This study evaluates the influence of the presence of oxygenated groups created onto the surface of activated carbon (AC) on its ability to disperse platinum (Pt) or palladium (Pd) particles and on its catalytic performance to drive the transformation of glycerol into lactic acid. AC pretreatment consisted of oxidation in the presence of HNO3 aqueous solutions conducted at 50, 70, and 90 degrees C, aiming at creating oxygenated groups on the support surface. The catalytic activities of Pt/AC and Pd/AC catalysts were evaluated in the production of lactic acid from both glycerol and crude glycerin. Lower-temperature pretreatments provided catalytic supports showing higher metal uptakes together with similar catalytic activity conversion and yield for both metals (5% Pt/AC and 10% Pd/AC). The catalysts were stable in five reaction cycles, and only negligible activity loss was detected.