We use the directional slacks-based measure of efficiency and inverse distance weighting method to analyze the spatial pattern evolution of the industrial green total factor productivity of 108 cities in the Yangtze R...We use the directional slacks-based measure of efficiency and inverse distance weighting method to analyze the spatial pattern evolution of the industrial green total factor productivity of 108 cities in the Yangtze River Economic Belt in 2003–2013.Results show that both the subprime mortgage crisis and ‘the new normal' had significant negative effects on productivity growth,leading to the different spatial patterns between 2003–2008 and 2009–2013.Before 2008,green poles had gathered around some capital cities and formed a tripartite pattern,which was a typical core-periphery pattern.Due to a combination of the polarization and the diffusion effects,capital cities became the growth poles and ‘core' regions,while surrounding areas became the ‘periphery'.This was mainly caused by the innate advantage of capital cities and ‘the rise of central China' strategy.After 2008,the tripartite pattern changed to a multi-poles pattern where green poles continuously and densely spread in the midstream and downstream areas.This is due to the regional difference in the leading effect of green poles.The leading effect of green poles in midstream and downstream areas has changed from polarization to diffusion,while the polarization effect still leads in the upstream area.展开更多
Metal-organic frameworks(MOFs)which consist of metal ions and organic ligands,have been considered as promising precursors for designing efficient electrocatalysts.Herein,we report ultra-low ruthenium(Ru)doped defecti...Metal-organic frameworks(MOFs)which consist of metal ions and organic ligands,have been considered as promising precursors for designing efficient electrocatalysts.Herein,we report ultra-low ruthenium(Ru)doped defective CoFe-MOF(Ru@CoFe/D-MOF)hollow nanorods by the NaBH4 reduction strategy at room temperature for efficient oxygen evolution reaction(OER).The partial reduction process endowed the catalysts with rich oxygen vacancies(O_(v))and low coordinated CoFe nanoparticles(CoFe NPs),which have advantages in exposing abundant active sites.In addition,benefiting from the defective features and heterostructure surfaces,an ultra-low amount of Ru could be stabilized on the surface of CoFe/D-MOFs to further enhance their catalytic activity.Consequently,the well-designed Ru@CoFe/D-MOFs demonstrated excellent OER performance with a low overpotential(η=265 mV at 10 mA cm^(-2)),good overall water splitting activity(1.56 V at 10 mA cm^(-2))and long-term stability for more than 40 hours in alkaline solution.The mechanistic analysis validated that the ultra-low amount of Ru was able to optimize the electronic configuration of CoFe/D-MOFs and tailor the adsorption between the OER intermediates and the heterostructure surface,thus leading to enhanced OER performance.展开更多
The structural and compositional modulation of inexpensive hydroxides is not only important,but also an ongoing challenge for the preparation of efficient oxygen evolution reaction(OER)electrocatalysts.Herein,a three-...The structural and compositional modulation of inexpensive hydroxides is not only important,but also an ongoing challenge for the preparation of efficient oxygen evolution reaction(OER)electrocatalysts.Herein,a three-dimensional(3D)structural catalyst(Co-CAT/NiFe-LDH/CNFs)is successfully synthesized by the in situ growth of a conductive metal–organic framework on NiFe layered double hydroxide nanosheets.Density functional theory(DFT)calculations demonstrated that the sluggish kinetics of the OER can be improved by increasing the conductivity and changing the hydrophilicity of the catalyst.Accordingly,the synergistic effect between Co-CAT and NiFe LDH leads to a superior catalytic performance compared to that of Pt/C.In addition,the as-assembled Zn–air battery exhibits excellent stability and a high power density of 327.09 mW cm^(−2) for 56 h and 112.04 mW cm^(−2) for 11.5 h in both liquid and solid electrolytes,respectively.展开更多
The energy barrier for the rate-determining step(RDS)is exceptionally critical for the catalytic oxygen evolution reaction(OER)efficiency of an electrocatalyst;however,facilely decreasing the energy barrier of RDS and...The energy barrier for the rate-determining step(RDS)is exceptionally critical for the catalytic oxygen evolution reaction(OER)efficiency of an electrocatalyst;however,facilely decreasing the energy barrier of RDS and realizing the precise manipulation of the reaction process remains challenging.Herein,through constructing a nanosheet assembled sunflower-like Co(OH)_(2) with Ir,Fe codoping,the electronic structure and binding strengths with oxygen-involved intermediates of Co active sites are considerably moderated.First-principles calculations and comprehensive characterizations suggest that Fe and Ir codoping significantly lowers the electrochemical reaction barrier and promotes the OER reaction kinetics by precisely accelerating the formation process of*O.Moreover,the nanosheet-assembled open architectures enable the catalyst with plentiful catalytically active sites and facilitate mass transport and electron transfer.As a result,the optimal electrocatalyst can exhibit outstanding oxygen-evolving activity with an ultralow overpotential of 254 mV at 10 mA cm^(-2).This study realizes the precise manipulation of the reaction energy barrier of OER via Ir,Fe dual doping,which will be a generic paradigm for designing advanced yet cost-effective electrocatalysts.展开更多
基金Under the auspices of the post-funded project of National Social Science Foundation of China(No.16FJL009)
文摘We use the directional slacks-based measure of efficiency and inverse distance weighting method to analyze the spatial pattern evolution of the industrial green total factor productivity of 108 cities in the Yangtze River Economic Belt in 2003–2013.Results show that both the subprime mortgage crisis and ‘the new normal' had significant negative effects on productivity growth,leading to the different spatial patterns between 2003–2008 and 2009–2013.Before 2008,green poles had gathered around some capital cities and formed a tripartite pattern,which was a typical core-periphery pattern.Due to a combination of the polarization and the diffusion effects,capital cities became the growth poles and ‘core' regions,while surrounding areas became the ‘periphery'.This was mainly caused by the innate advantage of capital cities and ‘the rise of central China' strategy.After 2008,the tripartite pattern changed to a multi-poles pattern where green poles continuously and densely spread in the midstream and downstream areas.This is due to the regional difference in the leading effect of green poles.The leading effect of green poles in midstream and downstream areas has changed from polarization to diffusion,while the polarization effect still leads in the upstream area.
