On metal blocking in micropores of carbon supports

Platinum catalysts prepared on activated carbon supports of different origi n are compared in the hydrogenation of cyclohexene and cyclooctene, which d iffer much in their reactivity. A decrease in the catalytic activity upon d ecreasing the dimensions of the micropores in the support and the size of t he supported metal particles has been confirmed. The results give evidence against a trivial role of the diffusional factor in such an effect and indi cate complete blocking of part of the metal surface in narrow pores.