Flame sprayed tri-metallic Pt–Sn–X/Al2O3 catalysts (X = Ce, Zn, and K) for propane dehydration

Trimetallic nanocrystalline Pt–Sn–X/Al2O3 catalysts (X = Ce, Zn, and K) consisting of 0.3 wt.% Pt, 1 wt.% Sn, and 0.5 wt.% X have been prepared by one-step flame spray pyrolysis (FSP). As shown by the X-ray diffraction (XRD) and the transmission electron microscopy (TEM) results, the as-synthesized FSP-made catalysts were consisted of single-crystalline γ-alumina particles with average primary particle sizes 8 to 9 nm. The N2 physisorption results revealed that all the catalysts contained only the macropore structure. The catalytic properties of the FSP-made catalysts were investigated in the dehydration of propane. Addition of Ce during FSP synthesis resulted in higher Pt dispersion as well as improved catalytic activity and stability than the non-promoted Pt–Sn/Al2O3. An opposite trend was found with the ones doped with Zn and K in which high surface coverage of Zn and K resulted in a significant loss of Pt active sites. The mechanism for the formation of the trimetallic nanoparticles during one-step FSP synthesis appeared to depend strongly on the differences in the vapor pressure of the metals and the alumina support in flame.

Graphical abstractFlame-made trimetallic nanocrystalline Pt–Sn–X/Al2O3 catalysts (X = Ce, Zn, and K) were consisted of single-crystalline γ-alumina particles with particle size of 10 to 13 nm. Addition of Ce during FSP synthesis resulted in higher Pt dispersion as well as the improved catalytic activity and stability, while an opposite trend was found with the ones doped with Zn and K.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► Prepare trimetallic nanocrystalline Pt-Sn-X/Al2O3 catalysts by FSP techniques. ► Catalysts for propane dehydrogenation. ► Addition with Ce improved the Pt metal dispersion, catalytic activity and stability. ► Opposite trend was found on Zn and K by high surface coverage on Pt metal surface.