Highly active transition metal nitrides are desirable for electrocatalytic reactions,but their long-term stability is still unsatisfactory and thus limiting commercial applications.Herein,for the first time,we report ...Highly active transition metal nitrides are desirable for electrocatalytic reactions,but their long-term stability is still unsatisfactory and thus limiting commercial applications.Herein,for the first time,we report a unique and universal room-temperature urea plasma method for controllable synthesis of N-doped carbon coated metal(Fe,Co,Ni,etc.)nitrides arrays electrocatalysts.The preformed metal oxides arrays can be successfully converted into metal nitrides arrays with preserved nanostructures and a thin layer of N-doped carbon(N-C)via one-step urea plasma.Typically,as a representative case,N-C@CoN nanowire arrays are illustrated and corresponding formation mechanism by plasma is proposed.Notably,the designed N-C@Co N catalysts deliver excellent electrocatalytic activity and long-term stability both in oxygen evolution reaction(OER)and urea oxidation reaction(UOR).For OER,a low overpotential(264 mV at 10 mA/cm^(2))and high stability(>50 h at 20 mA/cm^(2))are acquired.For UOR,a current density of100 m A/cm^(2) is achieved at only 1.39 V and maintain over 100 h.Theoretical calculations reveal that the synergetic coupling effect of CoN and N-C can significantly facilitate the charge-transfer process,optimize adsorbed intermediates binding strength and further greatly decrease the energy barrier.This strategy provides a novel method for fabrication of N-C@metal nitrides as highly active and stable catalysts.展开更多
High-performance electrocatalysts for water splitting are desired due to the urgent requirement of clean and sustainable hydrogen production.To reduce the energy barrier,herein,we adopt a facile in-situ surface modifi...High-performance electrocatalysts for water splitting are desired due to the urgent requirement of clean and sustainable hydrogen production.To reduce the energy barrier,herein,we adopt a facile in-situ surface modification strategy to develop a low-cost and efficient electrocatalyst for water splitting.The synthesized mulberry-like NiS/Ni nanoparticles exhibit excellent catalytic performance for water splitting.Small overpotentials of 301 and 161 mV are needed to drive the current density of 10 mA cm^-2 accompanying with remarkably low Tafel slopes of 46 and 74 mV dec^-1 for oxygen evolution reaction(OER)and hydrogen evolution reaction(HER),respectively.Meanwhile,a robust electrochemical stability is demonstrated.Further high-resolution X-ray photoelectron spectroscopy analyses reveal that the intrinsic HER activity improvement is attributed to the electron-enriched S on the strongly coupled NiS and Ni interface,which simultaneously facilitates the important electron transfer,consistent with the electrochemical impedance results.The post characterizations demonstrate that surface reconstructed oxyhydroxide contributes to the OER activity and NiS/Ni is an OER precatalyst.This structure construction with in-situ formation of active interface provides an effective way to design efficient electrocatalysts for energy conversion.展开更多
Nano structured LiFexMn1-xPO4 （x=0, 0.2, 0.4） materials were successfully prepared by one-step reflux method in a water/PEG400 mixed solvent, and were coated by carbon using glucose as the precursor. The materials w...Nano structured LiFexMn1-xPO4 （x=0, 0.2, 0.4） materials were successfully prepared by one-step reflux method in a water/PEG400 mixed solvent, and were coated by carbon using glucose as the precursor. The materials were characterized by X-ray diffraction （XRD）, field emission scanning electron microscopy （FESEM） and transmission electron microscopy （TEM）. The electrochemical properties of the materials were investigated by galvanostatic cycling, cyclic voltammetry （CV） and electrochemical impedance spectroscopy （EIS）. It was found that the materials consisted of nanorods with a diameter of 50 nm and a length of 500 nm. Galvanostatic cycling showed that the capacity of LiMnPO4 could be largely increased by Fe2＋ substitution. At a current rate of C/20, the capacity of the three samples （x=0, 0.2, 0.4） were 47, 107 and 150 mA-h.g-1, respectively. CV result showed that the Fe2＋ substitution could decrease the polarization during charging/discharging, ac- celerating the electrochemical process. EIS result showed that the Fe2＋ substitution could decrease the charge transfer resistance between the electrode and electrolyte, as well as increase the Li-ion diffusion coefficient in the bulk material, resulting in an improved electrochemical performance.展开更多
基金supported by National Natural Science Foundation of China(No.52073252)Science and Technology Department of Zhejiang Province(No.2023C01231)+2 种基金Key Research and Development Project of Science and Technology Department of Sichuan Province(No.2022YFSY0004)Key Laboratory of Engineering Dielectrics and Its Application(Harbin University of Science and Technology)Ministry of Education(No.KFM 202202),and the Open Project Program of the State Key Laboratory of New textile Materials and Advanced Processing Technologies(No.FZ2021009)。
