Effects of functional group concentration, type, and configuration on their saturation of methanol adsorption on functionalized graphite

•Initial MeOH molecule adsorbed on the strongest active site of functional groups.•Adsorption then occurred on the weaker active sites until they became saturated.•Properties of surface Fns were studied separately on their saturation.•Local saturations of Fns were identified.•Adsorption at loadings higher than the saturation was unchanged with Fn properties.