Developing a synthesis technique to control the morphology and component distribution of transition metal bi-functional electrocatalysts is of great significance for superior performance.Herein,a novel electrocatalyst...Developing a synthesis technique to control the morphology and component distribution of transition metal bi-functional electrocatalysts is of great significance for superior performance.Herein,a novel electrocatalyst has been synthesized via a one-step pyrolysis reaction of Ni(OH)_(2) nanosheets and dicyandiamide under an argon atmosphere at relatively low temperature,in which Ni/Ni_(3)C core–shell nanoparticles were encapsulated in bamboo-like N-doped carbon nanotubes and the Ni_(3)C component was homogeneously distributed in the wall of the nanotubes.Ultrathin Ni(OH)_(2) nanosheets prepared by solvothermal synthesis play an important role in the distribution of the Ni component and the formation of tube morphology.The core–shell nanoparticles and the homogeneously distributed Ni_(3)C component drastically enhance the catalytic performance.The as-prepared sample obtained by using optimized preparation conditions exhibits outstanding HER and OER activities in alkaline solution with an overpotential of 184 mV for the HER and 277 mV for the OER with a current density of 10 mA cm^(−2) and long-term durability with a 10 h continuous test.Superior electrocatalytic performance is ascribed to the effect of unique morphology and composition distribution.Additionally,the catalyst shows excellent overall water splitting properties and high stability.展开更多
The development of high-performance and low-cost anode materials plays a crucial role in the commercialization of sodium-ion batteries(SIBs).Coke coal is an excellent carbon precursor with high carbon content,wide dis...The development of high-performance and low-cost anode materials plays a crucial role in the commercialization of sodium-ion batteries(SIBs).Coke coal is an excellent carbon precursor with high carbon content,wide distribution,and abundant reserves.Nevertheless,the microcrystalline structure of coke coal-based pyrolytic carbon is relatively regular with narrow interlayer spacing,resulting in poor electrochemical performance.Herein,a coal-based carbon microcrystalline heterostructure with greatly improved structural disordering was fabricated via the cross-linking reaction between functional groups of coke coal and sucrose with the assistance of a molten salt system.Unlike coke coal-based pyrolytic carbon(BCoal-700),the coal-based carbon microcrystalline heterostructure material(BCoal-SM-700)exhibited a significantly increased Na-storage capacity from 125.4 to 286.5 mA h g^(−1),with excellent cycle and rate performance.When assembled into a sodium-ion hybrid capacitor,it exhibited an energy density of 103 W h kg^(−1) at a power density of 216 W kg^(−1).The molten salt procedure offers a simple,eco-friendly,and recyclable approach for the synthesis of coal/sucrose microcrystalline heterostructure carbon materials that can exhibit excellent Na-storage performance,making them promising candidates for SIBs.展开更多
Solving the issues of interface defects and carrier recombination in Fe_(2)O_(3)photoanodes is of great significance for enhancing their photoelectrochemical water splitting performance.Herein,a semiconductor material...Solving the issues of interface defects and carrier recombination in Fe_(2)O_(3)photoanodes is of great significance for enhancing their photoelectrochemical water splitting performance.Herein,a semiconductor material,MoO_(3),was incorporated in Fe_(2)O_(3)nanorods as a composite photoanode.Compared to pristine Fe_(2)O_(3),the Fe_(2)O_(3)/MoO_(3)-350 photoanode achieved a 3.2-fold increase in photocurrent density by varying the number of impregnations,reaching 1.09 mA cm^(-2)at a bias of 1.23 VRHE under 100 mW cm^(-2)illumination.In the PEC water splitting reaction,the Fe_(2)O_(3)/MoO_(3)-350 photoanode exhibited significantly improved H_(2)and O2 production rates.The experimental results showed that the change in surface state distribution and the positively shifted surface state distribution(N_(ss))center induced by the introduction of MoO_(3)promoted the transfer of photogenerated charges and the kinetics of interfacial water oxidation.Therefore,this study contributes to an in-depth understanding of the influence of interfacial structural regulation on the surface-state distribution and provides a reference for the rational design of photoanode materials.展开更多
基金supported by the National Natural Science Foundation of China(grant no.51572109 and 51772130).
