Photocatalysis offers a sustainable means for the oxidative removal of low concentrations of NOx(NO,NO2,N2O,N2O5,etc.)from the atmosphere.Layered double hydroxides(LDHs)are promising candidate photocatalysts owing to ...Photocatalysis offers a sustainable means for the oxidative removal of low concentrations of NOx(NO,NO2,N2O,N2O5,etc.)from the atmosphere.Layered double hydroxides(LDHs)are promising candidate photocatalysts owing to their unique layered and tunable chemical structures and abundant surface hydroxide(OH)moieties,which are hydroxyl radical(OH)precursors.However,the practical applications of LDHs are limited by their poor charge-separation ability and insufficient active sites.Herein,we developed a facile N_(2)H_(4)-driven etching approach to introduce dual Ni^(2+)and OHvacancies(Niv and OHv,respectively)into NiFe-LDH nanosheets(hereafter referred to as NiFe-LDH-et)to facilitate improved charge-carrier separation and active Lewis acidic site(Fe^(3+)and Ni^(2+)exposed at OHv)formation.In contrast to inert pristine LDH,NiFe-LDH-et actively removed NO under visible-light illumination.Specifically,Ni_(76)Fe_(24)-LDH-et etched with 1.50 mmol·L^(-1)N_(2)H_(4)solution removed 32.8%of the NO in continuously flowing air(NO feed concentration:500 parts per billion(ppb))under visible-light illumination,thereby outperforming most reported catalysts.Experimental and theoretical data revealed that the dual vacancies promoted the production of reactive oxygen species(O_(2)·^(-)andOH)and the adsorption of NO on the LDH.In situ spectroscopy demonstrated that NO was preferentially adsorbed at Lewis acidic sites,particularly exposed Fe^(3+)sites,converted into NO+,and subsequently oxidized to NO3without the notable formation of the more toxic intermediate NO2,thereby alleviating risks associated with its production and emission.展开更多
We report a one‐pot surfactant‐free wet‐chemical reduction approach to the synthesis of palladium/titanium nitride(Pd/TiN)and Pd/carbon(Pd/C)composites,in which^5 nm Pd NPs were uniformly dispersed on TiN or C.In t...We report a one‐pot surfactant‐free wet‐chemical reduction approach to the synthesis of palladium/titanium nitride(Pd/TiN)and Pd/carbon(Pd/C)composites,in which^5 nm Pd NPs were uniformly dispersed on TiN or C.In terms of catalytic performance,Pd/TiN showed enhanced efficiency and stability compared with those of Pd/C and bare TiN in the electrocatalytic hydrodechlorination(EHDC)reaction of 2,4‐dichlorophenol(2,4‐DCP)in aqueous solution.The superior performance of Pd/TiN arises from the promotion effect of TiN.Strong metal‐support interactions modified the electronic structure of Pd,which optimized generation of H*ads and 2,4‐DCP adsorption/activation.The cathode potential plays a vital role in controlling the EHDC efficiency and the product distribution.A working potential of?0.80 V was shown to be optimal for achieving the highest EHDC efficiency and maximizing conversion of 2,4‐DCP to phenol(P).Our studies of the reaction pathway show that EHDC of 2,4‐DCP on Pd/TiN proceeded by 2,4‐DCP→p‐chlorophenol(p‐CP),o‐chlorophenol(o‐CP)→P;however,Pd/TiN presented little selectivity for cleavage of p‐C‐Cl vs o‐C‐Cl.This work presents a new approach to enhancing Pd performance towards EHDC through the effects of a support.The strategy demonstrated here could also be extended to design highly efficient catalysts for other hydrogenation reactions.展开更多
