The deep-processing utility of pure hydrogen sulfide (H_(2)S) is a significant direction in natural gas chemical industry.Herein,a brand-new strategy of H_(2)S conversion by a,β-unsaturated carboxylate esters into th...The deep-processing utility of pure hydrogen sulfide (H_(2)S) is a significant direction in natural gas chemical industry.Herein,a brand-new strategy of H_(2)S conversion by a,β-unsaturated carboxylate esters into thiols or thioethers using task-specific carboxylate ionic liquids (ILs) as catalyst has been developed,firstly accomplishing the phase separation of product and catalyst without introducing the third component.It can be considered as a cascade reaction in which the product selectivity can be controlled by adjusting the molar ratio of H_(2)S to a,β-unsaturated carboxylate esters.Also,the effects of ILs with different anions and cations,intermittent feeding operations,as well as pressure-time kinetic behaviors on cascade reaction were investigated.Furthermore,the proposed interaction mechanism of H_(2)S conversion using butyl acrylate catalyzed by[Emim][Ac]was revealed by DFT-based theoretical calculation.The approach enables the self-phase separation promotion of catalyst and product and achieves 99%quantitative conversion under mild conditions in the absence of solvent,making the entire process ecologically benign.High-efficiency reaction activity can still be maintained after ten cycles of the catalyst.Therefore,the good results,combined with its simplicity of operation and the high recyclability of the catalyst,make this green method environmentally friendly and cost-effective.It is anticipated that this self-separation method mediated by task-specific ILs will provide a feasible strategy for H_(2)S utilization,which will guide its application on an industrial scale.展开更多
Development of high efficient and stable water oxidation catalysts is essential for the realization of industrial water-splitting systems. Herein, a novel approach involving an in-situ transformation of Co(OH)2 nanosh...Development of high efficient and stable water oxidation catalysts is essential for the realization of industrial water-splitting systems. Herein, a novel approach involving an in-situ transformation of Co(OH)2 nanosheets into NH4 CoPO4·H2 O nanoplates on Co foil is reported. As a 3 D self-supported oxygen revolution reaction(OER) electrocatalyst, the as-prepared NH4 CoPO4·H2 O/Co exhibits remarkable catalytic activity and exceptional stability. Specifically, it can deliver a current density of 10 m A cm^(-2) at a quite low overpotential of 254 m V with a small Tafel slope of 64.4 m V dec-1 in alkaline electrolyte. Through experimental study and theoretical analysis, the excellent OER performance can be attributed to enriched exposed active sites, favorable electron/proton transfer and mass transport, and its unique asymmetric local atomic and electronic structure. Thus, this present research not only provides a practicable in-situ transformation strategy to design 3 D self-supported electrocatalysts, but also enlightens a new way of developing transition-metal phosphates for efficient and stable water oxidation at atomic level.展开更多
The hydrogen abstraction reaction from H_(2)S by OH is of key importance in understanding of the causes of acid rain,air pollution,and climate change.In this work,the reaction OH+H_(2)S→H_(2)O+SH is investigated on a...The hydrogen abstraction reaction from H_(2)S by OH is of key importance in understanding of the causes of acid rain,air pollution,and climate change.In this work,the reaction OH+H_(2)S→H_(2)O+SH is investigated on a recently developed ab initio-based globally accurate potential energy surface by the time-dependent wave packet approach under a reduceddimensional model.This reaction behaves like a barrier-less reaction at low collision energies and like an activated reaction with a well-defined barrier at high collision energies.Exciting either the symmetric or antisymmetric stretching mode of the molecule H_(2)S enhances the reactivity more than exciting the bending mode,which is rationalized by the coupling strength of each normal mode with the reaction coordinate.In addition,the modespecific rate constant shows a remarkable non-Arrhenius temperature dependence.展开更多
How to effectively improve Zn^(2+)-storage properties is now becoming an urgent issue in the development of high-energy-density aqueous zinc-ion batteries.Here,a new method is proposed to massively increase the electr...How to effectively improve Zn^(2+)-storage properties is now becoming an urgent issue in the development of high-energy-density aqueous zinc-ion batteries.Here,a new method is proposed to massively increase the electrochemical capacity of aqueous Zn/V_(5)O_(12)·6H_(2)Obatteries.By adding a small amount of platinum(Pt,1.5 wt.%)and keeping other factors constant,the V_(5)O_(12)·6H_(2)O-Pt electrodes deliver a much higher specific capacity(440 m Ah g^(-1)at 500 m A g^(-1))than do V_(5)O_(12)·6H_(2)Oelectrodes(270 m Ah g^(-1)at500 m A g^(-1)).The structural and morphological evolution of V_(5)O_(12)·6H_(2)Oduring cycling results in Zn^(2+)ion insertion/extraction and the formation/disappearance of the zinc hydroxyl complex(Zn_(4)SO_(4)(OH)_(6)·5H_(2)O,ZHS),where the latter is closely related to the surface redox reaction,promoting Zn^(2+)ion stripping/plating on the Zn anode and consequently leading to extra electron transfer.Electrochemical tests in the absence of oxygen reveal that the Pt additive has no contribution and is even counterproductive to electric conductivity but favors remarkable enhancement of the pseudocapacitance.Accordingly,it is apparent that a strong causal relationship exists between Pt and the ZHS.In consideration of the catalytic application for oxygen reduction,Pt is expected to play a vital role in enhancing the electrochemical capacity through the pseudo-Zn-air reaction.This finding introduces a new strategy for achieving high-performance aqueous zinc-ion batteries.展开更多
基金sponsored by the National Natural Science Foundation of China (Nos. 22208140 and 22078145)。
文摘The deep-processing utility of pure hydrogen sulfide (H_(2)S) is a significant direction in natural gas chemical industry.Herein,a brand-new strategy of H_(2)S conversion by a,β-unsaturated carboxylate esters into thiols or thioethers using task-specific carboxylate ionic liquids (ILs) as catalyst has been developed,firstly accomplishing the phase separation of product and catalyst without introducing the third component.It can be considered as a cascade reaction in which the product selectivity can be controlled by adjusting the molar ratio of H_(2)S to a,β-unsaturated carboxylate esters.Also,the effects of ILs with different anions and cations,intermittent feeding operations,as well as pressure-time kinetic behaviors on cascade reaction were investigated.Furthermore,the proposed interaction mechanism of H_(2)S conversion using butyl acrylate catalyzed by[Emim][Ac]was revealed by DFT-based theoretical calculation.The approach enables the self-phase separation promotion of catalyst and product and achieves 99%quantitative conversion under mild conditions in the absence of solvent,making the entire process ecologically benign.High-efficiency reaction activity can still be maintained after ten cycles of the catalyst.Therefore,the good results,combined with its simplicity of operation and the high recyclability of the catalyst,make this green method environmentally friendly and cost-effective.It is anticipated that this self-separation method mediated by task-specific ILs will provide a feasible strategy for H_(2)S utilization,which will guide its application on an industrial scale.
