N-containing silane coupling agent modified Pd/(α-Al2O3) catalyst for
semi-hydrogenation of acetylene
Abstract
A highly dispersed monometallic palladium catalyst for selective
hydrogenation of acetylene was prepared using N-containing silane
coupling agent (SCA) as a modifier. The catalyst exhibited 90.3%
ethylene selectivity with full acetylene conversion under 240 °C with a
GHSV(C2H2) of 1200 h-1 and performs good stability within a 200 h
tolerance test. Characterization results reveal that the excellent
ethylene selectivity is mainly derived from the special Pd nanoparticle
structure with Pd (111) lattice relaxation and distortion. The
N-containing SCA modified catalyst shows more C atoms penetrating into
the Pd lattice to form a stable PdC phase. This unique structure
possesses an obvious suppression of hydrogen migration from the bulk Pd
hydride to the surface and makes the catalyst have more abundant
spillover hydrogen on the carrier surface. In addition, it has also
weakened the ethylene adsorption ability and led a strong interaction
between the Pd nanoparticles and surface.