油浸式变压器中的微量水分严重影响着变压器的油纸绝缘性能,实现变压器中微量水分的在线监测至关重要。文中以水分子(H_(2)O)在NiO掺杂MoTe_(2)单层上的吸附结构、吸附能(E_(a))、电荷转移量(ΔQ)、态密度(DOS)、最高占据及最低未占据...油浸式变压器中的微量水分严重影响着变压器的油纸绝缘性能,实现变压器中微量水分的在线监测至关重要。文中以水分子(H_(2)O)在NiO掺杂MoTe_(2)单层上的吸附结构、吸附能(E_(a))、电荷转移量(ΔQ)、态密度(DOS)、最高占据及最低未占据分子轨道(HOMO⁃LUMO)、功函数(WF)和差分电荷密度(DCD)为计算对象,基于泛函密度函数理论(density function theory,DFT)计算研究了过渡金属氧化物(NiO)掺杂对单层MoTe_(2)吸附参数和电子性质的影响。结果表明:与本征单层MoTe_(2)相比,过渡金属氧化物(NiO)掺杂单层MoTe_(2)的化学活性明显增强。此外,NiO掺杂的单层MoTe_(2)对H_(2)O分子均表现出优异的吸附及解吸附能力。因此,基于NiO掺杂的单层MoTe_(2)气敏材料可进一步用于在油浸式变压器微量水分的在线监测领域。展开更多
The hydrogen evolution reaction(HER) is a key process in electrocatalytic water splitting for hydrogen production,yet it is often limited by sluggish H^(*)-OH adsorption and H*binding kinetics.We obtained Rumodified N...The hydrogen evolution reaction(HER) is a key process in electrocatalytic water splitting for hydrogen production,yet it is often limited by sluggish H^(*)-OH adsorption and H*binding kinetics.We obtained Rumodified Ni O nanoparticles(Ru-Ni O/NF) with enhanced HER properties by substituting ruthenium(Ru)for Ni atoms in the Ni O(200) crystalline facets on nickel foam by a one-step electrodeposition technique.This novel catalyst exhibits a significantly reduced H^(*)-OH adsorption energy and improved kinetics,with an overpotential of only 60 mV at 10 mA/cm^(2) and a Tafel slope of 26.19 mV/dec.The Ru-Ni O/NF maintains its activity for over 115 h,outperforming NiO/NF by reducing the overpotential by 177 mV.DFT calculations confirm that the addition of Ru to NiO enhances the HER kinetics by modifying the electronic structure,optimizing the surface chemistry,stabilizing the intermediates,lowering the energy barriers,and facilitating efficient charge transfer through a robust three-dimensional structure,resulting in a change in the rate-limiting step and a significant reduction in the Gibbs free energy.This study presents a highly efficient HER catalyst and offers insights into designing advanced NiO-based electrocatalysts by reducing reaction energy barriers.展开更多
Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improv...Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improved mass transfer and stability.Herein,self-supported crystalline/amorphous NiO/Ni(OH)_(2)nanosheet arrays on nickel foam(NF)are fabricated via an in-situ dissolution-deposition hydrothermal growing of Ni(OH)_(2)nanosheets without additional metal sources assisted by a common Lewis base,EDTA,followed by a rapid calcination at 300℃in air.The as-prepared EDTA-NF-12 h exhibits high OER and HER performance under alkaline conditions,requiring 235 mV and 158 mV,respectively,to reach 10 mA cm^(-2),and the decent performance can be maintained for 24 h without obvious degradation.The dual interfaces,i.e.,the dense crystalline/amorphous interfaces within the NiO/Ni(OH)_(2)nanosheet arrays,as well as the intimate interfaces between nanoarrays and NF,both serve as reaction active sites,facilitate electron transfer,and endow the catalyst with high activity and stability.Furthermore,by applying EDTA-Ni^(2+)and other Lewis bases with varying basicities instead of EDTA,the interfaces with the NF substrate are found to promote the formation of crystalline/amorphous interfaces within the nanosheets.This study offers appealing opportunities for tailoring the electrocatalytic performance of self-supported electrodes via dual interface engineering.展开更多
