowledged
文摘The Ru-catalyzed carbonylation of alkenes with CO_(2)as a C1 surrogate and imidazole chlorides as the promotor is investigated by a combination of computational and experimental study.The conversion rate of CO_(2)to CO is positively correlated with the efficiency of both hydroesterification and hydroformylation,which is found facilitated in the presence of chloride additives with a decreasing order of BmimCl~B3MimCl>BmmimCl~LiCl.Taking the hydroesterification with MeOH as a representative example,BmimCl bearing C-H functionality at the C^(2)site of the cation assists the reduction of CO_(2)to CO as a hydrogen donor medium,with the anion and cation acting in a synergistic fashion.Subsequent insertion of CO_(2)into the formed Ru-H bond with the assistance of chloride anion produces the Ru-COOH species,which ultimately accelerates the activation of CO_(2).
基金the National Energy R&D Center of Petroleum Refining Technology(RIPP,SINOPEC)the National Natural Science Foundation of China(22078347)the Key Research and Development Program of Hebei Province,China(21373303D).
文摘As one of the important aspects of upgrading coal tar,the ultra-deep removal of metal ions via the complexation method was investigated by screening four complexing agents and performing density functional theory(DFT)simulations.Analysis of the compositions and contents of the metallic compounds in the coal tar revealed that the main components were iron and calcium naphthenates.Direct filtration reduced the mechanical impurity content from 0.24%to 0.0752%,indicating that most of the large particles could be easily removed.Among the four complexing agents,namely,acetic acid,oxalic acid,citric acid,and ethylenediaminetetraacetic acid,oxalic acid exhibited the best demetallization performance.The DFT simulations suggested that the high performance of oxalic acid originated from its 1:1 coordination mode,rigid dicarboxyl structure,and greater binding energy.
基金funding by National Natural Science Foundation of China (No. 51978643)Youth Innovation Promotion Association of CAS (Y201814)The National Youth Talent Support Program of China。
文摘N-doped reduced graphene oxide quantum dots(N-rGQDs) have attracted more and more attention in efficient catalytic degradation of aqueous organic pollutants.However,the synthesis of N-rGQDs is generally a complex and high energy required process for the reduction and N-doping steps.In this study,a facile and green fabrication approach of N-rGQDs is established,based on a metal-free Fenton reaction without additional energy-input.The N structures of N-rGQDs play a significant role in the promotion of their catalytic performance.The N-rGQDs with relatively high percentage of aromatic nitrogen(NAr-rGQDs) perform excellent catalytic activities,with which the degradation efficiency of pollutant is enhanced by 25 times.Density functional theory(DFT) calculation also indicates aromatic nitrogen structures with electron-rich sites are prone to transfer electron,presenting a key role in the catalytic reaction.This metal-free Fenton process provides a green and costeffective strategy for one-step fabrication of N-rGQDs with controllable features and potential environmental catalytic applications.
基金supported by the National Key Research and Development Program of China(No.2019YFA0705603)the Heibei Natural Science Foundation of China,China,the National Natural Science Foundation of China(No.22078341)+1 种基金the Hebei Natural Science Foundation(No.B2020103028)Sincerely appreciate Prof.Suojiang Zhang(IPE,CAS)for his careful academic guidance and great support.
文摘Take after the advantages of lithium-ion battery (LIB) and redox flow battery (RFB), semi-solid flow battery (SSFB) is a promising electrochemical energy storage device in renewable energy utilization. The flowable slurry electrode realizes decouple of energy and power density, while it also brings about new challenge to SSFBs, electron transport between active material and the out circuit. In this consideration, three types of current collectors (CCs) are applied to study the resistance and electrochemical performances of slurry cathodes within pouch cells for the first time. It proves that the electronic resistance (Re) between slurry electrode and the CC plays a decisive role in SSFB operation, and it is so large when Al foil is adopted that the cell cannot even work. Contact angle between Ketjen black (KB) slurry without active material (AM) and the CC is a preliminarily sign for the Re, the smaller the angle, the lower the resistance, and the better electrochemical performance of the cell.
