Designing highly active and stable noble-metal-free electrocatalysts for water splitting over a wide pH range is critical yet remains significantly challenging.In this work,Mo-doped CoP nanoparticles(Mo-CoP)supported ...Designing highly active and stable noble-metal-free electrocatalysts for water splitting over a wide pH range is critical yet remains significantly challenging.In this work,Mo-doped CoP nanoparticles(Mo-CoP)supported and enwrapped by porous single-atomic-Co doped carbon framework(Co-N-C)were designed and prepared by a simple one-pot pyrolysis method.The Mo-CoP/Co-N-C electrocatalyst exhibits superior performance with low overpotentials of only 45 mV for hydrogen evolution reaction(HER)and 201 mV for oxygen evolution reaction(OER)in 1 M KOH at 10 mA cm^(-2)current density.Such excellent catalytic activity can be ascribed to enhanced intrinsic activity,large surface area,and highly exposed active sites.Meanwhile,an extremely small overpotential of only 250 mV is required for a large current density of 500 mA cm^(-2)in HER,which exceeds the performance of benchmark 10%Pt/C.Besides,Mo-CoP/Co-N-C also exhibits superior HER performance in acidic and neutral mediums,with overpotentials of only 41 and 98 mV in 0.5 M H_(2)SO_(4),and 1 M PBS,respectively,thus achieving efficient water splitting at a wide pH range.The long-term stabilities are guaranteed with no significant decline of catalytic activities for more than 24 h in all electrolytes,which can be ascribed to the carbon layer encapsulation structure.Addition-ally,in overall water splitting,the electrocatalytic cell consisting of the as-synthesized Mo-CoP/Co-N-C only requires a cell voltage of 1.611 V at 100 mA cm^(-2)with excellent stability,exceeding that of the benchmark Pt/C||RuO(2) couple(1.645 V at 100 mA cm^(-2)).This work not only presents a highly efficient electrocatalyst for pH-universal water splitting but also provides a new perspective for the design and construction of transition metal catalysts with excellent stability.展开更多
Antibiotic pollution in aqueous solutions seriously endangers the natural environment and public health.In this work,Mo-doped transition metal FeCo–Se metal aerogels(MAs)were investigated as bifunctional catalysts fo...Antibiotic pollution in aqueous solutions seriously endangers the natural environment and public health.In this work,Mo-doped transition metal FeCo–Se metal aerogels(MAs)were investigated as bifunctional catalysts for the removal of sulfamethazine(SMT)in solution.The optimal Mo_(0.3)Fe_(1)Co_(3)–Se catalyst can remove 97.7% of SMT within 60 min(SMT content:10 mg/L,current intensity:10 mA/cm 2).The unique porous cross-linked structure of aerogel confered the catalyst sufficient active sites and efficient mass transfer channels.For the anode,Mo_(0.3)Fe_(1)Co_(3)–Se MAs exhibits superior oxygen evolution reaction(OER)property,with an overpotential of only 235 mV(10 mA/cm 2).Compared with Fe_(1)Co_(3) MAs or Mo_(0.3)Fe_(1)Co_(3) MAs,density functional theory(DFT)demonstrated that the better catalytic capacity of Mo_(0.3)Fe_(1)Co_(3)–Se MAs is attributed to the doping of Mo species and selenization lowers the energy barrier for the*OOH to O_(2) step in the OER process.Excellent OER perfor-mance ensures the self-oxygenation in this system,avoiding the addition of air or oxygen in the traditional electro-Fenton process.For the cathode,Mo doping can lead to the lattice contraction and metallic character of CoSe_(2),which is beneficial to accelerate electron transfer.The adjacent Co active sites effectively adsorb*OOH and inhibit the breakage of the O–O bond.Rotating ring disk electrode(RRDE)test indicated that Mo_(0.3)Fe_(1)Co_(3)–Se MAs has an excellent 2e^(-)ORR activity with H_(2)O_(2) selectivity up to 88%,and the generated H_(2)O_(2) is activated by the adjacent Fe site through heterogeneous Fenton process to generate⋅OH.展开更多
Summary What is already known about this topic?Worldwide,tuberculosis(TB)continues to be the most important cause of death from a single infectious agent,and China has a high TB burden.Although the reported incidence ...Summary What is already known about this topic?Worldwide,tuberculosis(TB)continues to be the most important cause of death from a single infectious agent,and China has a high TB burden.Although the reported incidence of TB in students is lower than that in general population,TB outbreaks in schools have continuously been reported in the past years,suggesting that schools are a high-risk setting for TB transmission.展开更多