The porous NiO nanoplates modified with rGO nanosheets and SnO_(2)nanoparticles are developed for accurate and rapid ppb-level NO_(2)detection.The developed SnO_(2)/NiO/rGO sensor towards 50 ppm NO_(2)gas demonstrates...The porous NiO nanoplates modified with rGO nanosheets and SnO_(2)nanoparticles are developed for accurate and rapid ppb-level NO_(2)detection.The developed SnO_(2)/NiO/rGO sensor towards 50 ppm NO_(2)gas demonstrates an excellent gas-sensing response of 14.8 at 23℃,which is 3.03 times that of Ni O/rGO sensor(4.89)and 6.49 times that of NiO sensor(2.28),respectively.The developed SnO_(2)/NiO/rGO sensor exhibits faster response/recovery speed(12.7/32.8 s@5 ppm),with extra-low theoretical detection limit of 0.15 ppb at room temperature.More fascinatingly,our sensors indicate great sensitivity,outstanding repeatability and long-term stability for longer than 7 weeks.Additionally,it also suggests that 1℃and 1%relative humidity have the same effect on the SnO_(2)/NiO/rGO sensor signal as approximately 13 ppb and 7.0 ppb NO_(2)gas change,respectively.Such excellent properties are mainly attributed to the large surface-to-volume ratio,which provides active sites to NO_(2)gas spread,adsorption and diffusion on material surface in redox reaction.Moreover,the ternary heterojunctions formed by NiO,rGO and SnO_(2)may serve as highly conductive channels to accelerate carrier transfer and abundant oxygen vacancies to reduce the adsorption energy for O_(2)and NO_(2)gas,thus further improving performance of the sensors.展开更多
文摘油浸式变压器中的微量水分严重影响着变压器的油纸绝缘性能,实现变压器中微量水分的在线监测至关重要。文中以水分子(H_(2)O)在NiO掺杂MoTe_(2)单层上的吸附结构、吸附能(E_(a))、电荷转移量(ΔQ)、态密度(DOS)、最高占据及最低未占据分子轨道(HOMO⁃LUMO)、功函数(WF)和差分电荷密度(DCD)为计算对象,基于泛函密度函数理论(density function theory,DFT)计算研究了过渡金属氧化物(NiO)掺杂对单层MoTe_(2)吸附参数和电子性质的影响。结果表明:与本征单层MoTe_(2)相比,过渡金属氧化物(NiO)掺杂单层MoTe_(2)的化学活性明显增强。此外,NiO掺杂的单层MoTe_(2)对H_(2)O分子均表现出优异的吸附及解吸附能力。因此,基于NiO掺杂的单层MoTe_(2)气敏材料可进一步用于在油浸式变压器微量水分的在线监测领域。
基金supported by the National Natural Science Foundation of China (No.22275052)Department of Science and Technology of Hubei Province (Nos.2025AFA111 and 2024CSA076)。
文摘The hydrogen evolution reaction(HER) is a key process in electrocatalytic water splitting for hydrogen production,yet it is often limited by sluggish H^(*)-OH adsorption and H*binding kinetics.We obtained Rumodified Ni O nanoparticles(Ru-Ni O/NF) with enhanced HER properties by substituting ruthenium(Ru)for Ni atoms in the Ni O(200) crystalline facets on nickel foam by a one-step electrodeposition technique.This novel catalyst exhibits a significantly reduced H^(*)-OH adsorption energy and improved kinetics,with an overpotential of only 60 mV at 10 mA/cm^(2) and a Tafel slope of 26.19 mV/dec.The Ru-Ni O/NF maintains its activity for over 115 h,outperforming NiO/NF by reducing the overpotential by 177 mV.DFT calculations confirm that the addition of Ru to NiO enhances the HER kinetics by modifying the electronic structure,optimizing the surface chemistry,stabilizing the intermediates,lowering the energy barriers,and facilitating efficient charge transfer through a robust three-dimensional structure,resulting in a change in the rate-limiting step and a significant reduction in the Gibbs free energy.This study presents a highly efficient HER catalyst and offers insights into designing advanced NiO-based electrocatalysts by reducing reaction energy barriers.
