Exfoliated graphite was prepared by chemical route and then further subjected to thermal oxidation and sonication for size reduction and increased interlayer spacing in natural flake graphite. Exfoliated graphite/ABS ...Exfoliated graphite was prepared by chemical route and then further subjected to thermal oxidation and sonication for size reduction and increased interlayer spacing in natural flake graphite. Exfoliated graphite/ABS composites were pre-pared with varying filler concentration by solution casting method. Exfoliated graphite and composites were character-ised by scanning electron microscopy and energy dispersive X-ray analysis, Fourier transform infrared spectroscopy and X-ray diffractometry techniques. After thermal exfoliation significant peak of graphite at 2? = 26.4? disappeared completely, confirming successful exfoliation of graphite. SEM images revealed homogeneous dispersion of exfoliated graphite in the matrix and EDAX confirmed successful reduction of graphite oxide.展开更多
We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate.The mass ratio of graphite to Al(H_(2)PO_(4))_(3) change...We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate.The mass ratio of graphite to Al(H_(2)PO_(4))_(3) changed from 0.5:1 to 4:1,and the impregnation time changed from 1 to 7 h.The typical composite phase change thermal storage materials doped with the as-treated graphite were fabricated using form-stable technique.To investigate the oxidation and anti-oxidation behavior of the impregnated graphite at high temperatures,the samples were put into a muffle furnace for a cyclic heat test.Based on SEM,EDS,DSC techniques,analyses on the impregnated technique suggested an optimized processing conditions of a 3 h impregnation time with the ratio of graphite:Al(H_(2)PO_(4))_(3) as 1:3 for graphite impregnation treatment.Further investigations on high-temperature phase change heat storage materials doped by the treated graphite suggested excellent oxidation resistance and thermal cycling performance.展开更多
As an alternative to lithium-ion batteries,aqueous zinc-graphite batteries(ZnGBs)are being explored as safer and low-cost options with the expectation of scalability to large energy storage systems.However,the current...As an alternative to lithium-ion batteries,aqueous zinc-graphite batteries(ZnGBs)are being explored as safer and low-cost options with the expectation of scalability to large energy storage systems.However,the currently adopted polyatomic and metal complex anion intercalation process at the graphite electrode in ZnGB exhibits poor electrochemical performances.Alternatively,incorporating halogen anions offers exceptional electrochemical performance to graphite electrodes due to their redox process.In this work,ZnGBs are assembled using a LiCl/ZnCl2/KBr^(-)based water-in-salt electrolyte,which efficiently supplies bromide(Br^(−))ions for conversion into Br_(x)^(−)and facilitates Br_(2)intercalation at the graphite electrode.The conversion and intercalation of bromine together enable the ZnGB to achieve a discharge capacity of 2.73 mAh/cm^(2)with 91.0%of coulombic efficiency(CE)while supporting high current density operations of up to 150 mA/cm^(2).With high energy density(4.56 Wh/cm^(2)),high power density(199.5 mW/cm^(2)),and excellent rate capability(∼93.0%CE at 150 mA/cm^(2)),the ZnGB is shown to operate efficiently for as much as 800 cycles.Beguilingly,an anode-free ZnGB offers enhanced stability for up to 1100 cycles without performance decay,matching the electrochemical performance of Zn metal electrodes.This work provides insights into the bromine reaction mechanism at graphite electrodes and the role of surface exfoliation in enabling efficient Br_(x)^(−)formation,along with Br_(2)intercalation,for achieving high-performance ZnGBs.展开更多
