J. Houzvicka et al., THE ROLE OF CARBONACEOUS DEPOSITS AND SUPPORT IMPURITIES IN THE SELECTIVE HYDROGENATION OF ETHYNE, Catalysis letters, 30(1-4), 1995, pp. 289-296
In order to elucidate the role of carbonaceous deposits, the hydrogena
tion of ethyne over silica supported Pt and Pd catalysts has been stud
ied in a micro-pulse reactor. When a pure silica support (Aerosil) was
used, the conversion decreased with an increasing number of ethyne pu
lses led over the reactor. Simultaneously, the selectivity towards eth
ene increased. When less pure silica (Kieselgel) was used as a support
, the opposite effect was observed. These results are explained by ass
uming that the carbonaceous deposits are not active, but influence the
selectivity of the uncovered metal surface by diminishing the average
ensemble size available for the reaction. Impurities in the support c
an alter the behaviour of the catalysts.