Three hydrocarbon adsorbers of honeycomb shape were prepared using a slurry coating method according to the cell density and geometric surface area of a ceramic substrate. Adsorption isotherms of CO and two VOCs (2,2,4-trimethylpentane and toluene) on three adsorbers were measured using a volumetric adsorption apparatus. The isotherms of CO were measured at 303.15 K, and equilibrium experiments for two VOCs were carried out at 303.15 K, 323.15 K, and 343.15 K. The amount of CO adsorbed and metal dispersion was increased with the increase of geometric surface area. The amount of toluene adsorbed was higher than that of 2,2,4-trimethylpentane for all samples. The increase of geometric surface area led to an increase in the amount adsorbed. The equilibrium data of two VOCs were correlated by the Langmuir and the Langmuir-Freundlich isotherms. The latter isotherm predicted equilibrium data better than the former isotherm.