Membrane-based separation is a promising technology to eliminate water impurities from the oil phase.However,it remains a great challenge to separate water from highly emulsified viscous oil owing to the high stabilit...Membrane-based separation is a promising technology to eliminate water impurities from the oil phase.However,it remains a great challenge to separate water from highly emulsified viscous oil owing to the high stability of the water droplets in oil.Herein we report a surface wettability engineering on an alumina ceramic membrane to achieve an efficient separation of a water-in-oil(W/O)emulsion.Silanes with different carbon chain lengths and fluorinated status were introduced to endow the alumina membrane with different surface wettabilities.While all the modified membranes exhibited excellent separation of the W/O without Span 80(surfactant),the one with amphiphobic wettability and lowest surface energy failed to separate the Span 80 stabilized W/O.The presence of Span 80 reduced the interfacial tension of water droplets,making them easier to deform and penetrate the modified membrane with the lowest surface energy.It reveals that engineering proper surface wettability is the key to separating the oil and water phases.Besides,the modified membranes maintained decent separation performance and stability under long-term run separation of the emulsified W/O.展开更多
This work reported a facile approach to surface oxygen vacancy(O_(v))-enriched urchin-like TiO_(2) microparticles(U-TiO_(2)),which were highly effective and durable in catalyzing selective nitrate reduction to ammonia...This work reported a facile approach to surface oxygen vacancy(O_(v))-enriched urchin-like TiO_(2) microparticles(U-TiO_(2)),which were highly effective and durable in catalyzing selective nitrate reduction to ammonia(NOgRR),Specifically,the U-TiO_(2)delivered a mass activity of 1.15 min^(-1)mg^(-1)calyst.a low yield of toxic NO_(2)^(-)-N intermediate(≤0.4mg/L)and an exceptional high NH_(3)^(-)-N selectivity of 98.1%in treating 22.5 mg/L of NO_(3)^(-)-N under a potential of-0.60V vs.RHE,outperforming most of the reported oxidebased catalysts.When comparing the performance of U-TiO_(2)with that of the solid amorphous TiO_(2) counterpart(A-TiO_(2))that had close particle size but more O_(v) on surfaces,we identified that the O_(v) was the reactive sites,but rather than its content,the NO_(3)RR kinetics were primarily limited by the electron and mass transfer at U-TiO_(2)/water interfaces.Accordingly,the superior performance of U-TiO_(2)to A-TiO_(2)could be ascribed to the hierarchical urchin-like structure in U-TiO_(2).The in-situ DEMS test revealed that the NO_(3)RR on U-TiO_(2)followed a pathway of ^(*)NO_(3)^(-)→^(*)NO_(2)^(-)→^(*)NO→^(*)N→^(*)NH^(-)→^(*)NH_(2)→^(*)NH_(3).We also demonstrated that the U-TiO_(2) could keep its robust performance under a wide NO_(3)^(-)-N concentration range and in the presence of some co-existing ions(such as Ca^(2+),Cl^(-),Mg^(2+)).However,the presence of humic acid and CO_(3)^(2-) in water slowed down the NO_(3)RR on U-TiO_(2).This work provides a more fundamental insight into the O_(v)-driven NO_(3)RR process on TiO_(2),which should benefit for the development of eficient TiO_(2)-based catalvsts.展开更多
Nitrate(NO_(3)^(-))is widely found in wastewater,which is harmful to human health and water environmental.Electrochemical reduction can convert NO_(3)^(-)to high value-added ammonia(NH)3)/ammonium(NH_(4)^(+))for pollu...Nitrate(NO_(3)^(-))is widely found in wastewater,which is harmful to human health and water environmental.Electrochemical reduction can convert NO_(3)^(-)to high value-added ammonia(NH)3)/ammonium(NH_(4)^(+))for pollutant removal and resource recovery.Currently,electrochemical nitrate reduction to produce ammonia(ENRA)is mostly focused on the preparation of high-performance catalysts,while ignoring the prerequisite for industrial application as the stable operation and optimal regulation of the process.Therefore,the review focused on wastewater treatment,based on the mechanism of electrochemical nitrate reduction for ammonia production and reactor construction(reactor,power supply system),then summarized the operation control strategies(such as reduction potential,nitrate concentration,inorganic ions,p H)that should be noted for ENRA.Finally,the challenges(system structure,economy)and prospects(ammonia recovery process,construction of large-scale ENRA system,application of real wastewater)of the field as it moves towards commercialization were discussed.It is hoped that this review will facilitate the scaling up of ENRA in the wastewater treatment field.展开更多
