The impact of vacancy defective MgH_(2)(001)/(110)surface on the dehydrogenation of MgH_(2)@Ni-CNTs:A mechanistic investigation  

作　　者：Congwen Duan Xinya Wang Haimei Wang Mengmeng Wu Yuchen Fan Jinhui Wu Ting Qu Bogu Liu Lianxi Hu Poqian Liang Fei Wang Ying Wu 

机构地区：[1]Hebei Key Lab of Power Plant Flue Gas Multi-Pollutants Control,Department of Environmental Science and Engineering,North China Electric Power University,Baoding 071003,China [2]Institute of Energy Power Innovation,North China Electric Power University,No.2 Beinong Road,Changping District,Beijing 102206,China [3]School of Materials Science and Engineering,Harbin Institute of Technology,Harbin 150001,China [4]College of Materials Science and Engineering,Sichuan University,Chengdu 610065,China

出　　处：《Journal of Materials Science & Technology》2024年第22期77-85,共9页材料科学技术（英文版）

基　　金：financed by the National Key Research and Development Program of China(Grant No.2021YFB3802400);the National Natural Science Foundation of China(Grants Nos.52071141,52271212,52201250,and 51771056);the Natural Science Foundation of Hebei Province(Grant No.E2018502054);the Fundamental Research Funds for the Central Universities(Grant No.2023MS148).

摘　　要：The vacancy defect exhibits a remarkable improvement in the dehydriding property of MgH_(2)@Ni-CNTs.However,the corresponding mechanism is still not fully understood.Herein,the impact of vacancy defects on the dehydrogenation properties of MgH_(2)@Ni-CNTs was studied by DFT simulation,and the corresponding models were constructed based on MS.The dehydrogenation process of MgH_(2)can be regarded as the dissociation of Mg-H and desorption of H_(2)from the MgH_(2)surface.In view of the whole dehydrogenation,the dissociation of H^(−)is the rate-determining step,which is the main reason for restricting the dehydrogenation kinetics.Compared with vacancy vacancy-defective MgH_(2)(001)surface,the appearance of vacancy defects on the(110)surface substantially reduces the energy barrier required for H dissociation to 0.070 Ha.The reason is that vacancy defects accelerate the transition of electrons from the H^(−)s orbit to the Mg^(2+)3s orbit,resulting in a decrement of the Mg-H bond strength,which makes H atoms more easily dissociated from the MgH_(2)(110)surface.Therefore,the existence of vacancy defects improves the dehydriding kinetic of MgH_(2).Most importantly,this research offers crucial directions for developing hydrogen storage materials as well as a potential fix for the slow dehydrogenation kinetics of nano-confined MgH_(2).

关 键 词：MgH_(2) Vacancy defect Hydrogen storage Hydrogen dissociation and desorption 

分 类 号：TQ116.2[化学工程—无机化工]