Sustainable ammonia synthesis at ambient conditions that relies on renewable sources of energy and feedstocks is globally sought to replace the Haber-Bosch process.Here,using nitrogen and water as raw materials,a nont...Sustainable ammonia synthesis at ambient conditions that relies on renewable sources of energy and feedstocks is globally sought to replace the Haber-Bosch process.Here,using nitrogen and water as raw materials,a nonthermal plasma catalysis approach is demonstrated as an effective powerto-chemicals conversion strategy for ammonia production.By sustaining a highly reactive environment,successful plasma-catalytic production of NH_(3) was achieved from the dissociation of N_(2) and H_(2)O under mild conditions.Plasma-induced vibrational excitation is found to decrease the N_(2) and H_(2)O dissociation barriers,with the presence of matched catalysts in the nonthermal plasma discharge reactor contributing significantly to molecular dissociation on the catalyst surface.Density functional theory calculations for the activation energy barrier for the dissociation suggest that ruthenium catalysts supported on magnesium oxide exhibit superior performance over other catalysts in NH_(3) production by lowering the activation energy for the dissociative adsorption of N_(2) down to 1.07 eV.The highest production rate,2.67 mmol gcat.^(-1) h^(-1),was obtained using ruthenium catalyst supported on magnesium oxide.This work highlights the potential of nonthermal plasma catalysis for the activation of renewable sources to serve as a new platform for sustainable ammonia production.展开更多
Cation effect has emerged as a promising strategy for modulating the product distribution during the electrocatalytic CO_(2)reduction reaction(CO_(2)RR).However,the strategy of solely increasing bulk cation concentrat...Cation effect has emerged as a promising strategy for modulating the product distribution during the electrocatalytic CO_(2)reduction reaction(CO_(2)RR).However,the strategy of solely increasing bulk cation concentration in the electrolyte to intensify cation effect at the electrode interface exacerbates carbonate formation issue.Therefore,it is crucial to achieve local cation enrichment at the electrolyte interface without increasing bulk cation concentration.Herein,we propose a"surface charge density modulation"strategy to strengthen interfacial electric field,intensifying the local cation effect at the electrode interface in a low-concentration electrolyte.We implement this strategy using leaf-like CuO nanosheets,introducing a high-curvature morphology into the catalysts.As a result,the CuO nanosheets display 3.4-fold enhancement in Faradic efficiency(FE)of multi-carbon products(C_(2+))compared to CuO nanospheres with low-curvature.In-situ Raman spectroscopy and control experiment varying concentration of K^(+)reveal the mechanism on how the cation effect and interfacial electric field influence CO_(2)RR performance.展开更多
Conjugated polymers(CPs),organic macromolecules with a linear backbone of alternating C–C and C=C bonds,possess unique semiconductive properties,providing new opportunities for organic electronics,photonics,informati...Conjugated polymers(CPs),organic macromolecules with a linear backbone of alternating C–C and C=C bonds,possess unique semiconductive properties,providing new opportunities for organic electronics,photonics,information,and energy devices.Seeking the metallic or metallic-like,even superconducting properties beyond semiconductivity in CPs is always one of the ultimate goals in polymer science and condensed matter.Only two metallic and semi-metallic transport cases—aniline-derived polyaniline and thiophene-derived poly(3,4-ethylenedioxythiophene)—have been reported since the development of CPs for four decades.Controllable synthesis is a key challenge in discovering more cases.Here we report the metallic-like transport behavior of another CP,polypyrrole(PPy).We observe that the transport behavior of PPy changes from semiconductor to insulator-metal transition,and gradually realizes metallic-like performance when the crystalline degree increases.Using a generalized Einstein relation model,we rationalized the mechanism behind the observation.The metallic-like transport in PPy demonstrates electron strong correlation and phonon–electron interaction in soft condensation matter,and may find practical applications of CPs in electrics and spintronics.展开更多
Achieving high selectivity is vital for the practical application of electrocatalytic CO_(2)reduction reaction(CO_(2)RR).While CO and HCOOH are both possible two-electron reduction products,significantly fewer electro...Achieving high selectivity is vital for the practical application of electrocatalytic CO_(2)reduction reaction(CO_(2)RR).While CO and HCOOH are both possible two-electron reduction products,significantly fewer electrocatalysts are known to selectively produce HCOOH,and very few maintain this selectivity across diverse reaction conditions.Herein,we report a dinuclear nickel complex,[Ni_(2)^(II)(tpy)2(l-bpp)(l-Cl)](PF_(6))_(2)(1,bpp=3,5-bis(2-pyridyl)pyrazolato,tpy=terpyridine),designed with pre-organized dual Ni sites for highly selective CO_(2)-to-HCOOH electrocatalysis under a broad range of conditions.The bpp bridging ligand creates a well-suited space for CO_(2)binding,and its balanced structural rigidity and flexibility allow the intermetallic distance to adjust,accommodating the conformational changes of CO_(2)during catalysis.This structural feature enables complex 1 to catalyze the CO_(2)-to-HCOOH conversion with high selectivity in acidic,neutral,and basic environments,under both