基金National Natural Science Foundation of China(Grant No.52073199,51873136)the Jiangsu Provincial Natural Science Foundation(Grant No.BK 20190762).
文摘Metal-organic frameworks(MOFs)which consist of metal ions and organic ligands,have been considered as promising precursors for designing efficient electrocatalysts.Herein,we report ultra-low ruthenium(Ru)doped defective CoFe-MOF(Ru@CoFe/D-MOF)hollow nanorods by the NaBH4 reduction strategy at room temperature for efficient oxygen evolution reaction(OER).The partial reduction process endowed the catalysts with rich oxygen vacancies(O_(v))and low coordinated CoFe nanoparticles(CoFe NPs),which have advantages in exposing abundant active sites.In addition,benefiting from the defective features and heterostructure surfaces,an ultra-low amount of Ru could be stabilized on the surface of CoFe/D-MOFs to further enhance their catalytic activity.Consequently,the well-designed Ru@CoFe/D-MOFs demonstrated excellent OER performance with a low overpotential(η=265 mV at 10 mA cm^(-2)),good overall water splitting activity(1.56 V at 10 mA cm^(-2))and long-term stability for more than 40 hours in alkaline solution.The mechanistic analysis validated that the ultra-low amount of Ru was able to optimize the electronic configuration of CoFe/D-MOFs and tailor the adsorption between the OER intermediates and the heterostructure surface,thus leading to enhanced OER performance.
基金support from the following sources:the National Natural Science Foundation of China(NSFC)(Grants 51772073,51762013)the Key Project of Hebei Natural Science Foundation(E2020201030)+2 种基金the Second Batch of Young Talent of Hebei Province(No.70280016160250,No.70280011808)the Key Fund in Hebei Province Department of Education China(ZD2021014)the China Postdoctoral Science Foundation(No.2021M701718).
文摘The structural and compositional modulation of inexpensive hydroxides is not only important,but also an ongoing challenge for the preparation of efficient oxygen evolution reaction(OER)electrocatalysts.Herein,a three-dimensional(3D)structural catalyst(Co-CAT/NiFe-LDH/CNFs)is successfully synthesized by the in situ growth of a conductive metal–organic framework on NiFe layered double hydroxide nanosheets.Density functional theory(DFT)calculations demonstrated that the sluggish kinetics of the OER can be improved by increasing the conductivity and changing the hydrophilicity of the catalyst.Accordingly,the synergistic effect between Co-CAT and NiFe LDH leads to a superior catalytic performance compared to that of Pt/C.In addition,the as-assembled Zn–air battery exhibits excellent stability and a high power density of 327.09 mW cm^(−2) for 56 h and 112.04 mW cm^(−2) for 11.5 h in both liquid and solid electrolytes,respectively.
基金supported by the start-up funding to H.Xu from Changzhou University(ZMF22020055)grants from Advanced Catalysis and Green Manufacturing Collaborative Innovation Center(ACGM2022-10-01),Changzhou University.
文摘The energy barrier for the rate-determining step(RDS)is exceptionally critical for the catalytic oxygen evolution reaction(OER)efficiency of an electrocatalyst;however,facilely decreasing the energy barrier of RDS and realizing the precise manipulation of the reaction process remains challenging.Herein,through constructing a nanosheet assembled sunflower-like Co(OH)_(2) with Ir,Fe codoping,the electronic structure and binding strengths with oxygen-involved intermediates of Co active sites are considerably moderated.First-principles calculations and comprehensive characterizations suggest that Fe and Ir codoping significantly lowers the electrochemical reaction barrier and promotes the OER reaction kinetics by precisely accelerating the formation process of*O.Moreover,the nanosheet-assembled open architectures enable the catalyst with plentiful catalytically active sites and facilitate mass transport and electron transfer.As a result,the optimal electrocatalyst can exhibit outstanding oxygen-evolving activity with an ultralow overpotential of 254 mV at 10 mA cm^(-2).This study realizes the precise manipulation of the reaction energy barrier of OER via Ir,Fe dual doping,which will be a generic paradigm for designing advanced yet cost-effective electrocatalysts.
