The decomposition of ethanol was studied using carbon catalysts with a
different nature of the surface. They were prepared from poly(furfury
l alcohol). The catalytic tests were performed in a flow reactor in th
e temperature range 323-633 K. Dehydration and dehydrogenation of etha
nol, as well as acetal formation, occur under the conditions applied.
The products are ethene plus diethyl ether, acetaldehyde and 1,1'-diet
hoxyethane, respectively. The study supports previous findings that ox
idation with nitric acid enhances dehydration activity and selectivity
, whereas introduction of Ni2+ ions increases dehydrogenation activity
and selectivity. The supported Ni2+ cations, in the hydrated form, ac
t as additional active centers for dehydrogenation. In addition, both
these surface modifications also enhance carbon catalytic activity and
selectivity for the acetal formation. The acetal results from a secon
dary reaction between the formed acetaldehyde and ethanol on acidic ce
nters located on the outer surface of the catalyst.