The high operating temperatures and slow kinetics limit the application of MgH_(2)-based hydrogen storage materials.Here,a composite of Ni_(3)ZnC_(0.7)/carbon nanotubes loaded onto a melamine sponge-derived carbon(MS)...The high operating temperatures and slow kinetics limit the application of MgH_(2)-based hydrogen storage materials.Here,a composite of Ni_(3)ZnC_(0.7)/carbon nanotubes loaded onto a melamine sponge-derived carbon(MS)skeleton is prepared and loaded onto MgH_(2).During dehydrogenation,Ni_(3)ZnC_(0.7)reacts with MgH_(2)and in situ changes to Mg_(2)Ni/Zn.The transformation of Mg_(2)Ni/Mg_(2)NiH_(4) serves as a“hydrogen pump”,providing diffusion channels for hydrogen atoms and molecules to promote the de-/hydrogenation processes.Moreover,Zn/MgZn_(2) provides the catalytic sites for the transformation of Mg/MgH_(2).The length of the Mg-H bond is elongated from 1.72 to 1.995Å,and the dissociation energy barrier of MgH_(2)is reduced from 1.55 to 0.49 eV.As a result,MgH_(2)with 2.5 wt%MS@Ni_(3)ZnC_(0.7)can absorb 5.18 wt%H_(2)at 423 K within 200 s,and its initial dehydrogenation temperature is reduced to 585 K.After 20 cycles,the dehydrogenation capacity retention is determined to be 94.6%.This work demonstrates an efficient non-stoichiometric metal carbide catalyst for MgH_(2).展开更多
The Ni-coated carbon nanotubes(Ni@CNT)composite was synthesized by the facile“filtration+calcination”of Ni-based metal−organic framework(MOF)precursor and the obtained composite was used as a catalyst for MgH_(2).Mg...The Ni-coated carbon nanotubes(Ni@CNT)composite was synthesized by the facile“filtration+calcination”of Ni-based metal−organic framework(MOF)precursor and the obtained composite was used as a catalyst for MgH_(2).MgH_(2)was mixed evenly with different amounts of Ni@CNT(2.5,5.0 and 7.5,wt.%)through ball milling.The MgH_(2)−5wt.%Ni@CNT can absorb 5.2 wt.%H_(2)at 423 K in 200 s and release about 3.75 wt.%H_(2)at 573 K in 1000 s.And its dehydrogenation and rehydrogenation activation energies are reduced to 87.63 and 45.28 kJ/mol(H_(2)).The in-situ generated Mg_(2)Ni/Mg_(2)NiH4 exhibits a good catalytic effect due to the provided more diffusion channels that can be used as“hydrogen pump”.And the presence of carbon nanotubes improves the properties of MgH_(2)to some extent.展开更多
MgH2is considered as a promising hydrogen storage material for its high hydrogen storage capacity,low cost and abundant resource advantages.However,the low kinetics and high enthalpy formation of MgH_(2)limit its wide...MgH2is considered as a promising hydrogen storage material for its high hydrogen storage capacity,low cost and abundant resource advantages.However,the low kinetics and high enthalpy formation of MgH_(2)limit its wide application.From the perspective of adding catalysts to enhance the hydrogen storage properties of Mg-MgH_(2),this article elaborated the main catalysts based on Ti and Nb transition elements,including single oxide catalysts,binary oxides catalysts(combined with Ni,Na,Sr,V,etc.),multiple catalysts bound to carbon,and composite catalysts with Ti and Nb elements combined with MXene phase.Moreover,the main pathways of various catalysts to reduce the reaction activity and broaden the hydrogen desorption channel were also analyzed.The Ti-based catalysts can enhance the reactive sites of the matrix by forming multivalent states,while Nb-based catalysts broaden the hydrogen reaction channels by forming tiny Nb.By improving the size structure and enhancing the grain size stability,combined with carbon materials should be the future considerations.展开更多
