Earth-abundant and nontoxic Sn-based materials have been regarded as promising catalysts for the electrochemical conversion of CO_(2)to C1 products,e.g.,CO and formate.However,it is still difficult for Snbased materia...Earth-abundant and nontoxic Sn-based materials have been regarded as promising catalysts for the electrochemical conversion of CO_(2)to C1 products,e.g.,CO and formate.However,it is still difficult for Snbased materials to obtain satisfactory performance at low-to-moderate overpotentials.Herein,a simple and facile electrospinning technique is utilized to prepare a composite of a bimetallic Sn-Co oxide/carbon matrix with a hollow nanotube structure(Sn Co-HNT).Sn Co-HNT can maintain>90%faradaic efficiencies for C1 products within a wide potential range from-0.6 VRHE to-1.2 VRHE,and a highest 94.1%selectivity towards CO in an H-type cell.Moreover,a 91.2%faradaic efficiency with a 241.3 m A cm^(-2)partial current density for C1 products could be achieved using a flow cell.According to theoretical calculations,the fusing of Sn/Co oxides on the carbon matrix accelerates electron transfer at the atomic level,causing electron deficiency of Sn centers and reversible variation between Co^(2+)and Co^(3+)centers.The synergistic effect of the Sn/Co composition improves the electron affinity of the catalyst surface,which is conducive to the adsorption and stabilization of key intermediates and eventually increases the catalytic activity in CO_(2)electroreduction.This study could provide a new strategy for the construction of oxide-derived catalysts for CO_(2)electroreduction.展开更多
In this paper,we study the Cauchy problem for the nonlinear Schrodinger equations with Coulomb potential i■_(t)u+△u+k/|x|u=λ/|u|^(p-l)u with 1<p≤5 on R^(3).Our results reveal the influence of the long range pot...In this paper,we study the Cauchy problem for the nonlinear Schrodinger equations with Coulomb potential i■_(t)u+△u+k/|x|u=λ/|u|^(p-l)u with 1<p≤5 on R^(3).Our results reveal the influence of the long range potential K|x|^(-1)on the existence and scattering theories for nonlinear Schrodinger equations.In particular,we prove the global existence when the Coulomb potential is attractive,i.e.,when K>0,and the scattering theory when the Coulomb potential is repulsive,i.e.,when K≤O.The argument is based on the newlyestablished interaction Morawetz-type inequalities and the equivalence of Sobolev norms for the Laplacian operator with the Coulomb potential.展开更多
Mineral oxidation leaching in the anode area is the key step in slurry electrolysis.By adopting the slow linear potential scanning method during slurry electrolysis,this study investigated the steady-state polarizatio...Mineral oxidation leaching in the anode area is the key step in slurry electrolysis.By adopting the slow linear potential scanning method during slurry electrolysis,this study investigated the steady-state polarization curve of a pure stibnite mineral on a graphite anode.In addition,the influence of the mineral particle size,liquid–solid ratio,stirring speed,and temperature on the collision oxidation of the mineral with the anode was studied.Based on the different oxidation reactions,the potential range can be divided into three intervals:the low-potential interval with a potential lower than 0.75 V,an intermediatepotential interval with a potential within 0.75–1.2 V,and a high-potential interval with a potential higher than 1.2 V.The collision oxidation of the mineral with the anode occurred in all three intervals.The oxidation of Sb(III)also appeared in the intermediate-and high-potential intervals,and chlorine evolution occurred in the high-potential interval.Therefore,the low-potential interval was determined to be a suitable potential interval for the slurry electrolysis process.In the low-potential interval,the particle size,liquid–solid ratio,and stirring speed had little effect on the oxidation rate of the minerals.As the temperature increased,the stibnite oxidation rate and exchange current density increased.Overall,the direct collision oxidation rate of stibnite was relatively low and the current densities under all the investigated conditions were lower than 0.4 mA·cm^(-2.This indicates that it is difficult to realize industrial production while relying solely on this process.展开更多
