Kinetics of n-hexane oxidation on the surface of activated carbon was investigated at different temperatures. The diffusion step of this reaction was determined and estimated. The spatial structure of activated carbon was reconstructed using electron micrographs and measurements. The relation between this structure and diffusivity of n-hexane was determined in the form of an intrication coefficient. Two currents of diffusion into the volume of activated carbon were ascertained. Relations between the intrication coefficient and the topology of the intricated space are suggested.