homogeneous(non-aqueous)and heterogeneous(aqueous)conditions.In homogeneous catalysis,Faradaic efficiencies>95%for HCOOH production were achieved in dimethylformamide solutions with phenol,water,or triethylamine as proton sources.In heterogeneous catalysis,Faradaic efficiencies>92%were obtained in CO_(2)-saturated 0.1 mol L^(−1)KHCO_(3)aqueous solutions in H-cells.Furthermore,gas diffusion electrode-based flow cells achieved Faradaic efficiencies>90%in 1.0 mol L^(−1)KOH aqueous solutions,with a large HCOOH production current density of>150 mA cm^(−2)and a turnover frequency of 110 s^(−1).In situ infrared spectroelectrochemistry,operando X-ray absorption spectroscopy,and computational investigations demonstrate that the two Ni sites of 1 collaboratively bind CO_(2)and facilitate the ensuing hydrogenation step,promoting selective HCOOH formation.This work presents an unparalleled example of a molecular electrocatalyst for selective CO_(2)-to-HCOOH conversion across diverse conditions and highlights the critical role of pre-organized,cooperative metal sites in CO_(2)activation.展开更多
The development of heterogeneous catalysts with a well-defined micro structure to promote their activity and stability for electrocatalyfic CO2 reduction has been shown to be a promising strategy. In this work, Cu nan...The development of heterogeneous catalysts with a well-defined micro structure to promote their activity and stability for electrocatalyfic CO2 reduction has been shown to be a promising strategy. In this work, Cu nanoparticles （- 4 nm in diameter） embedded in N-doped carbon （Cu@NC） arrays were fabricated by thermal decomposition of copper tetracyanoquinodimethane （CuTCNQ） under N2. Compared to polycrystalline copper electrodes, the Cu@NC arrays provide a significantly improved number of catalytically active sites. This resulted in a 0.7 V positive shift in onset potential, producing a catalytic current density an order magnitude larger at a potential of -2.7 V vs. Fc/Fc＋ （Fc = ferrocene） in dimethylformamide （DMF）. By controlling the water content in the DMF solvent, the CO2 reduction product distribution can be tuned. Under optimal conditions （0.5 vol.% water）, 64% HCOO^-, 20% CO, and 13% H2 were obtained. The Cu@NC arrays exhibited excellent catalytic stability with only a 0.5% decrease in the steady-state catalytic current during 6 h of electrolysis. The three-dimensional （3D） array structure of the Cu@NC was demonstrated to be effective for improving the catalytic activity of copper based catalysts while maintaining long-term catalytic stability.展开更多
Electronic technology,based on signal conversion induced by voltage stimulation,forms the core foundation of the state-of-the-art intelligent devices,tools,and equipment.Such conversions are inherently binary and limi...Electronic technology,based on signal conversion induced by voltage stimulation,forms the core foundation of the state-of-the-art intelligent devices,tools,and equipment.Such conversions are inherently binary and limited because they rely solely on voltage,which presents challenges for many emerging frontier applications.Here,a two-dimensional ordered conjugated system of reduced graphene oxide/polypyrrole(rGO/PPy)has been developed.Multi-stimulus response signal adapters have been constructed,utilizing the electrical anisotropy inherent in the rGO/PPy system.This electrical anisotropy,derived from the quasi-two-dimensional geometry of rGO/PPy,enables the device to produce distinct electrical signals in response to various stimuli.With effective responses to light and pressure,the two most common input stimuli other than voltage,it can output quaternary/denary signals and visual optical signals,as well as enables information encryption using passive devices.Furthermore,the signal adapter demonstrates high cyclic stability under repeated pressure and/or light loading.The successful development of this low-cost,scalable signal adapter paves the way for the next-generation of intelligent systems,promising advancements in human-computer interaction,electronic skin,biological implant equipment,and related fields.展开更多
基金partially supported by the Australian Research Council(ARC)the National Science Fund for Distinguished Young Scholars(grant number 51925703)。
文摘Sustainable ammonia synthesis at ambient conditions that relies on renewable sources of energy and feedstocks is globally sought to replace the Haber-Bosch process.Here,using nitrogen and water as raw materials,a nonthermal plasma catalysis approach is demonstrated as an effective powerto-chemicals conversion strategy for ammonia production.By sustaining a highly reactive environment,successful plasma-catalytic production of NH_(3) was achieved from the dissociation of N_(2) and H_(2)O under mild conditions.Plasma-induced vibrational excitation is found to decrease the N_(2) and H_(2)O dissociation barriers,with the presence of matched catalysts in the nonthermal plasma discharge reactor contributing significantly to molecular dissociation on the catalyst surface.Density functional theory calculations for the activation energy barrier for the dissociation suggest that ruthenium catalysts supported on magnesium oxide exhibit superior performance over other catalysts in NH_(3) production by lowering the activation energy for the dissociative adsorption of N_(2) down to 1.07 eV.The highest production rate,2.67 mmol gcat.^(-1) h^(-1),was obtained using ruthenium catalyst supported on magnesium oxide.This work highlights the potential of nonthermal plasma catalysis for the activation of renewable sources to serve as a new platform for sustainable ammonia production.