基金supported by the National Natural Science Foundation of China(U21A20312,22172099,21975162,51902209)the Natural Science Foundation of Guangdong(2020A1515010840)the Shenzhen Science and Technology Program(SGDX20201103095802006,RCBS20200714114819161,JCYJ20190808111801674,JCYJ20200109105803806,RCYX20200714114535052)。
文摘Earth-abundant and nontoxic Sn-based materials have been regarded as promising catalysts for the electrochemical conversion of CO_(2)to C1 products,e.g.,CO and formate.However,it is still difficult for Snbased materials to obtain satisfactory performance at low-to-moderate overpotentials.Herein,a simple and facile electrospinning technique is utilized to prepare a composite of a bimetallic Sn-Co oxide/carbon matrix with a hollow nanotube structure(Sn Co-HNT).Sn Co-HNT can maintain>90%faradaic efficiencies for C1 products within a wide potential range from-0.6 VRHE to-1.2 VRHE,and a highest 94.1%selectivity towards CO in an H-type cell.Moreover,a 91.2%faradaic efficiency with a 241.3 m A cm^(-2)partial current density for C1 products could be achieved using a flow cell.According to theoretical calculations,the fusing of Sn/Co oxides on the carbon matrix accelerates electron transfer at the atomic level,causing electron deficiency of Sn centers and reversible variation between Co^(2+)and Co^(3+)centers.The synergistic effect of the Sn/Co composition improves the electron affinity of the catalyst surface,which is conducive to the adsorption and stabilization of key intermediates and eventually increases the catalytic activity in CO_(2)electroreduction.This study could provide a new strategy for the construction of oxide-derived catalysts for CO_(2)electroreduction.
基金The authors were supported by NSFC(12126409,12026407,11831004)the J.Zheng was also supported by Beijing Natural Science Foundation(1222019)。
文摘In this paper,we study the Cauchy problem for the nonlinear Schrodinger equations with Coulomb potential i■_(t)u+△u+k/|x|u=λ/|u|^(p-l)u with 1<p≤5 on R^(3).Our results reveal the influence of the long range potential K|x|^(-1)on the existence and scattering theories for nonlinear Schrodinger equations.In particular,we prove the global existence when the Coulomb potential is attractive,i.e.,when K>0,and the scattering theory when the Coulomb potential is repulsive,i.e.,when K≤O.The argument is based on the newlyestablished interaction Morawetz-type inequalities and the equivalence of Sobolev norms for the Laplacian operator with the Coulomb potential.
基金supported by the National Key Research&Development Program of China(2019YFC1908404)the Major Science and Technology Projects of Qinghai Province(2018-GXA7)the National Natural Science Foundation of China(51604030)。
文摘Mineral oxidation leaching in the anode area is the key step in slurry electrolysis.By adopting the slow linear potential scanning method during slurry electrolysis,this study investigated the steady-state polarization curve of a pure stibnite mineral on a graphite anode.In addition,the influence of the mineral particle size,liquid–solid ratio,stirring speed,and temperature on the collision oxidation of the mineral with the anode was studied.Based on the different oxidation reactions,the potential range can be divided into three intervals:the low-potential interval with a potential lower than 0.75 V,an intermediatepotential interval with a potential within 0.75–1.2 V,and a high-potential interval with a potential higher than 1.2 V.The collision oxidation of the mineral with the anode occurred in all three intervals.The oxidation of Sb(III)also appeared in the intermediate-and high-potential intervals,and chlorine evolution occurred in the high-potential interval.Therefore,the low-potential interval was determined to be a suitable potential interval for the slurry electrolysis process.In the low-potential interval,the particle size,liquid–solid ratio,and stirring speed had little effect on the oxidation rate of the minerals.As the temperature increased,the stibnite oxidation rate and exchange current density increased.Overall,the direct collision oxidation rate of stibnite was relatively low and the current densities under all the investigated conditions were lower than 0.4 mA·cm^(-2.This indicates that it is difficult to realize industrial production while relying solely on this process.