电控离子交换技术(electrochemically switched ion exchange,ESIX)是将电活性离子交换材料(EXIMs)沉积或涂覆在导电基底上,通过电化学控制导电基底上活性材料氧化还原状态实现目标离子置入与释放,从而实现离子的分离。该技术具有痕量...电控离子交换技术(electrochemically switched ion exchange,ESIX)是将电活性离子交换材料(EXIMs)沉积或涂覆在导电基底上,通过电化学控制导电基底上活性材料氧化还原状态实现目标离子置入与释放,从而实现离子的分离。该技术具有痕量提取、无二次污染、速率可控、高选择性等优点。通过共沉淀法制备Ni Fe Mn LDH,并将其与碳纳米管(CNTs)、聚偏二氟乙烯(PVDF)混合涂覆到石墨板上,制得NiFeMn LDH/CNTs/PVDF膜电极。NiFeMn LDH层板上具有丰富的羟基官能团,可与W(Ⅵ)发生羟基配位;层间的阴离子与W(Ⅵ)进行离子交换,可为W(Ⅵ)提供丰富的活性位点。在ESIX系统中,膜电极对W(Ⅵ)的吸附容量可达122.10 mg·g^(-1),且W(Ⅵ)与Mo(Ⅵ)、Cl^(-)、■分离因子(■)分别为1.25、19.60、35.80,实现了W(Ⅵ)选择性分离。此外,该膜电极具有优异的循环稳定性,为钨的高效分离提供了新的方向。展开更多
The oxygen reduction reaction(ORR)is a crucial process in Zn-air systems,and the catalyst plays a significant role in this reaction.However,reported catalysts often suffer from poor durability and stability during the...The oxygen reduction reaction(ORR)is a crucial process in Zn-air systems,and the catalyst plays a significant role in this reaction.However,reported catalysts often suffer from poor durability and stability during the ORR process.Herein,we synthesized La-Fe bimetallic nanoparticles encapsulated in a N-doped porous carbon dodecahedron(La-Fe/NC)originated from ZIF-8 by a simple direct carbonization.The La-Fe/NC catalyst had a numerous mesopores and dendritic outer layer generated by carbon nanotubes(CNTs),forming a high conductivity network that helped to optimize electron transfer and mass transport in the ORR process.The effect of different doping transition metals and metal ratios on the ORR activity of Zn-air batteries was investigated.In alkaline media,the La-Fe/NC showed the highest ORR catalytic activity,with a half-wave potential(E_(1/2))of 0.879 V(vs.RHE,Pt/C 0.845 V).After 5000 cycles,the E_(1/2)of the La-Fe/NC catalyst only decreased by 7 m V,and its performance in stability tests and methanol tolerance tests was superior to Pt/C.When used as the air electrode in a Zn-air battery,the La-Fe/NC catalyst demonstrated an excellent specific capacity of 755 m Ah/g and a peak power density of179.8 m W/cm~2.The results provide important insights for the development of high-performance Zn-air batteries and new directions for the design of ORR catalysts.展开更多
The organic pollutants,such as quaternary ammonium compounds,in high salinity flowback water from shale gas extraction may pose a severe risk to public health.Conventional biological technologies have limited effectiv...The organic pollutants,such as quaternary ammonium compounds,in high salinity flowback water from shale gas extraction may pose a severe risk to public health.Conventional biological technologies have limited effectiveness in the treatment of high-salt wastewaters,whereas electrocatalytic oxidation has shown potential for treating organic pollutants in high-salt flowback water.This study developed a carbon nanotubes(CNTs)doped Ru/Ir oxide coated Ti electrode CNTs-(Ru_(x)Ir_(y)O_(2))/Ti,which exhibited enhanced electrocatalytic performance for the treatment of quaternary ammonium compound in high-salt wastewater compared to the control metal oxide coated Ti anode(Ru_(x)Ir_(y)O_(2))/Ti,with pseudofirst-order reaction rate constant improved from 7.36×10^(-3) to 1.12×10^(-2) min−1.Moreover,the CNTs-(Ru_(x)Ir_(y)O_(2))/Ti anode electrocatalytic oxidation system exhibited excellent cycling stability.Mechanism studies indicated that the CNTs-(Ru_(x)Ir_(y)O_(2))/Ti electrode enhanced singlet oxygen(^(1)O_(2))generation,which played a major role in pollutant degradation.Furthermore,the formation of high concentrations of HClO and H_(2)O_(2) further facilitated the generation of ^(1)O_(2).This study may provide an efficient and green technology for the treatment of organic pollutants in high-salt shale gas flowback water.展开更多
