Hydriding and dehydriding properties of MgH_(2)-x wt.%NiMn_(9.3)Al_(4.0)Co_(14.1)Fe_(3.6)(x=10,25,50)nanocomposites have been investigated in present work.Doped alloy was prepared by arc melting method and ball milled...Hydriding and dehydriding properties of MgH_(2)-x wt.%NiMn_(9.3)Al_(4.0)Co_(14.1)Fe_(3.6)(x=10,25,50)nanocomposites have been investigated in present work.Doped alloy was prepared by arc melting method and ball milled with MgH_(2)to get nanocomposites.Onset temperature as low as 180℃was observed for MgH_(2)-50 wt%system which is 80℃lower than the as-milled MgH_(2)giving 131.34 KJ/mol activation energy.Structural analysis shows tetragonal,orthorhombic and monoclinic phases for MgH_(2),Al_(60)Mn_(11)Ni_(4)and Mg_(2)NiH_(4).Morphology by SEM were undertaken to investigate the effect of hydrogenation on nanostructured alloy.DSC studies show a single broad exothermic peak in the temperature range 48℃-353℃after alloy addition in MgH_(2).These results indicate that the hydrogenation properties of MgH_(2)nanocomposite have been improved compared to the as-milled MgH_(2).展开更多
The deposition of ultrafine single-atom nickel particles on Nb_(2)C(MXene)was successfully achieved using a wet chemistry method to synthesize Ni@Nb_(2)C composite.This study explored the effect of Ni@Nb_(2)C on the h...The deposition of ultrafine single-atom nickel particles on Nb_(2)C(MXene)was successfully achieved using a wet chemistry method to synthesize Ni@Nb_(2)C composite.This study explored the effect of Ni@Nb_(2)C on the hydrogen absorption and desorption properties of MgH_(2) through theoretical calculations and experimental investigations.Under the catalytic action of Ni@Nb2C,the initial dehydrogenation temperature of MgH_(2) was reduced by 121℃,with approximately 4.26 wt.% of H_(2) desorbed at 225℃ in 100 min.The dehydrogenation activation energy of the MgH_(2)+Ni@Nb_(2)C composite dropped to 86.7 kJ·mol^(-1),a reduction of 60.5 kJ·mol^(-1) compared to pure MgH_(2).Density functional theory calculations indicated that the incorporation of Ni@Nb_(2)C enhanced the performance of MgH_(2) performance by improving interactions among Nb_(2)C,Ni,Mg,and H atoms.In the Ni@Nb_(2)C+MgH_(2) system,the lengths of Mg-H bonds(1.91-1.99 A)were found to be longer than those observed in pure MgH_(2)(1.71 A).The dehydrogenation energy for this system(1.08 eV)was lower than that for Nb_(2)C(1.52 eV).These findings suggest that the synergistic effect of Ni and Nb2C significantly enhances the hydrogenation/dehydrogenation kinetics of MgH_(2),thereby introducing a novel approach for catalytic modification of solid hydrogen storage materials through synergistic actions.展开更多
基金Priyanka Meena is thankful to Malaviya National Institute of Technology(MNIT),Jaipur for providing Institute Assis-tant fellowship for PhD work.
文摘Hydriding and dehydriding properties of MgH_(2)-x wt.%NiMn_(9.3)Al_(4.0)Co_(14.1)Fe_(3.6)(x=10,25,50)nanocomposites have been investigated in present work.Doped alloy was prepared by arc melting method and ball milled with MgH_(2)to get nanocomposites.Onset temperature as low as 180℃was observed for MgH_(2)-50 wt%system which is 80℃lower than the as-milled MgH_(2)giving 131.34 KJ/mol activation energy.Structural analysis shows tetragonal,orthorhombic and monoclinic phases for MgH_(2),Al_(60)Mn_(11)Ni_(4)and Mg_(2)NiH_(4).Morphology by SEM were undertaken to investigate the effect of hydrogenation on nanostructured alloy.DSC studies show a single broad exothermic peak in the temperature range 48℃-353℃after alloy addition in MgH_(2).These results indicate that the hydrogenation properties of MgH_(2)nanocomposite have been improved compared to the as-milled MgH_(2).
基金financially supported by the National Natural Science Foundation of China under Grant numbers 22379030,52001079 and 52261038the Guangxi Key Laboratory of Green Manufacturing for Ecological Aluminum Industry(GXGMEA2024)the Nanning Excellent Young Talents Cultivation Project for Scientific and Technological Innovation and Entrepreneurship(RC20220102).
文摘The deposition of ultrafine single-atom nickel particles on Nb_(2)C(MXene)was successfully achieved using a wet chemistry method to synthesize Ni@Nb_(2)C composite.This study explored the effect of Ni@Nb_(2)C on the hydrogen absorption and desorption properties of MgH_(2) through theoretical calculations and experimental investigations.Under the catalytic action of Ni@Nb2C,the initial dehydrogenation temperature of MgH_(2) was reduced by 121℃,with approximately 4.26 wt.% of H_(2) desorbed at 225℃ in 100 min.The dehydrogenation activation energy of the MgH_(2)+Ni@Nb_(2)C composite dropped to 86.7 kJ·mol^(-1),a reduction of 60.5 kJ·mol^(-1) compared to pure MgH_(2).Density functional theory calculations indicated that the incorporation of Ni@Nb_(2)C enhanced the performance of MgH_(2) performance by improving interactions among Nb_(2)C,Ni,Mg,and H atoms.In the Ni@Nb_(2)C+MgH_(2) system,the lengths of Mg-H bonds(1.91-1.99 A)were found to be longer than those observed in pure MgH_(2)(1.71 A).The dehydrogenation energy for this system(1.08 eV)was lower than that for Nb_(2)C(1.52 eV).These findings suggest that the synergistic effect of Ni and Nb2C significantly enhances the hydrogenation/dehydrogenation kinetics of MgH_(2),thereby introducing a novel approach for catalytic modification of solid hydrogen storage materials through synergistic actions.
