To modify the thermodynamics and kinetic performance of magnesium hydride(MgH_(2))for solid-state hydrogen storage,Ni_(3)V_(2)O_(8)-rGO(rGO represents reduced graphene oxide)and Ni_(3)V_(2)O_(8)nanocomposites were pre...To modify the thermodynamics and kinetic performance of magnesium hydride(MgH_(2))for solid-state hydrogen storage,Ni_(3)V_(2)O_(8)-rGO(rGO represents reduced graphene oxide)and Ni_(3)V_(2)O_(8)nanocomposites were prepared by hydrothermal and subsequent heat treatment.The beginning hydrogen desorption temperature of 7 wt.%Ni_(3)V_(2)O_(8)-rGO modified MgH_(2)was reduced to 208℃,while the additive-free MgH_(2)and 7 wt.%Ni_(3)V_(2)O_(8)doped MgH_(2)appeared to discharge hydrogen at 340 and 226℃,respectively.A charging capacity of about 4.7 wt.%H_(2)for MgH_(2)+7 wt.%Ni_(3)V_(2)O_(8)-rGO was achieved at 125℃ in 10 min,while the dehydrogenated MgH_(2)took 60 min to absorb only 4.6 wt.%H_(2)at 215℃.The microstructure analysis confirmed that the in-situ generated Mg_(2)Ni/Mg_(2)N_(i)H_(4) and metallic V contributed significantly to the enhanced performance of MgH_(2).In addition,the presence of rGO in the MgH_(2)+7 wt.%Ni_(3)V_(2)O_(8)-rGO composite reduced particle aggregation tendency of Mg/MgH_(2),leading to improving the cyclic stability of MgH_(2)during 20 cycles.展开更多
Mn nanoparticles(nano-Mn)were successfully synthesized and doped into MgH_(2) to improve its de/hydrogenation properties.Compared with MgH_(2),the onset desorption temperature of 10 wt.%nano-Mn modified MgH_(2) was de...Mn nanoparticles(nano-Mn)were successfully synthesized and doped into MgH_(2) to improve its de/hydrogenation properties.Compared with MgH_(2),the onset desorption temperature of 10 wt.%nano-Mn modified MgH_(2) was decreased to 175℃ and 6.7,6.5 and 6.1 wt.%hydrogen could be released within 5,10 and 25 min at 300,275 and 250℃,respectively.Besides,the composite started to take up hydrogen at room temperature and absorbed 2.0 wt.%hydrogen within 30 min at low temperature of 50℃.The hydrogenation activation energy of MgH_(2) was reduced from(72.5±2.7)to(18.8±0.2)kJ/mol after doping with 10 wt.%nano-Mn.In addition,the MgH_(2)+10 wt.%nano-Mn composite exhibited superior cyclic property,maintaining 92%initial capacity after 20 cycles.展开更多
The exploration of efficient,long-lived and cost-effective transition metal catalysts is highly desirable for the practical hydrogen storage of magnesium hydride(MgH_(2)) in sustainable energy devices.Herein,FeCoNiCrT...The exploration of efficient,long-lived and cost-effective transition metal catalysts is highly desirable for the practical hydrogen storage of magnesium hydride(MgH_(2)) in sustainable energy devices.Herein,FeCoNiCrTi high-entropy alloy(HEA) nanosheets were prepared via a facile wet chemical ball milling strategy and they were introduced into MgH_(2) to boost the hydrogen storage performance.The refined HEA exhibited superior catalytic activity on MgH_(2).In contrast to additive-free MgH_(2),the initial desorption temperature of the constructed MgH_(2)-HEA composite was reduced from 330.0 to 198.5℃ and a remarkable 51% reduction in the dehydrogenation activation energy was achieved.Besides,the MgH_(2)-HEA composite only required one-twentieth time of that consumed by pure MgH_(2) to absorb 5.0 wt% of H_(2) at 225℃.The synergy between the "hydrogen pumping" effect of Mg_2Ni/Mg_2NiH_4 and Mg_2Co/Mg_2CoH_5 couples,as well as the good dispersion of Fe,Cr and Ti on the surface of MgH_(2) contributed to the enhanced de/hydrogenation performance of the MgH_(2)-HEA composites.This study furnishes important steering for the design and fabrication of multiple transition metal catalysts and may push the commercial application of magnesium-based hydrides one step forward.展开更多
Magnesium hydride(MgH_(2)),which possesses high hydrogen density of 7.6 wt%,abundant resource and non-toxicity,has captured intense attention as one of the potential hydrogen storage materials.However,the practical ap...Magnesium hydride(MgH_(2)),which possesses high hydrogen density of 7.6 wt%,abundant resource and non-toxicity,has captured intense attention as one of the potential hydrogen storage materials.However,the practical application of Mg/MgH_(2) system is suffering from high thermal stability,sluggish absorption and desorption kinetics.Herein,two-dimensional(2D) vanadium nanosheets(V_(NS)) were successfully prepared via a facile wet chemical ball milling method and proved to be highly effective on improving the hydrogen storage performance of MgH_(2).For instance,the MgH_(2)+7 wt% V_(NS) composite began to release hydrogen at 187.2℃,152 ℃ lower than that of additive-free MgH_(2).At 300℃,6.3 wt% hydrogen was released from the MgH_(2)+7 wt% V_(NS) composite within 10 min.In addition,the fully dehydrogenated sample could absorb hydrogen even at room temperature under hydrogen pressure of 3.2 MPa.X-ray diffractometer(XRD) and transmission electron microscopy(TEM)results confirmed metallic vanadium served as catalytic unit for facilitating the de/rehydrogenation reaction of MgH_(2).This finding presents an example of facile synthesis of two-dimensional(2D) vanadium with excellent catalysis,which may shed light on future design and preparation of highly effective layered catalysts for hydrogen storage and other energy-related areas.展开更多
基金the financial support from the National Natural Science Foundation of China(No.51801078).