The expandable graphite(EG)modified TiO_(2) nanocomposites were prepared by the high shearmethod using the TiO_(2) nanoparticles(NPs)and EG as precursors,in which the amount of EG doped in TiO_(2) was 10 wt.%.Followed...The expandable graphite(EG)modified TiO_(2) nanocomposites were prepared by the high shearmethod using the TiO_(2) nanoparticles(NPs)and EG as precursors,in which the amount of EG doped in TiO_(2) was 10 wt.%.Followed by the impregnation method,adjusting the pH of the solution to 10,and using the electrostatic adsorption to achieve spatial confinement,the Pt elementswere mainly distributed on the exposed TiO_(2),thus generating the Pt/10EG-TiO_(2)-10 catalyst.The best CO oxidation activity with the excellent resistance to H_(2)O and SO_(2) was obtained over the Pt/10EG-TiO_(2)-10 catalyst:CO conversion after 36 hr of the reaction was ca.85%under the harsh condition of 10 vol.%H_(2)O and 100 ppm SO_(2) at a high gaseous hourly space velocity(GHSV)of 400,000 hr−1.Physicochemical properties of the catalystswere characterized by various techniques.The results showed that the electrostatic adsorption,which riveted the Pt elements mainly on the exposed TiO_(2) of the support surface,reduced the dispersion of Pt NPs on EG and achieved the effective dispersion of Pt NPs,hence significantly improving CO oxidation activity over the Pt/10EG-TiO_(2)-10 catalyst.The 10 wt.%EG doped in TiO_(2) caused the TiO_(2) support to form a more hydrophobic surface,which reduced the adsorption of H_(2)O and SO_(2) on the catalyst,greatly inhibited deposition of the TiOSO_(4) and formation of the PtSO4 species as well as suppressed the oxidation of SO_(2),thus resulting in an improvement in the resistance to H_(2)O and SO_(2) of the Pt/10EG-TiO_(2)-10 catalyst.展开更多
Mixed polyanion phosphate Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is regarded as the most promising cathode material for sodium-ion batteries(SIBs),due to its high structural stability and low-cost environmental frien...Mixed polyanion phosphate Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is regarded as the most promising cathode material for sodium-ion batteries(SIBs),due to its high structural stability and low-cost environmental friendliness.However,its intrinsic low conductivity and sluggish Na^(+)diffusion restricted the fast-charge and low-temperature sodium storage.Herein,an NFPP composite encapsulated by in-situ pyrolytic carbon and coupled with expanded graphite(NFPP@C/EG)was constructed via a sol-gel method followed by a ballmill procedure.Due to the dual-carbon modified strategy,this NFPP@C/EG only enhanced the electronic conductivity,but also endowed more channels for Na^(+)diffusion.As cathode for SIBs,the optimized NFPP(M-NFPP@C/EG)delivers excellent rate capability(capacity of~80.5 mAh/g at 50 C)and outstanding cycling stability(11000 cycles at 50 C with capacity retention of 89.85%).Additionally,cyclic voltammetry(CV)confirmed that its sodium storage behavior is pseudocapacitance-controlled,with in-situ electrochemical impedance spectroscopy(EIS)further elucidating improvements in electrode reaction kinetics.At lower temperatures(0℃),M-NFPP@C/EG demonstrated exceptional cycling performance(8800 cycles at 10 C with capacity retention of 95.81%).Moreover,pouch cells also exhibited excellent stability.This research demonstrates the feasibility of a dual carbon modification strategy in enhancing NFPP and proposes a low-cost,high-rate,and ultra-stable cathode material for SIBs.展开更多
