Herein, nanoporous Al2O3, CeO2, TiO2, ZrO2,
and SnO2 were used
as the supports for Pd nanoparticles, and effects of surface characteristics
on catalytic performances for dehydrogenation of 2-[(n-methylcyclohexyl)methyl]piperidine (H12-MBP) as the H2-rich liquid organic hydrogen carrier were investigated. The
H2 yield, dehydrogenation rate, product selectivity, and
recyclability of the supported Pd catalysts depended on the metal
oxide support and Pd loading. The H2 yield and reaction
rate of the Al2O3 supporting 5 wt % Pd with
a mean size of 5.76 nm were the highest (75.8%) and the fastest (k
1
= 0.076 min–1), respectively, of all the catalysts. CeO2 exhibited
the highest reducibility and the best supporting ability for Pd nanoparticles,
which thus dispersed Pd with the smallest mean size of 3.45 nm. Although
this catalyst exhibited a lower H2 yield (67.1%) and a
slower reaction rate (k
1
= 0.030 min–1) than Al2O3, it showed the best recyclability without a significant loss of
activity during four consecutive runs, which could be attributed to
the strong metal–support interaction of Pd to the surface of
CeO2. The H2 yield and the dehydrogenation rate
were systematically correlated with the surface characteristics of
the metal oxides, such as acidity, adsorption affinity (adsorption
energy), and charge transfer value of H12-MBP, which were
determined via combined experimental and theoretical studies.