基金financially supported by Carl Tryggers Stiftelse foundation(No.18:175)the financial support from the Swedish Energy Agency(P47500-1)+5 种基金K.C.Wang Education Foundation(No.GJTD-201804)the financial support from the National Natural Science Foundation of China(No.21890764)the financial supports from the National Natural Science Foundation of China(No.21838010)the financial support from the National Natural Science Foundation of China(No.21776276)the National Natural Science Foundation of China(21701024)the Foundation for Distinguished Young Talents in Higher Education of Fujian Province(GY-Z17067)
文摘The CO_(2)solubilities(including CO_(2)Henry’s constant)in physical-and chemical-based ILs/DESs and the COSMO-RS models describing these properties were comprehensively collected and summarized.The summarized results indicate that chemical-based ILs/DESs are superior to physical-based ILs/DESs for CO_(2)capture,especially those ILs have functionalized cation and anion,and superbase DESs;some of the superbase DESs have higher CO_(2)solubilities than those of ILs;the best physical-and chemical-based ILs,as well as physical-and chemicalbased DESs are[BMIM][BF4](4.20 mol kg^(-1)),[DETAH][Im](11.91 mol kg^(-1)),[L-Arg]-Gly 1:6(4.92 mol kg^(-1))and TBD-EG 1:4(12.90 mol kg^(-1)),respectively.Besides the original COSMO-RS mainly providing qualitative predictions,six corrected COSMO-RS models have been proposed to improve the prediction performance based on the experimental data,but only one model is with universal parameters.The newly determined experimental results were further used to verify the perditions of original and corrected COSMO-RS models.The comparison indicates that the original COSMO-RS qualitatively predicts CO_(2)solubility for some but not all ILs/DESs,while the quantitative prediction is incapable at all.The original COSMO-RS is capable to predict CO_(2)Henry’s constant qualitatively for both physical-based ILs and DESs,and quantitative prediction is only available for DESs.For the corrected COSMO-RS models,only the model with universal parameters provides quantitative predictions for CO_(2)solubility in physical-based DESs,while other corrected models always show large deviations(>83%)compared with the experimental CO_(2)Henry’s constants.
基金financial support:The National Natural Science Foundation of China(21922814,21921005,21676273,21961160745,U1507203,31961133019)the Youth Innovation Promotion Association,CAS(Grant Nos.2016043)+1 种基金Beijing Natural Science Foundation(20194086)China Petroleum Enterprise Cooperation Project(PRIKY17094)。
文摘A novel hybrid material consisted of carbon covered Fe_(3)O_(4)nanoparticles and MoS_(2)nanoflower(FCM)was designed and prepared by micelle-assisted hydrothermal methods.Multiple techniques,including X-Ray diffraction(XRD),high-resolution transmission electron microscopy(HRTEM)and X-ray photoelectron spectroscopy(XPS)were employed to characterize it.The results show that FCM has a flower-like morphology with a 330 nm Fe_(3)O_(4)core as well as 70 nm highly crystalline MoS_(2)shell.FCM is superparamagnetic with a saturation magnetization of 35 emu g-1.Then hydrocracking of Canadian bitumen residue(CBR)was applied to estimate its catalytic activity.The results show that FCM exhibits superior catalytic hydrocracking activity compared to bulk MoS_(2)and commercial oil-dispersed Mo(CO)6 by the same Mo loading.Further measurement by elemental analysis,XPS and XRD reveals that the MoS_(2)nanoflower with abundant catalytic active sites and covered carbon layer with anti-coke ability donate to the superior upgrading performance.Besides,the catalysts can be easily recovered by the external magnetic field.This work provides a novel kind magnetic nanocatalyst which is potential for slurry-phase hydrocracking applications.■2020,Institute of Process Engineering,Chinese Academy of Sciences.Publishing services by Elsevier B.V.on behalf of KeAi Communications Co.,Ltd.This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).
基金supported by the Innovation Academy for Green Manufacture, Chinese Academy of Sciences (IAGM-2019A08)。
文摘The surface species transformation of oxidized carrollite processing with NaHS and KBX was investigated.Flotation and contact angle tests indicate that the combination of NaHS and KBX takes a better flotation performance than adding NaHS or KBX alone.Thermodynamic analysis,X-ray photoelectron spectroscopy(XPS) and Fourier transform infrared(FTIR) results confirm the stronger chemisorption of KBX occurs on the oxidized carrollite surface with NaHS,which is beneficial to remove the cobalt oxides,thus contributing to the superior floatability.Interestingly,less elemental sulfur was observed on the carrollite surface as the interaction of NaHS and KBX than adding NaHS alone.It suggests that elemental sulfur is not the main contributor to the restored floatability of oxidized carrollite through sulfidisation.This study provided a new perspective to correlate the surface species with xanthate adsorption and oxidized carrollite flotation through determining the various intermediate products.
