ZrO2晶相对Mo基纳米结构ZrO2加氢脱硫催化剂活性的影响

在四方相态及单斜相态纳米ZrO2上担载理论单分子层的MoO3，以噻吩加氢脱硫为模型反应，考察其加氢脱硫（HDS）催化活性。用吡啶吸附红外和氨吸附程序升温脱附技术表征了ZrO2载体的表面酸特征。结果表明，四方相态的ZrO2上Broensted(B)酸位极少，单斜相态ZrO2表面则同时拥有B酸位和Lewis(L)酸位。结合ZrO2晶相结构上的差异及表面酸性测定的实验结果，分析了ZrO2晶相对Mo基纳米结构ZrO2加氢脱硫催化剂活性的影响。结果表明，由于单斜相ZrO2具有较多的B酸位，当比表面 积相同时，Mo基单斜相ZrO2的HDS催化活性高于相应的Mo基四方相ZrO2的活性。对ZrO2载体进行SO4^2-改性的考察表明，B酸位对噻吩加氢脱硫反应有重要作用。

EFFECT OF ZIRCONIA CRYSTAL PHASE ON THE ACTIVITY OF Mo-BASED NANOSTRUCTURE ZIRCONIA HDS CATALYSTS

Hydro desulfurization (HDS) catalysts of monolayer MoO 3 supported on tetragonal and monoclinic zirconia were prepared. HDS of thiophene was chosen as the model reaction in a pulse microreactor gas chromatography system to evaluate the activity of catalysts. The IR spectra of pyridine adsorption and ammonia TPD techniques were used to characterize the surface acidic features of zirconia supports. The results showed that Brnsted (B) acid sites rarely existed on tetragonal zirconia while both B acid sites and Lewis acid sites were present on the surface of monoclinic zirconia. The difference of catalytic activity between Mo based tetragonal and monoclinic zirconia HDS catalysts was observed--the latter gave a higher activity than the former did in the case of same specific surface area. The analysis on the structural difference and the results of acidic measurements showed that more B acid sites on monoclinic zirconia made it a superior support for HDS compared with tetragonal zirconia. The investigation on the SO 2- 4 modification of zirconia indicated that B acid sites played an important role in HDS reaction.