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以程序升温脱附(TPD)技术对H_2O(g)在Cu-ZnO-Al_2O_3型低温变换催化剂上的脱附行为进行研究。TPD谱图定性分析发现,当温度低于350℃时,该催化剂中的ZnAl_2O_4对H_2O(g)显示出两种不同能量分布的活泼部位;在定量解析TPD谱图时,引入了分段函数的概念,提出了以T_f法解决TPD曲线出现重叠峰、拖尾的复杂情况时,覆盖度θ的求值问题。并发展了脱附速率等温线法,使之对于多峰的TPD谱图亦能计算出相应的动力学参数。根据试验数据进行计算,得到了H_2O(g)在Cu-ZnO-Al_2O_3型低温变换催化剂上的脱附动力学参数,建立了脱附速率方程。
The desorption behavior of H_2O (g) on Cu-ZnO-Al_2O_3 low temperature shift catalyst was investigated by temperature programmed desorption (TPD). The qualitative analysis of TPD spectra showed that when the temperature was below 350 ℃, ZnAl_2O_4 exhibited two active sites for H_2O (g) with different energy distributions. When the TPD spectra were quantitatively analyzed, a piecewise function Concept, the T_f method is proposed to solve the problem of evaluating the coverage θ when the complex peaks and tails of TPD curves appear. And developed the desorption rate isotherm method, which makes it possible to calculate the corresponding kinetic parameters for the multimodal TPD spectra. Based on the experimental data, the desorption kinetics parameters of H_2O (g) on Cu-ZnO-Al_2O_3 low temperature shift catalyst were obtained, and the desorption rate equation was established.