Developing high-efficient non-platinum （Pt） catalysts for oxygen reduction reaction （ORR） is the key to reduce the usage of Pt and the palladium （Pd）-based cata- lyst is a promising alternative. Here, we present...Developing high-efficient non-platinum （Pt） catalysts for oxygen reduction reaction （ORR） is the key to reduce the usage of Pt and the palladium （Pd）-based cata- lyst is a promising alternative. Here, we presented a facile approach to core/shell FePd/Pd nanoparticle （NP） catalyst with the FePd core in chemically ordered face-centered tetragonal （fct-） structure and the shell in controlled thickness from 0.32 to 0.81 nm via the thermal annealing of FePd NP followed by an electro-anodization process. With a 0.71 nm-thick Pd shell, the fct-FePd/Pd shows a robust catalytic activity and durability for ORR with the mass activities at 0.85 and 0.90 V reaching 453 and 96.7 A/mgpd, respectively, which are about 3.0 and 2.1 times higher than those of commercial Pt in alkaline media. This work presents a new class of non-Pt catalyst with superior performance to Pt for ORR catalysis, and the strategy demonstrated here can be extended to design highefficient catalysts for other chemical reactions.展开更多
An inexpensive Fe doped aluminoborate consisted of 18% Fe in PKU-1 material that exhibits high selectivity of 4-hydroxymethy-2,2-dimethyl^(-1),3-dioxolane (Solketal, 98.3%), considerable activity (TOF 51.7 h-1), and r...An inexpensive Fe doped aluminoborate consisted of 18% Fe in PKU-1 material that exhibits high selectivity of 4-hydroxymethy-2,2-dimethyl^(-1),3-dioxolane (Solketal, 98.3%), considerable activity (TOF 51.7 h-1), and recyclable ability in the ketalization of glycerol to Solketal with acetone at 318 K has been developed. Our study demonstrated that the structure of Fe (less agglomerated iron species vs. FeO clusters) can be tuned by changing Fe loading in the PKU-1 material, which correlated well with experimental observations. Furthermore, the surface boron sites were promoted by iron loading and behaved as Lewis-acid sites to facilitate the reaction process of glycerol ketalization, while the Solketal selectivity was closely related with the structure of iron species in PKU-1, which was proved by kinetic studies, density function theory (DFT) calculations, and a series of spectroscopy studies. This investigation demonstrates that the surface B sites can play important roles in the reaction instead of being spectators.展开更多
Here we report a facile defect-engineering strategy on the support to optimize the metal-support interaction and enhance the metal’s electrocatalytic hydrodechlo rination perfo rmance in converting 2,4-dichlorophenol...Here we report a facile defect-engineering strategy on the support to optimize the metal-support interaction and enhance the metal’s electrocatalytic hydrodechlo rination perfo rmance in converting 2,4-dichlorophenol(2,4-DCP)to phenol.The specific activity of the Pd nanoparticles(Pd NPs)on defective polymer carbon nitride(Pd/PCN-x)reaches 0.09 min^(-1) m^-2Pd,which is 1.5 times that of the Pd NPs supported on the perfect PCN(Pd/PCN-0).The combined experimental and theoretical results demonstrate that the strong adsorption of phenol on Pd/PCN-0 passivates the active sites,limiting the dechlorination progress.The PCN-x containing-C≡N defects can effectively mediate the spatial configuration and electronic structure of Pd NPs,and promote the preferential adsorption of 2,4-DCP rather than phenol,resulting in an enhanced dechlorination efficiency.展开更多
基金the supports from Debris of the Anthropocene to Resources(DotA2)Lab at NTU.