文摘Developing a synthesis technique to control the morphology and component distribution of transition metal bi-functional electrocatalysts is of great significance for superior performance.Herein,a novel electrocatalyst has been synthesized via a one-step pyrolysis reaction of Ni(OH)_(2) nanosheets and dicyandiamide under an argon atmosphere at relatively low temperature,in which Ni/Ni_(3)C core–shell nanoparticles were encapsulated in bamboo-like N-doped carbon nanotubes and the Ni_(3)C component was homogeneously distributed in the wall of the nanotubes.Ultrathin Ni(OH)_(2) nanosheets prepared by solvothermal synthesis play an important role in the distribution of the Ni component and the formation of tube morphology.The core–shell nanoparticles and the homogeneously distributed Ni_(3)C component drastically enhance the catalytic performance.The as-prepared sample obtained by using optimized preparation conditions exhibits outstanding HER and OER activities in alkaline solution with an overpotential of 184 mV for the HER and 277 mV for the OER with a current density of 10 mA cm^(−2) and long-term durability with a 10 h continuous test.Superior electrocatalytic performance is ascribed to the effect of unique morphology and composition distribution.Additionally,the catalyst shows excellent overall water splitting properties and high stability.
基金supported by the National Natural Science Foundation of China(NSFC,22005023 and 52072021)the Beijing Municipal Science and Technology Commission(Grant No.Z181100004718007)the Fundamental Research Funds for the Central Universities(buctrc202141).
文摘The development of high-performance and low-cost anode materials plays a crucial role in the commercialization of sodium-ion batteries(SIBs).Coke coal is an excellent carbon precursor with high carbon content,wide distribution,and abundant reserves.Nevertheless,the microcrystalline structure of coke coal-based pyrolytic carbon is relatively regular with narrow interlayer spacing,resulting in poor electrochemical performance.Herein,a coal-based carbon microcrystalline heterostructure with greatly improved structural disordering was fabricated via the cross-linking reaction between functional groups of coke coal and sucrose with the assistance of a molten salt system.Unlike coke coal-based pyrolytic carbon(BCoal-700),the coal-based carbon microcrystalline heterostructure material(BCoal-SM-700)exhibited a significantly increased Na-storage capacity from 125.4 to 286.5 mA h g^(−1),with excellent cycle and rate performance.When assembled into a sodium-ion hybrid capacitor,it exhibited an energy density of 103 W h kg^(−1) at a power density of 216 W kg^(−1).The molten salt procedure offers a simple,eco-friendly,and recyclable approach for the synthesis of coal/sucrose microcrystalline heterostructure carbon materials that can exhibit excellent Na-storage performance,making them promising candidates for SIBs.
基金supported by the open research fund of Songshan Lake Materials Laboratory(2021SLABFK04)Foundation of Innovation Team 2020,Liaoning ProvinceNatural Science Foundation of Liaoning Province(2022-MS-170,2022-BS-108).
文摘Solving the issues of interface defects and carrier recombination in Fe_(2)O_(3)photoanodes is of great significance for enhancing their photoelectrochemical water splitting performance.Herein,a semiconductor material,MoO_(3),was incorporated in Fe_(2)O_(3)nanorods as a composite photoanode.Compared to pristine Fe_(2)O_(3),the Fe_(2)O_(3)/MoO_(3)-350 photoanode achieved a 3.2-fold increase in photocurrent density by varying the number of impregnations,reaching 1.09 mA cm^(-2)at a bias of 1.23 VRHE under 100 mW cm^(-2)illumination.In the PEC water splitting reaction,the Fe_(2)O_(3)/MoO_(3)-350 photoanode exhibited significantly improved H_(2)and O2 production rates.The experimental results showed that the change in surface state distribution and the positively shifted surface state distribution(N_(ss))center induced by the introduction of MoO_(3)promoted the transfer of photogenerated charges and the kinetics of interfacial water oxidation.Therefore,this study contributes to an in-depth understanding of the influence of interfacial structural regulation on the surface-state distribution and provides a reference for the rational design of photoanode materials.