To effectively enhance the catalytic activity of NiS,NiS particles confined into carbon fibers were prepared by electrostatic spinning followed pyrolyzation and NiS particles decorating was performed by further hydrot...To effectively enhance the catalytic activity of NiS,NiS particles confined into carbon fibers were prepared by electrostatic spinning followed pyrolyzation and NiS particles decorating was performed by further hydrothermal loading.The decorated NiS exhibits particle(NiS@PAN-NiS)and needle-like(NiS@PAN-NiS^(*))morphologies.After adding the catalysts into MgH_(2),the synthesized MgH_(2)-5 wt%NiS@PAN-NiS composite can absorb 2.6 wt%hydrogen at 353 K and release 5.0 wt%hydrogen within 1 h at 573 K.The initial hydrogen desorption temperature was reduced to 539 K.The activation energies for hydrogen absorption/desorption were greatly reduced to 66.76 and 89.95 kJ mol^(-1),respectively.The method of confining by electrospinning and particle decoration by hydrothermal loading reduce NiS particle agglomeration.The Mg_(2)Ni/Mg_(2)NiH_(4)hydrogen pump formed by reaction between NiS and MgH_(2)effectively enhanced hydrogen absorption and desorption kinetics.The formed MgS also improved the catalytic activity on the transformation of Mg and MgH_(2).Moreover,the carbon fibers should influence the contact between in situ formed MgS and Mg_(2)Ni,providing more catalytic sites and hydrogen diffusion pathways.The construction of NiS/carbon fibers confined NiS composite by carbon fibers derived from pyrolyzation as medium provides considerable way for designing NiS-based catalysts to enhance the hydrogen storage performances of MgH_(2).展开更多
基金supported by the National Natural Science Foundation of China(No.52101274)the Natural Science Foundation of Shandong Province(Nos.ZR2020QE011 and ZR2022ME089)+2 种基金Youth Top Talent Foundation of Yantai University(No.2219008)Graduate Innovation Foundation of Yantai University(No.GIFYTU2240)College Student Innovation and Entrepreneurship Training Program Project(No.202311066088).
文摘The high operating temperatures and slow kinetics limit the application of MgH_(2)-based hydrogen storage materials.Here,a composite of Ni_(3)ZnC_(0.7)/carbon nanotubes loaded onto a melamine sponge-derived carbon(MS)skeleton is prepared and loaded onto MgH_(2).During dehydrogenation,Ni_(3)ZnC_(0.7)reacts with MgH_(2)and in situ changes to Mg_(2)Ni/Zn.The transformation of Mg_(2)Ni/Mg_(2)NiH_(4) serves as a“hydrogen pump”,providing diffusion channels for hydrogen atoms and molecules to promote the de-/hydrogenation processes.Moreover,Zn/MgZn_(2) provides the catalytic sites for the transformation of Mg/MgH_(2).The length of the Mg-H bond is elongated from 1.72 to 1.995Å,and the dissociation energy barrier of MgH_(2)is reduced from 1.55 to 0.49 eV.As a result,MgH_(2)with 2.5 wt%MS@Ni_(3)ZnC_(0.7)can absorb 5.18 wt%H_(2)at 423 K within 200 s,and its initial dehydrogenation temperature is reduced to 585 K.After 20 cycles,the dehydrogenation capacity retention is determined to be 94.6%.This work demonstrates an efficient non-stoichiometric metal carbide catalyst for MgH_(2).
基金the National Natural Science Foundation of China(Nos.52101274,51731002)Natural Science Foundation of Shandong Province,China(Nos.ZR2020QE011,ZR2022ME089)+1 种基金Youth Top Talent Foundation of Yantai University,China(No.2219008)Graduate Innovation Foundation of Yantai University,China(No.GIFYTU2240).
文摘The Ni-coated carbon nanotubes(Ni@CNT)composite was synthesized by the facile“filtration+calcination”of Ni-based metal−organic framework(MOF)precursor and the obtained composite was used as a catalyst for MgH_(2).MgH_(2)was mixed evenly with different amounts of Ni@CNT(2.5,5.0 and 7.5,wt.%)through ball milling.The MgH_(2)−5wt.%Ni@CNT can absorb 5.2 wt.%H_(2)at 423 K in 200 s and release about 3.75 wt.%H_(2)at 573 K in 1000 s.And its dehydrogenation and rehydrogenation activation energies are reduced to 87.63 and 45.28 kJ/mol(H_(2)).The in-situ generated Mg_(2)Ni/Mg_(2)NiH4 exhibits a good catalytic effect due to the provided more diffusion channels that can be used as“hydrogen pump”.And the presence of carbon nanotubes improves the properties of MgH_(2)to some extent.