The main difficulty for the recovery of Nd-Fe-B bonded magnet wastes is how to completely remove the epoxy resins.In this study,chemical reaction and physical dissolution were combined to remove the epoxy resins by ad...The main difficulty for the recovery of Nd-Fe-B bonded magnet wastes is how to completely remove the epoxy resins.In this study,chemical reaction and physical dissolution were combined to remove the epoxy resins by adding ammonia-water and mixed organic solvents.Ammonia-water can react with the epoxy functional group of epoxy resin to generate polyols.Mixed organic solvents of alcohol,dimethyl formamide(DMF),and tetrahydrofuran(THF) can dissolve the generated polyols and residual epoxy resins.Under the optimum processing conditions,the epoxy resins in the waste magnetic powders are substantially removed.The oxygen and carbon contents in the recycled magnetic powder are reduced from 13500 × 10^(-6) to 1600 × 10^(-6) and from 19500 × 10^(-6) to 2100 × 10^(-6) with the reduction ratio of88.1% and 89.2%,respectively.The recycled magnetic powder presents improved magnetic properties with MS of 1.306 × 10^(-1) A·m^(2)/g,Mr of 0.926 × 10^(-1) A·m^(2)/g,Hcj of 1.170 T,and(BH)max of 125.732 kJ/m^(3),which reach 99.8%,99.4%,95.9%,and 96.9% of the original magnetic powders,respectively.展开更多
Distributed matrix-scaled consensus is a kind of generalized cooperative control problem and has broad applications in the field of social network and engineering.This paper addresses the robust distributed matrix-sca...Distributed matrix-scaled consensus is a kind of generalized cooperative control problem and has broad applications in the field of social network and engineering.This paper addresses the robust distributed matrix-scaled consensus of perturbed multi-agent systems suffering from unknown disturbances.Distributed discontinuous protocols are first proposed to drive agents to achieve cluster consensus and suppress the effect of disturbances.Adaptive protocols with time-varying gains obeying differential equations are also designed,which are completely distributed and rely on no global information.Using the boundary layer technique,smooth protocols are proposed to avoid the unexpected chattering effect due to discontinuous functions.As a cost,under the designed smooth protocols,the defined matrix-scaled consensus error tends to a residual set rather than zero,in which the residual bound is arbitrary small by choosing proper parameters.Moreover,distributed dynamic event-based matrix-scalar consensus controllers are also proposed to avoid continuous communications.Simulation examples are provided to further verify the designed algorithms.展开更多
基金The authors gratefully thank the National Natural Science Foun-dation of China(Nos.22278431 and 21776302)for the financial support of this work.
文摘Designing highly active and stable noble-metal-free electrocatalysts for water splitting over a wide pH range is critical yet remains significantly challenging.In this work,Mo-doped CoP nanoparticles(Mo-CoP)supported and enwrapped by porous single-atomic-Co doped carbon framework(Co-N-C)were designed and prepared by a simple one-pot pyrolysis method.The Mo-CoP/Co-N-C electrocatalyst exhibits superior performance with low overpotentials of only 45 mV for hydrogen evolution reaction(HER)and 201 mV for oxygen evolution reaction(OER)in 1 M KOH at 10 mA cm^(-2)current density.Such excellent catalytic activity can be ascribed to enhanced intrinsic activity,large surface area,and highly exposed active sites.Meanwhile,an extremely small overpotential of only 250 mV is required for a large current density of 500 mA cm^(-2)in HER,which exceeds the performance of benchmark 10%Pt/C.Besides,Mo-CoP/Co-N-C also exhibits superior HER performance in acidic and neutral mediums,with overpotentials of only 41 and 98 mV in 0.5 M H_(2)SO_(4),and 1 M PBS,respectively,thus achieving efficient water splitting at a wide pH range.The long-term stabilities are guaranteed with no significant decline of catalytic activities for more than 24 h in all electrolytes,which can be ascribed to the carbon layer encapsulation structure.Addition-ally,in overall water splitting,the electrocatalytic cell consisting of the as-synthesized Mo-CoP/Co-N-C only requires a cell voltage of 1.611 V at 100 mA cm^(-2)with excellent stability,exceeding that of the benchmark Pt/C||RuO(2) couple(1.645 V at 100 mA cm^(-2)).This work not only presents a highly efficient electrocatalyst for pH-universal water splitting but also provides a new perspective for the design and construction of transition metal catalysts with excellent stability.
基金Thanks for the support of the National Natural Science Foundation of China(No.21776308)in this work.