基金the foundation of Guangdong Engineering Technology Research Center for Hydrogen Energy and Fuel Cells,the Guangdong Provincial Department of Education Innovation Project(No.2022KQNCX056)the Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515110354 and 2021A1515110582)。
文摘Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improved mass transfer and stability.Herein,self-supported crystalline/amorphous NiO/Ni(OH)_(2)nanosheet arrays on nickel foam(NF)are fabricated via an in-situ dissolution-deposition hydrothermal growing of Ni(OH)_(2)nanosheets without additional metal sources assisted by a common Lewis base,EDTA,followed by a rapid calcination at 300℃in air.The as-prepared EDTA-NF-12 h exhibits high OER and HER performance under alkaline conditions,requiring 235 mV and 158 mV,respectively,to reach 10 mA cm^(-2),and the decent performance can be maintained for 24 h without obvious degradation.The dual interfaces,i.e.,the dense crystalline/amorphous interfaces within the NiO/Ni(OH)_(2)nanosheet arrays,as well as the intimate interfaces between nanoarrays and NF,both serve as reaction active sites,facilitate electron transfer,and endow the catalyst with high activity and stability.Furthermore,by applying EDTA-Ni^(2+)and other Lewis bases with varying basicities instead of EDTA,the interfaces with the NF substrate are found to promote the formation of crystalline/amorphous interfaces within the nanosheets.This study offers appealing opportunities for tailoring the electrocatalytic performance of self-supported electrodes via dual interface engineering.
基金funded by the National Natural Science Foundation of China(No.62364002)Key Scientific Research Projects of Universities in Henan Province(No.24A510014)+5 种基金Xinjiang-Changji Vocational Education Alliance Special Project(No.2050305)National Laboratory of Solid State Microstructures,Nanjing University(No.M36001)Jiangsu Key Laboratory of Optoelectronic Information Functional Materials,Nanjing University(No.ndgd2024005)Henan Province Higher Education College Student Innovation Training Program Project(No.202410478019)the Doctoral Research Initiation Fund Project,Zhoukou Normal University(No.ZKNUC2022018)the Natural Science Foundation Project of Xinjiang Uygur Autonomous Region(No.2022D01C006)。
文摘The porous NiO nanoplates modified with rGO nanosheets and SnO_(2)nanoparticles are developed for accurate and rapid ppb-level NO_(2)detection.The developed SnO_(2)/NiO/rGO sensor towards 50 ppm NO_(2)gas demonstrates an excellent gas-sensing response of 14.8 at 23℃,which is 3.03 times that of Ni O/rGO sensor(4.89)and 6.49 times that of NiO sensor(2.28),respectively.The developed SnO_(2)/NiO/rGO sensor exhibits faster response/recovery speed(12.7/32.8 s@5 ppm),with extra-low theoretical detection limit of 0.15 ppb at room temperature.More fascinatingly,our sensors indicate great sensitivity,outstanding repeatability and long-term stability for longer than 7 weeks.Additionally,it also suggests that 1℃and 1%relative humidity have the same effect on the SnO_(2)/NiO/rGO sensor signal as approximately 13 ppb and 7.0 ppb NO_(2)gas change,respectively.Such excellent properties are mainly attributed to the large surface-to-volume ratio,which provides active sites to NO_(2)gas spread,adsorption and diffusion on material surface in redox reaction.Moreover,the ternary heterojunctions formed by NiO,rGO and SnO_(2)may serve as highly conductive channels to accelerate carrier transfer and abundant oxygen vacancies to reduce the adsorption energy for O_(2)and NO_(2)gas,thus further improving performance of the sensors.