基金supported by the National Natural Science Foundation of China(Nos.U22B20143 and 22478121)Shanghai Municipal Science and Technology Major Project,the Science and Technology Commission of Shanghai Municipality(No.22dz1205900)+1 种基金the Fundamental Research Funds for the Central Universities(No.JKD01241702)F.W.L.acknowledges the financial support from the ARC Centre of Excellence for Green Electrochemical Transformation of Carbon Dioxide(No.CE230100017).
文摘Cation effect has emerged as a promising strategy for modulating the product distribution during the electrocatalytic CO_(2)reduction reaction(CO_(2)RR).However,the strategy of solely increasing bulk cation concentration in the electrolyte to intensify cation effect at the electrode interface exacerbates carbonate formation issue.Therefore,it is crucial to achieve local cation enrichment at the electrolyte interface without increasing bulk cation concentration.Herein,we propose a"surface charge density modulation"strategy to strengthen interfacial electric field,intensifying the local cation effect at the electrode interface in a low-concentration electrolyte.We implement this strategy using leaf-like CuO nanosheets,introducing a high-curvature morphology into the catalysts.As a result,the CuO nanosheets display 3.4-fold enhancement in Faradic efficiency(FE)of multi-carbon products(C_(2+))compared to CuO nanospheres with low-curvature.In-situ Raman spectroscopy and control experiment varying concentration of K^(+)reveal the mechanism on how the cation effect and interfacial electric field influence CO_(2)RR performance.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.21875266 and 21622407)the Beijing National Laboratory for Molecular Sciences(Grant No.BNLMS201909)the‘Transformational Technologies for Clean Energy and Demonstration’Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA21010214).The authors wish to thank Professor C Li for their discussion and support.
文摘Conjugated polymers(CPs),organic macromolecules with a linear backbone of alternating C–C and C=C bonds,possess unique semiconductive properties,providing new opportunities for organic electronics,photonics,information,and energy devices.Seeking the metallic or metallic-like,even superconducting properties beyond semiconductivity in CPs is always one of the ultimate goals in polymer science and condensed matter.Only two metallic and semi-metallic transport cases—aniline-derived polyaniline and thiophene-derived poly(3,4-ethylenedioxythiophene)—have been reported since the development of CPs for four decades.Controllable synthesis is a key challenge in discovering more cases.Here we report the metallic-like transport behavior of another CP,polypyrrole(PPy).We observe that the transport behavior of PPy changes from semiconductor to insulator-metal transition,and gradually realizes metallic-like performance when the crystalline degree increases.Using a generalized Einstein relation model,we rationalized the mechanism behind the observation.The metallic-like transport in PPy demonstrates electron strong correlation and phonon–electron interaction in soft condensation matter,and may find practical applications of CPs in electrics and spintronics.