In this study,carbon nanotubes(CNTs)/AlSi10Mg composite parts with CNTs contents ranging from 0.0 to 2.0wt.%were successfully fabricated via laser powder bed fusion(LPBF)with laser scan speeds ranging from 900 to 1,90...In this study,carbon nanotubes(CNTs)/AlSi10Mg composite parts with CNTs contents ranging from 0.0 to 2.0wt.%were successfully fabricated via laser powder bed fusion(LPBF)with laser scan speeds ranging from 900 to 1,900 mm·s^(-1).Uniform dispersion of CNTs in the powders can be achieved when their content is below 2.0wt.%.In the LPBF samples,the morphology of the CNTs is found to be directly related to their content.Especially,the length of CNTs in samples prepared by LPBF increases as the CNT content increases.The length of CNTs is approximately 200-300 nm in the 1.0wt.%CNTs/AlSi10Mg composites and approximately 500-1,000 nm in the 2.0wt.%CNTs/AlSi10Mg composites.The hardness of the composites reaches its highest value of 143.3 HV when the CNTs content is 1.0wt.%and the laser scan speed is 1,300 mm·s^(-1).It is found that the self-lubricating properties of the CNTs improve the tribological properties of the composites.The coefficient of friction(CoF)and wear rate of the samples decrease with increasing CNT content.At a CNTs content of 2.0wt.%,the CoF and wear rate of the composite decrease by approximately 14%and 30%,respectively,compared to the unreinforced matrix.The presence of CNTs leads to a more complete and refined network microstructure within the samples.Both the CNTs and the aluminum carbide contribute to the Orowan mechanism and the Hall-Petch effect within the matrix.展开更多
文摘电控离子交换技术(electrochemically switched ion exchange,ESIX)是将电活性离子交换材料(EXIMs)沉积或涂覆在导电基底上,通过电化学控制导电基底上活性材料氧化还原状态实现目标离子置入与释放,从而实现离子的分离。该技术具有痕量提取、无二次污染、速率可控、高选择性等优点。通过共沉淀法制备Ni Fe Mn LDH,并将其与碳纳米管(CNTs)、聚偏二氟乙烯(PVDF)混合涂覆到石墨板上,制得NiFeMn LDH/CNTs/PVDF膜电极。NiFeMn LDH层板上具有丰富的羟基官能团,可与W(Ⅵ)发生羟基配位;层间的阴离子与W(Ⅵ)进行离子交换,可为W(Ⅵ)提供丰富的活性位点。在ESIX系统中,膜电极对W(Ⅵ)的吸附容量可达122.10 mg·g^(-1),且W(Ⅵ)与Mo(Ⅵ)、Cl^(-)、■分离因子(■)分别为1.25、19.60、35.80,实现了W(Ⅵ)选择性分离。此外,该膜电极具有优异的循环稳定性,为钨的高效分离提供了新的方向。
基金supported by the National Natural Science Foundation of China(No.22278291)the Natural Science Foundation of Shanxi Province(Nos.202203021211145 and 202303021221257)+1 种基金the National Key Research and Development(R&D)Program of China(No.2020YFB1505803)the Key Research and Development(R&D)Projects of Shanxi Province(No.202102070301018)。
文摘The oxygen reduction reaction(ORR)is a crucial process in Zn-air systems,and the catalyst plays a significant role in this reaction.However,reported catalysts often suffer from poor durability and stability during the ORR process.Herein,we synthesized La-Fe bimetallic nanoparticles encapsulated in a N-doped porous carbon dodecahedron(La-Fe/NC)originated from ZIF-8 by a simple direct carbonization.The La-Fe/NC catalyst had a numerous mesopores and dendritic outer layer generated by carbon nanotubes(CNTs),forming a high conductivity network that helped to optimize electron transfer and mass transport in the ORR process.The effect of different doping transition metals and metal ratios on the ORR activity of Zn-air batteries was investigated.In alkaline media,the La-Fe/NC showed the highest ORR catalytic activity,with a half-wave potential(E_(1/2))of 0.879 V(vs.RHE,Pt/C 0.845 V).After 5000 cycles,the E_(1/2)of the La-Fe/NC catalyst only decreased by 7 m V,and its performance in stability tests and methanol tolerance tests was superior to Pt/C.When used as the air electrode in a Zn-air battery,the La-Fe/NC catalyst demonstrated an excellent specific capacity of 755 m Ah/g and a peak power density of179.8 m W/cm~2.The results provide important insights for the development of high-performance Zn-air batteries and new directions for the design of ORR catalysts.
