为进一步了解在容性耦合等离子体放电时的放电机理与入射到极板处的粒子状态,通过Particle-In-Cell/Monte Carlo Collision(PIC/MCC)程序模拟氩气与甲烷混合气体放电,分别对不同Ar/CH_(4)比例和不同极板间隙条件下的电子密度、CH_(4)^(+...为进一步了解在容性耦合等离子体放电时的放电机理与入射到极板处的粒子状态,通过Particle-In-Cell/Monte Carlo Collision(PIC/MCC)程序模拟氩气与甲烷混合气体放电,分别对不同Ar/CH_(4)比例和不同极板间隙条件下的电子密度、CH_(4)^(+)、CH_(3)^(+)基团粒子浓度、电子能量概率(EEPF)分布,以及对到达极板边界粒子的能量角度分布和粒子种类进行模拟计算。模拟结果表明:在固定Ar/CH_(4)为9∶1时随着极板间距的增大,放电中心的电子密度、Ar^(+)、CH_(2)^(-)和H^(-)离子密度均呈现先下降后上升的趋势,而CH_(4)^(+)与CH_(3)^(+)离子密度变化趋势正好相反;极板间距增大时,电子能量概率分布由双麦克斯韦分布变为单麦克斯韦分布;到达极板中电子占比较大,随极板间距的变小,到达极板处的Ar^(+)概率先降低后升高,到达极板的CH_(4)^(+)、CH_(3)^(+)和CH_(2)^(+)离子比例随极板间距增加而增加。在固定极板间距时,随CH_(4)含量的增加,放电中心的电子密度、Ar^(+)密度均呈现下降趋势,CH_(4)^(+)、CH_(3)^(+)、CH_(2)^(-)和H^(-)离子的密度均呈上升趋势;极板间距的变化对EEPF分布的影响比CH_(4)比例变化的影响更加明显;随CH_(4)含量的增加,到达极板的电子占比变化不明显,Ar^(+)离子的占比明显减小,而到达极板处的CH_(4)^(+)、CH_(3)^(+)、CH_(2)^(+)和其余的离子比例均有增加。展开更多
Plasma-induced surface graft copolymerization of acrylic acid on polypropylene non-woven fabric(PP-g-AA)andpolypropylene membrane were reported.The extents of grafting were controlled by the plasma and polymerizationc...Plasma-induced surface graft copolymerization of acrylic acid on polypropylene non-woven fabric(PP-g-AA)andpolypropylene membrane were reported.The extents of grafting were controlled by the plasma and polymerizationcondition.Hexadecyltrimethyl ammonium bromide was then coupled with the carboxyl group of PP-g-AA to obtain apolyion complex(PIC).At last,CF_4 plasma was used to give PICs hydrophobic property.The moisture regain and water-repellency of the processed PICs was investigated.The surfaces were characterized using ATR FT-IR and XPS.The resultindicates that the products have very high ability to adsorb moisture,even better than cotton fiber.At the same time,theproducts show excellent hydrophobic property,which can't be wetted by those reagents whose surface tensions were higherthan 327 mN/m.展开更多
The polarized electric field inside piezoelectric materials has been proven to be a promising technique to boost photogenerated charge separation.Herein,a novel flexible SnFe_(2)O_(4)/ZnIn_(2)S_(4)/polyvinylidene fluo...The polarized electric field inside piezoelectric materials has been proven to be a promising technique to boost photogenerated charge separation.Herein,a novel flexible SnFe_(2)O_(4)/ZnIn_(2)S_(4)/polyvinylidene fluoride((CH2CF2)_(n),PVDF)(P-SZ)film piezophotocatalyst was successfully synthesized by combining PVDF,an organic piezoelectric material,with a SnFe_(2)O_(4)/ZnIn_(2)S_(4)(SFO/ZIS)type II heterojunction photocatalyst.The hydrogen evolution rate of SFO/ZIS heterojunction with a SFO content of 5%is about 846.79μmol·h^(−1)·g^(−1),which is 3.6 times that of pristine ZIS.Furthermore,after being combined with PVDF,the optimum hydrogen evolution rate of P-SZ is about 1652.7μmol·h^(−1)·g^(−1)in the presence of ultrasound,which exceeds that of 5%SFO/ZIS by an approximate factor of 2.0.Based on experimental results,the mechanism of the improved photocatalytic performance of P-SZ was proposed on the basis of the piezoelectric field in PVDF and the formed heterojunction between SFO and ZIS,which effectively boosted the separation of photoinduced charges.This work provides an efficient strategy for multi-path collection and utilization of natural solar and vibrational energy to enhance photoactivity.展开更多