基金supported by the National Natural Science Foundation of China(22325202,22371177,22171176,and 22361142751)Fok Ying-Tong Education Foundation for Outstanding Young Teachers in University+3 种基金Key Research and Development Program of Shaanxi(2023-YBGY-296)Fundamental Research Funds for the Central Universities(GK202403004 and GK202306001)Research Funds from Shaanxi Normal UniversityARC Centre of Excellence for Green Electrochemical Transformation of Carbon Dioxide(CE230100017)funded by the Australian Government。
文摘Achieving high selectivity is vital for the practical application of electrocatalytic CO_(2)reduction reaction(CO_(2)RR).While CO and HCOOH are both possible two-electron reduction products,significantly fewer electrocatalysts are known to selectively produce HCOOH,and very few maintain this selectivity across diverse reaction conditions.Herein,we report a dinuclear nickel complex,[Ni_(2)^(II)(tpy)2(l-bpp)(l-Cl)](PF_(6))_(2)(1,bpp=3,5-bis(2-pyridyl)pyrazolato,tpy=terpyridine),designed with pre-organized dual Ni sites for highly selective CO_(2)-to-HCOOH electrocatalysis under a broad range of conditions.The bpp bridging ligand creates a well-suited space for CO_(2)binding,and its balanced structural rigidity and flexibility allow the intermetallic distance to adjust,accommodating the conformational changes of CO_(2)during catalysis.This structural feature enables complex 1 to catalyze the CO_(2)-to-HCOOH conversion with high selectivity in acidic,neutral,and basic environments,under both homogeneous(non-aqueous)and heterogeneous(aqueous)conditions.In homogeneous catalysis,Faradaic efficiencies>95%for HCOOH production were achieved in dimethylformamide solutions with phenol,water,or triethylamine as proton sources.In heterogeneous catalysis,Faradaic efficiencies>92%were obtained in CO_(2)-saturated 0.1 mol L^(−1)KHCO_(3)aqueous solutions in H-cells.Furthermore,gas diffusion electrode-based flow cells achieved Faradaic efficiencies>90%in 1.0 mol L^(−1)KOH aqueous solutions,with a large HCOOH production current density of>150 mA cm^(−2)and a turnover frequency of 110 s^(−1).In situ infrared spectroelectrochemistry,operando X-ray absorption spectroscopy,and computational investigations demonstrate that the two Ni sites of 1 collaboratively bind CO_(2)and facilitate the ensuing hydrogenation step,promoting selective HCOOH formation.This work presents an unparalleled example of a molecular electrocatalyst for selective CO_(2)-to-HCOOH conversion across diverse conditions and highlights the critical role of pre-organized,cooperative metal sites in CO_(2)activation.
文摘The development of heterogeneous catalysts with a well-defined micro structure to promote their activity and stability for electrocatalyfic CO2 reduction has been shown to be a promising strategy. In this work, Cu nanoparticles （- 4 nm in diameter） embedded in N-doped carbon （Cu@NC） arrays were fabricated by thermal decomposition of copper tetracyanoquinodimethane （CuTCNQ） under N2. Compared to polycrystalline copper electrodes, the Cu@NC arrays provide a significantly improved number of catalytically active sites. This resulted in a 0.7 V positive shift in onset potential, producing a catalytic current density an order magnitude larger at a potential of -2.7 V vs. Fc/Fc＋ （Fc = ferrocene） in dimethylformamide （DMF）. By controlling the water content in the DMF solvent, the CO2 reduction product distribution can be tuned. Under optimal conditions （0.5 vol.% water）, 64% HCOO^-, 20% CO, and 13% H2 were obtained. The Cu@NC arrays exhibited excellent catalytic stability with only a 0.5% decrease in the steady-state catalytic current during 6 h of electrolysis. The three-dimensional （3D） array structure of the Cu@NC was demonstrated to be effective for improving the catalytic activity of copper based catalysts while maintaining long-term catalytic stability.
基金supported by Beijing Natural Science Foundation(2232069)the National Natural Science Foundation of China(21875266)the Research Start-up Fund of Ningbo University of Technology(2130011540030)。
文摘Electronic technology,based on signal conversion induced by voltage stimulation,forms the core foundation of the state-of-the-art intelligent devices,tools,and equipment.Such conversions are inherently binary and limited because they rely solely on voltage,which presents challenges for many emerging frontier applications.Here,a two-dimensional ordered conjugated system of reduced graphene oxide/polypyrrole(rGO/PPy)has been developed.Multi-stimulus response signal adapters have been constructed,utilizing the electrical anisotropy inherent in the rGO/PPy system.This electrical anisotropy,derived from the quasi-two-dimensional geometry of rGO/PPy,enables the device to produce distinct electrical signals in response to various stimuli.With effective responses to light and pressure,the two most common input stimuli other than voltage,it can output quaternary/denary signals and visual optical signals,as well as enables information encryption using passive devices.Furthermore,the signal adapter demonstrates high cyclic stability under repeated pressure and/or light loading.The successful development of this low-cost,scalable signal adapter paves the way for the next-generation of intelligent systems,promising advancements in human-computer interaction,electronic skin,biological implant equipment,and related fields.
