Spinel oxides containing Co and Ni are a promising substitute as a noble metal catalyst for methane combustion.Achieving a complete oxidation of methane under 400°C remains challenging,andhydrothermal 60 h NiClit...Spinel oxides containing Co and Ni are a promising substitute as a noble metal catalyst for methane combustion.Achieving a complete oxidation of methane under 400°C remains challenging,andhydrothermal 60 h NiClittle impact on activity,especially at high space velocities due to the long hydrothermal time with less absorbed oxygen species and crystal defects.Overall,these results help clarify methane activa-tion mechanisms and aid the development of more efficient low-cost catalysts.展开更多
A robust oxygen‐related electrocatalyst,composed of spinel iron‐cobalt oxide and nitrogen‐dopedordered mesoporous carbon(NOMC),was developed for rechargeable metal‐air batteries.Electrochemicaltests revealed that ...A robust oxygen‐related electrocatalyst,composed of spinel iron‐cobalt oxide and nitrogen‐dopedordered mesoporous carbon(NOMC),was developed for rechargeable metal‐air batteries.Electrochemicaltests revealed that the optimal catalyst Fe_(0.5)Co/NOMC exhibits superior activity with ahalf‐wave potential of 0.89 V(vs.reversible hydrogen electrode)for the oxygen reduction reactionand an overpotential of 0.31 V at 10 mA cm^(−2)for the oxygen evolution reaction.For demonstration,the catalyst was used in the assembly of a rechargeable zinc‐air battery,which exhibited an exceptionallyhigh energy density of 820 Wh kg−1 at 100 mA cm^(−2),a high power density of 153 mW cm^(−2)at1.0 V,and superior cycling stability up to 432 cycles(144 h)under ambient air.展开更多
Oxygen evolution reaction is one of the key processes in the promising renewable energy technique of electrocatalytic water splitting.Developing high ecient oxygen evolution reaction(OER)catalysts requires determinati...Oxygen evolution reaction is one of the key processes in the promising renewable energy technique of electrocatalytic water splitting.Developing high ecient oxygen evolution reaction(OER)catalysts requires determination of the optimal values of the descriptor parameters.Using spinel CoFe2O4 as the model catalyst,this work demonstrates that irradiation with pulsed UV laser can control the quantity of surface oxygen vacancy and thus modify the OER activity,in a volcano-shape evolution trend.This strategy sheds light on quantita-tively investigation of the relationship between surface cation valence,anion vacancy,and physicochemical properties of transition-metal-based compounds.展开更多
Efficient and affordable electrocatalysts for reversible oxygen reduction and oxygen evolution reactions(ORR and OER,respectively)are highly sought-after for use in rechargeable metal-air batteries.However,the constru...Efficient and affordable electrocatalysts for reversible oxygen reduction and oxygen evolution reactions(ORR and OER,respectively)are highly sought-after for use in rechargeable metal-air batteries.However,the construction of high-performance electrocatalysts that possess both largely accessible active sites and superior ORR/OER intrinsic activities is challenging.Herein,we report the design and successful preparation of a 3D hierarchically porous graphene framework with interconnected interlayer macropores and in-plane mesopores,enriched with pyridinic-nitrogen-cobalt(pyri-N-Co)active sites,namely,CoFe/3D-NLG.The pyri-N-Co bonding significantly accelerates sluggish oxygen electrocatalysis kinetics,in turn substantially improving the intrinsic ORR/OER activities per active site,while copious interlayer macropores and in-plane mesopores enable ultra-efficient mass transfer throughout the graphene architecture,thus ensuring sufficient exposure of accessible pyri-N-Co active sites to the reagents.Such a robust catalyst structure endows CoFe/3D-NLG with a remarkably enhanced reversible oxygen electrocatalysis performance,with the ORR half-wave potential identical to that of the benchmark Pt/C catalyst,and OER activity far surpassing that of the noble-metal-based RuO2 catalyst.Moreover,when employed as an air electrode for a rechargeable Zn-air battery,CoFe/3D-NLG manifests an exceedingly high open-circuit voltage(1.56 V),high peak power density(213 mW cm^(–2)),ultra-low charge/discharge voltage(0.63 V),and excellent charge/discharge cycling stability,outperforming state-of-the-art noble-metal electrocatalysts.展开更多
Rechargeable Zn-air batteries gained significant attention in the past few years, due to their low cost, environmentally friendliness,and high theoretical specific energy density [1]. However, with slowness and comple...Rechargeable Zn-air batteries gained significant attention in the past few years, due to their low cost, environmentally friendliness,and high theoretical specific energy density [1]. However, with slowness and complexity of reactions in the air electrode during working condition, rechargeable Zn-air batteries cannot be good at engineering practice.展开更多
基金supported by the National Natural Science Foundation of China(50572051,50672041)National High-Tech Research and Development Program of China(863)(2006AA03Z218)National Key Basic Research Program of China(973)(2007CB607504)~~
基金supported by the National Key Research and Development Program of China (2016YFC0204301)~~
文摘Spinel oxides containing Co and Ni are a promising substitute as a noble metal catalyst for methane combustion.Achieving a complete oxidation of methane under 400°C remains challenging,andhydrothermal 60 h NiClittle impact on activity,especially at high space velocities due to the long hydrothermal time with less absorbed oxygen species and crystal defects.Overall,these results help clarify methane activa-tion mechanisms and aid the development of more efficient low-cost catalysts.
