Activated carbon monoliths are synthesized from coconut shell and used as support for copper oxide and metallic copper catalysts. The obtained support is texturally characterized by a superficial BET area of 1427 m2/g and because of the impregnation and activation process, this value can decrease to as low as 526 m2/g for the catalysts. The catalysts and support are both of microporous nature. The obtained catalysts are characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and by temperature programmed reduction (TPR). The catalytic oxidation of methylene blue solutions was performed since the application for treating wastewaters is of interest, as these can have great impacts on aqueous ecosystems. Out of all the synthesized catalysts, those with the highest concentration of metallic copper as active phase showed the highest catalytic activity.