Oxidized nanocarbons(ONCs)have been regarded as efficient electrocatalysts for H2O2 production.However,wet chemical procedures involving large volumes of strong acid and long synthetic time are usually needed to obtai...Oxidized nanocarbons(ONCs)have been regarded as efficient electrocatalysts for H2O2 production.However,wet chemical procedures involving large volumes of strong acid and long synthetic time are usually needed to obtain these ONCs.Herein,a plasma activation strategy is developed as a rapid and environmentally benign approach to obtain various ONCs,including oxidized multiwalled carbon nanotubes,single-walled carbon nanotube,graphene,and super P carbon black.After a few minutes of plasma activation,oxygen-containing functional groups and defects can be effectively introduced onto the surface of nanocarbons.Enhanced electrocatalytic activity and selectivity are demonstrated by the plasma-ONCs for H2O2 production.Taking oxidized multiwalled carbon nanotubes as an example,high selectivity(up to 95%)and activity(0.75 V at 1 mA cm^(−2))can be achieved in alkaline solution.Moreover,ex situ x-ray photoelectron spectroscopy and in situ Raman measurements reveal that C–O,C=O,edge defect,and sp2 basal planar defect are probably the active sites.展开更多
Supercapacitors have high power densities, high efficiencies, and long cycling lifetimes; however, to enable their wider use, their energy densities must be significantly improved. The design and synthesis of improved...Supercapacitors have high power densities, high efficiencies, and long cycling lifetimes; however, to enable their wider use, their energy densities must be significantly improved. The design and synthesis of improved carbon materials with better capacitance, rate performance, and cycling stability has emerged as the main theme of supercapacitor research. Herein, we report a facile synthetic method to prepare nitrogen-rich carbon particles based on a continuous aerosol- spraying process. The method yields particles that have high surface areas, a uniform microporous structure, and are highly N-doped, resulting in a synergism that enables the construction of supercapacitors with high energy and power density for use in both aqueous and commercial organic electrolytes. Furthermore, we have used density functional theory calculations to show that the improved performance is due to the enhanced wettability and ion adsorption interactions at the carbon/electrolyte interface that result from nitrogen doping. These findings provide new insights into the role of heteroatom doping in the capacitance enhancement of carbon materials; in addition, our method offers an efficient route for large-scale production of doped carbon.展开更多
Surface-redox pseudocapacitive nanomaterials show promise for fast-charging energy storage.However,their high surface area usually leads to low density,which is not conducive to achieving both high volumetric capacity...Surface-redox pseudocapacitive nanomaterials show promise for fast-charging energy storage.However,their high surface area usually leads to low density,which is not conducive to achieving both high volumetric capacity and high-rate capability.Herein,we demonstrate that TiO_(2)nanosheets(meso-TiO_(2)-NSs)with densely packed mesoporous are capable of fast pseudocapacitance-dominated sodium-ion storage,as well as high volumetric and gravimetric capacities.Through compressing treatment,the compaction density of meso-TiO_(2)-NSs is up to~1.6g/cm^(2),combined with high surface area and high porosity with mesopore channels for rapid Na+diffusion.The compacted meso-TiO_(2)-NSs electrodes achieve high pseudocapacitance(93.6%of total charge at 1mV/s),high-rate capability(up to 10 A/g),and long-term cycling stability(10,000 cycles).More importantly,the space-efficiently packed structure enables high volumetric capacity.The thick-film meso-TiO_(2)-NSs anode with the mass loading of 10mg/cm^(2)delivers a gravimetric capacity of 165 mAh/g and a volumetric capacity of 223 mAh/cm^(3)at 5 mA/cm^(2),much higher than those of commercial hard carbon anode(80mAh/g and 86mAh/cm^(3)).This work highlights a pathway for designing a dense nanostructure that enables fast charge kinetics for high-density sodium-ion storage.展开更多
基金National Natural Science Foundation of China(No.12075002)the Outstanding Youth Fund of Anhui Province(No.2008085J21)+1 种基金the Anhui Provincial Supporting Program for Excellent Young Talents in Universities(No.gxyqZD2019005)the Innovation and Entrepreneurship Project of Overseas Returnees in Anhui Province(No.2019LCX018).
