As opposed to polycrystalline Pt nanoparticles, which are easily synthesized using common methods, facet-controlled Pt nanoparticles, which actively and selectively catalyze several reactions, are synthesized under harsh conditions using specific chemical agents. To overcome this limitation, this study proposes a simple method that enables the simultaneous synthesis of both facet-controlled nanoparticles and their supports. Using this simple method, facetcontrolled carbon-supported Pt nanoparticles were synthesized via the electrospinning of a mixture solution containing a Pt precursor and polyvinylidene fluoride (PVDF), followed by the sequential dehydrofluorination and carbonization of the polymeric nanofibers. During the carbonization process, among the different gases (CO, ethylene, CO2, and C10H18O2) that were generated from the decomposition of the polymeric nanofibers, CO was selectively adsorbed onto the Pt surface, resulting in the formation of (200) facet-dominant Pt nanoparticles. Additionally, electrochemical analysis using the structure-sensitive characteristics of oxygen reduction reactions, as well as general analysis tools, also confirmed the formation of the (200) facet.