文摘Antibiotic pollution in aqueous solutions seriously endangers the natural environment and public health.In this work,Mo-doped transition metal FeCo–Se metal aerogels(MAs)were investigated as bifunctional catalysts for the removal of sulfamethazine(SMT)in solution.The optimal Mo_(0.3)Fe_(1)Co_(3)–Se catalyst can remove 97.7% of SMT within 60 min(SMT content:10 mg/L,current intensity:10 mA/cm 2).The unique porous cross-linked structure of aerogel confered the catalyst sufficient active sites and efficient mass transfer channels.For the anode,Mo_(0.3)Fe_(1)Co_(3)–Se MAs exhibits superior oxygen evolution reaction(OER)property,with an overpotential of only 235 mV(10 mA/cm 2).Compared with Fe_(1)Co_(3) MAs or Mo_(0.3)Fe_(1)Co_(3) MAs,density functional theory(DFT)demonstrated that the better catalytic capacity of Mo_(0.3)Fe_(1)Co_(3)–Se MAs is attributed to the doping of Mo species and selenization lowers the energy barrier for the*OOH to O_(2) step in the OER process.Excellent OER perfor-mance ensures the self-oxygenation in this system,avoiding the addition of air or oxygen in the traditional electro-Fenton process.For the cathode,Mo doping can lead to the lattice contraction and metallic character of CoSe_(2),which is beneficial to accelerate electron transfer.The adjacent Co active sites effectively adsorb*OOH and inhibit the breakage of the O–O bond.Rotating ring disk electrode(RRDE)test indicated that Mo_(0.3)Fe_(1)Co_(3)–Se MAs has an excellent 2e^(-)ORR activity with H_(2)O_(2) selectivity up to 88%,and the generated H_(2)O_(2) is activated by the adjacent Fe site through heterogeneous Fenton process to generate⋅OH.
基金This work was supported by the Major Science and Technology Fund Project of Xinjiang Uygur Autonomous Region(2017A03006-1)the Center for Disease Control and Prevention Research Fund Project of Xinjiang Uygur Autonomous Region(2019001).
文摘Summary What is already known about this topic?Worldwide,tuberculosis(TB)continues to be the most important cause of death from a single infectious agent,and China has a high TB burden.Although the reported incidence of TB in students is lower than that in general population,TB outbreaks in schools have continuously been reported in the past years,suggesting that schools are a high-risk setting for TB transmission.
基金Project supported by the National Key Research and Development Program of China (YFC1903405)Major Science and Technology Projects of Anhui Province (201903a07020002)+1 种基金the Beijing Municipal Natural Science Foundation (2172012)Program of Top Disciplines Construction in Beijing(PXM2019014204500031),China。
文摘The main difficulty for the recovery of Nd-Fe-B bonded magnet wastes is how to completely remove the epoxy resins.In this study,chemical reaction and physical dissolution were combined to remove the epoxy resins by adding ammonia-water and mixed organic solvents.Ammonia-water can react with the epoxy functional group of epoxy resin to generate polyols.Mixed organic solvents of alcohol,dimethyl formamide(DMF),and tetrahydrofuran(THF) can dissolve the generated polyols and residual epoxy resins.Under the optimum processing conditions,the epoxy resins in the waste magnetic powders are substantially removed.The oxygen and carbon contents in the recycled magnetic powder are reduced from 13500 × 10^(-6) to 1600 × 10^(-6) and from 19500 × 10^(-6) to 2100 × 10^(-6) with the reduction ratio of88.1% and 89.2%,respectively.The recycled magnetic powder presents improved magnetic properties with MS of 1.306 × 10^(-1) A·m^(2)/g,Mr of 0.926 × 10^(-1) A·m^(2)/g,Hcj of 1.170 T,and(BH)max of 125.732 kJ/m^(3),which reach 99.8%,99.4%,95.9%,and 96.9% of the original magnetic powders,respectively.
基金supported in part by the National Key Research and Development Program of China(No.2020AAA0108905)by the National Natural Science Foundation of China(Nos.62103302,62273262,62088101)+7 种基金by the Shanghai Sailing Program(No.21YF1450300)by the Shanghai Chenguang Program(No.22CGA19)by the Shanghai Municipal Science and Technology Major Project(No.2021SHZDZX0100)by the Shanghai Science and Technology Planning Project(Nos.21ZR1466400,22QA1408500)by the Shanghai Municipal Commission of Science and Technology Project(No.19511132101)by the Fundamental Research Funds for the Central Universities(No.2022-5-YB-05)by the Industry,Education and Research Innovation Foundation of Chinese University(Nos.2021ZYA02008,2021ZYA03004)by the Special Fund for Independent Innovation of Aero Engine Corporation of China(No.ZZCX-2021-007).
文摘Distributed matrix-scaled consensus is a kind of generalized cooperative control problem and has broad applications in the field of social network and engineering.This paper addresses the robust distributed matrix-scaled consensus of perturbed multi-agent systems suffering from unknown disturbances.Distributed discontinuous protocols are first proposed to drive agents to achieve cluster consensus and suppress the effect of disturbances.Adaptive protocols with time-varying gains obeying differential equations are also designed,which are completely distributed and rely on no global information.Using the boundary layer technique,smooth protocols are proposed to avoid the unexpected chattering effect due to discontinuous functions.As a cost,under the designed smooth protocols,the defined matrix-scaled consensus error tends to a residual set rather than zero,in which the residual bound is arbitrary small by choosing proper parameters.Moreover,distributed dynamic event-based matrix-scalar consensus controllers are also proposed to avoid continuous communications.Simulation examples are provided to further verify the designed algorithms.