文摘Oxidized nanocarbons(ONCs)have been regarded as efficient electrocatalysts for H2O2 production.However,wet chemical procedures involving large volumes of strong acid and long synthetic time are usually needed to obtain these ONCs.Herein,a plasma activation strategy is developed as a rapid and environmentally benign approach to obtain various ONCs,including oxidized multiwalled carbon nanotubes,single-walled carbon nanotube,graphene,and super P carbon black.After a few minutes of plasma activation,oxygen-containing functional groups and defects can be effectively introduced onto the surface of nanocarbons.Enhanced electrocatalytic activity and selectivity are demonstrated by the plasma-ONCs for H2O2 production.Taking oxidized multiwalled carbon nanotubes as an example,high selectivity(up to 95%)and activity(0.75 V at 1 mA cm^(−2))can be achieved in alkaline solution.Moreover,ex situ x-ray photoelectron spectroscopy and in situ Raman measurements reveal that C–O,C=O,edge defect,and sp2 basal planar defect are probably the active sites.
基金This work is partially supported by the National Natural Science Foundation of China （No. 51376054）.
文摘Supercapacitors have high power densities, high efficiencies, and long cycling lifetimes; however, to enable their wider use, their energy densities must be significantly improved. The design and synthesis of improved carbon materials with better capacitance, rate performance, and cycling stability has emerged as the main theme of supercapacitor research. Herein, we report a facile synthetic method to prepare nitrogen-rich carbon particles based on a continuous aerosol- spraying process. The method yields particles that have high surface areas, a uniform microporous structure, and are highly N-doped, resulting in a synergism that enables the construction of supercapacitors with high energy and power density for use in both aqueous and commercial organic electrolytes. Furthermore, we have used density functional theory calculations to show that the improved performance is due to the enhanced wettability and ion adsorption interactions at the carbon/electrolyte interface that result from nitrogen doping. These findings provide new insights into the role of heteroatom doping in the capacitance enhancement of carbon materials; in addition, our method offers an efficient route for large-scale production of doped carbon.
基金support from the National Natural Science Foundation of China(Nos.22005256,22179-113),the Natural Science Foundation of Fujian Province of China(No.2020J01034)Fundamental Research Funds for the Central Universities(Nos.20720210045,2072-0210084)+4 种基金Science and Technology Projects of Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM)(No.HRTP-2022-19)Kun Lan acknowledges the support from the National Natural Science Foundation of China(No.22205118)the“Junma"Program of Inner Mongolia University(No.21300-5223715)the Grassland Talent Program of Inner Mongolia Autonomous Region of China.Haobin Wu acknowledges the support the Zhejiang Provincial Natural Science Foundation(No.LR21E020003)the National Natural Science Foundation of China(No.22005266).
文摘Surface-redox pseudocapacitive nanomaterials show promise for fast-charging energy storage.However,their high surface area usually leads to low density,which is not conducive to achieving both high volumetric capacity and high-rate capability.Herein,we demonstrate that TiO_(2)nanosheets(meso-TiO_(2)-NSs)with densely packed mesoporous are capable of fast pseudocapacitance-dominated sodium-ion storage,as well as high volumetric and gravimetric capacities.Through compressing treatment,the compaction density of meso-TiO_(2)-NSs is up to~1.6g/cm^(2),combined with high surface area and high porosity with mesopore channels for rapid Na+diffusion.The compacted meso-TiO_(2)-NSs electrodes achieve high pseudocapacitance(93.6%of total charge at 1mV/s),high-rate capability(up to 10 A/g),and long-term cycling stability(10,000 cycles).More importantly,the space-efficiently packed structure enables high volumetric capacity.The thick-film meso-TiO_(2)-NSs anode with the mass loading of 10mg/cm^(2)delivers a gravimetric capacity of 165 mAh/g and a volumetric capacity of 223 mAh/cm^(3)at 5 mA/cm^(2),much higher than those of commercial hard carbon anode(80mAh/g and 86mAh/cm^(3)).This work highlights a pathway for designing a dense nanostructure that enables fast charge kinetics for high-density sodium-ion storage.