以废打印机壳PC/ABS再生粒子(R-PC/ABS)为基体材料,对苯二酚双(二苯基磷酸脂)(HDP)和梯形倍半硅氧烷(TSQ)为阻燃剂,采用熔融共混制备了无卤阻燃PC/ABS,对其阻燃性能、力学性能、尺寸稳定性和负荷热变形温度(HDT)进行分析,结果发现,TSQ...以废打印机壳PC/ABS再生粒子(R-PC/ABS)为基体材料,对苯二酚双(二苯基磷酸脂)(HDP)和梯形倍半硅氧烷(TSQ)为阻燃剂,采用熔融共混制备了无卤阻燃PC/ABS,对其阻燃性能、力学性能、尺寸稳定性和负荷热变形温度(HDT)进行分析,结果发现,TSQ可以阻燃R-PC/ABS,并且,对力学性能、尺寸稳定性和HDT影响较小,R-PC/ABS/0.8TSQ的LOI为29.8%,阻燃达到3.0 mm V-0和2.0 mm V-1级;HDP可以有效地阻燃R-PC/ABS,但是,对力学性能、尺寸稳定性和HDT的负面影响较大,R-PC/ABS/12HDP的LOI为36.1%,阻燃可达到UL 941.0 mm V-0级,与R-PC/ABS相比,HDT、拉伸强度、弯曲强度、弯曲模量和缺口冲击强度分别降低了20.2℃、26.6%、14.5%、16.9%和60.9%;R-PC/ABS/0.8TSQ/6HDP的LOI为35.7%,阻燃级别达到UL 941.0 mm V-0级,与R-PC/ABS/12HDP相比,模后收缩率(PMS)降低了19.7%,HDT、拉伸强度、弯曲强度、弯曲模量和缺口冲击强度分别提高了13℃、21.0%、11.3%、14.3%和85.9%。展开更多
[Objective] The aim was to develop a rapid,simple method for determination of cadmium and lead in sugarcane samples by graphite furnace atomic absorption spectrometry.[Method] The method for determination of Cd and Pb...[Objective] The aim was to develop a rapid,simple method for determination of cadmium and lead in sugarcane samples by graphite furnace atomic absorption spectrometry.[Method] The method for determination of Cd and Pb in sugarcane by combined graphite furnace atomic absorption spectrometry and microwave digestion was used.[Result] The concentration curve was linear within the range of 0-0.80 μg/L the detection limits of Cd and Pb was 0.015 and 0.030 μg/L,respectively.The precision for elevenfold determination of Cd and of Pb at the 0.40 μg/L level were 1.8% and 2.3%（RSD）,respectively.Recoveries of 96.7%-98.2% for Cd and 104.6%-106.7% for Pb were obtained for two sugarcane samples and one certified reference material.[Conclusion] The proposed method has the advantages of simple operation,high sensitivity,and high efficiency;it was successfully used for determination of Cd and Pb in sugarcane samples.展开更多
文摘Exfoliated graphite was prepared by chemical route and then further subjected to thermal oxidation and sonication for size reduction and increased interlayer spacing in natural flake graphite. Exfoliated graphite/ABS composites were pre-pared with varying filler concentration by solution casting method. Exfoliated graphite and composites were character-ised by scanning electron microscopy and energy dispersive X-ray analysis, Fourier transform infrared spectroscopy and X-ray diffractometry techniques. After thermal exfoliation significant peak of graphite at 2? = 26.4? disappeared completely, confirming successful exfoliation of graphite. SEM images revealed homogeneous dispersion of exfoliated graphite in the matrix and EDAX confirmed successful reduction of graphite oxide.
基金Funded by Scientific and Technological Innovation Project of Carbon Emission Peak and Carbon Neutrality of Jiangsu Province(No.BE2022028-4)。
文摘We adopted the solution impregnation route with aluminum dihydrogen phosphate solution as liquid medium for effective surface modification on graphite substrate.The mass ratio of graphite to Al(H_(2)PO_(4))_(3) changed from 0.5:1 to 4:1,and the impregnation time changed from 1 to 7 h.The typical composite phase change thermal storage materials doped with the as-treated graphite were fabricated using form-stable technique.To investigate the oxidation and anti-oxidation behavior of the impregnated graphite at high temperatures,the samples were put into a muffle furnace for a cyclic heat test.Based on SEM,EDS,DSC techniques,analyses on the impregnated technique suggested an optimized processing conditions of a 3 h impregnation time with the ratio of graphite:Al(H_(2)PO_(4))_(3) as 1:3 for graphite impregnation treatment.Further investigations on high-temperature phase change heat storage materials doped by the treated graphite suggested excellent oxidation resistance and thermal cycling performance.
