The invention relates to a carbon-supported PtRu anode catalyst for direct methanol fuel cells (DMFC) which has a platinum/ruthenium content in the range from 80 to 98 wt. %, preferably in the range from 85 to 98 wt. %, particularly preferably in the range from 85 to 95 wt. % (based on the total weight of the catalyst), on a carbon-based electrically conductive support material and has a mean particle size of less than 3 nm. The catalyst is prepared using a carbon black support material having a specific surface area (measured by the BET method) in the range from 1000 to 2000 m2/g by means of a reduction process using chemical reducing agents with addition of organic acids. Electrodes and membrane-electrode units containing the catalyst according to the invention having a high precious metal loading have an electrode layer thickness of less than 80 μm at a PtRu loading per unit area of the electrode of from 6 to 12 mg of PtRu/cm2 and lead to improved electric power in direct methanol fuel cells.