Green preparation of self-supporting platinum nanoflower catalyst and its electrocatalytic oxidation performance of methanol

•NaOH-KOH low temperature molten salt was used as flux for preparing Pt nanoflower catalyst.•The catalyst has 3D self-supporting framework and clean surface with lots of active sites.•The product can be directly used for electrochemical catalysis without any pretreatment.•The Pt nanoflower catalyst exhibited excellent performance in MOR.