基金The authors acknowledge the University of Sharjah for financial support through a competitive research project grant(project number:23020406277)。
文摘As an alternative to lithium-ion batteries,aqueous zinc-graphite batteries(ZnGBs)are being explored as safer and low-cost options with the expectation of scalability to large energy storage systems.However,the currently adopted polyatomic and metal complex anion intercalation process at the graphite electrode in ZnGB exhibits poor electrochemical performances.Alternatively,incorporating halogen anions offers exceptional electrochemical performance to graphite electrodes due to their redox process.In this work,ZnGBs are assembled using a LiCl/ZnCl2/KBr^(-)based water-in-salt electrolyte,which efficiently supplies bromide(Br^(−))ions for conversion into Br_(x)^(−)and facilitates Br_(2)intercalation at the graphite electrode.The conversion and intercalation of bromine together enable the ZnGB to achieve a discharge capacity of 2.73 mAh/cm^(2)with 91.0%of coulombic efficiency(CE)while supporting high current density operations of up to 150 mA/cm^(2).With high energy density(4.56 Wh/cm^(2)),high power density(199.5 mW/cm^(2)),and excellent rate capability(∼93.0%CE at 150 mA/cm^(2)),the ZnGB is shown to operate efficiently for as much as 800 cycles.Beguilingly,an anode-free ZnGB offers enhanced stability for up to 1100 cycles without performance decay,matching the electrochemical performance of Zn metal electrodes.This work provides insights into the bromine reaction mechanism at graphite electrodes and the role of surface exfoliation in enabling efficient Br_(x)^(−)formation,along with Br_(2)intercalation,for achieving high-performance ZnGBs.
基金supported by the National Key R&D Program of China (No.2017YFC0210303).
文摘The expandable graphite(EG)modified TiO_(2) nanocomposites were prepared by the high shearmethod using the TiO_(2) nanoparticles(NPs)and EG as precursors,in which the amount of EG doped in TiO_(2) was 10 wt.%.Followed by the impregnation method,adjusting the pH of the solution to 10,and using the electrostatic adsorption to achieve spatial confinement,the Pt elementswere mainly distributed on the exposed TiO_(2),thus generating the Pt/10EG-TiO_(2)-10 catalyst.The best CO oxidation activity with the excellent resistance to H_(2)O and SO_(2) was obtained over the Pt/10EG-TiO_(2)-10 catalyst:CO conversion after 36 hr of the reaction was ca.85%under the harsh condition of 10 vol.%H_(2)O and 100 ppm SO_(2) at a high gaseous hourly space velocity(GHSV)of 400,000 hr−1.Physicochemical properties of the catalystswere characterized by various techniques.The results showed that the electrostatic adsorption,which riveted the Pt elements mainly on the exposed TiO_(2) of the support surface,reduced the dispersion of Pt NPs on EG and achieved the effective dispersion of Pt NPs,hence significantly improving CO oxidation activity over the Pt/10EG-TiO_(2)-10 catalyst.The 10 wt.%EG doped in TiO_(2) caused the TiO_(2) support to form a more hydrophobic surface,which reduced the adsorption of H_(2)O and SO_(2) on the catalyst,greatly inhibited deposition of the TiOSO_(4) and formation of the PtSO4 species as well as suppressed the oxidation of SO_(2),thus resulting in an improvement in the resistance to H_(2)O and SO_(2) of the Pt/10EG-TiO_(2)-10 catalyst.