In this work,the surface modification using a two-steps plasma etching has been developed for enhancing energy conversion performance in polytetrafluoroethylene(PTFE)triboelectric nanogenerator(TENG).Enhancing surface...In this work,the surface modification using a two-steps plasma etching has been developed for enhancing energy conversion performance in polytetrafluoroethylene(PTFE)triboelectric nanogenerator(TENG).Enhancing surface area by a powerful O_(2) and Ar bipolar pulse plasma etching without the use of CF_(4) gas has been demonstrated for the first time.TENG with modified surface PTFE using a sequential two-step O_(2)/Ar plasma has a superior power density of 9.9 W·m^(-2),which is almost thirty times higher than that of a pristine PTFE TENG.The synergistic combination of high surface area and charge trapping sites due to chemical bond defects achieved from the use of a sequential O_(2)/Ar plasma gives rise to the intensified triboelectric charge density and the enhancement of power output of PTFE-based TENG.The effects of plasma species and plasma etching sequence on surface morphologies and surface chemical species were investigated by a field emission scanning electron microscopy(FESEM),atomic force microscopy(AFM),and X-ray photoelectron spectroscopy(XPS).The correlation of surface morphology,chemical structure,and TENG performance was elucidated.In addition,the applications of mechanical energy harvesting for lighting,charging capacitors,keyboard sensing and operating a portable calculator were demonstrated.展开更多
The low intrinsic activity of Fe/N/C oxygen catalysts restricts their commercial application in the fuel cells technique;herein,we demonstrated the interface engineering of plasmonic induced Fe/N/C-F catalyst with pri...The low intrinsic activity of Fe/N/C oxygen catalysts restricts their commercial application in the fuel cells technique;herein,we demonstrated the interface engineering of plasmonic induced Fe/N/C-F catalyst with primarily enhanced oxygen reduction performance for fuel cells applications.The strong interaction between F and Fe-N4 active sites modifies the catalyst interfacial properties as revealed by X-ray absorption structure spectrum and density functional theory calculations,which changes the electronic structure of Fe-N active site resulting from more atoms around the active site participating in the reaction as well as super-hydrophobicity from C–F covalent bond.The hybrid contribution from active sites and carbon support is proposed to optimize the three-phase microenvironment efficiently in the catalysis electrode,thereby facilitating efficient oxygen reduction performance.High catalytic performance for oxygen reduction and fuel cells practical application catalyzed by Fe/N/C-F catalyst is thus verified,which offers a novel catalyst system for fuel cells technique.展开更多
文摘为进一步了解在容性耦合等离子体放电时的放电机理与入射到极板处的粒子状态,通过Particle-In-Cell/Monte Carlo Collision(PIC/MCC)程序模拟氩气与甲烷混合气体放电,分别对不同Ar/CH_(4)比例和不同极板间隙条件下的电子密度、CH_(4)^(+)、CH_(3)^(+)基团粒子浓度、电子能量概率(EEPF)分布,以及对到达极板边界粒子的能量角度分布和粒子种类进行模拟计算。模拟结果表明:在固定Ar/CH_(4)为9∶1时随着极板间距的增大,放电中心的电子密度、Ar^(+)、CH_(2)^(-)和H^(-)离子密度均呈现先下降后上升的趋势,而CH_(4)^(+)与CH_(3)^(+)离子密度变化趋势正好相反;极板间距增大时,电子能量概率分布由双麦克斯韦分布变为单麦克斯韦分布;到达极板中电子占比较大,随极板间距的变小,到达极板处的Ar^(+)概率先降低后升高,到达极板的CH_(4)^(+)、CH_(3)^(+)和CH_(2)^(+)离子比例随极板间距增加而增加。在固定极板间距时,随CH_(4)含量的增加,放电中心的电子密度、Ar^(+)密度均呈现下降趋势,CH_(4)^(+)、CH_(3)^(+)、CH_(2)^(-)和H^(-)离子的密度均呈上升趋势;极板间距的变化对EEPF分布的影响比CH_(4)比例变化的影响更加明显;随CH_(4)含量的增加,到达极板的电子占比变化不明显,Ar^(+)离子的占比明显减小,而到达极板处的CH_(4)^(+)、CH_(3)^(+)、CH_(2)^(+)和其余的离子比例均有增加。
文摘Plasma-induced surface graft copolymerization of acrylic acid on polypropylene non-woven fabric(PP-g-AA)andpolypropylene membrane were reported.The extents of grafting were controlled by the plasma and polymerizationcondition.Hexadecyltrimethyl ammonium bromide was then coupled with the carboxyl group of PP-g-AA to obtain apolyion complex(PIC).At last,CF_4 plasma was used to give PICs hydrophobic property.The moisture regain and water-repellency of the processed PICs was investigated.The surfaces were characterized using ATR FT-IR and XPS.The resultindicates that the products have very high ability to adsorb moisture,even better than cotton fiber.At the same time,theproducts show excellent hydrophobic property,which can't be wetted by those reagents whose surface tensions were higherthan 327 mN/m.
