物理化学学报
物理化學學報
물이화학학보
ACTA PHYSICO-CHIMICA SINICA
2014年
12期
2323-2327
,共5页
王家盛%韩树民%李媛%沈娜%张伟
王傢盛%韓樹民%李媛%瀋娜%張偉
왕가성%한수민%리원%침나%장위
储氢性能%MgH2%MgTiO3%催化活性%活化能
儲氫性能%MgH2%MgTiO3%催化活性%活化能
저경성능%MgH2%MgTiO3%최화활성%활화능
Hydrogen storage property%MgH2%MgTiO3%Catalytic activity%Activation energy
为了降低MgH2的吸放氢温度,提高其吸放氢动力学性能,本文通过球磨方法制备了MgH2+20%(w) MgTiO3复合储氢材料,并研究了其储氢性能. X射线衍射(XRD)结果表明, MgTiO3在与MgH2球磨过程中生成Mg2TiO4和TiO2,并且Mg2TiO4和TiO2在体系的吸放氢过程中保持稳定,能够对MgH2的吸放氢过程产生催化作用.程序升温脱附和吸/放氢动力学测试结果表明,添加MgTiO3后MgH2的初始放氢温度从389°C降至249°C.150°C下的吸氢量从0.977%(w)提高到2.902%(w),350°C下的放氢量从2.319%(w)提高到3.653%(w).同时, MgH2放氢反应的活化能从116 kJ?mol-1降至95.7 kJ?mol-1.与MgH2相比, MgH2+20%(w) MgTiO3复合材料的热力学与动力学性能均有显著提高,这主要是由于球磨和放氢过程中原位生成的TiO2和Mg2TiO4具有良好的催化活性.
為瞭降低MgH2的吸放氫溫度,提高其吸放氫動力學性能,本文通過毬磨方法製備瞭MgH2+20%(w) MgTiO3複閤儲氫材料,併研究瞭其儲氫性能. X射線衍射(XRD)結果錶明, MgTiO3在與MgH2毬磨過程中生成Mg2TiO4和TiO2,併且Mg2TiO4和TiO2在體繫的吸放氫過程中保持穩定,能夠對MgH2的吸放氫過程產生催化作用.程序升溫脫附和吸/放氫動力學測試結果錶明,添加MgTiO3後MgH2的初始放氫溫度從389°C降至249°C.150°C下的吸氫量從0.977%(w)提高到2.902%(w),350°C下的放氫量從2.319%(w)提高到3.653%(w).同時, MgH2放氫反應的活化能從116 kJ?mol-1降至95.7 kJ?mol-1.與MgH2相比, MgH2+20%(w) MgTiO3複閤材料的熱力學與動力學性能均有顯著提高,這主要是由于毬磨和放氫過程中原位生成的TiO2和Mg2TiO4具有良好的催化活性.
위료강저MgH2적흡방경온도,제고기흡방경동역학성능,본문통과구마방법제비료MgH2+20%(w) MgTiO3복합저경재료,병연구료기저경성능. X사선연사(XRD)결과표명, MgTiO3재여MgH2구마과정중생성Mg2TiO4화TiO2,병차Mg2TiO4화TiO2재체계적흡방경과정중보지은정,능구대MgH2적흡방경과정산생최화작용.정서승온탈부화흡/방경동역학측시결과표명,첨가MgTiO3후MgH2적초시방경온도종389°C강지249°C.150°C하적흡경량종0.977%(w)제고도2.902%(w),350°C하적방경량종2.319%(w)제고도3.653%(w).동시, MgH2방경반응적활화능종116 kJ?mol-1강지95.7 kJ?mol-1.여MgH2상비, MgH2+20%(w) MgTiO3복합재료적열역학여동역학성능균유현저제고,저주요시유우구마화방경과정중원위생성적TiO2화Mg2TiO4구유량호적최화활성.
With the aim of decreasing the dehydriding temperature and improving the hydriding/dehydriding kinetic properties of MgH2, we prepared MgH2+20%(w) MgTiO3 composite via bal-mil ing, and investigated the hydrogen storage properties of the composite. X-ray diffraction (XRD) results showed that the MgTiO3 decomposed into Mg2TiO4 and TiO2 during the bal-mil ing. These two resulting compounds remained stable during the hydriding/dehydriding processes, working as catalysts for the hydriding/dehydriding. Temperature-programmed-desorption (TPD) and hydriding/dehydriding kinetics tests showed that doping MgH2 with MgTiO3 lowered the onset dehydrogenation temperature of MgH2 from 389 to 249 °C, as wel as increasing the hydrogen absorption amount from 0.977%(w) to 2.902%(w) at 150 °C, and increasing the desorption amount from 2.319%(w) to 3.653%(w) at 350 °C. The MgTiO3 additive decreased the dehydriding activation energy of MgH2 from 116 to 95.7 kJ?mol-1. The thermodynamic and kinetic performance of the MgH2+20%(w) MgTiO3 composite was significantly improved compared with pristine MgH2, which was attributed to the high catalytic activity of the (in-situ formed) TiO2 and Mg2TiO4 during the bal-mil ing and dehydriding processes.
