CHARACTERISTICS AND CATALYTIC PROPERTIES OF Pd CATALYSTS SUPPORTED ON N-DOPED TiO2 IN SELECTIVE HYDROGENATION OF 1-HEPTYNE

Abstract

Characteristics and catalytic properties of the Pd/N-doped TiO2 catalysts were studied in the liquid-phase hydrogenation of 1-heptyne. The TiO2 support was prepared by sol-gel method using N-metylprrolidone (NMP) solution as the nitrogen source. The effects of calcination temperature and the amount of nitrogen doping on TiO2 supports were investigated. The catalysts were characterized by XRD, N2 physisorption, XPS, FT-IR, UV-vis, TEM and H2 chemisorption. The results showed that the Pd catalysts supported on N-doped TiO2 supports exhibited higher activity than the Pd catalysts supported on the non-modified TiO2 support. The catalyst prepared on the TiO2 supported that was modified with NMP of 20 ml and calcined at 300oC exhibited the best catalyst performance, in which high heptane selectivity (~90%) was obtained at complete conversion of 1-heptyne. The use of N-doped TiO2 resulted in larger catalyst surface area, smaller Pd paticles, higher amounts of Pd active sites, higher Pd dispersion and stronger metal-support interaction.