Efficient bifunctional catalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are vital for rechargeable Zn-air batteries(ZABs).Herein,an oxygen-respirable sponge-like Co@C–O–Cs catalyst with ...Efficient bifunctional catalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are vital for rechargeable Zn-air batteries(ZABs).Herein,an oxygen-respirable sponge-like Co@C–O–Cs catalyst with oxygen-rich active sites was designed and constructed for both ORR and OER by a facile carbon dot-assisted strategy.The aerophilic triphase interface of Co@C–O–Cs cathode efficiently boosts oxygen diffusion and transfer.The theoretical calculations and experimental studies revealed that the Co–C–COC active sites can redistribute the local charge density and lower the reaction energy barrier.The Co@C–O–Cs catalyst displays superior bifunctional catalytic activities with a half-wave potential of 0.82 V for ORR and an ultralow overpotential of 294 mV at 10 mA cm^(−2) for OER.Moreover,it can drive the liquid ZABs with high peak power density(106.4 mW cm^(−2)),specific capacity(720.7 mAh g^(−1)),outstanding long-term cycle stability(over 750 cycles at 10 mA cm^(−2)),and exhibits excellent feasibility in flexible all-solid-state ZABs.These findings provide new insights into the rational design of efficient bifunctional oxygen catalysts in rechargeable metal-air batteries.展开更多
Multiphase catalysis is used in many industrial processes;however,the reaction rate can be restricted by the low accessibility of gaseous reactants to the catalysts in water,especially for oxygen-dependent biocatalyti...Multiphase catalysis is used in many industrial processes;however,the reaction rate can be restricted by the low accessibility of gaseous reactants to the catalysts in water,especially for oxygen-dependent biocatalytic reactions.Despite the fact that solubility and diffusion rates of oxygen in many liquids(such as perfluorocarbon)are much higher than in water,multiphase reactions with a second liquid phase are still difficult to conduct,because the interaction efficiency between immiscible phases is extremely low.Herein,we report an efficient triphase biocatalytic system using oil core-silica shell oxygen nanocarriers.Such design offers the biocatalytic system an extremely large water-solid-oil triphase interfacial area and a short path required for oxygen diffusion.Moreover,the silica shell stabilizes the oil nanodroplets in water and prevents their aggregation.Using oxygen-dependent oxidase enzymatic reaction as an example,we demonstrate this efficient biocatalytic system for the oxidation of glucose,choline,lactate,and sucrose by substituting their corresponding oxidase counterparts.A rate enhancement by a factor of 10-30 is observed when the oxygen nanocarriers are introduced into reaction system.This strategy offers the opportunity to enhance the efficiency of other gaseous reactants involved in multiphase catalytic reactions.展开更多
Developing photoelectrochemical(PEC)bioassays based on the principle of a photocathodic measurement of enzymatic product H_(2)O_(2) is highly attractive because it can naturally avoid interfering signals arising from ...Developing photoelectrochemical(PEC)bioassays based on the principle of a photocathodic measurement of enzymatic product H_(2)O_(2) is highly attractive because it can naturally avoid interfering signals arising from reductive species inherent to biofluids.However,fluctuant oxygen levels in the analyte solution can compromise the accuracy of photocathodic bioanalysis and restrict its application because oxygen reduction potential is similar to H_(2)O_(2).Herein,we addressed this restriction by constructing a triphase biophotocathode with air–liquid–solid joint interfaces by immobilizing an oxidase enzyme film on the tip part of superhydrophobic p-type semiconductor nanowire arrays.Such a triphase biophotocathode has a reaction zone with steady and air phasedependent oxygen concentration which stabilizes and increases the oxidase kinetics,and enables the photocathodic measurement principle in reliable PEC bioassay development with high selectivity,good accuracy,and a wide linear detection range.Moreover,the biophotocathode shows good stability during repeated testing under light illumination.This reliable PEC bioassay system has broad potential in the fields of disease diagnosis,medical research,and environmental monitoring.展开更多