基金supported by General Program of National Natural Science Foundation of China(21878295)Beijing Natural Science Foundation(2192052)+1 种基金Swedish Science Council for financial supportpartial support from a grant from Ministry of Research and Innovation of Romania(CNCS-UEFISCDI,project number PN-III-P4-ID-PCCF-2016-0050,within PNCDI III)。
文摘Since Israelachvili and co-workers in 1970s first developed apparatuses to detect van der Waals forces of molecularly smooth mica surfaces confined down to 1.5 nm, these advanced surface techniques have been vastly explored and extended to detect a variety of intermolecular forces in fluids and biomolecular systems [1]. The Surface Forces Apparatus(SFA) is one representative, which has been widely applied in the cutting-edge fields. The most fascinating advantage of SFA is on its capability to detect the force at atomic level。
基金partially funded by the National Natural Science Foundation of China(52074255,52274412)。
文摘Silicon nanowires(SiNWs)have been used in a wide variety of applications over the past few decades due to their excellent material properties.The only drawback is the high production cost of SiNWs.The preparation of SiNWs from photovoltaic waste silicon(WSi)powders,which are high-volume industrial wastes,not only avoids the secondary energy consumption and environmental pollution caused by complicated recycling methods,but also realizes its high-value utilization.Herein,we present a method to rapidly convert photovoltaic WSi powders into SiNWs products.The flash heating and quenching provided by carbothermal shock induce the production of free silicon atoms from the WSi powders,which are rapidly reorganized and assembled into SiNWs during the vapor-phase process.This method allows for the one-step composite of SiNWs and carbon cloth(CC)and the formation of SiC at the interface of the silicon(Si)and carbon(C)contact to create a stable chemical connection.The obtained SiNWs-CC(SiNWs@CC)composites can be directly used as lithium anodes,exhibiting high initial coulombic efficiency(86.4%)and stable cycling specific capacity(2437.4 mA h g^(-1)at 0.5 A g^(-1)after 165 cycles).In addition,various SiNWs@C composite electrodes are easily prepared using this method.
基金financially supported by the National Key Research and Development Program of China (No.2016YFB0100104)National Natural Science Foundation of China (No. 21706261 and No. 21706262)+1 种基金Beijing Natural Science Foundation (No. L172045)Beijing-Tianjin-Hebei Cooperative Innovation Community Construction Project (18244409D)
文摘Lithium battery with high energy density and enhanced safety is undoubtedly the ideal choice for consumer electronics and electric vehicles.Metal anode such as lithium has been considered as the most effective way to enhance the energy density as it provides ultra-high theoretical capacity and the lowest redox potential.However,due to the low coulombic efficiency as well as safety concerns originated from dendrite issue of lithium,its further commercial utilization is hindered.Dendrite growth is a common phenomenon in metal electrodeposition while the plating process of Li is more complicated than other metals for its high reactivity nature.As a matter of fact,the Li plating process is accompanied with the generation of solid electrolyte interphase(SEI)in which the electrolyte plays a vital role.In this paper,recent advances of electrolytes for Li protect application are reviewed,from liquid to gel polymer and solid state,on which we find that although tremendous progress has been accomplished,there are still great challenges before Li metal anode could be commercially used.
基金This work was supported by the National Science Fund for Excellent Young Scholars(21922813)and Key Research Program of Frontier Sciences of CAS(QYZDB-SSWSLH022)+2 种基金National Key Projects for Fundamental Research and Development of China(2017YFB0603301)DNL Cooperation Fund,CAS(DNL180202)and Youth Innovation Promotion Association of CAS(2017066).The authors sincerely appreciate Prof.Suojiang Zhang(IPE,CAS)for his careful academic guidance and great support.