文摘Photocatalysis offers a sustainable means for the oxidative removal of low concentrations of NOx(NO,NO2,N2O,N2O5,etc.)from the atmosphere.Layered double hydroxides(LDHs)are promising candidate photocatalysts owing to their unique layered and tunable chemical structures and abundant surface hydroxide(OH)moieties,which are hydroxyl radical(OH)precursors.However,the practical applications of LDHs are limited by their poor charge-separation ability and insufficient active sites.Herein,we developed a facile N_(2)H_(4)-driven etching approach to introduce dual Ni^(2+)and OHvacancies(Niv and OHv,respectively)into NiFe-LDH nanosheets(hereafter referred to as NiFe-LDH-et)to facilitate improved charge-carrier separation and active Lewis acidic site(Fe^(3+)and Ni^(2+)exposed at OHv)formation.In contrast to inert pristine LDH,NiFe-LDH-et actively removed NO under visible-light illumination.Specifically,Ni_(76)Fe_(24)-LDH-et etched with 1.50 mmol·L^(-1)N_(2)H_(4)solution removed 32.8%of the NO in continuously flowing air(NO feed concentration:500 parts per billion(ppb))under visible-light illumination,thereby outperforming most reported catalysts.Experimental and theoretical data revealed that the dual vacancies promoted the production of reactive oxygen species(O_(2)·^(-)andOH)and the adsorption of NO on the LDH.In situ spectroscopy demonstrated that NO was preferentially adsorbed at Lewis acidic sites,particularly exposed Fe^(3+)sites,converted into NO+,and subsequently oxidized to NO3without the notable formation of the more toxic intermediate NO2,thereby alleviating risks associated with its production and emission.
基金supported by the National Natural Science Foundation of China(51508055,51502277)Chongqing Postdoctoral Science Foundation(Xm2016020)+2 种基金China Postdoctoral Science Foundation(2016M602660)Natural Science Foundation of Chongqing Science and Technology Commission(cstc2016jcyjA0154)Innovative Research Team of Chongqing(CXTDG201602014)~~
文摘We report a one‐pot surfactant‐free wet‐chemical reduction approach to the synthesis of palladium/titanium nitride(Pd/TiN)and Pd/carbon(Pd/C)composites,in which^5 nm Pd NPs were uniformly dispersed on TiN or C.In terms of catalytic performance,Pd/TiN showed enhanced efficiency and stability compared with those of Pd/C and bare TiN in the electrocatalytic hydrodechlorination(EHDC)reaction of 2,4‐dichlorophenol(2,4‐DCP)in aqueous solution.The superior performance of Pd/TiN arises from the promotion effect of TiN.Strong metal‐support interactions modified the electronic structure of Pd,which optimized generation of H*ads and 2,4‐DCP adsorption/activation.The cathode potential plays a vital role in controlling the EHDC efficiency and the product distribution.A working potential of?0.80 V was shown to be optimal for achieving the highest EHDC efficiency and maximizing conversion of 2,4‐DCP to phenol(P).Our studies of the reaction pathway show that EHDC of 2,4‐DCP on Pd/TiN proceeded by 2,4‐DCP→p‐chlorophenol(p‐CP),o‐chlorophenol(o‐CP)→P;however,Pd/TiN presented little selectivity for cleavage of p‐C‐Cl vs o‐C‐Cl.This work presents a new approach to enhancing Pd performance towards EHDC through the effects of a support.The strategy demonstrated here could also be extended to design highly efficient catalysts for other hydrogenation reactions.
基金supported by the Guangzhou Science and Technology Plan(No.202102020219)National Natural Science Foundation of China(No.51908565)High-level talent research startup project of Chongqing Technology and Business University(No.2356007)。
文摘Membrane-based separation is a promising technology to eliminate water impurities from the oil phase.However,it remains a great challenge to separate water from highly emulsified viscous oil owing to the high stability of the water droplets in oil.Herein we report a surface wettability engineering on an alumina ceramic membrane to achieve an efficient separation of a water-in-oil(W/O)emulsion.Silanes with different carbon chain lengths and fluorinated status were introduced to endow the alumina membrane with different surface wettabilities.While all the modified membranes exhibited excellent separation of the W/O without Span 80(surfactant),the one with amphiphobic wettability and lowest surface energy failed to separate the Span 80 stabilized W/O.The presence of Span 80 reduced the interfacial tension of water droplets,making them easier to deform and penetrate the modified membrane with the lowest surface energy.It reveals that engineering proper surface wettability is the key to separating the oil and water phases.Besides,the modified membranes maintained decent separation performance and stability under long-term run separation of the emulsified W/O.
