Spontaneously Bi decorated carbon supported Pt nanoparticles for formic acid electro-oxidation

► Selective decoration of Bi onto commercial Pt/C is carried out by a simple gas controlled surface potential modulation technique. ► Electrochemical measurements indicate Bi decorated Pt/C catalyst exhibits higher and much longer electrocatalytic performance for formic acid electro-oxidation due to a combination of the electronic effect and third-body effect. ► The 3.4 nm catalysts demonstrated higher performance over that of 2.4 nm due to decrease in Pt-COads bond strength. ► The onset potential for formic acid electro-oxidation reduced by more than 100 mV.