基金supported by the National Natural Science Foundation of China (51602128)the Research Foundation from University of Jinan (XKY1401, XBS1508, XBH1504)。
文摘Development of high efficient and stable water oxidation catalysts is essential for the realization of industrial water-splitting systems. Herein, a novel approach involving an in-situ transformation of Co(OH)2 nanosheets into NH4 CoPO4·H2 O nanoplates on Co foil is reported. As a 3 D self-supported oxygen revolution reaction(OER) electrocatalyst, the as-prepared NH4 CoPO4·H2 O/Co exhibits remarkable catalytic activity and exceptional stability. Specifically, it can deliver a current density of 10 m A cm^(-2) at a quite low overpotential of 254 m V with a small Tafel slope of 64.4 m V dec-1 in alkaline electrolyte. Through experimental study and theoretical analysis, the excellent OER performance can be attributed to enriched exposed active sites, favorable electron/proton transfer and mass transport, and its unique asymmetric local atomic and electronic structure. Thus, this present research not only provides a practicable in-situ transformation strategy to design 3 D self-supported electrocatalysts, but also enlightens a new way of developing transition-metal phosphates for efficient and stable water oxidation at atomic level.
基金supported by the National Natural Science Foundation of China(No.21973109 to Hongwei Song,No.21773297,No.21973108,and No.21921004 to Minghui Yang)the Ministry of Education,Singapore,under its Academic Research Fund Tier 1(RG83/20)to Yunpeng Lu。
文摘The hydrogen abstraction reaction from H_(2)S by OH is of key importance in understanding of the causes of acid rain,air pollution,and climate change.In this work,the reaction OH+H_(2)S→H_(2)O+SH is investigated on a recently developed ab initio-based globally accurate potential energy surface by the time-dependent wave packet approach under a reduceddimensional model.This reaction behaves like a barrier-less reaction at low collision energies and like an activated reaction with a well-defined barrier at high collision energies.Exciting either the symmetric or antisymmetric stretching mode of the molecule H_(2)S enhances the reactivity more than exciting the bending mode,which is rationalized by the coupling strength of each normal mode with the reaction coordinate.In addition,the modespecific rate constant shows a remarkable non-Arrhenius temperature dependence.
基金supported by the National Natural Science Foundation of China(91963210,U1801255,and 51872340)the Basic Scientific Research Fund of Sun Yat-Sen University(grant no.18lgpy06)
文摘How to effectively improve Zn^(2+)-storage properties is now becoming an urgent issue in the development of high-energy-density aqueous zinc-ion batteries.Here,a new method is proposed to massively increase the electrochemical capacity of aqueous Zn/V_(5)O_(12)·6H_(2)Obatteries.By adding a small amount of platinum(Pt,1.5 wt.%)and keeping other factors constant,the V_(5)O_(12)·6H_(2)O-Pt electrodes deliver a much higher specific capacity(440 m Ah g^(-1)at 500 m A g^(-1))than do V_(5)O_(12)·6H_(2)Oelectrodes(270 m Ah g^(-1)at500 m A g^(-1)).The structural and morphological evolution of V_(5)O_(12)·6H_(2)Oduring cycling results in Zn^(2+)ion insertion/extraction and the formation/disappearance of the zinc hydroxyl complex(Zn_(4)SO_(4)(OH)_(6)·5H_(2)O,ZHS),where the latter is closely related to the surface redox reaction,promoting Zn^(2+)ion stripping/plating on the Zn anode and consequently leading to extra electron transfer.Electrochemical tests in the absence of oxygen reveal that the Pt additive has no contribution and is even counterproductive to electric conductivity but favors remarkable enhancement of the pseudocapacitance.Accordingly,it is apparent that a strong causal relationship exists between Pt and the ZHS.In consideration of the catalytic application for oxygen reduction,Pt is expected to play a vital role in enhancing the electrochemical capacity through the pseudo-Zn-air reaction.This finding introduces a new strategy for achieving high-performance aqueous zinc-ion batteries.