基金supported by research programs of the National Natural Science Foundation of China(52101274)the Natural Science Foundation of Shandong Province(Nos.ZR2020QE011,ZR2022ME089)+2 种基金the Youth Top Talent Foundation of Yantai University(2219008)the Graduate Innovation Foundation of Yantai University(GGIFYTU2325)the College Student Innovation and Entrepreneurship Training Program Project(202311066088,202311066087)。
文摘MgH2is considered as a promising hydrogen storage material for its high hydrogen storage capacity,low cost and abundant resource advantages.However,the low kinetics and high enthalpy formation of MgH_(2)limit its wide application.From the perspective of adding catalysts to enhance the hydrogen storage properties of Mg-MgH_(2),this article elaborated the main catalysts based on Ti and Nb transition elements,including single oxide catalysts,binary oxides catalysts(combined with Ni,Na,Sr,V,etc.),multiple catalysts bound to carbon,and composite catalysts with Ti and Nb elements combined with MXene phase.Moreover,the main pathways of various catalysts to reduce the reaction activity and broaden the hydrogen desorption channel were also analyzed.The Ti-based catalysts can enhance the reactive sites of the matrix by forming multivalent states,while Nb-based catalysts broaden the hydrogen reaction channels by forming tiny Nb.By improving the size structure and enhancing the grain size stability,combined with carbon materials should be the future considerations.
基金financially supported by the National Natural Science Foundation of China(Nos.52101274 and 52472131)the Natural Science Foundation of Shandong Province(Nos.ZR2020QE011 and ZR2022ME089)+6 种基金Yantai Basic Research Project(No.2024JCYJ097)the Key Research and Development Projects of Shandong Province(No.2024TSGC0402)the Youth Top Talent Foundation of Yantai University(No.2219008)the Graduate Innovation Foundation of Yantai University(No.GIFYTU2240)the Natural Science Foundation of Qinghai Province for Distinguished Young Scholars(No.2025-ZJ-966J)the Talent Youth Project of Chinese Academy of Sciences(No.E410GC03)the CollegeStudent Innovation and Entrepreneurship Training Program Project(No.202311066088)
文摘To effectively enhance the catalytic activity of NiS,NiS particles confined into carbon fibers were prepared by electrostatic spinning followed pyrolyzation and NiS particles decorating was performed by further hydrothermal loading.The decorated NiS exhibits particle(NiS@PAN-NiS)and needle-like(NiS@PAN-NiS^(*))morphologies.After adding the catalysts into MgH_(2),the synthesized MgH_(2)-5 wt%NiS@PAN-NiS composite can absorb 2.6 wt%hydrogen at 353 K and release 5.0 wt%hydrogen within 1 h at 573 K.The initial hydrogen desorption temperature was reduced to 539 K.The activation energies for hydrogen absorption/desorption were greatly reduced to 66.76 and 89.95 kJ mol^(-1),respectively.The method of confining by electrospinning and particle decoration by hydrothermal loading reduce NiS particle agglomeration.The Mg_(2)Ni/Mg_(2)NiH_(4)hydrogen pump formed by reaction between NiS and MgH_(2)effectively enhanced hydrogen absorption and desorption kinetics.The formed MgS also improved the catalytic activity on the transformation of Mg and MgH_(2).Moreover,the carbon fibers should influence the contact between in situ formed MgS and Mg_(2)Ni,providing more catalytic sites and hydrogen diffusion pathways.The construction of NiS/carbon fibers confined NiS composite by carbon fibers derived from pyrolyzation as medium provides considerable way for designing NiS-based catalysts to enhance the hydrogen storage performances of MgH_(2).