Exploring cost-effective catalysts with high catalytic performance and long-term stability has always been a general concern for environment protection and energy conversion.Here,Au nanoparticles(NPs)embedded CuOx-CeO...Exploring cost-effective catalysts with high catalytic performance and long-term stability has always been a general concern for environment protection and energy conversion.Here,Au nanoparticles(NPs)embedded CuOx-CeO2 core/shell nanospheres(Au@CuOx-CeO2 CSNs)have been successfully prepared through a versatile one-pot method at ambient conditions.The spontaneous auto-redox reaction between HAuCl4 and Ce(OH)3 in aqueous solution triggered the self-assembly growth of micro-/nanostructural Au@CuOx-CeO2 CSNs.Meanwhile,the CuOx clusters in Au@CuOx-CeO2 CSNs are capable of improving the anti-sintering ability of Au NPs and providing synergistic catalysis benefits.As a result,the confined Au NPs exhibited extraordinary thermal stability even at a harsh thermal condition up to 700℃.In addition,before and after the severe calcination process,Au@CuOx-CeO2 CSNs can exhibit enhanced catalytic activity and excellent recyclability towards the hydrogenation of p-nitrophenol compared to previously reported nanocatalysts.The synergistic catalysis path between Au/CuOx/CeO2 triphasic interfaces was revealed by density functional theory(DFT)calculations.The CuOx clusters around the embedded Au NPs can provide moderate adsorption strength of p-nitrophenol,while the adjacent CeO2-supported Au NPs can facilitate the hydrogen dissociation to form H*species,which contributes to achieve the efficient reduction of p-nitrophenol.This study opens up new possibilities for developing high-efficient and sintering-resistant micro-/nanostructural nanocatalysts by exploiting multiphasic systems.展开更多
基金supported by the National Key Research and Development Program of China(No.2019YFC1907801)National Natural Science Foundation of China(No.52174286)+1 种基金the Science and Technology Innovation Program of Hunan Province(2021RC3014)Innovation-Driven Project of Central South University(No.2020CX007)。
文摘Efficient bifunctional catalysts for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are vital for rechargeable Zn-air batteries(ZABs).Herein,an oxygen-respirable sponge-like Co@C–O–Cs catalyst with oxygen-rich active sites was designed and constructed for both ORR and OER by a facile carbon dot-assisted strategy.The aerophilic triphase interface of Co@C–O–Cs cathode efficiently boosts oxygen diffusion and transfer.The theoretical calculations and experimental studies revealed that the Co–C–COC active sites can redistribute the local charge density and lower the reaction energy barrier.The Co@C–O–Cs catalyst displays superior bifunctional catalytic activities with a half-wave potential of 0.82 V for ORR and an ultralow overpotential of 294 mV at 10 mA cm^(−2) for OER.Moreover,it can drive the liquid ZABs with high peak power density(106.4 mW cm^(−2)),specific capacity(720.7 mAh g^(−1)),outstanding long-term cycle stability(over 750 cycles at 10 mA cm^(−2)),and exhibits excellent feasibility in flexible all-solid-state ZABs.These findings provide new insights into the rational design of efficient bifunctional oxygen catalysts in rechargeable metal-air batteries.
基金financially supported by the National Key R&D Program of China(2019YFA0709200)the National Natural Science Foundation of China(21988102,51772198,21975171)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
基金the National Key R&D Program of China(No.2019YFA0709200)the National Natural Science Foundation of China(Nos.21988102,51772198,21975171).