文摘To modify the thermodynamics and kinetic performance of magnesium hydride(MgH_(2))for solid-state hydrogen storage,Ni_(3)V_(2)O_(8)-rGO(rGO represents reduced graphene oxide)and Ni_(3)V_(2)O_(8)nanocomposites were prepared by hydrothermal and subsequent heat treatment.The beginning hydrogen desorption temperature of 7 wt.%Ni_(3)V_(2)O_(8)-rGO modified MgH_(2)was reduced to 208℃,while the additive-free MgH_(2)and 7 wt.%Ni_(3)V_(2)O_(8)doped MgH_(2)appeared to discharge hydrogen at 340 and 226℃,respectively.A charging capacity of about 4.7 wt.%H_(2)for MgH_(2)+7 wt.%Ni_(3)V_(2)O_(8)-rGO was achieved at 125℃ in 10 min,while the dehydrogenated MgH_(2)took 60 min to absorb only 4.6 wt.%H_(2)at 215℃.The microstructure analysis confirmed that the in-situ generated Mg_(2)Ni/Mg_(2)N_(i)H_(4) and metallic V contributed significantly to the enhanced performance of MgH_(2).In addition,the presence of rGO in the MgH_(2)+7 wt.%Ni_(3)V_(2)O_(8)-rGO composite reduced particle aggregation tendency of Mg/MgH_(2),leading to improving the cyclic stability of MgH_(2)during 20 cycles.
基金financial supports from the National Natural Science Foundation of China (No. 51801078)the Natural Science Foundation of Jiangsu Province, China (No. BK20180986)。
文摘Mn nanoparticles(nano-Mn)were successfully synthesized and doped into MgH_(2) to improve its de/hydrogenation properties.Compared with MgH_(2),the onset desorption temperature of 10 wt.%nano-Mn modified MgH_(2) was decreased to 175℃ and 6.7,6.5 and 6.1 wt.%hydrogen could be released within 5,10 and 25 min at 300,275 and 250℃,respectively.Besides,the composite started to take up hydrogen at room temperature and absorbed 2.0 wt.%hydrogen within 30 min at low temperature of 50℃.The hydrogenation activation energy of MgH_(2) was reduced from(72.5±2.7)to(18.8±0.2)kJ/mol after doping with 10 wt.%nano-Mn.In addition,the MgH_(2)+10 wt.%nano-Mn composite exhibited superior cyclic property,maintaining 92%initial capacity after 20 cycles.
基金the financial support from the National Natural Science Foundation of China (Grant No.51801078)。
文摘The exploration of efficient,long-lived and cost-effective transition metal catalysts is highly desirable for the practical hydrogen storage of magnesium hydride(MgH_(2)) in sustainable energy devices.Herein,FeCoNiCrTi high-entropy alloy(HEA) nanosheets were prepared via a facile wet chemical ball milling strategy and they were introduced into MgH_(2) to boost the hydrogen storage performance.The refined HEA exhibited superior catalytic activity on MgH_(2).In contrast to additive-free MgH_(2),the initial desorption temperature of the constructed MgH_(2)-HEA composite was reduced from 330.0 to 198.5℃ and a remarkable 51% reduction in the dehydrogenation activation energy was achieved.Besides,the MgH_(2)-HEA composite only required one-twentieth time of that consumed by pure MgH_(2) to absorb 5.0 wt% of H_(2) at 225℃.The synergy between the "hydrogen pumping" effect of Mg_2Ni/Mg_2NiH_4 and Mg_2Co/Mg_2CoH_5 couples,as well as the good dispersion of Fe,Cr and Ti on the surface of MgH_(2) contributed to the enhanced de/hydrogenation performance of the MgH_(2)-HEA composites.This study furnishes important steering for the design and fabrication of multiple transition metal catalysts and may push the commercial application of magnesium-based hydrides one step forward.
基金financially supported by the National Natural Science Foundation of China(No.51801078)the Natural Science Foundation of Jiangsu Province(No.BK20180986)。
文摘Magnesium hydride(MgH_(2)),which possesses high hydrogen density of 7.6 wt%,abundant resource and non-toxicity,has captured intense attention as one of the potential hydrogen storage materials.However,the practical application of Mg/MgH_(2) system is suffering from high thermal stability,sluggish absorption and desorption kinetics.Herein,two-dimensional(2D) vanadium nanosheets(V_(NS)) were successfully prepared via a facile wet chemical ball milling method and proved to be highly effective on improving the hydrogen storage performance of MgH_(2).For instance,the MgH_(2)+7 wt% V_(NS) composite began to release hydrogen at 187.2℃,152 ℃ lower than that of additive-free MgH_(2).At 300℃,6.3 wt% hydrogen was released from the MgH_(2)+7 wt% V_(NS) composite within 10 min.In addition,the fully dehydrogenated sample could absorb hydrogen even at room temperature under hydrogen pressure of 3.2 MPa.X-ray diffractometer(XRD) and transmission electron microscopy(TEM)results confirmed metallic vanadium served as catalytic unit for facilitating the de/rehydrogenation reaction of MgH_(2).This finding presents an example of facile synthesis of two-dimensional(2D) vanadium with excellent catalysis,which may shed light on future design and preparation of highly effective layered catalysts for hydrogen storage and other energy-related areas.
