A method is reported for the synthesis of novel catalytic nanoporous carbon membranes. Defect-free, nanoporous carbon films of 12.5- mum average thickness containing a dispersion of Pt-x were synthesized on macroporous stainless-steel supports. Ideal gas selectivities for the catalytic membranes were similar to those of inert nanoporous carbon membranes with He-N-2 = 58.6 and O-2-N-2 = 4.9. The selective hydrogenation of monoolefins (propylene, 1-butene, isobutylene) was used to probe the shape-selective catalytic properties and the transport selectivities of the membranes. The results were modeled using the linens regime of coupled adsorption, transport and reaction in the membrane. Model regression yielded 14.9, 19.7, and 18.4 kJ/mol for the activation energies of permeation for propylene, isobutylene, and 1-butene, respectively The system demonstrated selective reaction and transport favoring propane production with selectivity? ratios of 28.9:3.2:1 for propane:n-butane:isobutane at 125 degreesC.