EN
Nb2O5/Al2O3 materials prepared by sol-gel
method using aluminium hydroxychloride and potassium
niobate solutions were used as supports for nickel catalyst.
2 wt. % Ni catalysts were investigated by temperatureprogrammed
reduction, TEM, X-ray diffraction, hydrogen
chemisorption and high-resolution transmission electron
microscopy (HRTEM). Hydrodechlorination (HDC) of
1,2-dichloroethane (1,2-DCA) over alumina modified
by niobia supported nickel catalysts led to formation
of ethylene as desired product. Selectivity toward C2H4 increases from ~35% for 2%Ni/Al2O3 up to 90% for Ni/Nb2O5-
Al2O3. This phenomenon is an effect of the coexistence
of Nb2O5 and Al2O3. Niobia is preferentially located over
alumina, shaping the overall catalytic behavior of Nb2O5 – Al2O3 supported catalysts. This phenomenon could be
related with the changes between Brönsted and Lewis
acidic active sites ratio. Temperature programmed
hydrogenation (TPH) of post-reaction deposits showed
that during HDC on catalysts surface both carbon and
chlorine-containing species were formed. Application of
regeneration procedure (3h, 10%H2/Ar, 600°C) for spent
samples led to efficient reconstruction of active sites.