基金financial support by National Natural Science Foundation of China(Nos.22176019,51978110)the Science and Technology Research Program of Chongqing Municipal Education Commission(Nos.KJQN201800829,KJQN201900837,KJZD-K202000802,KJQN201901527)+1 种基金Chongqing Research Student Science and Technology Innovation Project(No.CYS22724)Innovation and Entrepreneurship Training Plan for College Students(No.202111799007).
文摘This work reported a facile approach to surface oxygen vacancy(O_(v))-enriched urchin-like TiO_(2) microparticles(U-TiO_(2)),which were highly effective and durable in catalyzing selective nitrate reduction to ammonia(NOgRR),Specifically,the U-TiO_(2)delivered a mass activity of 1.15 min^(-1)mg^(-1)calyst.a low yield of toxic NO_(2)^(-)-N intermediate(≤0.4mg/L)and an exceptional high NH_(3)^(-)-N selectivity of 98.1%in treating 22.5 mg/L of NO_(3)^(-)-N under a potential of-0.60V vs.RHE,outperforming most of the reported oxidebased catalysts.When comparing the performance of U-TiO_(2)with that of the solid amorphous TiO_(2) counterpart(A-TiO_(2))that had close particle size but more O_(v) on surfaces,we identified that the O_(v) was the reactive sites,but rather than its content,the NO_(3)RR kinetics were primarily limited by the electron and mass transfer at U-TiO_(2)/water interfaces.Accordingly,the superior performance of U-TiO_(2)to A-TiO_(2)could be ascribed to the hierarchical urchin-like structure in U-TiO_(2).The in-situ DEMS test revealed that the NO_(3)RR on U-TiO_(2)followed a pathway of ^(*)NO_(3)^(-)→^(*)NO_(2)^(-)→^(*)NO→^(*)N→^(*)NH^(-)→^(*)NH_(2)→^(*)NH_(3).We also demonstrated that the U-TiO_(2) could keep its robust performance under a wide NO_(3)^(-)-N concentration range and in the presence of some co-existing ions(such as Ca^(2+),Cl^(-),Mg^(2+)).However,the presence of humic acid and CO_(3)^(2-) in water slowed down the NO_(3)RR on U-TiO_(2).This work provides a more fundamental insight into the O_(v)-driven NO_(3)RR process on TiO_(2),which should benefit for the development of eficient TiO_(2)-based catalvsts.
基金supported by the National Natural Science Foundation of China(No.51508366)Natural Science Foundation of Jiangsu Province(No.BK20201450)+1 种基金Jiangsu Qinglan Project,Suzhou Science and Technology Planning Project(No.SS202016)Kunshan Science and Technology Planning Project(No.KSF202108)。
文摘Nitrate(NO_(3)^(-))is widely found in wastewater,which is harmful to human health and water environmental.Electrochemical reduction can convert NO_(3)^(-)to high value-added ammonia(NH)3)/ammonium(NH_(4)^(+))for pollutant removal and resource recovery.Currently,electrochemical nitrate reduction to produce ammonia(ENRA)is mostly focused on the preparation of high-performance catalysts,while ignoring the prerequisite for industrial application as the stable operation and optimal regulation of the process.Therefore,the review focused on wastewater treatment,based on the mechanism of electrochemical nitrate reduction for ammonia production and reactor construction(reactor,power supply system),then summarized the operation control strategies(such as reduction potential,nitrate concentration,inorganic ions,p H)that should be noted for ENRA.Finally,the challenges(system structure,economy)and prospects(ammonia recovery process,construction of large-scale ENRA system,application of real wastewater)of the field as it moves towards commercialization were discussed.It is hoped that this review will facilitate the scaling up of ENRA in the wastewater treatment field.