文摘The cycloaddition of CO2 with epoxides catalyzed by ionic liquids(ILs)has been a widely ongoing studied hot topic over the years.Recent experimental research has shown that the protic ionic liquids(PILs)behave stronger hydrogen proton donating ability than aprotic ionic liquids(APILs),and can effectively catalyze the cycloaddition of CO2.Unfortunately,the mechanistic explanation remains primarily unraveled.Herein,a detailed simulation study on the cycloaddition reaction catalyzed by PIL([HDBU][Mim])in comparison with APIL([MeDBU][Mim])re-action catalysts was conducted,including the three-step route(ring-opening of PO(propylene oxide),insertion of CO2 and ring-closure of propylene carbonate(PC))and two-step route(simultaneously ring-opening of PO and addition of CO2,and then ring-closure of PC).Based on the activation energy barrier of the rate-determining step,PIL preferentially activates PO as the optimal route for the reaction with the energy barrier of 23.2 kcal mol-1,while that of APIL is 31.2 kcal mol-1.The role of[HDBU]+in the reaction was also explored and found that the direct formation of intermolecular hydrogen bond(H-bond)between[HDBU]+and the reactants(PO+CO2)was unfavorable for the reaction,while the cooperation with the anion[Mim]-to assist indirectly was more conducive.To fully consider the reaction microenvironment of ILs,ONIOM calculation was used to study the solvent effect.At last,the above conclusions were further verified by the analysis of intermediates with charge,non-covalent interaction(NCI),and atoms in molecules(AIM)methods.The computational findings show that ILs studied in this work have dual functions of catalyst and solvent,enabling a microscopic understanding of the ILs catalyst for CO2 utilization as well as providing guidance for the rational design of more efficient ILs-based catalysts.
基金This research was financially supported by the National Natural Science Foundation of China(No.21878292,No.21606240,No.21878314)K.C.Wong Education Foundation(No.GJTD-2018-04)the Strategic Priority Research Program of Chinese Academy of Science(No.XDA21060300).
文摘It is very difficult to directly spin the lignocellulose without pretreatment.Ionic liquids(ILs)are promising solvent to dissolve lignocellulose to prepare cellulose fiber.However,the degree of cellulose polymerization(DP)is reduced when lignocellulose is dissolved in ILs,and the lignin removal rate is low.The elongation at break and tensile strength of the fibers obtained by spinning the lignocellulose dissolved in ILs are poor.In this paper,preparing cellulose fiber directly from lignocellulose based on dissolving corn stalk via[C4mim]Cl-L-arginine binary system is achieved.It shows that the removal rate of lignin can reach 92.35%and the purity of cellulose can reach 85.32%after corn stalk was dissolved at 150℃C for 11.5 h when the mass fraction of arginine is 2.5%.The elongation at break of fiber reached 10.12%and the tensile strength reached 420 MPa.It is mainly due to the fact that L-arginine not only inhibits the degradation of cellulose but also promotes the delignination.Without any pulping or pretreatment,preparing cellulose fibers via direct dissolution and extrusion may provide a simple and effective way to prepare many novel cellulose materials.
文摘In this paper,we propose“The Infinite Separation Principle”.This principle contains two implications:firstly,even exhausting all separation approaches,including chemical techniques,it is impossible to achieve 100%purity for separating a mixture;secondly,separation can continue infinitely without an endpoint.
基金supported by the National Key Research and Development Program of China, China (2017YFA0206803)the Innovation Academy for Green Manufacture of Chinese Academy of Science (IAGM2020C17)+1 种基金K. C. Wong Education Foundation (No. GJTD-2018-04)Supported by the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy, China (Grant. YLU-DNL Fund2021016)。
文摘Deep eutectic solvents(DESs) are now considered a new class of ionic liquid analogs that have been generously used in various fields.Herein, vanadium phosphorus oxide(VPO) catalysts are synthesized in combination with a deep eutectic solvent containing rare earth metal(rE-DES), and their catalytic performance in n-butane selective oxidation to produce maleic anhydride(MA) is evaluated. The rE-DES is produced from the interaction of choline chloride(ChCl) and rare earth metal salts(Cerium, Europium, Lanthanum, and Samarium metal salt)(ChCl:rE = 1:0.5–1:3) under mild conditions. It was found that DESs served as structural modifiers and electronic promoters during VPO synthesis. It regulated the chemical state of the catalyst surface, such as the vanadium valence state, acid-base properties, and ratios of V^(4+)/V^(5+),Lat–O/Sur–O and P/V. Various characterization techniques, such as FT-IR, DSC, XRD, SEM, EDS, TEM, Raman, TGA, NH3-TPD, and XPS,were used to examine its physical and chemical characteristics. These characteristics were correlated with the catalytic performance. The VPO catalyst modified by rE-DES showed a significant enhancement of n-butane conversion and MA selectivity while suppressing the selectivity of CO and CO_(2)as well as the CO/CO_(2)ratio compared to the unpromoted VPO catalyst. Especially for Ce-DES-VPO, it increased the n-butane conversion and MA mass yield up to approximately 11% and 10%, respectively. In addition, we evaluated the catalytic performance under different activation atmospheres.
