The development of highly active and stable reversible oxygen electrocatalysts is crucial for improving the efficiency of metal‐air battery devices.Herein,an efficient liquid exfoliation strategy was designed for pro...The development of highly active and stable reversible oxygen electrocatalysts is crucial for improving the efficiency of metal‐air battery devices.Herein,an efficient liquid exfoliation strategy was designed for producing silk‐like FeS2/NiS2 hybrid nanocrystals with enhanced reversible oxygen catalytic performance that displayed excellent properties for Zn‐air batteries.Because of the unique silk‐like morphology and interface nanocrystal structure,they can catalyze the oxygen evolution reaction(OER)efficiently with a low overpotential of 233 mV at j=10 mA cm?2.This is an improvement from the recently reported catalysts in 1.0 M KOH.Meanwhile,the oxygen reduction reaction(ORR)activity of the silk‐like FeS2/NiS2 hybrid nanocrystals showed an onset potential of 911 mV and a half‐wave potential of 640 mV.In addition,the reversible oxygen electrode activity of the silk‐like FeS2/NiS2 hybrid nanocrystals was calculated to be 0.823 V,based on the potential of the OER and ORR.Further,the homemade rechargeable Zn‐air batteries using FeS2/NiS2 hybrid nanocrystals as the air‐cathode displayed a high open‐circuit voltage of 1.25 V for more than 17 h and an excellent rechargeable performance for 25 h.The solid Zn‐air batteries exhibited an excellent rechargeable performance for 15 h.This study provided a new method for designing interface nanocrystals with a unique morphology for efficient multifunctional electrocatalysts in electrochemical reactions and renewable energy devices.展开更多
Cobalt-based oxides,with high abundance,good stability and excellent catalytic performance,are regarded as promising photocatalysts for artificial photosynthetic systems to alleviate foreseeable energy shortages and g...Cobalt-based oxides,with high abundance,good stability and excellent catalytic performance,are regarded as promising photocatalysts for artificial photosynthetic systems to alleviate foreseeable energy shortages and global warming.Herein,for the first time,a series of novel spongy porous CDs@CoOx materials were synthesized to act as an efficient and stable bifunctional photocatalyst for water oxidation and CO2 reduction.Notably,the preparation temperatures visibly influence the morphologies and photocatalytic performances of the CDs@CoOx.Under the optimal conditions,a maximum O2 yield of 40.4% and pretty apparent quantum efficiency(AQE)of 58.6% at 460 nm were obtained over CDs@CoOx-300 for water oxidation.Similarly,the optimized sample CDs@CoOx-300 manifests significant enhancement on the CO2-to-CO conversion with a high selectivity of 89.3% and CO generation rate of 8.1μmol/h,which is superior to most previous cobalt-based catalysts for CO2 reduction.The composite CDs@CoOx-300 not only exposes more active sites but also facilitates electron transport,which results in excellent photocatalytic activity.In addition,the boosted photocatalytic behavior is attributed to the synergistic effect between CoOx and CDs,which was verified by the photocatalytic activity control experiments and electrochemical characterization.The work offers a novel strategy to fabricate a high performance bifunctional photocatalyst for water oxidation and CO2 reduction.展开更多
Rationally manipulating the in‐situ formed catalytically active surface of catalysts remains a great challenge for a highly efficient water electrolysis.Here,we report a cationic oxidation method which can adjust the...Rationally manipulating the in‐situ formed catalytically active surface of catalysts remains a great challenge for a highly efficient water electrolysis.Here,we report a cationic oxidation method which can adjust the leaching of the in‐situ catalyst and promote the reconstruction of dynamic surface for the oxygen evolution reaction(OER).The chlorine doping can reduce the possibility of triggering in‐situ cobalt oxidation and chlorine leaching,leading to a transformation of the surface chlorine doped LaCoO_(3)(Cl‐LaCoO_(3))into an intricate amorphous(oxygen)hydroxide phase.And thus,Cl‐LaCoO_(3)nanocrystals shows an ultralow overpotential of 342 mV at the current density of 10 mA cm^(–2)and Tafel slope of 76.2 mV dec–1.Surface reconstructed Cl‐LaCoO_(3)is better than many of the most advanced OER catalysts and has proven significant stability.This work provides a new prospect for designing a high‐efficiency electrocatalyst with optimized perovskite‐structure in renewable energy system.展开更多
