Effect of thermal pretreatment on the surface structure of PtSn/SiO catalyst and its performance in acetic acid hydrogenation.

The effect of thermal pretreatment on the active sites and catalytic performances of PtSn/SiO catalyst in acetic acid (AcOH) hydrogenation was investigated in this article. The catalysts were characterized by N physical adsorption, X-ray diffraction, transmission electron microscopy, pyridine Fourier-transform infrared spectra, and H-O titration on its physicochemical properties. The results showed that Pt species were formed primarily in crystalline structure and no PtSn alloy was observed. Meanwhile, with the increment of thermal pretreatment temperature, Pt dispersion showed a decreasing trend due to the aggregation of Pt particles. Simultaneously, the amount of Lewis acid sites was remarkably influenced by such thermal pretreatment owning to the consequent physicochemical property variation of Sn species. Interestingly, the catalytic activity showed the similar variation trend with that of Lewis acid sites, confirming the important roles of Lewis acid sites in AcOH hydrogenation. Moreover, a balancing effect between exposed Pt and Lewis acid sites was obtained, resulting in the superior catalytic performance in AcOH hydrogenation. [ABSTRACT FROM AUTHOR]