基金supported by Shandong Provincial Natural Science Foundation,China(Nos.ZR2021ME046 and ZR2022ME179)Liaocheng University College Students Innovation and Entrepreneurship Training Program(No.2020205926).
文摘The polarized electric field inside piezoelectric materials has been proven to be a promising technique to boost photogenerated charge separation.Herein,a novel flexible SnFe_(2)O_(4)/ZnIn_(2)S_(4)/polyvinylidene fluoride((CH2CF2)_(n),PVDF)(P-SZ)film piezophotocatalyst was successfully synthesized by combining PVDF,an organic piezoelectric material,with a SnFe_(2)O_(4)/ZnIn_(2)S_(4)(SFO/ZIS)type II heterojunction photocatalyst.The hydrogen evolution rate of SFO/ZIS heterojunction with a SFO content of 5%is about 846.79μmol·h^(−1)·g^(−1),which is 3.6 times that of pristine ZIS.Furthermore,after being combined with PVDF,the optimum hydrogen evolution rate of P-SZ is about 1652.7μmol·h^(−1)·g^(−1)in the presence of ultrasound,which exceeds that of 5%SFO/ZIS by an approximate factor of 2.0.Based on experimental results,the mechanism of the improved photocatalytic performance of P-SZ was proposed on the basis of the piezoelectric field in PVDF and the formed heterojunction between SFO and ZIS,which effectively boosted the separation of photoinduced charges.This work provides an efficient strategy for multi-path collection and utilization of natural solar and vibrational energy to enhance photoactivity.
基金supported by the RNN program of the NANOTEC,NSTDA,Ministry of Higher Education,Science,Research and Innovation(MHESI)and Khon Kaen University,Thailand,the Thailand Research Fund(No.MRG6280196)the Thailand Center of Excellence in Physics(ThEP),and the Basic Research Fund of Khon Kaen University.
文摘In this work,the surface modification using a two-steps plasma etching has been developed for enhancing energy conversion performance in polytetrafluoroethylene(PTFE)triboelectric nanogenerator(TENG).Enhancing surface area by a powerful O_(2) and Ar bipolar pulse plasma etching without the use of CF_(4) gas has been demonstrated for the first time.TENG with modified surface PTFE using a sequential two-step O_(2)/Ar plasma has a superior power density of 9.9 W·m^(-2),which is almost thirty times higher than that of a pristine PTFE TENG.The synergistic combination of high surface area and charge trapping sites due to chemical bond defects achieved from the use of a sequential O_(2)/Ar plasma gives rise to the intensified triboelectric charge density and the enhancement of power output of PTFE-based TENG.The effects of plasma species and plasma etching sequence on surface morphologies and surface chemical species were investigated by a field emission scanning electron microscopy(FESEM),atomic force microscopy(AFM),and X-ray photoelectron spectroscopy(XPS).The correlation of surface morphology,chemical structure,and TENG performance was elucidated.In addition,the applications of mechanical energy harvesting for lighting,charging capacitors,keyboard sensing and operating a portable calculator were demonstrated.
基金the National Natural Science Foundation of China(Nos.21203008 and 21975025)Beijing Nature Science Foundation(No.2172051)+1 种基金State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University,and Shenzhen Science and Technology Innovation Committee(No.JCYJ20170817161445322)Thanks for Dr.Lirong Zheng(1W1B@Beijing Synchrotron Radiation Facility)for providing measurement time.We appreciate help from Dr.Jiaou Wang(4B9B@Beijing Synchrotron Radiation Facility)for XANES measurement.XPS measurements were performed in the Analysis&Testing Center,Beijing Institute of Technology.
文摘The low intrinsic activity of Fe/N/C oxygen catalysts restricts their commercial application in the fuel cells technique;herein,we demonstrated the interface engineering of plasmonic induced Fe/N/C-F catalyst with primarily enhanced oxygen reduction performance for fuel cells applications.The strong interaction between F and Fe-N4 active sites modifies the catalyst interfacial properties as revealed by X-ray absorption structure spectrum and density functional theory calculations,which changes the electronic structure of Fe-N active site resulting from more atoms around the active site participating in the reaction as well as super-hydrophobicity from C–F covalent bond.The hybrid contribution from active sites and carbon support is proposed to optimize the three-phase microenvironment efficiently in the catalysis electrode,thereby facilitating efficient oxygen reduction performance.High catalytic performance for oxygen reduction and fuel cells practical application catalyzed by Fe/N/C-F catalyst is thus verified,which offers a novel catalyst system for fuel cells technique.
