Reversible oxygen reaction plays a crucial role in rechargeable battery systems,but it is limited by the slow reaction kinetics.Herein,the ionic modulation of cobalt pentlandite coupled with nitrogen‐doped bowl‐like...Reversible oxygen reaction plays a crucial role in rechargeable battery systems,but it is limited by the slow reaction kinetics.Herein,the ionic modulation of cobalt pentlandite coupled with nitrogen‐doped bowl‐like hollow carbon sphere is well designed on octahedral and tetrahedral sites.The robust FexCo9−xS8‐NHCS‐V with iron replacing at the octahedron possesses prolonged metal sulfur bond and exhibits excellent bifunctional electrocatalytic performance towards oxygen reduction reaction(ORR,E_(1/2)=0.80 V vs.RHE)and excellent oxygen evolution reaction(OER,E_(j=10)=1.53 V vs.RHE)in 0.1 mol/L KOH.Accordingly,a rechargeable Zn‐air battery of Fe_(x)Co_(9−x)S_(8)‐NHCS‐V cathode endows high energy efficiency(102 mW cm^(−2)),and a microbial fuel cell achieves a high‐power density(791±42 mW m^(−2)),outperforming the benchmark Pt/C catalyst.展开更多
Layered double hydroxides(LDHs)with decent oxygen evolution reaction(OER)activity have been extensively studied in the fields of energy storage and conversion.However,their poor conductivity,ease of agglomeration,and ...Layered double hydroxides(LDHs)with decent oxygen evolution reaction(OER)activity have been extensively studied in the fields of energy storage and conversion.However,their poor conductivity,ease of agglomeration,and low intrinsic activity limit their practical application.To date,improvement of the intrinsic activity and stability of NiFe-LDHs through the introduction of heteroatoms or its combination with other conductive substrates to enhance their water-splitting performance has drawn increasing attention.In this study,vertically interlaced ternary phosphatised nickel/iron hybrids grown on the surface of titanium carbide flakes(NiFe P/MXene)were successfully synthesised through a hydrothermal reaction and phosphating calcination process.The optimised NiFe P/MXene exhibited a low overpotential of 286 m V at 10 m A cm^(-2) and a Tafel slope of 35 m V dec^(-1) for the OER,which exceeded the performance of several existing NiFe-based catalysts.NiFe P/MXene was further used as a water-splitting anode in an alkaline electrolyte,exhibiting a cell voltage of only 1.61 V to achieve a current density of 10 m A cm^(-2).Density functional theory(DFT)calculations revealed that the combination of MXene acting as a conductive substrate and the phosphating process can effectively tune the electronic structure and density of the electrocatalyst surface to promote the energy level of the d-band centre,resulting in an enhanced OER performance.This study provides a valuable guideline for designing high-performance MXenesupported NiFe-based OER catalysts.展开更多
文摘Reversible oxygen reaction plays a crucial role in rechargeable battery systems,but it is limited by the slow reaction kinetics.Herein,the ionic modulation of cobalt pentlandite coupled with nitrogen‐doped bowl‐like hollow carbon sphere is well designed on octahedral and tetrahedral sites.The robust FexCo9−xS8‐NHCS‐V with iron replacing at the octahedron possesses prolonged metal sulfur bond and exhibits excellent bifunctional electrocatalytic performance towards oxygen reduction reaction(ORR,E_(1/2)=0.80 V vs.RHE)and excellent oxygen evolution reaction(OER,E_(j=10)=1.53 V vs.RHE)in 0.1 mol/L KOH.Accordingly,a rechargeable Zn‐air battery of Fe_(x)Co_(9−x)S_(8)‐NHCS‐V cathode endows high energy efficiency(102 mW cm^(−2)),and a microbial fuel cell achieves a high‐power density(791±42 mW m^(−2)),outperforming the benchmark Pt/C catalyst.
基金supported by the National Natural Science Foundation of China(21875048)the Outstanding Youth Project of Guangdong Natural Science Foundation(2020B1515020028)+1 种基金the Yangcheng Scholars Research Project of Guangzhou(201831820)the Science and Technology Research Project of Guangzhou(202002010007)。
文摘Layered double hydroxides(LDHs)with decent oxygen evolution reaction(OER)activity have been extensively studied in the fields of energy storage and conversion.However,their poor conductivity,ease of agglomeration,and low intrinsic activity limit their practical application.To date,improvement of the intrinsic activity and stability of NiFe-LDHs through the introduction of heteroatoms or its combination with other conductive substrates to enhance their water-splitting performance has drawn increasing attention.In this study,vertically interlaced ternary phosphatised nickel/iron hybrids grown on the surface of titanium carbide flakes(NiFe P/MXene)were successfully synthesised through a hydrothermal reaction and phosphating calcination process.The optimised NiFe P/MXene exhibited a low overpotential of 286 m V at 10 m A cm^(-2) and a Tafel slope of 35 m V dec^(-1) for the OER,which exceeded the performance of several existing NiFe-based catalysts.NiFe P/MXene was further used as a water-splitting anode in an alkaline electrolyte,exhibiting a cell voltage of only 1.61 V to achieve a current density of 10 m A cm^(-2).Density functional theory(DFT)calculations revealed that the combination of MXene acting as a conductive substrate and the phosphating process can effectively tune the electronic structure and density of the electrocatalyst surface to promote the energy level of the d-band centre,resulting in an enhanced OER performance.This study provides a valuable guideline for designing high-performance MXenesupported NiFe-based OER catalysts.
