Controllable synthesis of multimetal nanocrystals with hierarchical structures and tunable compositions are feasible to steeply improve the catalytic properties in fuel cells. Herein, trimetallic PtRhCo petal-assembled alloyed nanoflowers (PtRhCo PAANFs) were fabricated via a one-pot solvothermal method, which showed remarkable enlargement in specific activity and mass activity over PtRh0.25Co nanodentrites (NDs), PtRh1.5Co NDs, PtCo NDs and commercial Pt/C catalysts for ethylene glycol oxidation in 0.5 M KOH solution. The as-developed catalyst exhibited dramatically better CO tolerance and recoverability, coupling with the superior activity and durability for hydrogen evolution reaction (HER) in the alkaline electrolyte. This work demonstrates the significance of Rh in the alloy for improving the stability. This work offers a promising strategy for preparation of advanced trimetallic electrocatalysts for energy conversion applications. (C) 2019 Elsevier Inc. All rights reserved.