文摘Multiphase catalysis is used in many industrial processes;however,the reaction rate can be restricted by the low accessibility of gaseous reactants to the catalysts in water,especially for oxygen-dependent biocatalytic reactions.Despite the fact that solubility and diffusion rates of oxygen in many liquids(such as perfluorocarbon)are much higher than in water,multiphase reactions with a second liquid phase are still difficult to conduct,because the interaction efficiency between immiscible phases is extremely low.Herein,we report an efficient triphase biocatalytic system using oil core-silica shell oxygen nanocarriers.Such design offers the biocatalytic system an extremely large water-solid-oil triphase interfacial area and a short path required for oxygen diffusion.Moreover,the silica shell stabilizes the oil nanodroplets in water and prevents their aggregation.Using oxygen-dependent oxidase enzymatic reaction as an example,we demonstrate this efficient biocatalytic system for the oxidation of glucose,choline,lactate,and sucrose by substituting their corresponding oxidase counterparts.A rate enhancement by a factor of 10-30 is observed when the oxygen nanocarriers are introduced into reaction system.This strategy offers the opportunity to enhance the efficiency of other gaseous reactants involved in multiphase catalytic reactions.
基金supported by the National Key R&D Program of China(no.2019YFA0709200)National Natural Science Foundation of China(nos.21988102,51772198,and 22002101).
文摘Developing photoelectrochemical(PEC)bioassays based on the principle of a photocathodic measurement of enzymatic product H_(2)O_(2) is highly attractive because it can naturally avoid interfering signals arising from reductive species inherent to biofluids.However,fluctuant oxygen levels in the analyte solution can compromise the accuracy of photocathodic bioanalysis and restrict its application because oxygen reduction potential is similar to H_(2)O_(2).Herein,we addressed this restriction by constructing a triphase biophotocathode with air–liquid–solid joint interfaces by immobilizing an oxidase enzyme film on the tip part of superhydrophobic p-type semiconductor nanowire arrays.Such a triphase biophotocathode has a reaction zone with steady and air phasedependent oxygen concentration which stabilizes and increases the oxidase kinetics,and enables the photocathodic measurement principle in reliable PEC bioassay development with high selectivity,good accuracy,and a wide linear detection range.Moreover,the biophotocathode shows good stability during repeated testing under light illumination.This reliable PEC bioassay system has broad potential in the fields of disease diagnosis,medical research,and environmental monitoring.
基金The authors are grateful for the financial support of the National Natural Science Foundation of China(Nos.21590791,21771005,21931001,and 21927901)Ministry of Science and Technology(MOST)of China(Nos.2014CB643803,2017YFA0205101,and 2017YFA0205104)+1 种基金The computational work was supported by the High-performance Computing Platform of Peking University.K.W.specifically thanks the National Postdoctoral Program for Innovative Talents under grant No.BX20190005the China Postdoctoral Science Foundation(No.2019M660293).
文摘Exploring cost-effective catalysts with high catalytic performance and long-term stability has always been a general concern for environment protection and energy conversion.Here,Au nanoparticles(NPs)embedded CuOx-CeO2 core/shell nanospheres(Au@CuOx-CeO2 CSNs)have been successfully prepared through a versatile one-pot method at ambient conditions.The spontaneous auto-redox reaction between HAuCl4 and Ce(OH)3 in aqueous solution triggered the self-assembly growth of micro-/nanostructural Au@CuOx-CeO2 CSNs.Meanwhile,the CuOx clusters in Au@CuOx-CeO2 CSNs are capable of improving the anti-sintering ability of Au NPs and providing synergistic catalysis benefits.As a result,the confined Au NPs exhibited extraordinary thermal stability even at a harsh thermal condition up to 700℃.In addition,before and after the severe calcination process,Au@CuOx-CeO2 CSNs can exhibit enhanced catalytic activity and excellent recyclability towards the hydrogenation of p-nitrophenol compared to previously reported nanocatalysts.The synergistic catalysis path between Au/CuOx/CeO2 triphasic interfaces was revealed by density functional theory(DFT)calculations.The CuOx clusters around the embedded Au NPs can provide moderate adsorption strength of p-nitrophenol,while the adjacent CeO2-supported Au NPs can facilitate the hydrogen dissociation to form H*species,which contributes to achieve the efficient reduction of p-nitrophenol.This study opens up new possibilities for developing high-efficient and sintering-resistant micro-/nanostructural nanocatalysts by exploiting multiphasic systems.