文摘A robust oxygen‐related electrocatalyst,composed of spinel iron‐cobalt oxide and nitrogen‐dopedordered mesoporous carbon(NOMC),was developed for rechargeable metal‐air batteries.Electrochemicaltests revealed that the optimal catalyst Fe_(0.5)Co/NOMC exhibits superior activity with ahalf‐wave potential of 0.89 V(vs.reversible hydrogen electrode)for the oxygen reduction reactionand an overpotential of 0.31 V at 10 mA cm^(−2)for the oxygen evolution reaction.For demonstration,the catalyst was used in the assembly of a rechargeable zinc‐air battery,which exhibited an exceptionallyhigh energy density of 820 Wh kg−1 at 100 mA cm^(−2),a high power density of 153 mW cm^(−2)at1.0 V,and superior cycling stability up to 432 cycles(144 h)under ambient air.
基金supported by the National Key Basic Research Program of China (2016YFA0300102)the National Natural Science Foundation of China (No.11675179,No.U1532142,and No.11434009)the Fundamental Research Funds for the Central Universities
文摘Oxygen evolution reaction is one of the key processes in the promising renewable energy technique of electrocatalytic water splitting.Developing high ecient oxygen evolution reaction(OER)catalysts requires determination of the optimal values of the descriptor parameters.Using spinel CoFe2O4 as the model catalyst,this work demonstrates that irradiation with pulsed UV laser can control the quantity of surface oxygen vacancy and thus modify the OER activity,in a volcano-shape evolution trend.This strategy sheds light on quantita-tively investigation of the relationship between surface cation valence,anion vacancy,and physicochemical properties of transition-metal-based compounds.
文摘Efficient and affordable electrocatalysts for reversible oxygen reduction and oxygen evolution reactions(ORR and OER,respectively)are highly sought-after for use in rechargeable metal-air batteries.However,the construction of high-performance electrocatalysts that possess both largely accessible active sites and superior ORR/OER intrinsic activities is challenging.Herein,we report the design and successful preparation of a 3D hierarchically porous graphene framework with interconnected interlayer macropores and in-plane mesopores,enriched with pyridinic-nitrogen-cobalt(pyri-N-Co)active sites,namely,CoFe/3D-NLG.The pyri-N-Co bonding significantly accelerates sluggish oxygen electrocatalysis kinetics,in turn substantially improving the intrinsic ORR/OER activities per active site,while copious interlayer macropores and in-plane mesopores enable ultra-efficient mass transfer throughout the graphene architecture,thus ensuring sufficient exposure of accessible pyri-N-Co active sites to the reagents.Such a robust catalyst structure endows CoFe/3D-NLG with a remarkably enhanced reversible oxygen electrocatalysis performance,with the ORR half-wave potential identical to that of the benchmark Pt/C catalyst,and OER activity far surpassing that of the noble-metal-based RuO2 catalyst.Moreover,when employed as an air electrode for a rechargeable Zn-air battery,CoFe/3D-NLG manifests an exceedingly high open-circuit voltage(1.56 V),high peak power density(213 mW cm^(–2)),ultra-low charge/discharge voltage(0.63 V),and excellent charge/discharge cycling stability,outperforming state-of-the-art noble-metal electrocatalysts.
文摘Rechargeable Zn-air batteries gained significant attention in the past few years, due to their low cost, environmentally friendliness,and high theoretical specific energy density [1]. However, with slowness and complexity of reactions in the air electrode during working condition, rechargeable Zn-air batteries cannot be good at engineering practice.
