In this work, a synthesis method of residue-free PdPt nanodendrites on reduced graphene oxide (rGO) is reported. Using UV light as an energy trigger and methanol as the reducing agent, PdPt nanodendrites are synthesized with clean, residue-free surfaces (e.g., surfactant and polymer). In comparison with commercial Pd/C and Pt/C catalysts, the as-prepared PdPt nanodendrites on rGO have a large electrochemically active surface area, enhanced catalytic activity, high stability, and tolerance toward the ethanol oxidation reaction in alkaline media. Among the nanodendrite composites prepared, those containing a Pd:Pt ratio of 1:2 on rGO exhibit the best stability and durability, and their mass activity is 2.0 and 2.4 times greater than those of commercial Pt/C and Pd/C catalysts, respectively. This strategy presents an environmentally friendly way to fabricate other noble metal catalysts with improved catalytic activity and stability for use in direct alcohol fuel cells.