物理化学学报 >> 1989, Vol. 5 >> Issue (03): 367-369.doi: 10.3866/PKU.WHXB19890322

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V2O5表面氧和晶格氧的热脱附性能

徐卫星; 杨上闰; 傅献彩   

  1. 南京大学化学系
  • 收稿日期:1987-11-23 修回日期:1988-05-10 发布日期:1989-06-15
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THERMAL DESORPTION PROPERTIES OF THE SURFACE AND LATTICE OXYGEN OF V2O5

Xu Weixin; Yang Shangrun*; Fu Xiancai   

  1. Department of Chemistry; Nanjing University
  • Received:1987-11-23 Revised:1988-05-10 Published:1989-06-15
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Abstract:

The existence of the surface and the lattice oxygen of V_2O_5 has been investigated by the temperature programmed desorption-mass spectrography (TPD-MS) technique. Four peaks were recorded for a TPD-MS run. They are tentatively assigned to be the adsorbed oxygen (Ⅰ, Ⅱ), the surface lattice oxygen (Ⅲ), and the lattice oxygen in the bulk. The ratio of the oxygen of peak Ⅳ to all of the oxygen in V_2O_5 (see Table 1 ) is 0.20 which implies that the lattice oxygen in the bulk of V_2O_5 desorbes according to the reaction:
V_2O_5→V_2O_4+1/2O_2
Its activation energy of desorption E_d is 217 kJ.mol~(-1) with a pre-exponential factor A=2.3×10~8 s~(-1) (2nd order). On the contrary, the E_d and A for peak III are 386 kJ.mol~(-1) and 1.4×10~(23) s~(-1) (1st order), respectively.
The difference between our TPD result and that of the references [4,3] has been discussed.