文摘Highly active transition metal nitrides are desirable for electrocatalytic reactions,but their long-term stability is still unsatisfactory and thus limiting commercial applications.Herein,for the first time,we report a unique and universal room-temperature urea plasma method for controllable synthesis of N-doped carbon coated metal(Fe,Co,Ni,etc.)nitrides arrays electrocatalysts.The preformed metal oxides arrays can be successfully converted into metal nitrides arrays with preserved nanostructures and a thin layer of N-doped carbon(N-C)via one-step urea plasma.Typically,as a representative case,N-C@CoN nanowire arrays are illustrated and corresponding formation mechanism by plasma is proposed.Notably,the designed N-C@Co N catalysts deliver excellent electrocatalytic activity and long-term stability both in oxygen evolution reaction(OER)and urea oxidation reaction(UOR).For OER,a low overpotential(264 mV at 10 mA/cm^(2))and high stability(>50 h at 20 mA/cm^(2))are acquired.For UOR,a current density of100 m A/cm^(2) is achieved at only 1.39 V and maintain over 100 h.Theoretical calculations reveal that the synergetic coupling effect of CoN and N-C can significantly facilitate the charge-transfer process,optimize adsorbed intermediates binding strength and further greatly decrease the energy barrier.This strategy provides a novel method for fabrication of N-C@metal nitrides as highly active and stable catalysts.
基金This work was financailly supported by the National Natural Science Foundation of China(Nos.51722204 and 51802145)the National Key Basic Research Program of China(No.2014CB931702)+2 种基金the Sichuan Science and Technology Program(Nos.2018RZ0082 and 2019JDRC0070)the Fundamental Research Fund for the Central Universities(No.A03018023801053)the Open Project of Jiangsu Key Laboratory for Carbon-Based Functional Materials Devices at Soochow University(No.KJS1807).
文摘High-performance electrocatalysts for water splitting are desired due to the urgent requirement of clean and sustainable hydrogen production.To reduce the energy barrier,herein,we adopt a facile in-situ surface modification strategy to develop a low-cost and efficient electrocatalyst for water splitting.The synthesized mulberry-like NiS/Ni nanoparticles exhibit excellent catalytic performance for water splitting.Small overpotentials of 301 and 161 mV are needed to drive the current density of 10 mA cm^-2 accompanying with remarkably low Tafel slopes of 46 and 74 mV dec^-1 for oxygen evolution reaction(OER)and hydrogen evolution reaction(HER),respectively.Meanwhile,a robust electrochemical stability is demonstrated.Further high-resolution X-ray photoelectron spectroscopy analyses reveal that the intrinsic HER activity improvement is attributed to the electron-enriched S on the strongly coupled NiS and Ni interface,which simultaneously facilitates the important electron transfer,consistent with the electrochemical impedance results.The post characterizations demonstrate that surface reconstructed oxyhydroxide contributes to the OER activity and NiS/Ni is an OER precatalyst.This structure construction with in-situ formation of active interface provides an effective way to design efficient electrocatalysts for energy conversion.
基金supported by Zijin Program of Zhejiang University, Chinathe Fundamental Research Funds for the Central Universities (No. 2010QNA4003)+3 种基金the Ph.D.Programs Foundation of Ministry of Education of China(No. 20100101120024)the Foundation of Education Office of Zhejiang Province, China (No. Y201016484)the Qianjiang Talents Project of Science Technology Department of Zhejiang Province, China (No. 2011R10021)the National Natural Science Foundation of China (No.51101139)
文摘Nano structured LiFexMn1-xPO4 （x=0, 0.2, 0.4） materials were successfully prepared by one-step reflux method in a water/PEG400 mixed solvent, and were coated by carbon using glucose as the precursor. The materials were characterized by X-ray diffraction （XRD）, field emission scanning electron microscopy （FESEM） and transmission electron microscopy （TEM）. The electrochemical properties of the materials were investigated by galvanostatic cycling, cyclic voltammetry （CV） and electrochemical impedance spectroscopy （EIS）. It was found that the materials consisted of nanorods with a diameter of 50 nm and a length of 500 nm. Galvanostatic cycling showed that the capacity of LiMnPO4 could be largely increased by Fe2＋ substitution. At a current rate of C/20, the capacity of the three samples （x=0, 0.2, 0.4） were 47, 107 and 150 mA-h.g-1, respectively. CV result showed that the Fe2＋ substitution could decrease the polarization during charging/discharging, ac- celerating the electrochemical process. EIS result showed that the Fe2＋ substitution could decrease the charge transfer resistance between the electrode and electrolyte, as well as increase the Li-ion diffusion coefficient in the bulk material, resulting in an improved electrochemical performance.