基金supported by the National Key Research and Development Program of China(No.2022YFB2502000)the National Natural Science Foundation of China(Nos.U21A20332,51771076,U21A200970,52301266)the Science and Technology Planning Project of Guangzhou(No.2024A04J3332)。
文摘Mixed polyanion phosphate Na_(4)Fe_(3)(PO_(4))_(2)P_(2)O_(7)(NFPP)is regarded as the most promising cathode material for sodium-ion batteries(SIBs),due to its high structural stability and low-cost environmental friendliness.However,its intrinsic low conductivity and sluggish Na^(+)diffusion restricted the fast-charge and low-temperature sodium storage.Herein,an NFPP composite encapsulated by in-situ pyrolytic carbon and coupled with expanded graphite(NFPP@C/EG)was constructed via a sol-gel method followed by a ballmill procedure.Due to the dual-carbon modified strategy,this NFPP@C/EG only enhanced the electronic conductivity,but also endowed more channels for Na^(+)diffusion.As cathode for SIBs,the optimized NFPP(M-NFPP@C/EG)delivers excellent rate capability(capacity of~80.5 mAh/g at 50 C)and outstanding cycling stability(11000 cycles at 50 C with capacity retention of 89.85%).Additionally,cyclic voltammetry(CV)confirmed that its sodium storage behavior is pseudocapacitance-controlled,with in-situ electrochemical impedance spectroscopy(EIS)further elucidating improvements in electrode reaction kinetics.At lower temperatures(0℃),M-NFPP@C/EG demonstrated exceptional cycling performance(8800 cycles at 10 C with capacity retention of 95.81%).Moreover,pouch cells also exhibited excellent stability.This research demonstrates the feasibility of a dual carbon modification strategy in enhancing NFPP and proposes a low-cost,high-rate,and ultra-stable cathode material for SIBs.
文摘以废打印机壳PC/ABS再生粒子(R-PC/ABS)为基体材料,对苯二酚双(二苯基磷酸脂)(HDP)和梯形倍半硅氧烷(TSQ)为阻燃剂,采用熔融共混制备了无卤阻燃PC/ABS,对其阻燃性能、力学性能、尺寸稳定性和负荷热变形温度(HDT)进行分析,结果发现,TSQ可以阻燃R-PC/ABS,并且,对力学性能、尺寸稳定性和HDT影响较小,R-PC/ABS/0.8TSQ的LOI为29.8%,阻燃达到3.0 mm V-0和2.0 mm V-1级;HDP可以有效地阻燃R-PC/ABS,但是,对力学性能、尺寸稳定性和HDT的负面影响较大,R-PC/ABS/12HDP的LOI为36.1%,阻燃可达到UL 941.0 mm V-0级,与R-PC/ABS相比,HDT、拉伸强度、弯曲强度、弯曲模量和缺口冲击强度分别降低了20.2℃、26.6%、14.5%、16.9%和60.9%;R-PC/ABS/0.8TSQ/6HDP的LOI为35.7%,阻燃级别达到UL 941.0 mm V-0级,与R-PC/ABS/12HDP相比,模后收缩率(PMS)降低了19.7%,HDT、拉伸强度、弯曲强度、弯曲模量和缺口冲击强度分别提高了13℃、21.0%、11.3%、14.3%和85.9%。
基金Supported by Fund of Guangxi Sugarcane Research Institute(G2008011)~~
文摘[Objective] The aim was to develop a rapid,simple method for determination of cadmium and lead in sugarcane samples by graphite furnace atomic absorption spectrometry.[Method] The method for determination of Cd and Pb in sugarcane by combined graphite furnace atomic absorption spectrometry and microwave digestion was used.[Result] The concentration curve was linear within the range of 0-0.80 μg/L the detection limits of Cd and Pb was 0.015 and 0.030 μg/L,respectively.The precision for elevenfold determination of Cd and of Pb at the 0.40 μg/L level were 1.8% and 2.3%（RSD）,respectively.Recoveries of 96.7%-98.2% for Cd and 104.6%-106.7% for Pb were obtained for two sugarcane samples and one certified reference material.[Conclusion] The proposed method has the advantages of simple operation,high sensitivity,and high efficiency;it was successfully used for determination of Cd and Pb in sugarcane samples.
