The objective of this study is to synthesize and modify Pd doped ceria with surface treatment procedures, including calcination, reduction and RF non-thermal plasma techniques, to form small Pd clusters or single atoms on the surfaces of Pd-ceria catalysts for selective hydrogenation of acetylene in ethylene. PdCeO2 solid solution catalysts were synthesized via the co-precipitation method and evaluated for selective hydrogenation of acetylene in excess ethylene reactions. 0.15% PdCeO2-HP-600 (modified with hydrogen plasma followed by calcination at 600°C) showed the best performance among the catalysts tested, with the highest acetylene conversion of 68.3% and excellent ethylene selectivity of 97.8% at 200°C under the reaction condition of H2/C2H2/C2H4=3/1/99 at a space velocity of 60,000 cc/g.h It was revealed that high calcination temperature can induce the strong metal support interaction (SMSI) effect and change the structure of ceria, especially at 800°C. The higher the calcination temperature used, the higher conversion activity of the catalyst. It’s proposed that the SMSI effect places Pd clusters at an electron-deficient state with a slightly positive charge, therefore, the formation of Pd–H is more thermodynamically unfavorable resulting higher. In addition, calcination temperature dictate the movement of Pd in Pd-ceria structure, low calcination temperature tends to move Pd into PdCeO2 lattice while high calcination temperature tends to move Pd out of PdCeO2 lattice.

Investigation of Pd-Ceria catalysts for selective hydrogenation of acetylene in ethylene

254th National Meeting (2017)

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