基金Acknowledgments This work was supported by the Key Projects of Applied Technology Development in Chongqing （cstc2014yykfB900027, the Science and Technology Project of Chongqing Municipal Education Commission （KJI500601） and the Natural Science Foundation of Chongqing Science and Technology Commission （cstc2015jcyjA20007）.
文摘Developing high-efficient non-platinum （Pt） catalysts for oxygen reduction reaction （ORR） is the key to reduce the usage of Pt and the palladium （Pd）-based cata- lyst is a promising alternative. Here, we presented a facile approach to core/shell FePd/Pd nanoparticle （NP） catalyst with the FePd core in chemically ordered face-centered tetragonal （fct-） structure and the shell in controlled thickness from 0.32 to 0.81 nm via the thermal annealing of FePd NP followed by an electro-anodization process. With a 0.71 nm-thick Pd shell, the fct-FePd/Pd shows a robust catalytic activity and durability for ORR with the mass activities at 0.85 and 0.90 V reaching 453 and 96.7 A/mgpd, respectively, which are about 3.0 and 2.1 times higher than those of commercial Pt in alkaline media. This work presents a new class of non-Pt catalyst with superior performance to Pt for ORR catalysis, and the strategy demonstrated here can be extended to design highefficient catalysts for other chemical reactions.
基金financially supported by the Scientific and Technological Research Program of Chongqing Municipal Education Commission (Nos. KJQN202000823 and KJZD-K201900802)Research project of Chongqing Technology and Business University(No. 1956058)+2 种基金Scientific Platform ProjectMinistry of Education (No. fykf201905)US Department of Energy Office of Basic Energy Sciences,Division of Chemical,Biological and Geological Sciences (No. DE-FG02-86ER13622.A000) for support of this research。
文摘An inexpensive Fe doped aluminoborate consisted of 18% Fe in PKU-1 material that exhibits high selectivity of 4-hydroxymethy-2,2-dimethyl^(-1),3-dioxolane (Solketal, 98.3%), considerable activity (TOF 51.7 h-1), and recyclable ability in the ketalization of glycerol to Solketal with acetone at 318 K has been developed. Our study demonstrated that the structure of Fe (less agglomerated iron species vs. FeO clusters) can be tuned by changing Fe loading in the PKU-1 material, which correlated well with experimental observations. Furthermore, the surface boron sites were promoted by iron loading and behaved as Lewis-acid sites to facilitate the reaction process of glycerol ketalization, while the Solketal selectivity was closely related with the structure of iron species in PKU-1, which was proved by kinetic studies, density function theory (DFT) calculations, and a series of spectroscopy studies. This investigation demonstrates that the surface B sites can play important roles in the reaction instead of being spectators.
基金the National Key R&D Program of China(No.2019YFD1100300)National Natural Science Foundation of China(Nos.41877396,51708157)+2 种基金Shenzhen Key Technology R&D Program of China(No.JSGG20180507183210868)the State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(Nos.ES201905,2020TS02)State Key Laboratory of Separation Membranes and Membrane Processes(Tianjin Polytechnic University,No.M2-201701)。
文摘Here we report a facile defect-engineering strategy on the support to optimize the metal-support interaction and enhance the metal’s electrocatalytic hydrodechlo rination perfo rmance in converting 2,4-dichlorophenol(2,4-DCP)to phenol.The specific activity of the Pd nanoparticles(Pd NPs)on defective polymer carbon nitride(Pd/PCN-x)reaches 0.09 min^(-1) m^-2Pd,which is 1.5 times that of the Pd NPs supported on the perfect PCN(Pd/PCN-0).The combined experimental and theoretical results demonstrate that the strong adsorption of phenol on Pd/PCN-0 passivates the active sites,limiting the dechlorination progress.The PCN-x containing-C≡N defects can effectively mediate the spatial configuration and electronic structure of Pd NPs,and promote the preferential adsorption of 2,4-DCP rather than phenol,resulting in an enhanced dechlorination efficiency.
