The performance of Pd/Pt-based electrocatalysts is closely correlated with their surface structure, size and composition. Herein, we prepared uniformly distributed ultra-small PtPd alloyed nanoparticles (PtPd ANPs, similar to 5 nm) within a robust three-dimensional nitrogen-doped reduced graphene oxide (3D-N-rGO) under hydrothermal conditions. L-Hydroxyproline was employed as reductant, N-doping and swelling agent for 3D-N-rGO. The size and shape of graphene hydrogels were easily adjusted by controlling the reaction temperature, and the formation mechanism was discussed in details. Then, the product was explored for ethylene glycol oxidation reaction (EGOR) and hydrogen evolution reaction (HER). The catalytic activity of PtPd ANPs/3D-N-rGO towards HER is close to the state-of-the-art Pt/C catalyst, and better than that of Pt/C in the case of EGOR. This study has shed some lights on the universal approach to develop next-generation catalysts, which is of great significance for direct alcohol fuel cells. (C) 2018 Elsevier Ltd. All rights reserved.