基金supported by the National Natural Science Foundation of China(Nos.52200186 and 52070025)Chongqing Natural Science Foundation(No.CSTB2024NSCQ-MSX0407)+1 种基金the National Key Research and Development Program of China(No.2019YFC1805502)Chongqing Municipal Human Resources and Social Security Bureau(No.2309013519935095).
文摘The organic pollutants,such as quaternary ammonium compounds,in high salinity flowback water from shale gas extraction may pose a severe risk to public health.Conventional biological technologies have limited effectiveness in the treatment of high-salt wastewaters,whereas electrocatalytic oxidation has shown potential for treating organic pollutants in high-salt flowback water.This study developed a carbon nanotubes(CNTs)doped Ru/Ir oxide coated Ti electrode CNTs-(Ru_(x)Ir_(y)O_(2))/Ti,which exhibited enhanced electrocatalytic performance for the treatment of quaternary ammonium compound in high-salt wastewater compared to the control metal oxide coated Ti anode(Ru_(x)Ir_(y)O_(2))/Ti,with pseudofirst-order reaction rate constant improved from 7.36×10^(-3) to 1.12×10^(-2) min−1.Moreover,the CNTs-(Ru_(x)Ir_(y)O_(2))/Ti anode electrocatalytic oxidation system exhibited excellent cycling stability.Mechanism studies indicated that the CNTs-(Ru_(x)Ir_(y)O_(2))/Ti electrode enhanced singlet oxygen(^(1)O_(2))generation,which played a major role in pollutant degradation.Furthermore,the formation of high concentrations of HClO and H_(2)O_(2) further facilitated the generation of ^(1)O_(2).This study may provide an efficient and green technology for the treatment of organic pollutants in high-salt shale gas flowback water.
基金supported by the Natural Science Foundation of Jiangsu Higher Education Institutions of China(Grant No.23KJD460003)the Scientific Research Foundation for High-level Talents of Nanjing Institute of Technology(Grant No.YKJ202103)the National Natural Science Foundation of China(Grant Nos.92463301,92163215,52205471,52305470).
文摘In this study,carbon nanotubes(CNTs)/AlSi10Mg composite parts with CNTs contents ranging from 0.0 to 2.0wt.%were successfully fabricated via laser powder bed fusion(LPBF)with laser scan speeds ranging from 900 to 1,900 mm·s^(-1).Uniform dispersion of CNTs in the powders can be achieved when their content is below 2.0wt.%.In the LPBF samples,the morphology of the CNTs is found to be directly related to their content.Especially,the length of CNTs in samples prepared by LPBF increases as the CNT content increases.The length of CNTs is approximately 200-300 nm in the 1.0wt.%CNTs/AlSi10Mg composites and approximately 500-1,000 nm in the 2.0wt.%CNTs/AlSi10Mg composites.The hardness of the composites reaches its highest value of 143.3 HV when the CNTs content is 1.0wt.%and the laser scan speed is 1,300 mm·s^(-1).It is found that the self-lubricating properties of the CNTs improve the tribological properties of the composites.The coefficient of friction(CoF)and wear rate of the samples decrease with increasing CNT content.At a CNTs content of 2.0wt.%,the CoF and wear rate of the composite decrease by approximately 14%and 30%,respectively,compared to the unreinforced matrix.The presence of CNTs leads to a more complete and refined network microstructure within the samples.Both the CNTs and the aluminum carbide contribute to the Orowan mechanism and the Hall-Petch effect within the matrix.