基金supported by the National Basic Research Program of China(21571089,21503102,51571125)the Fundamental Research Funds for the Central Universities(lzujbky-2016-k02,lzujbky-2018-k08,lzujbky-2017-it42)~~
文摘The development of highly active and stable reversible oxygen electrocatalysts is crucial for improving the efficiency of metal‐air battery devices.Herein,an efficient liquid exfoliation strategy was designed for producing silk‐like FeS2/NiS2 hybrid nanocrystals with enhanced reversible oxygen catalytic performance that displayed excellent properties for Zn‐air batteries.Because of the unique silk‐like morphology and interface nanocrystal structure,they can catalyze the oxygen evolution reaction(OER)efficiently with a low overpotential of 233 mV at j=10 mA cm?2.This is an improvement from the recently reported catalysts in 1.0 M KOH.Meanwhile,the oxygen reduction reaction(ORR)activity of the silk‐like FeS2/NiS2 hybrid nanocrystals showed an onset potential of 911 mV and a half‐wave potential of 640 mV.In addition,the reversible oxygen electrode activity of the silk‐like FeS2/NiS2 hybrid nanocrystals was calculated to be 0.823 V,based on the potential of the OER and ORR.Further,the homemade rechargeable Zn‐air batteries using FeS2/NiS2 hybrid nanocrystals as the air‐cathode displayed a high open‐circuit voltage of 1.25 V for more than 17 h and an excellent rechargeable performance for 25 h.The solid Zn‐air batteries exhibited an excellent rechargeable performance for 15 h.This study provided a new method for designing interface nanocrystals with a unique morphology for efficient multifunctional electrocatalysts in electrochemical reactions and renewable energy devices.
文摘Cobalt-based oxides,with high abundance,good stability and excellent catalytic performance,are regarded as promising photocatalysts for artificial photosynthetic systems to alleviate foreseeable energy shortages and global warming.Herein,for the first time,a series of novel spongy porous CDs@CoOx materials were synthesized to act as an efficient and stable bifunctional photocatalyst for water oxidation and CO2 reduction.Notably,the preparation temperatures visibly influence the morphologies and photocatalytic performances of the CDs@CoOx.Under the optimal conditions,a maximum O2 yield of 40.4% and pretty apparent quantum efficiency(AQE)of 58.6% at 460 nm were obtained over CDs@CoOx-300 for water oxidation.Similarly,the optimized sample CDs@CoOx-300 manifests significant enhancement on the CO2-to-CO conversion with a high selectivity of 89.3% and CO generation rate of 8.1μmol/h,which is superior to most previous cobalt-based catalysts for CO2 reduction.The composite CDs@CoOx-300 not only exposes more active sites but also facilitates electron transport,which results in excellent photocatalytic activity.In addition,the boosted photocatalytic behavior is attributed to the synergistic effect between CoOx and CDs,which was verified by the photocatalytic activity control experiments and electrochemical characterization.The work offers a novel strategy to fabricate a high performance bifunctional photocatalyst for water oxidation and CO2 reduction.
文摘Rationally manipulating the in‐situ formed catalytically active surface of catalysts remains a great challenge for a highly efficient water electrolysis.Here,we report a cationic oxidation method which can adjust the leaching of the in‐situ catalyst and promote the reconstruction of dynamic surface for the oxygen evolution reaction(OER).The chlorine doping can reduce the possibility of triggering in‐situ cobalt oxidation and chlorine leaching,leading to a transformation of the surface chlorine doped LaCoO_(3)(Cl‐LaCoO_(3))into an intricate amorphous(oxygen)hydroxide phase.And thus,Cl‐LaCoO_(3)nanocrystals shows an ultralow overpotential of 342 mV at the current density of 10 mA cm^(–2)and Tafel slope of 76.2 mV dec–1.Surface reconstructed Cl‐LaCoO_(3)is better than many of the most advanced OER catalysts and has proven significant stability.This work provides a new prospect for designing a high‐efficiency electrocatalyst with optimized perovskite‐structure in renewable energy system.
基金supported by the National Natural Science Foundation of China(21403097)the Fundamental Research Funds for the Central Universities,China(lzujbky-2016-45)~~
